Brainscape's Knowledge GenomeTM

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


See full index

BIOL 213 > Chapter 6 > Flashcards

Chapter 6 Flashcards

1
Q

Fluid mosaic model

A

The general structure of membranes is known as the fluid mosaic model

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

Cholesterol

A

-is a flat hydrophobic molecule
-Cholesterol in eukaryotic cell membranes prevents “close packing” of phospholipids
-at colder temperatures membrane still maintains fluid-like motion
-conversely, at high temperatures the hydrophobic cholesterol helps hold membrane together
-temperature adaptation in some animals involves adjusting the amount of cholesterol in their membranes

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

Fluidity depends on

A

-temperature, lipid composition (saturated vs unsaturated), ad cholesterol percentage

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

Peripheral membrane proteins

A

Lack exposed hydrophobic groups and do not penetrate the bilayer. They may be anchored to lipid groups however

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

Integral membrane protiens

A

have hydrophobic and hydrophilic regions or domains. Some extend across the lipid bilayer (transmembrane); others are partially embedded

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

Transmembrane proteins

A

extend all the way through the phospholipid bilayer

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

domain

A

different parts of the protein that have different functions

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

anchored membrane proteins

A

membrane proteins that have fatty acids or other lipid groups covalently attached

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

Lipid-rafts

A

While some membrane proteins can move freely within the bilayer, others are anchored to a specific region
-Free diffusion is limited by the cytoskeleton and protein-protein interactions

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

Freeze-fracturing

A

a technique that reveals proteins that are embedded in the phospholipid bilayers of cellular membranes. Electron microscopy is then used to examine the structure

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

fluorescent microscopy

A

can be used to visualize “tagged” membrane proteins and lipids

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

Patch-Clamp

A

experimentation creates membrane “plugs”

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

Functions of membrane proteins

A

-Process information (signals and signaling receptors)
-Organize chemical reactions
-Transform energy
-Cell recognition and adhesion
-Transport into and out of the cell

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

Information processing

A

Binding of a specific ligand can initiate, stop, or modify cell functions.

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

Organizing chemical reactions

A

-Many cellular processes involve a series of enzyme-catalyzed reactions- all the molecules must come together for these to occur. Forms an “assembly line” of enzymes

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

Some transform energy…

A

Inner mitochondrial membranes-energy from fuel molecules is transformed to ATP
-Thylakoid membranes of chloroplasts transform light energy to chemical bonds

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

Cell recognition and adhesion

A

-Membranes also have carbohydrates on the outer surface that serve as recognition sites for other cells and molecules
-Glycolipids- carbohydrate+lipid
-Glycoproteins-carbohydrate+protein

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

Homotypic

A

The same molecule sticks out from both cells and forms a bond

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

Heterotypic

A

the cells have different protiens

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

Cell junctions

A

specialized structures that hold cells together

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

Tight junctions

A

help ensure directional movement of materials
-a quilted seal, air and water tight

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

Desmosomes

A

link adjacent cells tightly but permit materials to move around them in the intercellular space, similar to “spot welds”

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

Gap junctions

A

let adjacent cells communicate

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

apical membrane

A

faces the lumen or “outside” the body

25
Q

Basolateral membrane

A

base and lateral membranes. Those membranes that face other cells or the interstitial compartment, the “inside” of the body

26
Q

Extracellular Matrix (ECM)

A

-Composed of collagen, hyaline, proteoglycans and cellulose
-For example; bone, cartilage, and the cellulose of plant walls

27
Q

Integrin

A

transmembrane protein that binds to the matrix outside epithelial cells and to actin filaments inside the cells
-binding can be noncovalent and reversible. This allows signaling between intracellular (inside) and intercellular (outside) environments

28
Q

Selective permeability

A

some substances can pass through but not others

29
Q

Passive transport

A

No outside energy required (diffusion)

30
Q

Active transport

A

energy required

31
Q

Diffusioin

A

The process of random movement from an area of high concentration to an area of low concentration until equilibrium is reached

