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OCR A-level Biology > Biological Membranes > Flashcards

Flashcards in Biological Membranes Deck (11)
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1

What is the role of the plasma membrane

Separates cell components from surroundings

Regulates material transport

Contains enzymes used in reactions

Cell signalling

Site of chemical reactions

2

What is the role of organelle membranes

Allows each organelle to perform a specific function (compartmentalisation)

Site for reactions

some form vesicles when pinched off (RER, Golgi apparatus)

3

What is the name of the model displaying the plasma membrane

Fluid Mosaic Model

4

What is the role of Cholesterol in the Plasma membrane

Maintains fluidity of the membrane

5

What is the role of Carrier and Channel protiens

To move solutes in and out of the cell that are to large to move in via simple diffusion

Use Active transport and facilitated diffusion

6

What is the name of the bilayer that makes up the membrane

Phospholipid Bilayer

7

How the Myelin Sheath membrane on a neurone differ to that of a regular cell

The sheath has multiple layers of membrane cause by flattened cells

The membrane is about 20% protein and 76% lipid to provide electrical insulation

8

What types of molecules can diffuse through the phospholipid bilayer

Some small molecules like Oxygen and CO2

Lipid soluble molecules even if they are larger (e.g steroid hormones)

9

How is the concentration gradient maintained when CO2 and Oxygen are constantly diffusing into plant cells

Oxygen is used up by the mitochondria for respiration in working cells

CO2 diffuses into the palisade mesophyll cells and then the chloroplasts to be used in photosynthesis

10

What types of molecules require facilitated diffusion

Small Polar molecules

they are unable to pass through the bilayer due to the hydrophobic properties of the fatty acid tails.

11

What feature of many membranes allows water to move through more rapidly

Aquaporins