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54 Cards in this Set
- Front
- Back
What is the plasma membrane and what does it do? |
Separated the internal environment of the cell from its external environment; regulates the entrance and exit of molecules in the cell |
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The consistent internal environment of a cell is called ___. |
Homeostasis |
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What molecule stiffens the phospholipid bilayer and controls fluidity? |
Cholesterol |
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Which parts of the phospholipid bilayer are hydrophobic and which are hydrophilic? |
Polar heads, hydrophilic Polar tails, hydrophobic |
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What 2 types of proteins can a membrane have? |
Peripheral or integral |
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What are peripheral proteins? |
Associated with only one part of the membrane |
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What are integral proteins? |
Span the whole membrane |
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What are glycolipids? |
Lipids attached to carbohydrates |
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What are glycoproteins? |
Proteins attached to carbohydrates |
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What are channel proteins and what is their nickname? |
Channels that allow solutes to pass through the membrane; "pores" |
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What are carrier proteins and their nickname? |
Combine with a solute in order for it to pass through the membrane; "pumps" |
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What are cell recognition proteins? |
Glycoproteins that help the body recognize when it is invaded by pathogens |
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What are receptor proteins? |
Have a shape that allows specific molecules to bind causing the receptor to change shape and initiate a cellular response |
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What do enzyme proteins do? |
Make chemical reactions go faster |
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What does it mean to go "down" on a concentration gradient? |
From higher to lower concentration |
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What does it mean to go "up" a concentration gradient? |
Going from lower to higher concentration. Requires input of energy |
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What does selectively permeable mean? |
Blocks certain things and lets certain things pass |
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Which molecules can freely cross the membrane and which can't depends on ___. |
Size Polarity, charge |
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What are examples of the small, noncharged molecules that can pass the membrane |
CO2, O2, glycerol, alcohol |
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Can water pass through the plasma membrane? Why/why not |
NO; it is polar |
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What are aquaporins? |
Special channels that allow water to cross the membrane |
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What things CANNOT freely cross the membrane? |
Large molecules, ions, and charged molecules |
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How can large molecules, ions, and charged molecules pass the membrane? |
Channel proteins Carrier proteins Vesicle formations |
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What's a solution? |
Contains a solute and a solvent |
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What is diffusion? |
The movement of molecules from a higher to a lower concentration |
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When all molecules are spread evenly it's called ___. |
Equilibrium |
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What kind of molecule can go straight through the lipid bilayer memebrane? |
Gasses; O2 and CO2 |
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What factors influence the rate of diffusion? |
Temperature (higher temp, quicker diffusion) Pressure Electrical currents Size of molecule |
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What is osmosis? |
Diffusion of water across a selectively permeable membrane |
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What is osmotic pressure? |
The pressure that develops in a system due to osmosis |
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What is an isotonic solution? |
The solute concentration is equal inside and outside the cell |
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What is a hypotonic solution? |
There's more solute outside the cell than inside the cell |
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What is a hypertonic solution? |
There's more solute inside the cell than outside |
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What happens to an animal cell in an isotonic solution? |
There's no gain or loss of water and 0.9% salt in the blood |
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What is cytolysis and hemolysis? |
Cell bursts; blood cell bursts |
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What happens to an animal cell in a hypotonic solution? |
It gains water. Too much water. And bursts |
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What does crenation mean? |
Shrivel |
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What happens to an animal cell in a hypertonic solution? |
The cell loses water and shrivels |
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What happens to a plant cell in an isotonic solution? |
No gain or loss of water |
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What happens to a plant cell in a hypotonic solution? |
It gains water. Turgor pressure keeps it erect and the cell wall keeps it from bursting. |
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What is plasmolysis? |
Cytoplasm shrinks |
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What happens to a plant cell in a hypertonic solution? |
The cell loses water and shrivels. The plant dies |
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What do carrier proteins combine with to transport across the membrane? |
Molecules or ions |
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What 2 Linda's of transport do carrier proteins do? |
Facilitated transport Active transport |
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What is facilitated transport? Is ATP required? |
Molecules are transported down their concentration gradient; no |
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What is active transport? Is ATP required? |
Molecules move up the concentration gradient; yes |
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How are macromolecules transported in and out of the cell? |
Vesicle formation |
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What's it called when a macromolecule exits a cell? |
Exocytosis |
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What's it called when a macromolecule enters a cell? |
Endocytosis |
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What are the 3 types of endocytosis? |
Phagocytosis Pinocytosis Receptor-mediated endocytosis |
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What is phagocytosis? |
When cells take in large matter such as food molecules, viruses, or whole cells |
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What is phagocytosis? |
When cells take in large matter such as food molecules, viruses, or whole cells (amoeba & macrophages) |
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What is pinocytosis? |
When cells take in liquids and small particles dissolved in liquid (blood cells, plant root cells) |
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What is receptor-mediated endocytosis? |
A type of pinocytosis that involves a coated pit (placental cells) |