Brainscape's Knowledge GenomeTM

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


See full index

BIOL 107 > Introduction to membranes > Flashcards

Introduction to membranes Flashcards

1
Q

Plasma membrane

A

a boundary that
separates living cell from its surroundings

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

Plasma membrane exhibits selective permeability

A

allowing some
substances to cross it more easily than others

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

Introduction to Membranes- The spherical phospholipid bilayer is

A

the basic structure of
all biological membranes

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

liposome

A

spherical lipid bilayer
(cross-section is shown

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

Membranes are made of

A

proteins and lipids

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

most abundant lipid in the
plasma membrane

A

Phospholipids

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

(Singer and Nicholson, 1972)

A

“Fluid Mosaic Model”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • membrane is a fluid structure with a _______ appearance because it contains different types of ______ embedded in it.

different membranes can contain ______

A

”mosaic”, proteins,
different proteins

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

Proteins of the bilayer can be classified into two main groups:

A

1) integral
2) peripheral

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

(or intrinsic) membrane proteins
- embedded in the bilayer due to at least one portion of the protein
being hydrophobic

A

integral - Proteins of the bilayer

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

(or extrinsic) membrane proteins
- attached loosely to the surface of the membrane
(usually by interacting with an integral protein)

A

peripheral - Proteins of the bilayer

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

Please label

A
  1. Integral membrane proteins
  2. Peripheral membrane proteins
  3. Hydrophilic
  4. Hydrophobic
  5. Hydrophilic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In addition to phospholipids and proteins,
membranes can contain other components:

A

Glycoproteins, Glycolipids, Cholesterol

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

membrane proteins that have a
sugar attached
- important function in cell recognition

A

Glycoproteins

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

membrane lipids that have a
sugar attached

A

Glycolipids

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

inserts between phospholipid
molecules
- influences membrane permeability and
fluidity

A

Cholesterol

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

Variability in the type and number of these different
components gives different membranes

A

specific properties

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

Please label

A
  1. Glycoproteins
  2. Glycolipids
  3. Cholesterol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Biological membranes are fluid at

A

physiological temperature

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

Phospholipids and some proteins in the membrane can

A

move

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

Please label

A
  1. Phospholipids drift laterally
  2. Phospholipids rarely
    flip-flop transversely
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Biological membranes- High temperature will cause an increase in _____. gaps in the membrane will form if ________

A

fluidity, temperature goes high enough

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

membrane can become more permeable at ___________

A

high temperatures

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

All membranes will turn solid if temperature goes _______ ,called _______.

A

low enough, phase transition

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

Temperature at which phase transition occurs depends on the composition
of the membrane:

A
  1. Length of fatty acids in the phospholipid
  2. “Shape” of fatty acids in the phospholipid
    (influenced by double bonds)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Phase transition composition:

A
  1. Length of fatty acids in the phospholipid
    - Short chains have less stable interactions with each other
    - therefore, a lower temp required to keep them in a solid structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Phase transition composition:

A
  1. “Shape” of fatty acids in the phospholipid
    (influenced by double bonds)
    - Double bonds cause structural kinks, decreasing ability of chains to
    pack together (as discussed previously)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  1. Cholesterol also has an effect on
A

membrane fluidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Cholesterol acts as a _______ maintain membrane fluidity at a
greater range of _______.

A

“fluidity buffer”, temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Cholesterol interferes with the __________

A

lateral movement of phospholipids (reducing membrane fluidity at moderate temperatures)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Cholesterol prevents close packing of _______________________.

A

phospholipids at lower temperatures
(solidification occurs at a lower temperature)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

-Cholesterol is very important (and prevalent) in _________ (e.g. As much as ___ of the lipid in some nerve cells is cholesterol)
- - Cholesterol is not in _________.

A
  • animal cell membranes, 25%
  • prokaryote membranes, and plant cells have very little, if any.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are the proteins doing in the membrane?
Six major functions for membrane proteins:

A
  1. Transport of molecules
    into or out of cell
  2. Enzymatic reactions
    near the membrane
  3. Signaling via receptors
  4. Cell-cell recognition
  5. Intercellular attachment
  6. Attachment of the
    cell to extracellular
    matrix proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the proteins doing in the membrane?

A

Transport of molecules
into or out of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are the proteins doing in the membrane?

