Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Cell Membraines (Chapter 4) > Flashcards

Cell Membraines (Chapter 4) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What do membranes do?

A

Control what passed through them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Are membranes partially permeable?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the three SIMPLE ways substances can move across a membrane?

A

Osmosis

Diffusion

Active transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What molecules form a continuous bilayer?

A

Phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the cell membrane model called a fluid mosaic model?

A

Phospholipids are constantly moving and it looks like a bit like a mosaic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is cholesterols role in the bilayer?

A

Binds to the phospholipid tails causing them to pack more closely- restricting movement making it more rigid

Helps keep animal cell walls more rigid/ and support eg. Red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What types of proteins are present in the bilayer?

A

Channel proteins

Carrier proteins

Receptor proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are glycoproteins?

A

Proteins which have a polysaccharide chain attached to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are glycolipids?

A

Lipids which have a polysaccharide chain attached to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Can proteins move sideways and also be fixed in position in the bilayer?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In a phospholipid what is the head?

A

Hydrophilic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In a phospholipid what is the tail?

A

Hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is the phospholipid bilayer arranged?

A

Phospholipid heads face outwards and tails inwards

Centre of the bilayer is hydrophobic- membrane does not allow water soluble substances in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which required practical investigates the permeability of cell membranes?

A

Beetroot cylinders- pigment leakage

Investigate temperature, concentration etc ………

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to the permeability of the cell membrane in temperatures below 0°c?

A

HIGHLY PERMEABLE

Phospholipids do not have much energy so don’t move much
Phospholipids packed closer together

Channel and carrier proteins deform
Ice crystals can pierce membrane

Increases permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to the permeability of the cell membrane between 0°c & 45°c?

A

Phospholipids can move around and aren’t tightly packed together

MEMBRANE IS PARTIALLY PERMEABLE

As temperature increases phospholipids move more which increases permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to the permeability of the membrane at temperatures above 45°c?

A

Phospholipids start to melt

BECOMES MORE PERMEABLE

Water inside cell expands putting pressure on membrane
Channel and carrier proteins deform- cannot control entry and exit

18
Q

Define diffusion

A

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.

19
Q

Can molecules diffuse in both directions?

A

Yes
But the net movement will be to the area of lower concentration. This continues until particles are evenly distributed throughout the liquid or gas.

20
Q

Is diffusion passive?

A

Yes it does not require metabolic energy

(Requires kinetic energy)

21
Q

What is simple diffusion?

A

When molecules diffuse directly through a cell membrane

22
Q

What is facilitated diffusion?

A

Where large or charged molecules, diffuse through carrier or channel proteins in the membrane.

23
Q

Is facilitated diffusion passive?

A

Yes it does not require metabolic energy

(Requires kinetic energy)

24
Q

What do carrier proteins do?

A

Move large molecules across membranes

25
Q

How do carrier proteins work?

A

Large molecule attaches

Protein changes shape

Releases the molecule on the other side of the

26
Q

What do channel proteins do?

A

Allows charged particles to diffuse through the membrane

27
Q

What are the three factors that affect the rate of simple diffusion.

A

The concentration gradient

Thickness of the exchange surface

The surface area

28
Q

How do microvilli increase the surface area for faster diffusion?

A

Large surface area- can increase it by 600 times

29
Q

What are the two factors that affect the rate of facilitated diffusion?

A

Concentration gradient

Number of channel or carrier proteins

30
Q

Define osmosis

A

Osmosis is the diffusion of water molecules across a partially permeable membrane, from an area of higher water potential to an area of lower water potential

31
Q

What is water potential?

A

Water potential is the likelihood of water molecules to diffuse in and out of a solution

32
Q

Does pure water have a high water potential?

A

Yes the highest

All solutions have a lower one than water

33
Q

Define isotonic

A

When two solutions have the same water potential

34
Q

List the three factors which effect the rate of osmosis

A

Water potential gradient

Thickness of exchange surface

Surface area of the exchange surface

35
Q

What is the required practical linked to water potential.

A

Using potato cylinders

5 serial dilutions using sucrose and water

Measure mass change %

36
Q

What is active transport?

A

Active transport uses energy to move molecules and ions across membranes usually against a concentration gradient

37
Q

Which protein is usually involved in active transport?

A

Carrier proteins

38
Q

What are the two main differences between active transport and facilitated diffusion?

A

Active transport usually moves molecules form a low to high concentration, in facilitated diffusion they move from a high to low concentration

Active transport requires metabolic energy (ATP) facilitated diffusion does not

39
Q

How does ATP release energy?

A

Undergoes hydrolysis splitting it into ADP and Pi (inorganic phosphate)

This releases energy

40
Q

What is a co-transporter?

A

A type of carrier proteins which binds to two molecules at a time

41
Q

How does co transport work?

A

Concentration gradient of one of the molecules is used to move the other molecule against its own concentration gradient

42
Q

Explain the 4 steps of co-transport of glucose in the ileum of the small intestine?

A

Sodium ions actively transported out of the epithelial cell into the blood via sodium-potassium pump, this creates a concentration gradient of sodium ions.

This causes sodium ions to diffuse from the lumen of ileum into epithelial cell, down their concentration gradient. Via sodium-glucose co-transporter proteins.

The co-transporter carries glucose into the cell with sodium- glucose concentration inside cell increases.

Glucose diffuses out of the cell into the blood, down its concentration gradient through a protein channel via facilitated diffusion .

Biology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions