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Flashcards in Membranes Deck (25):
1

What factors affect membrane permeability?

Steroid content - the more steroid that makes up the membrane the less permeable it is

Temperature- an increase in temperature results in an increase in fluidity

2

What factors effect the rate of diffusion?

Concentration gradient
Size of particles
Size of membrane
Surface area
Distance between regions
Temperature

3

What is diffusion?

Diffusion is the movement of molecules or ions from a region of high concentration to a region of low concentration

4

What is facilitated diffusion?

This is a form of diffusion that uses carrier and Chanel proteins to allow faster movement.

5

I’m facilitated diffusion what do the channel proteins allow entry to?

Charged particles that cannot diffuse easily across the non polar centre of the phospholipid bi layer.

6

What do the carrier proteins allow transport to?

Larger polar molecules such as sugars and amino acids.

7

What is osmosis?

Osmosis is the movement of water molecules from a region of high water potential to an area of low water potential through a partially permeable membrane.

8

What is solute potential?

The measure of the reduction in water potential due to solute molecules being present

9

Pressure potential

The pressure exerted on the cell contents by the cell wall and membrane

10

What is turgidity?

When water enter the cell via osmosis, filling the cell and pushing the cell membrane against the cell wall

11

What is plasmolysis?

The opposite of turgidly, when water leaves the cell and the cell membrane is pulled away from the cell wall - the cell becomes flaccid

12

What is a hypertonic solution?

Strong solution

13

What is a hypotonic solution?

Weak solution

14

What is an isotonic solution?

Solution has the same water potential as the cell

15

What is active transport?

Active transports is the uptake of molecules or ions agains a concentration gradient using energy from respiration (atp)

16

What is endocytosis?

During endocytosis the cell membrane wraps it’s set around the material and brings it into the cytoplasm in a vesicle. There are two types:
Phagocytosis
Pinocytosis

17

What is phagocytosis?

Solid material is taken into the cell

18

What is pinocytosis?

When liquid is taken into the cell

19

What is exocytosis?

Exocytosis is the reverse of endocytosis - taking material out of the cell.

20

What is the process of endocytosis?

Material is brought into the cell in a vesicle, lysosomes use with the vesicle, emptying their enzymes into it. The enzymes digest the contents and the products are released into the cytoplasm

21

What is the function of the plasma membrane?

Controls the movements of molecules into and out of the cell
Allows identification
Maintains a difference of concertration of ions / molecules inside and outside the cell
Encourages cell division
Internal membranes allow compartmentalisation

22

What is the plasma membrane made of?

Phospholipids
Proteins

23

Intrinsic proteins?

Span the membrane

24

Extrinsic

Only one layer - top or bottom

25

What do glycoproteins do?

Cell signalling
Cell recognition
Binding cells together