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347 Cards in this Set
- Front
- Back
What is cell theory?
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1. cell is the smallest structural functional living unit
2. activity of an organism depends on the individual and collective activities of its cells 3. principle of complementarity of structure and function: the biochemical activities of a cell are determined by its subcellular structure 4. the continuity of life has a cellular basis |
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Cells differ in what ways?
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size, shape, subcellular components and functions
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There are over _____ different types of human cells.
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200
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Human cells have three basic parts. What are they?
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1. plasma membrane
2. cytoplasm 3. nucleus |
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What is the control center of a cell?
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the nucleus
|
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What provides the other boundary for a cell?
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plasma membrane
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What is the intracellular fluid that contains subcellular structures called?
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cytoplasm
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There are subcellular structures in the cytoplasm. What are they called?
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organelles
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What is the plasma membrane?
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- a double layered membrane composed of phospholipids, cholesterol and proteins
- encloses cellular contents and defines cell boundaries |
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What does this statement best describe:
" a double-layered membrane composed of phospholipids, cholesterol, and proteins " |
plasma membrane
|
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What does this statement best describe:
" encloses cellular contents and defines cell boundary" |
plasma membrane
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What does it mean to say that the plasma membrane follows a "fluid mosaic model?"
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- the plasma membrane is semi-fluid with proteins that float through it in a changing mosaic pattern
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What are the components of the plasma membrane?
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membrane lipids, membrane proteins and peripheral proteins
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What are the three types of membrane lipids that are involved in the plasma membrane?
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phospholipids, glycolipids and cholesterol
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Phospholipids make up ____ of the lipids in the plasma membrane
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75%
|
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What best describes the following statements:
" forms the bulk of the lipid bilayer " |
phospholipids
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What best describes the following statement:
" has phosphate heads that are polar and hydrophilic " |
phospholipids
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What best describes the following statement:
" has fatty acid tails that are nonpolar and hydrophobic " |
phospholipids
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Phospholipids have phosphate heads that are _________.
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polar/hydrophilic
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Phospholipids have fatty acid tails that are ________.
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nonpolar/hydrophobic
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Phospholipids have ________ that are polar and hydrophillic.
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phosphate heads
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Phospholipids have _________ that are nonpolar and hydrophobic.
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fatty acid tails
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Glycolipids make up _____ of the membrane lipids involved with the plasma membrane.
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5%
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Glycolipids are lipids with polar _____ groups on outer membrane surfaces.
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sugar
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________ are lipids with polar sugar groups on outer membrane surfaces.
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glycolipids
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________ act as adhesives to bind cells together.
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Glycolipids
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Cholesterol makes up _______ of the lipids involved in the plasma membrane.
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20%
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Cholesterol are ______ with a polar hydroxyl region and a nonpolar fused ring.
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lipids
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Cholesterol are lipids with a polar _______ region and a nonpolar fused ring.
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hydroxyl
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Cholesterol are lipids with a ______ hydroxyl region and a nonpolar fused ring.
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polar
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Cholesterol are lipids with a polar hydroxyl region and a ________ fused ring.
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nonpolar
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Cholesterol are lipids with a polar hydroxyl region and a nonpolar ______.
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ring
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What best describes this statement:
" Increases membrane stability and fluidity " |
cholesterol
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What is the function of cholesterol?
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- to increase membrane stability and fluidity
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What is another term for membrane proteins?
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integral proteins
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What best describes this statement:
" firmly embedded in the membrane" |
integral proteins
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Integral proteins have both a _______ region and a _______ region, similar to phospholipids.
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hydrophobic; hydrophillic
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Channels/pores are examples of what type of organic compound?
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integral protein
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What do channels/pores do in terms of the plasma membrane?
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transport small water-soluble molecules and ions across the membrane
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What do carriers do in terms of the plasma membrane?
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binds to a substance and moves it across the membrane
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What do receptors do in terms of the plasma membrane?
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- relays signals from hormones or other chemical messengers to the inside of the cell
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What best describes this statement:
" binds to a substance and moves it across the membrane " |
carrier/transport protein : type of integral protein
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What are transport proteins?
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a type of integral protein that spans the membrane. It may provide a hydrophillic channel across the membrane that is selective for a particular solute. Some transport proteins hydrolyze ATP as an energy source to actively pump substances across the membrane.
|
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What best describes this statement:
" a type of integral protein that spans the membrane. It may provide a hydrophillic channel across the membrane that is selective for a particular solute." |
carrier/transport protein
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What are receptor proteins?
