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82 Cards in this Set
- Front
- Back
In animals, are the outside of the cell rigid?
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No, they are not rigid
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Why are the outside of animal cells not rigid?
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Mainly to hold one cell to the next cell.
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What is the glue substance that holds the cells together in animal cells?
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glycocalix
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What is the glycocalix made ofand what is it's texture?
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Proteins modified with sugar.
1.) Fibronectin 2.) Collagen -Slimy texture |
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What keeps the animals cells together? Binding to one another and allow communication?
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1.) Tight Junctions
2.) Desmosomes 3.) Jap Junctions |
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What are Tight Junctions?
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1.) Prevent extracellular material from infultrating the cell.
"Barriers" |
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What are Desmosomes?
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1.) Fuzzy Rivets
Protein material that rivet cells together. |
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What are Jap Junctions?
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"Analagous to Plasmodesmata"
-Little pores that allow the pentration of small solutes from one cell to the next. "Act as Communication channels" |
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What is the primary function of the plasma membrane?
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Separates the inside of the cell from the outside world.
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What are the major components of the Plasma membrane?
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1.) Phospholipids
2.) Cholesterol(animal cells) 3.) Proteins |
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Why are Phospholipids so important to the structure?
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- Capability to form membrane bilayers.
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What two properties make the bilayer so important?
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Because the Phosphate head is hydrophilic and will interact with water.
Tails are hydrophobic |
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How wide is the membrane bilayer?
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8 nanometres in width
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What is a mosaic?
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-Mixture of proteins of different types in the phospholipid bylayer.
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What are integral proteins?
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intergrated in the P bilayer
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What are peripheral proteins?
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on the outside of the P bilayer
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What are unilameller proteins?
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imbedded in only one half of the bilayer
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How are the proteins organized in, on and around the P Bilayer?
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-from the perspective of the proteins, they are ASYMMETRIC
-Outside proteins and outside material is different from the inside. |
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What major feature does the membrane bilayer have that allow the proteins capability to move through the bilayer?
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-Membrane is neither solid nor liquid. It is a compromise between fluidity and structural integrity
-SEMI-FLUID STATE |
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What is the function of cholesterol in the P bilayer?
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Function of cholesterol is the modulate the semi- fluid state in animal cells. Fluidity Buffer
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What distinguishes different cells from one another? Eg-Human from Mouse cell
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Signal Proteins on the membranes
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What is cell fusion? Eg-Hybrid cells
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-Experiment to show that proteins have the ability to move along the cell membrane. Eg-Human/Mouse cell fused to target signal protein movement
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What structure of the proteins are important to the cell membrane?
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Tertiary structure
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Why is tertiary structure important to the embedded protiens.
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Hydrophobic vs Hydrophilic amino acids. Hydrophobic part is on the inside and hydrophililc on the outside.
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What end of the protein is on the extracellular side of the membrane?
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N-terminus (HydroPhillic)
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What end of the protein is on the Cytoplasmic Side.
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C-Terminus. (Hydrophobic)
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What are the properties of the membrane that makes it a selective barrier between a cell and it's environment?
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1.) Double barrier
-prevent hydrophobic molecules from enterind -prevents hydrophilic molecules from entering |
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What can diffuse or enter the P bilayer?
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Small hydroPHOBIC compounds
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What type of compunds can diffuse(go through without help passively) through the P lipid bilayer?
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1.) Gases
2.) uncharged small polar molecules 3.) Water can diffuse |
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What type of compunds cannot diffuse through the P lipid bilayer?
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1.) IONS -charged molecules
eg- acetate, ammonium, Na+ etc.. 2.) Larger Polar Molecules eg- sugars, (sucrose), amino acids, proteins |
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Why are Ions impermisable to the P bilayer?
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Penetrate - Differential Diffussion of different compounds through the membrane.
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What problems are caused by Differential Diffusion?
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1.) Water can go through but Glucose cannot
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What does diffusion mean?
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the unimpaired movement of soluble materials from one area to another until and equilibrium is reached.
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Make up question
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the diffusion of one solute does not impact onthe difusion of other solutes
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What direction does the diffusion take place?
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Direction of solutes is from an area of hifh concentration to an area of low concentration.
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What happens to the concentration of the solutes at Equilibrium during diffusion?
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The concentration of the different solutes will be uniform.
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What is Osmosis?
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-Movement of water accross a semi-permiable membrane in response to a difference in solute concentration accros that membrane.
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What happens to a plant cell that is in a hypotonic solution?
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1.) water will enter the cell
2.) membrane will expand 3.) Cell wall does not burst 4.) cell pressure increased |
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What is Turgor Pressure?
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-Pressure bulit up by water entering the plant cell due to the rigid cell wall.
