More Flashcards AQA AS Biology

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  • Created by: Alice
  • Created on: 20-05-14 16:45
How do we work out percentage change?
Initial - Final value then divided by Initial Value then x100
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Why is the membrane model "fluid mosaic"?
Molecules within the membrane are able to move and there is a mixture of phospholipid and protein which vary in size and shape
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Describe the cell membrane structure.
Double layer of phospholipid molecules, heads on outside as hydrophilic, tails on inside as hydrophobic
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What is the difference between an extrinsic and intrinsic protein?
Extrinsic only on surface, intrinsic passes through whole membrane with pores
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What is the function of cholestrol in the membrane?
Adds strength
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Glycoproteins and glycolipids - how do they differ?
Glycolipids provide mechanical support, glycoproteins act as a recognition site for chemicals
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Due to the polar nature of the bilayer, what enters and exits?
Lipid-soluble molecules can enter and exit, water-soluble molecules cannot
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How does a phospholipid form?
Two fatty acids and phosphate - joined by condensation, contains glycerol
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In Prokaryotic Cells, what is the function of the mesosome?
Respiration and cell division
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In Prokaryotic Cells, what is the function of the cell wall?
Mechanical support and prevent osmotic lysis
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In Prokaryotic Cells, what is the function of the flagellum?
Cell movement
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In Prokaryotic Cells, what is the function of the capsule?
Slime layer for antibiotic protection
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In Prokaryotic Cells, what is the function of the plasmid?
Genes for survival in adverse conditions
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True or false: in Prokaryotes, there are lots of membrane bound organelles.
False.
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How does Cholera cause diarrhoea?
Cholera toxin adheres to cells, open chloride ion channel. Chloride ions diffuse out into the lumen from the cells, making the lumen's water potential more negative in the small intestine. Water moves from cells to dilute the lumen in a conc grad.
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How does Cholera cause disease?
Bacteria adheres to cells. Secrets toxin. Opens Chloride Ion Channel, Chloride ions diffuse into lumen. Lumen has more neg WP, water moves in to dilute it. Cells become more negative so water moves from blood to dilute them by osmosis. WPG
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What causes diarrhoea?
Damage to intestinal microvilli, excessive secretion of water due to toxins, damage to lining of epithelial cells
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Why do we need ORS?
Water not being absorbed from intestine, being lost from cells. Need to replace ions and electrolytes.
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What are the five components of ORS and why do we need them?
Water for rehydration, Potassium for sodium-potassium pump and appetite, Glucose for respiration and uptake of sodium ions, Sodium to replace lost ions and make most of sodium-glucose carriers, electrolytes to prevent electrolyte imbalance
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Other cards in this set

Card 2

Front

Why is the membrane model "fluid mosaic"?

Back

Molecules within the membrane are able to move and there is a mixture of phospholipid and protein which vary in size and shape

Card 3

Front

Describe the cell membrane structure.

Back

Preview of the front of card 3

Card 4

Front

What is the difference between an extrinsic and intrinsic protein?

Back

Preview of the front of card 4

Card 5

Front

What is the function of cholestrol in the membrane?

Back

Preview of the front of card 5
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