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- used for signal transduction
- a membrane protein exposed to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. The external signal may cause a change in the shape in the protein that initiates a chain of chemical reactions in the cell. |
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What best describes this statement:
"a membrane protein exposed to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger" |
a receptor: a type of membrane protein
|
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What are peripheral proteins?
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- loosely attached to integral proteins
- form a filament network on the intracellular surface - include glycoproteins on extracellular surface |
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Elements of the cytoskeleton and extracellular matrix may be anchored to __________, which help maintain cell shape and fix the location of certain _________.
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membrane proteins; membrane proteins.
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Some _________ serve as identification tags that are specifically recognized by other cells.
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glycoproteins ; type of peripheral protein.
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Glycoproteins are a type of _____ protein.
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peripheral
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What do receptors do in terms of the plasma membrane?
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- relays signals from hormones or other chemical messengers to the inside of the cell
|
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What best describes this statement:
" binds to a substance and moves it across the membrane " |
carrier/transport protein : type of integral protein
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What are transport proteins?
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a type of integral protein that spans the membrane. It may provide a hydrophillic channel across the membrane that is selective for a particular solute. Some transport proteins hydrolyze ATP as an energy source to actively pump substances across the membrane.
|
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What best describes this statement:
" a type of integral protein that spans the membrane. It may provide a hydrophillic channel across the membrane that is selective for a particular solute." |
carrier/transport protein
|
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What are receptor proteins?
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- used for signal transduction
- a membrane protein exposed to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. The external signal may cause a change in the shape in the protein that initiates a chain of chemical reactions in the cell. |
|
What best describes this statement:
"a membrane protein exposed to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger" |
a receptor: a type of membrane protein
|
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What are peripheral proteins?
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- loosely attached to integral proteins
- form a filament network on the intracellular surface - include glycoproteins on extracellular surface |
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Elements of the cytoskeleton and extracellular matrix may be anchored to __________, which help maintain cell shape and fix the location of certain _________.
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membrane proteins; membrane proteins.
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Some _________ serve as identification tags that are specifically recognized by other cells.
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glycoproteins ; type of peripheral protein.
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Glycoproteins are a type of _____ protein.
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peripheral
|
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What are the general functions of membrane proteins?
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1. act as transport/carrier proteins
2. serve as receptors for signal transduction 3. attachment to the cytoskeleton 4. enzymatic activity 5. intercellular joining |
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Membrane proteins of adjacent cells may be hooked together in various kinds of _______ .
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intercellular junctions.
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What is interstitial fluid?
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extracellular fluid derived from blood that supplies cells with amino acids, sugars, fatty acids, vitamins, hormones, neurotransmitters and salts
|
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Is interstitial fluid intracellular fluid or extraceullular fluid?
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extracellular fluid
|
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Plasma membranes are ______ permeable, meaning they allow some substances to pass through easily and others to be excluded.
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selectively
|
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What does it mean to say the plasma membrane is selectively permeable?
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the membrane allows some substances to pass through easily and excludes other substances.
|
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What type of membrane transport is best described by the statement :
" No cellular energy required " |
passive transport
|
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What type of membrane transport is best described by the statement:
" substance moves down its concentration gradient " |
passive transport
|
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What type of membrane transport is best described by the statement:
" uses energy from ATP to transport substances against their concentration gradient " |
active transport
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What is passive transport?
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- no cellular energy required
- substance moves down its concentration gradient |
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In passive transport, a substance moves ______ its concentration gradient.
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down
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In active transport, a substance moves ______ its concentration gradient.
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up / against
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What determines whether or not a substrate can passively permeate a membrane?
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- lipid solubility of a substance
- channels of appropriate size - carrier proteins |
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What are the types of passive processes?
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- simple diffusion
- facilitated diffusion (carrier and channel mediated) - osmosis - filtration |
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Is simple diffusion active or passive?
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passive
|
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Is facilitated diffusion active or passive?
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passive
|
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Is carrier-mediated diffusion active or passive?
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passive
|
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Is channel-mediated diffusion active or passive?
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passive
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Is osmosis active or passive?
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passive
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Is filtration active or passive?
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passive
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What is simple diffusion?
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unassisted diffusion of lipid-soluble or very small particles through the bilayer
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What best describes this statement:
"unassisted diffusion of lipid-soluble or very small particles through the bilayer" |
simple diffusion
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What do transmembrane integral proteins transport?
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specific polar molecules (like sugars and amino acids )
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Sugars and amino acids go across the membrane how?
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using transmembrane integral proteins
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What is carrier-mediated facilitated diffusion?
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when binding of the substrate causes conformational changes in the carrier.
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What is facilitated diffusion?
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diffusion of substances across the bilayer with the help of channel proteins or carrier proteins.