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Whst is called Plasmolysis?
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-Plant cell will shrivel up as water is sent out of the cell.
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What is a Hypotonic cell?
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Cell that has released it's water and shriveled up
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What is a Hypertonic Cell?
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Cell that has absorbed water and has expanded. Animal cells will possibly burst.
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What is passive diffusion or passive transport?
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moving biochemicals and atomic or molecular substances across the cell membrane.NO ENERGY is involved
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What is Osmosis?
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Osmosis is the diffusion of water molecules across a selectively permeable membrane.
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How is osmosis a potential force?
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due to the movement of water in a closed unit
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What is the impact of osmosis on an animal cell in a hypotonic solution?
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the cell will shrivel
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What are the 4 kinds of Passive transport/diffusion?
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diffusion, facilitated diffusion, filtration and osmosis.
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What is the impact of osmosis on an animal cell in a hypertonic solution?
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The cell will burst
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What is Osmolarity?
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Osmolarity is a measure of the osmoles of solute per liter of solution. it is the concentration of all solutes
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What happens to the plant cell if the osmolarity inside the cell is greater than outside?
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Turgor pressure is increased.
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What does it mean when a cell interior and exterior are ISOTONIC or ISOOSMOTIC?
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the [] of the solute is the same on the inside and outside of the cell.
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When can hypotonic and hypertonic be used as terms?
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They are comparative terms. When one side is Hyo the other must be hyper.
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What is the first major functions of protein on the membrane?
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1.) transport of solutes (that cannot diffuse)in/out of cell
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What is the second major functions of protein on the membrane?
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Catalytic - membrane proteins are enzymes
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What is the third major functions of protein on the membrane?
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Signal Transduction -informs the inside of the cell what's going on outside
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What is the 4TH major functions of protein on the membrane?
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Proteins as receptors and cell-cell adhesion
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What is the fifth major functions of protein on the membrane?
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attachement of the membrane to the cytoplasm
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What strategies relative to transport accros the membrane do proteins employ?
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1.) Uniporters
2.) Symporters 3.) Antiporters |
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What's a uniporter?
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-selectively carry ONE type of molecule into the membrane
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What's a symporter?
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-selectively carry TWO types of molecules
-carry them always in the same direction |
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What's an antiporter?
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-selectively carry TWO types of molecules
-Carry them in opposite directions |
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What are the 2 types of uniporters?
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Carrier or Channel proteins
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What's a carrier protein?
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Uniporter carrier proteins work by binding to one molecule of solute at a time and transporting it with the solute gradient
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What's a channel protein?
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Uniporter channels open in response to a stimulus and allow the free flow of specific molecules
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What's a solute gradient?
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A series of progressively increasing or decreasing differences in the solute of a cell.
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What's facilitated diffusion?
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Diffusion facilitated by proteins , uniporters, symporter & antiporters
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What type of energy is need for facilitated diffusion?
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Note that no ATP or ion gradient is involved with facilitated diffusion.
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What is the major problem with Facilitated Diffusion?
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at equilibrium, the concentration may not be adequate needed for the cell.
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How often does a facilitate diffusion go to equilibirum?
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ALWAYS
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Explain Passive transport?
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-Diffusion
-Facilitated Diffusion (proteins) |
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What is Active Transport?
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Active transport is the process of moving particles with the use of applied energy across biological membrane against the concentration gradient.
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What are the types of energy needed for active transport?
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-ATP(from chemical reactions)
-Coupling to another chemical gradient |
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What is a symport system?
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A mechanism of transport across a membrane in which two different molecules move in the same direction.
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What is an example of a symport system?
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Proton pump takes a glucose molecule through the membrane to increase the concentration.
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What is a proton pump?
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is an integral membrane protein that is capable of moving protons across the membrane of a cell, mitochondrion, or other subcellular compartment.
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What does a proton pump generate across the membrane?
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-a Ph gradient
-an electrical charge inside and outside the membrane (generating a voltage) |
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How does the Proton pump change the Ph of the cell?
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Pumps H+ ions in or out of the cell and leaves OH groups behind.
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What is another name for a proton pump?
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-Electrogenic Pump
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What would happen if you had a sodium pump?
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-NaCl would break the bond and you are left with Na+, Cl-
Electrogenic pump |
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What are the two ways Eukarotic Cells transport bulk material in/out?
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Endocytosis
Exocytosis -use of transport vesicles fuse to the cell membrane and dump materials in/out |
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What are the different types of Endocytosis?
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1.) Solids - Phagocytosis
2.) Liquids/solutes Pinocytosis 3.) Receptor mediated Endocytosis |
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What is Receptor mediated Endocytosis?
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is a process by which cells internalize molecules (endocytosis) by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being internalized.
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