Ch 3: Cell Biology- Plasma Membrane/ Transport Mechanisms Flashcards

1
Q

Name 3 functions of the plasma membrane

A

• Separates the intracellular fluid (IF) from the extracellular
• Also known as the cell membrane
• Also encloses and supports cell contents
• Attaches cells to extracellular environment or to other cells
• Aids in communication
• Determines what moves into and out of cells

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

Define the words fluid and mosaic of fluid mosaic model of the plasma membrane

A

• Fluid = dynamic and constantly changing
• Mosaic = made of many tiny parts all working together
Composed of:
• Lipids
• Mostly phospholipids but also cholesterol and glycolipids
• Proteins
• Carbohydrates (part of glycocalyx)

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

What are the two components of membrane lipids?

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

________ interspersed among phospholipids. The amount determines the fluid nature of the membrane

A

Cholesterol

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

__________: bilayer. Polar heads facing water in exterior of the cell (hydrophilic); nonpolar tails faci interior of the membrane (hydrophobic).

A

Phospholipids

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

Fluid nature provides/ allows these 3 things

A

• Distribution of molecules within the membrane.

Phospholipids automatically reassembled if membrane is damaged.

Membranes can fuse with each other.

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

What are the two components of membrane proteins?

A

•Intergral membrane proteins
•Peripheral membrane proteins

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

Which type of membrane protein can form channels through the membrane?

A

Integral

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

________membrane proteins are attached to ________ proteins at either the inner surfaces of the lipid bilayer.

A

Peripheral; integral

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

Name the 3D shape or chemical characteristics that affect membrane protein functions

A

Markers, attachment sites, channels, receptors, enzymes, or carriers.

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

Glycoproteins or glycolipids are examples of

A

Marker molecules

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

What is the function of marker molecules?

A

Allow cells to identity one another or other molecules.
• Immunity.
• Recognition of oocyte by sperm cell.
• Intercellular communication.
• Glycocalyx - “sugar covering”

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

_______attach cells to other cells while _______ attach to extra cellular molecule

A

Cadherin; Integrins (integral proteins)

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

What are the 3 types of cell junctions and their general property

A

•Tight junctions - impermeable junctions
•Desmosomes - anchoring junctions (think like zippers)
•Gap junctions - cell connections with hollow cylinders
—-materials pass through cylinders from one cell to next

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

_________ binds cells together

A

Cell junctions

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

What cell junction anchors and works like a zipper?

A

Desmosomes

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

Cell junction with hollow cylinders

A

Gap junction

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

What protein includes channel proteins, carrier proteins and ATP-powered pumps?

A

Transport proteins

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

Hydrophilic region faces inward; charge determines molecules that can pass through is a characteristic of what?

A

Transport proteins

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

________ proteins- integral membrane proteins that form tiny channels through membrane

A

Channel

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

Leak Ion channels are always open and are responsible for the ________ of the plasma membrane ions at rest

A

Permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

_______(type of channel protein) can be open or closed by certain stimuli

A

Gated ion channel

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

Small molecules binding to proteins or glycoproteins is a characteristic of what type of channel protein?

A

Ligand-gated ion channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What must happen for a voltage-gated ion channel to open?

A

Charge change across the plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

T/F: Carrier proteins are also known as transport proteins.

A

False: transporters

26
Q

Intergral proteins moving ions, sugars or amino acids from one side of the membrane to the other is an example of ________ proteins

A

Carrier proteins

27
Q

Uniporters, symporters and antiporters are _______ of carrier proteins

A

Different Forms

28
Q

T/F: Uniporters move two ions/ molecules in the opposite directions at the same time

A

False: antiporters

29
Q

If antiporters move two ions/ molecules in the opposite directions at the same time, which carrier protein would do the opposite?

A

Symporters

30
Q

T/F: in ATP-powered pumps, rate of transport depends on the concentration of substrate and on concentration of ATP

A

True

31
Q

•Proteins or glycoproteins in membranes with an exposed receptor site on the cell’s outer surface.
•Can attach to specific chemical signal molecules and act as an intercellular communication system.

Are characteristics of _______ proteins

A

Receptor

32
Q

________: some act to catalyze reactions at outer/ inner surface of plasma membrane

A

Enzymes

33
Q

An example of enzymes would be

A

Surface cells of small intestine produce enzymes that digest dipeptides.

34
Q

The plasma membrane only allows certain substances to pass through it meaning it is

A

Selectively permeable

35
Q

Diffusion, osmosis and facilitated diffusion are examples of what?

A

Passive membrane transport

36
Q

Endocytosis and exocytosis are components of which type of transport

A

Vesicular transport

37
Q

What are the three types of transport through the plasma membrane?

A

Passive membrane transport.
• Diffusion.
• Osmosis.
• Facilitated diffusion.
Active membrane transport.
• Active transport.
• Secondary active transport.
Vesicular transport.
• Endocytosis.
• Exocytosis.

38
Q

Viscosity refers to

A

[in diffusion] The measure of a fluids resistance to flow

39
Q

The concentration difference between two points is known as

A

Concentration gradient [diffusion]

40
Q

Define Diffusion

A

Movement of solutes from an area of higher concentration to lower concentration in solution.

41
Q

T/F: water can move directly through plasma membrane (in between phospholipids) or through aquaporins

A

True

42
Q

Water diffused toward higher solute concentration (high solute, less water) across a membrane defines the process of

A

Osmosis

43
Q

T/F: osmosis= diffusion of water and is a form of passive transport

A

True

44
Q

In osmosis, distinguish between the terms isotonic, hypertonic and hypotonic

A

• Isotonic: cell neither shrinks nor swe
• Hypertonic: cell shrinks (creation).
• Hypotonic: cell swells (lysis).

45
Q

Lysis is the process of

A

Cell swelling

46
Q

Crenation is synonymous with hypertonic meaning the cell_____

A

Shrinks

47
Q

Osmosis: when solute concentration goes ____, water concentration goes_____

A

Up; down

48
Q

Protein carriers and channel proteins are required for which transport process to happen?

A

Facilitated diffusion

49
Q

• no ATP required.
• Move large, water soluble molecules or electrically charred molecules across the plasma membrane.
• Amino acids and glucose in, manufactured proteins out

Are characteristics of what process?

A

Facilitated diffusion

50
Q

What 4 factors affect the rate of diffusion?

A

•1. size of concentration gradient
•2. temperature of solution
•3. size of diffusing molecules
•4. viscosity of the solvent

51
Q

Sodium-potassium (Na +/ K +) pump that creates electrical potentials across membranes is an example of what?

A

Active transport

52
Q

T/F: Active transport does not require ATP

A

False

53
Q

Substances can be moved against their concentration gradients (that is, from low to high), allowing the substance to accumulate on one side of the plasma membrane is an example of

A

Active transport

54
Q

Define secondary active transport

A

Use of potential energy in concentration gradient of one substance (established by primary active transport) to help move another substance

55
Q

Movement of substances by formation or release of a vesicle.
Requires ATP.
Describes what type of transport

A

Vesicular transport

56
Q

_______(Cell eating): solid particle is ingested and large vesicle formed

A

Phagocytosis

57
Q

________(cell drinking): dissolves molecules ingested and small vesicles formed

A

Pinocytosis

58
Q

T/F: vesicular transport is receptor mediated meaning specific transport of materials to bind cells surface

A

True

59
Q

In DNA, what are the complementary base pairs and how many hydrogen bonds link them?

A

• C - G (3 hydrogen bonds link them)
• T - A (2 hydrogen bonds link them)

60
Q

_______= phosphate, sugar, nitrogen- containing base (A,G,C,T)

A

Nucleotide

61
Q

What do complementary base pairs (A,G,C,T) stand for?

A

nitrogen bases- (Adenine, Guanine, Thymine, and Cytosine)

62
Q

To synthesize proteins, we must do two steps, in order:

A

• 1.) Transcription
-DNA information coded in mRNA occurs in nucleus

• 2.) Translation
- mRNA decoded to assemble polypeptides Occurs in cytoplasm using ribosomes