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Certain liphophobic molecules (like glucose, amino acids and ions) pass through the membrane using what process?
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facilitated diffusion
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Why is facilitated diffusion considered "saturable" ?
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because the rate is determined by the number of carriers or channels
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What are the types of facilitated diffusion?
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carrier mediated and channel mediated
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What is channel-mediated facilitated diffusion?
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- aqueous channels/ pores formed by transmembrane proteins that selectively transport ions or water
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What process is best defined by:
" aqueous channels/pores formed by transmembrane proteins selectively transport ions or water " |
channel-mediated facilitated diffusion
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What are the two types of channel-mediated facilitated diffusion?
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leakage channels and gated channels
|
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What are the differences between leakage channels and gated channels?
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leakage channels are always open while gated channels are controlled by chemical or electrical signals
|
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What controls gated channels?
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chemical or electrical signals
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Leakage channels are _____ open.
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always
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Mostly ions are selected on basis of ____ and _____ to go through a channel protein.
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size ; charge
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What is osmosis?
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movement of water across the bilayer
|
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How does water diffuse through the plasma membrane?
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two ways:
1. through the lipid bilayer 2. through water channels called aquaporins |
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What is osmolarity dependent on?
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the total concentration of all solute particles in a solution
|
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Water concentration depends on the total _______ of solute particles, not the particular _______ of solute particles.
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number ; type
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When solutions of different osmolarity are seperated by a membrane, osmosis occurs until _______ is reached.
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equilibrium
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A solution with a higher osmolarity has a high or low concentration of water?
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low concentration of water
|
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When a membrane is permeable to both solutes and water, what happens?
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- solute and water molecules move down their concentration gradients in opposite directions
- fluid volume remains the same in both compartments |
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When a membrane is permeable to both solutes and water, solute and water molecules move _____ their concentration gradients in opposite directions.
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down
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When a membrane is permeable to both solutes and water, solute and water molecules move down their concentration gradients in _______ directions.
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opposite
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What happens to fluid volume in both compartments when a membrane is permeable to both solutes and water?
|
fluid volume remains the same, as solute and water molecules move down their concentration gradients in opposite directions.
|
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What happens to fluid volume in both compartments when a membrane is permeable to water and impermeable to solutes?
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fluid volume increases in the compartment with the higher osmolarity (meaning had less water, so water moves from more water to less water side).
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Can solutions have different volumes and identical osmolarities?
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yes; osmolarity is dependent on the total number of solute particles. has nothing to do with the amount of solvent or type of solute!
|
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When osmosis occurs, water does what?
|
enters or leaves the cell
|
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Why does osmosis matter?
|
a change in cell volume disrupts its function
|
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What is tonicity?
|
the ability of a solution to cause a change in cell volume by promoting osmotic flow of water
|
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What happens when a cell is in an isotonic solution?
|
it has the same solute concentration inside the cell as in the environment
- cells retain their normal size and shape because there is no net movement |
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What happens when a cell is placed in a hypertonic solution? Why?
|
- the cell may crenate
- water moves out of cells, so cells may shrink - less solute concentration and more water outside the cell. Inside the cell, more solute concentration and less water. So, water moves from higher concentration of water to lower concentration of water. So water would move out of the cell |
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What does it mean to say that cells crenate?
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shrink
|
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If a cell is crenating, you can guess that it is in a _________ environment.
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hypertonic
|
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If a cell is placed in a hypotonic solution, what would you expect to happen and why?
|
- Cells may lyse (burst)
- there is a lower solute and higher water concentration in the environment than in the cell. So, water would move from the environment into the cell. So, the cell might burst! |
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If a cell is lysing, you can guess that it is in a _________ environment.
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hypotonic
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Does the osmolarity of a cell change when placed in a hypotonic or hypertonic environment?
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NO! fluid volume changes.
Osmolarity doesn't change because solutes aren't moving in osmosis! |
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What is cytoplasm?
|
- cellular material contained within the plasma membrane; contains cytosol and organelles
|
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What is cytosol?
|
- viscous fluid in which other cytoplasmic components are suspended
- a portion of cytoplasm - composed of water and solutes |
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What are cytoplasmic organelles?
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- cellular components with specific functions
|
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What are known as the "metabolic machinery of a cell?"
|
cytoplasmic organelles
|
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What is composed of water with solutes?
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cytosol
|
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Does a nucleus have a membrane?
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yes
|
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Do lysosomes have membranes?
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yes
|
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Does endoplasmic reticulum (smooth/rough) have membranes?
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yes
|
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Do golgi apparatus have membranes?
|
yes
|
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Do mitochondria have membranes?
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yes
|
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Do peroxisomes have membranes?
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yes
|
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Do centrioles have membranes?
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no
|
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Do ribosomes have membranes?
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no
|
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Does the cytoskeleton have membranes?
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no
|
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What organelles have membranes?
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- nucleus
- lysosomes - endoplasmic reticulum - golgi apparatus - mitochondria - peroxisomes |
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What organelles are nonmembraneous?
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- cytoskeleton
- centrioles - ribosomes |
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What are ribosomes?
|
- granules containing protein and rRNA
- sites of protein synthesis |
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What are the sites of protein synthesis?
|
ribosomes
|
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What forms are ribosomes found in the cell?
|
free floating and membrane-bound to endoplasmic reticulum (rough)
|
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What organelles are ribosomes sometimes connected to?
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rough endoplasmic reticulum
|
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What do free ribosomes do?
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- float freely in cytoplasm
- synthesize soluble proteins that remain in the cell |
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Soluble proteins that remain in the cell are synthesized by ______ ______ (2 words).
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free ribosomes
|
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What synthesizes proteins to be incorporated into membranes or exported from the cell?
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- Membrane-bound ribosomes (bounded to rough ER)
- rough ER |
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Free ribosomes float freely in the ________.
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cytoplasm
|
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Membrane-bound ribosomes synthesize what kinds of proteins?
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proteins to be incorporated into membranes or exported from the cell.
|
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What does the endomembrane system do?
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- system of organelles that produce, store, and export biological molecules
|
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What organelles are a part of the endomembrane system?
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- nucleus
- nuclear envelope - rough ER - Gogli apparatus - Transport vesicle - lysosome - plasma membrane - vesicle - smooth ER |
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What is the structure of rough endoplasmic reticulum like?
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- interconnected membranes whose external surface is covered with ribosomes
- continuous with nuclear membrane |
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What synthesizes membrane integral proteins and phospholipids for cell's internal membranes?
|
- rough endoplasmic reticulum
|
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What is the structure of smooth endoplasmic reticulum like?
|
- interconnected membranes whose external surfaces lack ribosomes
- continuous with rough ER |
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What is smooth endoplasmic reticulum involved in?
|
- lipid synthesis and metabolism
- detoxification of chemicals and drugs in the liver and kidney - breaking down glycogen to glucose in the liver - storing and releasing calcium during muscle contraction |
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What are lysosomes involved in?
|
- digestive compartments that break down toxins and old, nonfunctional organelles
- contain digestive enzymes (acid hydrolases) |
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What is the structure of golgi apparatus like?
|
- stack of flattened membraneous sacs
|
|
What organelle is best described by the following statement:
" lipid synthesis and metabolism " |
smooth er
|
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What organelle is best described by the following statement:
" detoxification of chemicals and drugs in liver and kidney " |
smooth er
|
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What organelle is best described by the following statement:
" receives products from rough ER " |
golgi apapratus
|
|
What organelle is best described by the following statement:
" breaking down glycogen to glucose in the liver " |
smooth er
|
|
What organelle is best described by the following statement:
" storing and releasing calcium during muscle contraction " |
smooth er
|
|
What organelle is best described by the following statement:
" modifies, concentrates and packages proteins and lipids " |
golgi apparatus
|
|
What organelle is best described by the following statement:
" transports products to other cellular locations via vesicles " |
golgi apparatus
|
|
What organelle is best described by the following statement:
" digestive compartments that break down toxins and old, nonfunctional organelles " |
lysosomes
|
|
What organelle is best described by the following statement:
" contain digestive enzymes " |
lysosomes
|
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What is another term for digestive enzymes?
|
acid hydrolases
|
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What is another term for acid hydrolases?
|
digestive enzymes
|
|
What are mitochondria?
|
- cellular power plants
- sites of cellular respiration - generate ATP - double-membrane structure with cristae to maximize surface area - provide most of cell's ATP via aerobic cellular respiration - contain their own DNA and RNA |
|
What structure maximizes the surface area of mitochondria?
|
cristae
|
|
What organelle is best described by the following statement:
" cellular power plant " |
mitochondria
|
|
What organelle is best described by the following statement:
" sites of cellular respiration " |
mitochondira
|
|
What organelle is best described by the following statement :
" generate ATP " |
mitochondria
|
|
What organelle is best described by the following statement:
" double-membrane structure with cristae to maximize surface area " |
mitochondria
|
|
What organelle is best described by the following statement:
" provide most of cell's ATP via aerobic cellular respiration " |
mitochondria
|
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What organelle contain's its own genetic information independent from the cell's DNA/RNA?
|
mitochondria
|
|
What is the endosymbiotic theory?
