Brainscape's Knowledge GenomeTM

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


See full index

Bio 105 > Chapter 7: Membranes > Flashcards

Chapter 7: Membranes Flashcards

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

What is the function of the cellular membrane?

A
  1. Separates cells from surroundings
  2. Selective permeable
  3. Forms additional compartments in eukaryotic cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the cell membrane made up of?

A

Lipids, proteins, some carbs
The phospholipid bi layer is crucial

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

What’s the phospholipid bi-layer?

A

It’s an amphipathic molecule; meaning it’s both hydrophilic (heads) and hydrophobic (tails)

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

What’s an amphipathic molecule?

A

Both hydrophobic and hydrophilic regions

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

What’s the fluid mosaic model?

A

Proteins are embedded in bi-layer - they’re moving, but grouped specifically by function; lipids (smaller, faster)/proteins (bigger, slower) move sideways in membrane

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

What’s the effect of temperature on lipid fluidity?

A

As temps cool, the membrane solidifies

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

What’s the effect of phospholipids rich in unsaturated versus saturated fatty acids?

A

Phospholipids rich in unsaturated fatty acids stay fluid at a lower temperature because the kinks in their tails make it so they can’t pack tightly together

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

Why should membranes be fluid?

A

It affects permeability and movement of transport proteins

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

How does cholesterol impact lipid fluidity?

A

Steroid cholesterol is wedged between phospholipids - as temps increase, it restrains phospholipid movement because steroids are rigid in membrane
As temps decrease, it hinders solidification because it prevents tight packing

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

How have organisms adapted to extreme conditions that impact the phospholipid bi layer?

A

Fishing living in extreme cold have a high number of unsaturated hydrocarbon tails; wheat has a high number of unsaturated hydrocarbon tails in the fall in preparation for winter weather

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

What’s the relationship between phospholipids and proteins?

A

Phospholipids are the main fabric of the membrane; proteins determine the function - which differs depending on type of cell

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

What are the two types of membrane proteins?

A

Integral and peripheral

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

What are integral proteins?

A

Transmembrane usually; proteins that penetrate hydrophobic core of bilayer; center is hydrophobic, top and bottom is hydrophilic; hydrophobic region consists of non polar amino acids coiled into alpha helices

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

What are peripheral proteins?

A

Bound to surface of membrane - held in place by cytoskeleton on the cytoplasmic side

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

What are the six major functions of membrane proteins?

A

Transport, enzymatic activity, signal transduction; cell-cell recognition, intercellular joining, attachment to cytoskeleton/ECM

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

Transport function of membrane protein?

A

Transport protein spanning length of membrane may have a hydrophilic channel; may also shuttle substance by changing shape (would use ATP to pump)

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

How does the cell membrane attach to cytoskeleton/ECM?

A

Microfilaments bound to membrane proteins / also coordinates extra/intra cellular changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is signal transduction?

A

A receptor protein w/ a site for an external messenger; relays messages inside cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is recognition?

A

Identifies the cell as belonging to a specific type (glycoproteins)

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

What’s the relationship between HIV and receptor proteins?

A

Protein CD4 assists HIV in infecting cells - CCR5 is a co-receptor; people immune to HIV infection have a mutation is CCR5 is absent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is cell-to-cell recognition especially important for?

A

Sorting tissues/organs in embryos

22
Q

Surface molecules bond to what to recognize type of cell?

A

1 - glycolipids (carbohydrates bonded to lipids)
2 - glycoproteins (carbohydrates bonded to proteins)
*difference in surface carbohydrate functions as cell identification

23
Q

What can cross membranes?

A

small uncharged molecules & hydrophobic molecules (steroids)

24
Q

What can’t cross membranes?

A

Large molecules (sugar)
Anything hydrophilic, charged; ions, Na+, K+

25
Q

Is the membrane permeable to water?

A

Somewhat, but very slow - gets stuck in hydrophobic middle

26
Q

What two proteins aid in transport across lipid bilayer?

A

Channel proteins and carrier proteins

27
Q

Channel proteins are?

A

passive, hydrophilic tunnels, they use the concentration gradient and don’t require energy; aquaporin (water holes); ion channels

28
Q

Carrier proteins are?

A

integral proteins that bind to molecules and change their shape during passage to shuttle them across membrane - used in passive and active transport

29
Q

What is passive transport?

A

Movement across membrane requiring no energy; simple diffusion or facilitated transport

30
Q

What’s diffusion?

A

movement of substance particles to spread evenly; the particles move from high to low until equilibrium is reached; powered by potential energy, not real energy

31
Q

What’s osmosis?

A

Diffusion of a solvent down its concentration gradient - lower to higher solute concentration; equalizes solutes that can’t pass membrane

32
Q

What’s tonicity?

A

effect of a surrounding solution on a cell - whether it causes it to gain or lose water; a higher concentration of non penetrating solutes, water will leave the cell to equalize

33
Q

Isotonic cells?

A

same concentration across cell, no effect of H2O movement. Normal in animal cells, flaccid in plants

34
Q

Hypotonic cells?

A

Water enter cells faster than it can leave; dilute; animal cells will burst, plants cells prefer bc of cell wall

35
Q

Hypertonic?

A

Water leaves cell, animal cells will shrivel and die (why lakes can’t increase salinity); plants will wilt and die

36
Q

A solution that has a relatively high solute and low free water is

A

hypertonic

37
Q

A solution that has relative low solute and high free water is

A

hypotonic

38
Q

Osmoregulation

A

In animals cells (no cell wall), needed to regulate water

39
Q

What’s facilitated diffusion?

A

Passive transport via transmembrane transport proteins (channel & carrier)

40
Q

What’s active transport?

A

The use of ATP to move solutes against concentration gradient - done via carrier protein pump

41
Q

What does the sodium/potassium pump do?

A

Creates an electrograident by moving 3NA+ out of cell and 2Ka+ into cell

42
Q

What is the sodium, potassium pump process?

A
  1. Pump first binds to Na+ (inside cell)
  2. ATP enters, “phosphorylates” pump & changes shape
  3. Pump then releases Na+ outside cell
  4. Pump, now open, has configuration to fit K+
  5. Pump goes back to original shape (no ATP needed, functions like a spring) and releases K+ into cell
43
Q

When open to ECM, what can go into the sodium potassium pump?

A

2K+

44
Q

When open to the cytoplasm, what can go into the sodium potassium pump?

A

3NA+

45
Q

What are the two types of bulk transport?

A

-exocytosis
-endocytosis

46
Q

What’s exocytosis and example?

A

Transport out but fashion of vesicles to plasma membrane

Pancreas cells make insulin, secrete via exocytosis

47
Q

What’s endocytosis?

A

Transport in via phagocytosis, pinocytosis, receptor mediated endocytosis

48
Q

What’s phagocytosis?

A

Cellular eating; ingesting particles by cell membrane forming pseudopods and engulfing

49
Q

What’s pinocytosis?

A

Cellular drinking (liquids), much smaller folding

50
Q

What’s receptor mediated endocytosis?

A

Receptors in ECM/membrane - as substances pass, receptor binds to them; cell folds to it and brings them in
**takes a lot of energy, not used a lot

51
Q

Co-transport?

A

Active transport occurring at the same time as a concentration gradient

52
Q

Example of co-transport?

A

Plants use proton pumps to generate a H+ gradient; co-transporter moves H+ back down its concentration gradient with active transport of sucrose into cell

Bio 105 (5 decks)

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