A

Enzymatic reactions
near the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the proteins doing in the membrane?

A

Signaling via receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the proteins doing in the membrane?

A

Cell-cell recognition ( e.g., blood groups A and B
result from different
glycoproteins on blood cells )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are the proteins doing in the membrane?

A

Intercellular attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are the proteins doing in the membrane?

A

Attachment of the
cell to extracellular
matrix proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Transport- How is the movement of various molecules across the membrane
achieved (or prevented)?

A

3 ways: Diffusion, Facilitated diffusion, Active transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q
A

-Lipid bilayer is permeable to some substances, impermeable to others

-Main barrier is the Hydrophobic core of the bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

1) Diffusion (or Passive Transport)
- occurs best with_________.
- these are ______ in the bilayer and
can pass through quite quickly
- when such a molecule is more _______ on one side of a
membrane, __________________.
- i.e., molecules _______________.

A

-small hydrophobic molecules such as O2
- soluble
- concentrated
-diffusion occurs until equilibrium is reached
- “diffuse down their *
concentration gradient”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Diffusion (or Passive Transport)

A
  1. Net diffusion
  2. Net diffusion
  3. Equillibrium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Only certain molecules can pass through the membrane via ______.

A

diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Only certain molecules can pass through the membrane via diffusion

A
  1. hydrophobic
    molecules, very good
  2. small
    uncharged
    polar, fair to poor
  3. large
    uncharged
    polar, rarely, if ever,
    pass through

4.charged
(large or small), almost never
pass through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Osmosis: a special case of _______
- diffusion of _______ across a _____________.

A

-passive transport
- water, selectively permeable membrane
-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Please label-Water (solvent) follows the solute:

A
  1. Water molecules can
    pass through membrane,
    but sugar cannot
  2. Fewer
    solute
    molecules
  3. Water clusters
    around the solute
    4.More
    solute
    molecules
  4. Osmosis- Water moves from high to low free water concentration
    (or low to high solute concentration)
48
Q

the relative concentration of a solute in two solutions separated by a
membrane that it cannot cross. If water can pass freely, the solute [conc.] difference
determines whether cells gain or lose water.

A

Tonicity

49
Q

Pls label

A
  1. Hypotonic, Lysed, Turgid (normal)
  2. Isotonic, Normal, Flaccid
  3. Hypertonic, Shriveled, Plasmolyzed cell shrinks, membrane pulls away
    from the cell wall = plasmolysis
50
Q

-Facilitated Diffusion: _____________.
- specific molecules that are ______.

A

-Passive Transport Aided by Proteins
- impeded by the membrane but diffuse
passively with the aid of a transport protein

51
Q

Two types of transport proteins are used for facilitated diffusion:

A

1) Channel proteins:
2) Carrier proteins:

52
Q

1) Channel proteins:
- A specific channel protein usually
allows only one type of _______.
- __________ determine if the
channel is open or closed.

A

-molecule or
ion to pass through.
- Cellular conditions

53
Q

________are a type of channel protein that facilitates _______. Water
moves across the membrane ________ if it goes through a channel.

A
  • Aquaporins
  • osmosis
  • faster
54
Q

________ allow specific ions through. (i.e., usually a different protein for
each ion)

A

Ion channels

55
Q

Channel proteins can be ______, turned on or
off by __________.

A

-“gated”
-different stimuli (voltage, ligands, etc.)

56
Q

Please label

A
  1. Down the
    [conc.]
    gradient
  2. a “pore” or
    channel
57
Q

2) Carrier proteins:
- These undergo a subtle _________ to translocate a _________.

A
  • change in shape
    (conformational change)
  • solute
    across the membrane.
58
Q

2) Carrier proteins:
- specific for the _________
- solute also________
- protein has same_______

A

-molecule being transported
- diffuses down its concentration gradient
- affinity for target molecule on both sides of
the membrane (i.e., movement can occur in either direction, but
always down the concentration gradient)

59
Q

3) Active Transport: used to move a substance _________.
-Why do cells do this?
- To concentrate_______
-To expel_____
- To establish_____

A

-against the
concentration gradient
- nutrients in the cell
- waste
- voltage/chemical gradients

60
Q

3) Active Transport:
-Proteins involved in this type of transport are all_______.
- _________ for each substance.

A
  • Carrier proteins
  • specific carrier protein
61
Q

3) Active Transport:
- Compared to its surroundings, an animal cell maintains a high internal _________.
- to do this, a cell uses a ________ and __________.

A
  • conc. of K+ and low Na+
  • “sodium-potassium pump”
  • energy stored in a molecule called ATP
62
Q
  • ATP = ________.
  • breaks down to _______
  • ADP = _______.
  • Pi = ______.
A
  • adenosine triphosphate
  • ADP + Pi and
    releases energy
  • adenosine diphosphate
  • phosphate
63
Q

Active transport allows cells to establish and maintain________.

A

concentration
gradients that might not occur naturally

64
Q

Please label

A
  1. The sodiumpotassium pump
    is one type of active
    transport system
65
Q

Please label the sodium potassium pump

A
66
Q

-sodium potassium pump
- Starts with _____________.
- Ends with _______________.

A
  • 3 Na+ (in) + 2 K+ Start (out) + ATP
  • 3 Na+ (out) + 2 K+ (in) + ADP + Pi
67
Q

3 Na+ go out, and 2 K+ come in ____________.

A
  • creating an imbalance in charge
    across the membrane (inside is more negative than outside)
68
Q

Please label

A
  1. Fewer “+” ions
  2. More “+” ions
    3.Voltage
  3. Voltage = difference
    in electric potential
  4. membrane
69
Q

All cells exhibit a ______ across their plasma membranes

A

voltage

70
Q

The _____ distribution of ________ across
the plasma membrane is
called the__________.

-The inner side of the membrane is _______.

A
  • unequal
  • anions and/or cations
  • membrane
    potential.
    -negative
71
Q

e.g., cells typically have a membrane potential of _______

A

-50 to -200 mV

72
Q

For ions, two forces drive their diffusion across the membrane
- a difference in their ________
– a difference in _________

  • So ________ flow down their ________________.
A
  • concentration (chemical force)
  • total charge (electrical force)
    = electrochemical gradient

-charged molecules
-electrochemical gradient
(Not simply their conc. gradient)

73
Q

The pumps that are responsible for creating__________ are called _________.

A

-electrochemical gradients
- electrogenic pumps.

74
Q

-An important electrogenic pump in animal cells is the _______________.
- Plants, fungi and bacteria mainly use a _______.

A
  • sodium-potassium pump
  • proton pump
75
Q

Please label.

A

1.proton pump

76
Q

Another type of Active Transport: Cotransport (or coupled transport)
-_________ couple the _______ transport of a solute to the _______ transport of a _________

A
  • Cotransporters
  • “downhill”
    -“uphill”
  • second substance against its own concentration gradient
77
Q

please label the sucrose transport in a plant cell.

A
  1. proton pump
  2. sucrose-H+ cotransporter
  3. active transport has enough energy to pull the sucrose in
  4. using the protons falling through the electrochemical force that also moves the sucrose in
78
Q

Bulk Transport
- Big molecules (e.g. polysaccharides) must be transported using a _______.
- involves _______.
- Membrane is ______ and can bend into different shapes including _________

A
  • transport mechanism
  • formation of vesicles
  • flexible
  • pinching off into vesicles. This requires energy.
79
Q

– exporting substances out of the cell

A

Exocytosis (secretion)

80
Q

Please label

A
81
Q

Endocytosis (importing substances)
3 main types:

A

1.) Phagocytosis
(cell “eating”)

  1. 2) Pinocytosis
    (cell “drinking”)
  2. receptor-mediated
82
Q

3) receptor-mediated
Recall that receptors are a specific type of________ Receptors receive __________ This involves a _________ Each receptor only binds ___________.

A
  • membrane protein.
  • chemical signals from outside the cell
  • physical interaction between ligand and receptor
  • to ligands of a particular structure (often, only one type of molecule will bind
    to a specific receptor).
83
Q

Please label

A
84
Q

Please label

A
85
Q

Receptor-mediated endocytosis
- Receptors bind to a__________ that the cell needs to________. ___________ binds to these receptors on the ________, gathering them and the membrane into a ____ shape that eventually forms a ________. the particle (ligand) is used/consumed, and the receptors _________ back to the membrane

A

-Substance(ligand)
-Uptake
-Clatharin
-Inside of the cell
-pit
-Vesicle
-makes their way back

86
Q

An example of receptor-mediated endocytosis:__________
- _________ transport fats to cells via the__________.