|
mitochondria very similar to prokaryotes, used to be their very own organism!
|
|
What are peroxisomes?
|
- membranous sacs containing powerful oxidase and catalase enzymes that detoxify harmful substances
- neutralize dangerous free radicals |
|
what are free radicals?
|
highly reactive chemicals with unpaired electrons
|
|
What is best described by the following statement:
" membranous sacs containing powerful oxidase and catalase enzymes that detoxify harmful substances " |
peroxisomes
|
|
What is best described by the following statement:
" neutralizes dangerous free radicals " |
peroxisomes
|
|
What is the cytoskeleton?
|
- an elaborate network of fibers and rods throughout cytosol
- organizes structure and activities of cells - made up of microtubules, intermediate filaments and microfilaments |
|
What is made up of microtubules, intermediate filaments and microfilaments?
|
the cytoskeleton
|
|
What is best described by the following statement:
" elaborate network of fibers and rods throughout cytosol " |
cytoskeleton
|
|
What is best described by the following statement:
" organizes structure and activities of cell " |
cytoskeleton
|
|
What is best described by the following statement:
" thickest fibers of cytoskeleton " |
microtubules of cytoskeleton
|
|
What is best described by the following statement:
" dynamic hollow tubes made of alpha and beta tubulins " |
microtubules of cytoskeleton
|
|
Microtubules are dynamic hollow tubes made up of alpha and beta ________.
|
tubulins
|
|
What is best described by the following statement:
" serve as tracks along which organelles can move " |
microtubules of cytoskeleton
|
|
What is best described by the following statement:
" centrosome/microtubule organizing center, anchoring points from which microtubules radiate " |
microtubules of cytoskeleton
|
|
What determines the shape of cell and distribution of the organelles?
|
microtubules of cytoskeleton
|
|
What are microtubules?
|
- thickest fibers of cytoskeleton
- dynamic hollow tubes made up of alpha and beta tubulins - serve as tracks along which organelles can move - determines overall shape of cell and distribution of organelles |
|
What are intermediate filaments?
|
- cytoskeleton fibers thinner than microtubules but thicker than microfilaments
- tough, insoluble ropelike protein fibers |
|
What do the intermediate filaments do?
|
- resist pulling forces on the cell
|
|
What are the most stable cytoskeletal elements?
|
intermediate filaments
|
|
What part of the cytoskeleton is made up of keratin fibers?
|
intermediate filaments
|
|
intermediate filaments are made up of ______ fibers
|
keratin
|
|
Cytoskeletal fibers are ______ than microtubules but ______ than microfilaments
|
thinner ; thicker
|
|
Intermediate filaments are tough, insoluble protein fibers constructed like __________.
|
rope
|
|
What are the thinnnest cytoskeleton fibers?
|
microfilaments
|
|
What part of the cytoskeleton is made of actin protein?
|
microfilaments
|
|
What do microfilaments do?
|
resist compression and generate contractile force
|
|
What is best described by the following statement:
" resist compression and generate contractile force" |
microfilaments
|
|
Microfilaments are made of spherical protein subunits called ______.
|
actin
|
|
What are cellular extensions?
|
- cilia, microvilla and flagella
- short projections present on the outer surface of certain cell types |
|
What are cilia?
|
- short, whiplike appendages
- move substances over the cell's surface - made of microtubules arranged in a "9+2" arrangement |
|
What is best described by the following statement:
" short, whiplike appendages " |
cilia
|
|
What are flagella?
|
- longer appendages that help propel the entire cell
- made up of microtubles arranged in a " 9+2" arrangement |
|
What are microvilli?
|
- short, fingerlike projections of the plasma membrane
- increase the surface area for absorption - contain a core of actin filaments for stiffening |
|
What is best described by the following statement:
" longer appendages that help propel the entire cell " |
flagella
|
|
What is best described by the following statement:
" increase surface area for absorption " |
microvilli
|
|
What is best described by the following statement:
" contain a core of actin filaments for stiffening " |
microvilli
|
|
What is best described by the following statement:
" control center of the cell " |
nucleus
|
|
What is best described by the following statement :
" largest cellular organelle" |
nucleus
|
|
What is best described by the following statement:
" contains a nuclear envelope, nucleolus and chromatin " |
nucleus
|
|
What is the nucleus?
|
- control center of the cell
- contains the DNA - largest cellular organelle - contains the nuclear envelope, nucleolus, and chromatin |
|
What does it mean to say that most cells are uninucleate?
|
have one nucleus
|
|
What is an example of a cell that is uninucleate?
|
red blood cell
|
|
What is an example of a cell that is multinucleate?