32
Q

Equilibrium

A

particles continue to move but there is no net change in distribution

33
Q

Diffusion rate depends on…

A

-diameter of the molecules or ions
-Temperature of the solution
-concentration gradient

34
Q

Because of diffusion…

A

a concentration gradient is a form of potential energy

35
Q

Simple diffusion

A

small molecules pass through the lipid bilayer
-water and lipid-soluble molecules can diffuse across the membrane
-electrically charged and polar molecules can not pass through easily

36
Q

Osmosis

A

-The diffusion of water
-Water diffuses slowly, is the most abundant molecules in a living cell, universal solvent
-depends on the number of solute particles present not the type of particles

37
Q

Water follows salt…

A

Water will diffuse from the region of higher water
concentration (lower solute concentration) to
the region of lower water concentration (higher
solute concentration)

38
Q

Isotonic

A

Equal solute concentration (equal water concentration)

39
Q

Hypertonic

A

higher solute concentration

40
Q

Hypotonic

A

lower solute concentration

41
Q

osmotic lysis

A

Animal cells may burst when placed in a hypotonic solution

42
Q

Turgor pressure

A

Plant cells with rigid cell walls build up internal pressure that keeps more water from entering

43
Q

Facilitated diffusion

A

-a form of passive transport, no cellular energy required but cellular protein(s) and a concentration gradient necessary

44
Q

Carrier proteins

A

membrane proteins that bind some substances and speed their diffusion through the bilayer

45
Q

Channel proteins

A

have a central pore lined with polar amino acids

46
Q

Aquaporins

A

Water can cross a membrane by “hitchhiking” with hydrated ions or moving through the special water channels (aquaporins)
-Function of these proteins was determined by injecting the aquaporin mRNA into an oocyte

47
Q

Ion channels

A

-Specific channel proteins with hydrophilic pores
-Most are gated-can be closed or open to ion passage
-Gate opens when protein is stimulated to change shape. Stimulus can be a molecule (ligand-gated) or electrical charge resulting from many ions (voltage-gated)

48
Q

Active transport

A

moves substances against a concentration and/or electrical gradient-requires energy
-Energy source is often ATP

49
Q

Three kinds of proteins in active transport

A

-Uniporters
-Symporters
-Antiporters

50
Q

Primary active transport

A

requires direct hydrolysis of ATP

51
Q

Secondary active transport

A

energy comes from an ion concentration gradient that is established by primary active transport
-aids in uptake of amino acids and sugars
-uses symporters and antiporters

52
Q

Membrane potential

A

-A charge imbalance across a membrane
-measured membrane potential of animal cells; -70mV
-Membrane potential is mainly related to the concentration imbalance of Na+ and K+

53
Q

Endocytosis

A

processes that bring molecules and cells into a eukaryotic cell
-plasma membrane folds in or invaginates around the material forming a vesicle

54
Q

Exocytosis

A

Material in vesicles is expelled from a cell

55
Q

Why endo/exocytosis

A

-Macromolecules are too large to cross the membrane
-Large amounts of fluid may need to be taken in or expelled
-membranes need to be regenerated

56
Q

phagocytosis

A

molecules or entire cells are engulfed
-A food vacuole or phagosome forms which fuses with a lysosome
-some protists feed in this way
-Some white blood cells engulf foreign substances such as bacteria and viruses

57
Q

Pinocytosis

A

A vesicle forms to bring small dissolved substances or fluids into a cell. Vesicles are much smaller than in phagocytosis
-Pinocytosis is constant in endothelial cells

58
Q

Receptor mediated endocytosis

A

-High specific
-depends on receptor proteins to bind specific substances
-Sites are called clathrin coated pits coated with the protein clathrin

59
Q

Why exocytosis

A

-material in vesicles is expelled from a cell
-Indigestible materials are expelled
-other materials leave cells such as digestive enzymes and neurotransmitters
-Plasma membrane components (lipids, proteins, etc) replaced

BIOL 213 (13 decks)

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