Membranes Flashcards

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

What is the function of the plasma membrane?

A

To allow the passage of necessary molecules, protecting the cell

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

What are the four components of cellular membranes

A

Phospholipid bilayer, transmembrane proteins, interior protein network, cell surface markers

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

What are integral membrane proteins?

A

Span the lipid bilayer, nonpolar regions are embedded in the interior, polar regions protrude

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

What do integral proteins do?

A

playing critical roles in movement of molecules across bilayer and the transduction of energy and signals.

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

What is the 6 major functions of membrane proteins

A

transport,
enzymatic activity,
Receptor proteins (signal transduction)
cell-cell recognition,
intercellular joining (tight junctions)
attachment to the cytoskeleton and extracellular matrix
desmodomes
gap junctions

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

Why is membrane fluidity important?

A

for permeability and enzyme function

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

What factors impact the membrane fluidity?

A

Membrane composition and temperature

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

What roles do unsaturated fatty acids have in membranes

A

unsaturated fatty acids make membranes more fluid, and the kinks from the double bonds keep them from packing tightly

most membranes contain steroids like cholesterol which can increase or decrease membrane fluidity based on temperature

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

How does cholesterol act as a temperature buffer?

A

At cool temps; cholesterol maintains fluidity by preventing tight packing via double bonds

at warm temps: cholesterol restrains the movements of phospholipids, making it less fluid

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

How does selective permeability regular cells molecular traffic

A

small, nonpolar molecules can cross the membrane directly

large, polar molecules do not cross the membrane easily

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

what are the types of passive transport?

A

simple diffusion, osmosis, facilitated diffusion

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

what are the types of active transport?

A

Primary active, secondary active

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

What are the types of transport proteins

A

can be channel, carrier, pump, or cotransporter

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

What are 2 energy sources Active Transport:

A

ATP and the electrochemical gradient

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

What is passive transport

A

it is the movement of molecules down the concentration gradient (no energy)

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

what is osmosis

A

osmosis is the net diffusion of water across a membrane toward a higher solute concentration

17
Q

what is tonicity

A

the ability of a solution to cause a cell to gain or lose water

depends on concentration of non-penetrating solutes

18
Q

what is an isotonic solution

A

it is when the solute concentration is the same on the inside of the cell, therefore no net water movement occurs across the membrane

19
Q

what is a hypertonic solution

A

it is when the solute concentration is greater on the outside than the inside of the cell; causing water to rush out and shrink

20
Q

what is hypotonic solution

A

when the solution solute concentration is less than the inside of the cell; causing water to rush in and gain size

21
Q

what is facilitated diffusion?

A

they are passive carrier mechanisms that move molecules from higher to lower concentrations

22
Q

What is active transport?

A

they are energy dependent carrier mechanisms that move charged or polar molecules against their concentration gradient

23
Q

what are channel proteins

A
24
Q

What are membrane carbohydrates

A

they are either glycolipids or glycoproteins and face the extracellular side of the membrane

they are important for cell-cell recognition and communication

25
Q

Most lipid and some proteins move:

A

laterally

26
Q

what are the 3 conditions that detemne the direction of flow in a membrane

A

relative concentration on either side, voltage differences, and gated channels that may be opened or closed

27
Q

What drives the diffusion of K + through its channel (not the pump)

A

there is a higher concentration on the inside of the cell which drives the K+ out. However, the excessive positive charge on the outside of the cell impedes the diffusion of K+ out of the cell

28
Q

what do peripheral proteins do

A

cell-cell recognition, acting as enzymes, transportation

29
Q

what is a membrane pore

A

b-sheet barrel, allows water and small polar molecules to pass throguh

30
Q

what are the membrane components that move substances by facilitated diffusion

A

channel proteins, carrier proteins, porin (aquaporin)

31
Q

what is a co-transporter?

A

is a form of active transport because it is using the energy from one concentration gradient to transport another molecule across the membrane against its concentration gradient

32
Q

What are three specific protein types that transport sodium and what type of transport are they?

A

Na+ Channel: Facilitated diffusion (passive)

Na+/K+ Pump: Primary Active Transport

Na+/ glucose cotransporter: Seconary Active Transport

33
Q

Is ATP required for movement of glucose in a glucose transporter

A

no

34
Q

Is ATP required for the movement of glucose in a Na+/Glucose Transporter

A

no, its energy is supplied by the electrochemical gradient

35
Q

true or false: phospholipids and integral membrane proteins can move laterally along the plane of the plasma membrane

A

true

36
Q

true or false: in simple diffusion, the concentration of one substance affects the diffusion of another

A

false

37
Q

true or false: alpha helices and beta-sheets describe the tertiary structure of proteins

A

false, it describes the secondary

38
Q

True or false: DNA is found in the nucleus, mitochondria,and chloroplasts of eukaryotic cells

A

True

39
Q

what is the role of the ecm in animals

A

support, adhesion, movement, regulation