|
skeletal muscle cells, bone destruction cells and some liver cells are multinucleate
|
|
What does it mean to say that a cell is multinucleate?
|
has many nuclei
|
|
What is the nuclear envelope?
|
- double membrane barrier sounding the nucleus
- nuclear lamina - inner lining that helps maintain nuclear shape - nuclear pores - channels for transporting mRNA in and out of nucleus |
|
What is best described by the following statement:
" channels for transporting mRNA in and out of the nucleus " |
nuclear pores
|
|
What is best described by the following statement:
" inner lining that helps maintain nuclear shape " |
nuclear lamina
|
|
What are nuclear pores?
|
channels for transporting mRNA in and out nucleus
|
|
what is the nuclear lamina?
|
inner lining that helps maintain nuclear shape
|
|
What is the nucleolus?
|
- dark staining spherical body within nucleus
- involved in rRNA synthesis and ribosome subunit assembly |
|
What is best described by the following statement:
" dark-staining spherical body within nucleus " |
nucleolus
|
|
What is best described by the following statement:
" involved in rRNA synthesis and ribosome subunit assembly" |
nucleolus
|
|
What is chromatin?
|
- a complex of DNA, histone proteins, and RNA
- arranged in fundamental units called nucleosomes - condenses into chromosomes for cell division |
|
Chromatin condenses into _______ for cell division.
|
chromosomes
|
|
Chromatin is arranged in fundamental units called ________.
|
nucleosomes
|
|
what are "little balls of protein with DNA wrapped around them"?
|
histones
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What defines the life stages of a cell from formation to reproduction?
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cell cycle
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What is the cell cycle?
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defines the life stages of a cell from formation to reproduction
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Why do cells divide?
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- organism growth
- tissue repair - surface area to volume ratio |
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Explain why cells need to divide to maintain surface area to volume ratio.
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surface area doesn't increase at the same rate as volume. You need more surface area .... meaning you need more plasma membrane. So to get more plasma membrane, you divide!
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What are the two major phases of the cell cycle?
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interphase and the mitotic phase
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What is interphase?
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the period from cell formation to cell division (cell grows and carries out usual functions )
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What phase of the cell cycle is best described by the following statement:
" the period from cell formation to cell division " |
interphase
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What is the mitotic phase?
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when cell divides into two identical daughter cells
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What phases are within interphase?
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G1, S and G2
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What is the G1 phase?
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- first part of interphase
- gap 1 = vigorous growth - the cell is metabolically active - g1 checkpoint/restriction point - g0 = nondividing phase, go to if fail g1 checkpoint |
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What is the G1 checkpoint?
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the point cells have to pass in order to reach the S phase
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What happens if cells fail at the G1 checkpoint?
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they enter G0, a non-diving stage that cells enter if they fail to pass restriction point
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How long do cells normally stay in G1?
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no time limit, can last few days or many years
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The cell cycle is ________.
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continuous
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What is the S phase of interphase?
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- synthesis phase
- DNA is replicated, resulting in two identical copies of the genetic material |
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What is the G2 phase?
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- gap 2 phase of interphase
- preparation for division - synthesis of proteins needed for mitosis - G2 checkpoint |
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What is the G2 checkpoint?
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- checkpoint between G2 and mitosis
- cell must have adequate mitotic promoting factor to enter mitosis |
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Cells must have adequate ___________ to enter mitosis, as checked in the G2 checkpoint.
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mitotic promoting factor
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What phase is best described by:
" DNA is replicated " |
S phase of interphase
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What phase is best described by :
" cell is metabolically active " |
G1 of interphase
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What phase is best described by:
" synthesis of proteins needed for mitosis " |
G2 of interphase
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What is best described by:
" checkpoint that cells must pass in order to enter S phase " |
G1 checkpoint
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what is best described by the following statement:
" non-diving stage that cells enter if they fail to pass G1 checkpoint " |
G0
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What happens if cells don't have enough mitotic promoting factor?
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won't enter mitosis; fail G2 checkpoint
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What phase is best described by the following statement:
"vigorous growth" |
G1 of interphase
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What phase is best described by the following statement:
" preparation for division " |
G2 of interphase
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What are the stages of mitosis?
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1. prophase
2. metaphase 3. anaphase 4. telophase - cytokinesis followed by a return to interphase |
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Where does a cell go after it has finished mitosis?
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back to interphase!
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What is the formal definition of mitosis?
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- splitting of the nucleus
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Mitosis does not occur in most mature cells of _________ tissue, _______ muscle, and ______ muscle.
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nervous, skeletal, cardiac
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Mitosis is a _______ process.
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continuous
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What phase is best described by the following statement:
" chromatin condenses into chromosomes (with two chromatids joined at the centromere) " |
prophase
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What phase is best described by the following statement:
" mitotic spindle forms " |
prophase of mitosis
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What phase is best described by the following statement:
" centrosomes migrate toward opposite poles " |
prophase of mitosis
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What phase is best described by the following statement:
" nuclear envelope breaks down " |
prophase of mitosis
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What happens in prophase of mitosis?
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- chromatin condenses into chromosomes (with two chromatids joined at the centromere)
- mitotic spindle forms - centrosomes migrate toward opposite poles - nuclear envelope breaks down |
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Chromatin condenses into chromosomes (with two chromatids joined at the ________ )
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centromere
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What phase is best described by the following statement:
" centromeres of chromosomes are aligned at the cell's equator " |
metaphase of mitosis
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Chromosomes line up along what during metaphase of mitosis?
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the metaphase plate
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During which phase do chromatids become chromosomes?
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anaphase
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What is metaphase of mitosis?
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- centromeres of chromosomes are aligned at the cell's equator, causing chromosomes to line up along this midway plane called the metaphase plate
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What happens during anaphase of mitosis?
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- centromeres of chromosomes split simultaneously- each chromatid now becomes a chromosome
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What phase is best described by the following statement:
" chromosomes are pulled toward poles by motor proteins along the microtubule tracks " |
anaphase of mitosis
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What phase is best described by the following statement:
" begins when chromosome movement stops " |
telophase of mitosis
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What phase is best described by the following statement:
" the two sets of chromosomes uncoil/ decondense back into chromatin " |
telophase of mitosis
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What phase is best described by the following statement:
" new nuclear membrane forms around each chromatin mass" |
telophase of mitosis
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What phase is best described by the following statement:
" nucleoli reappear " |
telophase of mitosis
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What phase is best described by the following statement:
" spindles break down " |
telophase of mitosis
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What is telophase of mitosis?
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- begins when chromosomes stop moving
- the two sets of chromosomes uncoil/decondense back into chromatin - new nuclear membrane forms around each chromatin mass - nucleoli reappear - spindles break down |
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Cytokenesis actually begins during _____________.
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late anaphase
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What is best described by the following statement:
" not a specific phase but a description of the cytoplasmic pinching process" |
cytokenesis
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What is best described by the following statement:
" ring of actin microfilaments contracts to form a cleavage furrow " |
cytokenesis
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What is formed during cytokenesis?
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a cleavage furrow
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What is best described by the following statement:
" two daughter cells are pinched apart, each containing a nucleus identical to the original " |
cytokenesis
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What is essential for growth and maintenance of the cell?
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protein synthesis
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What occurs during cytokenesis?
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- ring of actin microfilaments contracts to form a cleavage furrow
- two daughter cells are pinched apart, each containing a nucleus identical to the original |
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What is the central dogma of molecular biology?
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DNA ---> mRNA ----> protein
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What is a gene?
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a segment of DNA that describes the instructions for creating a polypeptide chain
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What is best described by the following statement:
" a segment of DNA that describes the instructions for creating a polypeptide chain" |
gene
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A gene is _________ to form mRNA.
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transcribed
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An mRNA molecule is _________ to form a protein.
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translated
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Protein synthesis can be divided into three steps. What are they?
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1. transcription
2. pre-mRNA processing 3. translation |
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Where does transcription occur?
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in the nucleus
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Where does pre mRNA processing occur?
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in the nucleus
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Where is mRNA formed?
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in the nucleus
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Where does translation occur?
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in the cytosol / free floating ribosome
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Where is protein officially synthesized?
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in the ribosome in cytosol
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What is the definition of transcription?
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the synthesis of mRNA from a DNA template
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Transcription is the synthesis of _______ from ________.
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mRNA ; DNA template
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Transcription occurs in three stages. What are they?
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1. Initiation
2. Elongation 3. Termination |
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Transcription factors bind to the _________, a sequence specifying the start of the gene.
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promoter region of DNA
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What are transcription factors?
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they bind to the promoter and signal the RNA polymerase to bind to DNA to initiate transcription.
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Transcription factors bind to the promoter region of DNA, a sequence specifying the _________ of the gene.
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start site
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Transcription factors signal the binding of _________ near the start site.
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RNA polymerase
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___________ binds to the promoter, pries the two DNA strands, and initiates mRNA synthesis at the start point on the template strand.
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RNA polymerase
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RNA polymerase initiates mRNA synthesis at the start point on the _______ strand.