A
  • Fat delivery to cells
    -Lipoproteins
    -Bloodstream
87
Q

Label the lipoprotein

A
88
Q

specific proteins (called apolipoproteins) associate with the_________
- the proteins differ, depending on the_______.

  • receptors on the recipient cell recognize the _______.
A

-fat droplet
- lipoprotein
- apoprotein and promote endocytosis (involving coated-pits) and uptake of the fats.

89
Q

Too much cholesterol can build up in __________.

A

arteries and form plaques

90
Q

LDL (low density lipoprotein) low in _____,but highest in _______.
-LDL cholesterol is often referred to as

A

-density
-cholesterol.
- “bad” cholesterol

91
Q

HDL (high density lipoprotein) highest in density due to high ________.These particles can remove excess ________.
- HDL cholesterol is often referred to as ______.

A

-protein/lipid ratio
cholesterol from
blood vessels (and transport to it the liver for removal).
- Good cholesterol

92
Q

-Clathrin is a _____ protein that
helps facilitate ______.

A

-coat
- vesicle formation

93
Q

High levels of LDL vs. HDL can indicate higher risk of

A

cardiovascular disease

94
Q

Transporter Definitions
- systems that perform active transport using ATP directly
mediate

A

-“primary active transport” (e.g., the Na+/K+ pump)

95
Q

Transporter Definitions
- systems __________ that use carrier proteins
driven by ion gradients are said to mediate _______.

A
  • (such as sucrose-H+, above)
  • “secondary active
    transport”
96
Q

the carrier or transport proteins used in facilitated diffusion
or active transport are sometimes described as:

A

a) uniporters (those that
transport only one type of
molecule)

97
Q

the carrier or transport proteins used in facilitated diffusion
or active transport are sometimes described as:

A

b) symporters (transport two
different molecules in the same
direction)

98
Q

the carrier or transport proteins used in facilitated diffusion
or active transport are sometimes described as:

A

c) antiporters (transport two
different molecules in the
opposite direction)

99
Q

Review of Membranes and Transport:
Cellular membranes are fluid mosaics of_________

A

lipids and
proteins

100
Q

Review of Membranes and Transport:
Membrane structure results in________

A

selective permeability

101
Q

Review of Membranes and Transport:
Passive transport is diffusion of a substance across a
membrane with __________

A

no energy investment

102
Q

Review of Membranes and Transport:
Active transport uses _________

A

energy to move solutes against
gradients

103
Q

Review of Membranes and Transport:
Bulk transport across plasma membranes uses_________

A

exocytosis and endocytosis

104
Q

Bacterial Cell Walls
-provide _____,________ from bursting in_______ environments.
-Bacterial cells, like_______, contain a much higher ________, compared with their ________.

A

-shape
-protection
-hypertonic
-animal cells
-concentration
of many molecules
-environment

105
Q

Bacterial Cell Walls
-Almost all bacterial cell walls contain __________
-Most bacteria belong to one of two major classes, as
defined by their________
- The two types are distinguished by the_________ A procedure developed by _________.

A
  • peptidoglycan.
  • cell wall structure
  • Gram stain
  • Hans Gram (late 1800s)
106
Q

Pls label

A

1.Gram positive
2.gram negative

107
Q

Please label

A
108
Q

Please label

A
109
Q

Peptidoglycan
- a thin sheet composed of:
1. Chains of a repeating __________composed of two ________
i)_____________
ii)____________

2._________
-attached to ________
- bonds formed between________

A

-disaccharide
-monosaccharides
- N-acetylglucosamine (NAG)
- N-acetylmuramic acid (NAM)

-Small peptides
-NAM subunits of the chains
-peptides on adjacent chains
cross-link the chains and gives strength to the structure

110
Q

Peptidoglycan is a polymer of _____ and _______

A

-N-acetylglucosamine (NAG)
-N-acetylmuramic acid (NAM)

111
Q

Please label

A
112
Q

Please label

A
113
Q

For both Gram-positive and Gram-negative bacteria,
peptidoglycan is not _______

A

-a barrier to solutes.

114
Q

Peptidoglycan is synthesized only in

A

growing cells.

115
Q
A

BIOL 107 (14 decks)

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