Brainscape's Knowledge GenomeTM

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


See full index

Bio Module 2 > Biological membranes 2.5 > Flashcards

Biological membranes 2.5 Flashcards

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

What does a cell membrane consist of?

A

Phospholipids, carrier proteins, channel proteins, glycoproteins, glycolipids and cholesterol

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

What two structures can phospholipids form?

A

Bilayer and micelle

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

What are the functions of membranes?

A
  • allow selected molecules to move in and out the cell
  • keeps all cellular components inside the cell
  • site for biochemical reactions
  • allows a cell to change shape
  • allows cellular components to have separate conditions
  • isolating organelles from the rest of the cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which substances can pass through the phospholipid bilayer?

A
  • small polar molecules diffuse slowly (H20)
  • fat soluble substances
  • small non-polar molecules diffuse rapidly (O2 and CO2)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the membrane structure called?

A

Fluid mosaic model

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

Why is the mambrane structure called the fluid mosaic model?

A

The proteins floating around in the bilayer form a mosaic pattern and the phospholipids can move making the membrane fluid

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

What is the difference between extrinsic and intrinsic proteins?

A

Intrinsic proteins penetrate 2 layers of the bilayer and extrinsic only penetrates 1

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

What is a glycoprotein?

A

A lipid attached to a protein

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

What is a glycolipid?

A

A lipid attached to a phospholipid

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

How does a phospholipid form a bilayer?

A

The hydrophobic tails of the phospholipid turn in to face eachother and the hydrophilic heads face outwards to form hydrogen bonds with the water forming a bilayer

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

What does an intrinsic protein do?

A
  • consists of channel proteins that have pores and act as channels to allow ions to pass through the membrane
  • also contains carrier proteins which change their shape to carry specific (bigger) molecules across the membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does an extrinsic protein do?

A
  • provide structural support
  • act as enzymes, antigens or receptor sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do glycolipids do?

A

Act as antigens for cell recognition

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

What do glycoproteins do?

A
  • act as receptors for chemical signals
  • has a role in cell adhesion sometimes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does cholesterol do?

A
  • controls the fluidity of the membrane
  • provides mechanical support
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens if a membrane contains less cholesterol?

A

It becomes less fluid and less permeable

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

What are the three ways that substances can get in and out of a cell using no energy? (passive transport, no ATP)

A
  • osmosis
  • diffusion
  • facilitated diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the three ways that substances can get in and out of a cell using energy?

A
  • active transport
  • exocytosis
  • endocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do substances cross a membrane without using energy from respiration?

A

They use the kinetic energy from a higher body temperature to cross the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What affects the rate of diffusion?

A
  • Temperature
  • concentration gradient
  • diffusion distance
  • surface area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does facilitated diffusion transport?

A
  • polar molecules
  • charged molecules
  • large molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does it mean when a substance is insoluble?

A

The substance forms no hydrogen bonds with water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Define water potential and what is it measured in?

A
  • the tendancy of water molecules in a system to move
  • Kilo Pascals (KPa)
24
Q

What is the water potential of pure water?

A

0 KPa

25
Q

Where do water molecules move?

A

Water molecues always move from an area of high water potential to an area of low water potential?

26
Q

What happens if a solution is added to pure water?

A

Even if the volume of water stays the same, the WP decreases as there is less water that is free to move and more water is making hydrogen bonds

27
Q

What does crenated mean?

A

Shrivelled

28
Q

What is osmotic concentration?

A

It relates to the amount of dissolved solutes in a solution

29
Q

Do insoluble molecules affect water potential or osmotic concentration?

A

No

30
Q

What are the characteristic of a solution with a high volume of water and a low volume of solute?

A
  • low osmotic concentration
  • high water potential
  • dilute solution
31
Q

What are the characteristic of a solution with a low volume of water and a high volume of solute?

A
  • high osmotic concentration
  • low water potential
  • concentrated solution
32
Q

What do hypertonic and hypotonic relate to?

A

The solute

33
Q

What is isotonic?

A
  • when the WP outside the cell is the same as the WP of the cel cytoplasm
  • no net movement
34
Q

What is hypertonic?

A
  • when the WP of the outside of the cell is less than the WP of the cell cytoplasm
  • when the OC of the outside of the cell is higher than the OC of the cell cytoplasm
  • net movement of water out of the cell
  • animal cells crenate (flacid)
  • plant cells undergo plasmolysis
35
Q

What is hypotonic?

A
  • when the WP of the outside of the cell is more than the WP of the cell cytoplasm
  • when the OC outside the cell is lower than the OC of the cell cytoplasm
  • net movement of water into the cell
  • cells undergo lysis (turgid)
36
Q

When is active transport used?

A
  • to move substance across their concentration gradient
  • if diffusion isn’t fast enough for what the body needs
  • to set up a concentration gradient
37
Q

What does the word ‘pump’ usually relate to?

A

Active transport

38
Q

What does active transport require to work?

A

It requires energy in the form of ATP a molecule produced by respiration in the mitochondria

39
Q

How does active transport work?

A

A molecule binds itself to a carrier protein, then ATP attaches to the protein on the inside of the cell causing it to change shape and allowing the molecule to pass through

40
Q

What are endocytosis and exocytosis examples of?

A

Bulk transport

41
Q

What is bulk transport?

A

When extremely large substances need to be moved across a cell membrane

42
Q

How does the cell membrane move?

A

The cytoskeleton moves it

43
Q

What is endocytosis?

A

The bulk movement of substances into the cell and consists of phagocytosis and pinocytosis

44
Q

What is exocytosis?

A

The bulk movement of substances out of the cell

45
Q

What is phagocytosis?

A

The bulk movement of solid substances into the cell

46
Q

What is pinocytosis?

A

The bulk movement of liquid substances into the cell

47
Q

How can the vesicles move?

A

ATP is used to move them

48
Q

What are the three factors that affect membrane structure?

A
  • heat
  • cholesterol
  • solvents
49
Q

Why do membranes need to be fluid?

A
  • to allow diffusion of substances across the membrane
  • to allow the membrane to fuse with vesicles in endo/excocytosis
  • to enable the cell to move
50
Q

How does heat affect the membrane structure?

A
  • it increases kinetic energy, which creates gaps in the bilayer allowing molecules to pass through
  • proteins denature
51
Q

How does the cold affect the membrane structure?

A

Since water expands into ice in temperatures below freezing, the ice shards penetrate the membrane and push the phospholipids apart, increasing permeability

52
Q

How do solvents affect membrane structure?

A
  • Water is polar and is vital for creating membrane stability with the phospholipids
  • non-polar molecules can move into the bilayer and disrupt the structure by dissolving phospholipids
53
Q

How does cholesterol affect membrane structure?

A
  • it controls membrane fluidity
  • it increases mechanical strength and stability of membranes
54
Q

How does cholesterol affect membrane structure if the temperature is too high?

A
  • it decreases the fluidity
  • it binds to the phospholipid tails due to a chemical attraction which causes them to pack closer together, stabalising them
55
Q

How does cholesterol affect membrane structure if the temperature is too low?

A
  • it increases fluidity
  • it stops the phospholipid tails from packing too closely together by being in between the phospholipids

Bio Module 2 (6 decks)

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