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template
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The mRNA formed will have the same sequence as the ________ strand of DNA. (except thymines will be replaced with uracils)
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coding
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The mRNA formed will have a sequence complementary to that of the _______ strand of DNA.
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template
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RNA polymerase enzyme does what?
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oversees the synthesis of mRNA by unwinding the DNA template and moving along the DNA to add nucleotides to the mRNA that complement the DNA template strand
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RNA polymerase _______ the DNA template.
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unwinds
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RNA polymerase moves along DNA and adds _________ to the mRNA that complement the DNA template strand.
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nucleotides
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As the RNA polymerase moves along the template strand, elongating the mRNA transcript one base at a time it ______ the DNA double helix before it and rewinds the double helix behind it.
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unwinds
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At any given moment, 16-18 pairs of DNA are unwound and the most recently made RNA is still bound to DNA. This small region is called the _________.
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DNA-RNA hybrid.
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RNA polymerase reaches the gene's ___________ on the DNA, and releases pre-mRNA.
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termination signal
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mRNA synthesis ends when?
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When RNA polymerase reaches the termination signal. RNA polymerase and the completed mRNA transcript are released
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What occurs during pre-mRNA processing?
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1. RNA splicing
2. Cap and tail are added to mRNA |
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What does it mean to say that RNA is "spliced?"
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- introns (intervening sequences) are removed by spliceosomes
- exons (expressed sequences are brought together to form mRNA) |
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What are introns?
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intervening sequences that are removed from the final mRNA product during pre- mRNA processing by spliceosomes
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What are exons?
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expressed sequences that are joined together during pre-mRNA processing.
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Where are introns sliced out of the RNA product?
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in the nucleus
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mRNA is transported out of the ______ into the cytoplasm right before translation.
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nucleus
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mRNA is transported out of the nucleus into the ________ for translation.
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cytosol
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What is translation?
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the synthesis of a polypeptide from an mRNA template.
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What process is best described as:
" the synthesis of a polypeptide from an mRNA template " |
translation
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What three types of RNA are involved in translation?
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mRNA, tRNA and rRNA
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What is best described by the following statement:
" carries instructions for building a polypeptide, from gene in DNA to ribosomes in cytoplasm " |
mRNA
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What is best described by teh following statement:
" a structural component of ribosomes that, along with tRNA, helps translate message from mRNA" |
rRNA
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What is best described by the following statement:
" Bind to amino acids and pairs with bases of codons of mRNA at ribosome to begin process of protein synthesis" |
tRNA
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During translation, sets of three nucleotides called ______ specify each amino acid.
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codons
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What are codons?
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sets of three nucleotides that specify a particular amino acid
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What do mRNA's do in protein synthesis?
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carry instructions for building a polypeptide from gene in DNA to ribosomes in cytoplasm
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What do rRNA's do in protein synthesis?
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serve as structural components of ribosomes
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What do tRNA's do in protein synthesis?
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bind to amino acids and pair with bases of codons of mRNA at ribosome to begin process of protein synthesis.
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tRNA's bind to ________ and pair with bases of codons of mRNA at ribosome to begin process of protein synthesis.
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amino acids
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tRNA's bind to amino acids and pair with bases of _______ of mRNA at _______ to begin process of protein synthesis.
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codons ; ribosome
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a tRNA molecule carrying the complementary anticodon and the corresponding amino acid binds to the ______ during translation
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codon
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a tRNA molecule carrying the complementary _________ and the corresponding amino acid bind to the codon during translation.
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anticodon
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a tRNA molecule carrying the complementary anticodon and the corresponding ________ bind to the codon during translation.
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amino acid
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mRNA attaches to the ______ during translation.
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ribosome
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a _______ molecule carrying the complementary anticodon and the corresponding amino acid bind to the codon during translation.
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tRNA
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a tRNA molecule carrying the complementary anticodon and the corresponding amino acid bind to the codon during _________.
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translation
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_______ attaches to the ribosome during translation.
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mRNA
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The first codon enters the " _____ " site of the ribosome.
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A
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the first ______ enters the " A " site of the ribosome
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codon
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The first codon enters the "A" site of the ________.
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ribosome
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the ribosome moves along the ______ strand during translation.
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mRNA
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Codons move from the "A" site to the "_____" site to the "E" site while being read by the ribosome during translation.
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P
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Codons move from the "A" site to the "P" site to the _____ site while being read by the ribosome during translation.
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E
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After leaving the "E" site, the tRNA is released back into the cytoplasm where a new _______ will be attached to it.
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amino acid
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When the ribosome reaches the stop codon on the mRNA, what happens?
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the polypeptide is released
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What has to happen for the polypeptide to be released during translation?
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the ribosome has to reach the stop codon.
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