Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

My bio: Core principles > Cell membranes > Flashcards

Cell membranes Flashcards

1
Q

Roles of plasma membranes

A

Separates cell contents from outside environment
Regulates transport on nutrients in and out: selectively permeable
Recognition by antigens
Receptor sites

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

Function of internal membranes

A

Separate cell components from cytoplasm
Hold components of metabolic pathways in place e.g ribosomes on RER
Location of chemical reactions e.g respiration on cristae of mitochondria

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

Who proposed fluid mosaic model of plasma membranes

A

Singer and Nicholson, 1972

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

Why ‘fluid’ in fluid mosaic?

A

Phospholipid molecules move around each other

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

why ‘mosaic’ in fluid mosaic?

A

Proteins embedded between phospholipids vary in shape, size and pattern

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

What type of molecules does the phospholipid bolster allow to enter?

A

lipid- soluble molecules

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

What is phospholipid bilayer a barrier to?

A

Large polar molecules
Water soluble molecules
Ions

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

What is phospholipid bilayer freely permeable to?

A

Lipid soluble substances
Non polar molecules
Very small polar molecules e.g H2O, CO2, O2

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

What can vary permeability of membranes

A

Increase in temp, increase in Ek, vibrate faster. Membrane becomes more fluid so more permeable

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

Components of plasma membrane

A

Phospholipid bilayer
Proteins
Cholesterol
Glyco proteins/lipids

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

Distance across phospholipid bilayer

A

7nm

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

Proteins found in membrane?

A

Intrinsic and extrinsic

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

Intrinsic proteins?

A

Proteins that extend across bilayer

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

Function and types of intrinsic proteins

A

Provide structural support
Some are carrier proteins, some are channel proteins

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

Carrier proteins?

A

Move large polar molecules or water soluble substances e.g sugars and amino acids across bilayer by changing shape when the particular molecule attaches to the binding site

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

Channel proteins structure?

A

3d globular protein with hydrophilic R groups facing inwards to line the pore

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

Channel protein function?

A

Water filled, allowing water soluble molecules to pass through. Specific, bc of specific protein shape so each protein only allows specific molecules or ions through. Channel can be gated to ppen/close in specific circumstances

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

Extrinsic proteins

A

Either side of bilayer

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

cholesterol location?

A

Fits between fatty acids

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

Cholesterol function

A

Provide stability and rigidity bc they are between fatty acids

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

What is the glycocalyx?

A

Carbohydrate layer around membrane: glycoproteins and lipoproteins

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

Function of glycocalyx

A

Cell to cell communication, recognition and hormone reception

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

Concentration gradient?

A

Difference in concentration of a substance between two regions

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

Diffusion?

A

Passive movement of molecules from a region oc hight concentration to low concentration down a concentration gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
For molecules to move freely they must have?
Ek
26
7 factors affecting diffusion across bilayer?
Temp, SA, conc gradient, thickness of membrane, diffusion distance, size of molecule, lipid solubility
27
Equation for rate of diffusion
(surface area x difference in conc)÷ length of diffusion path
28
Facilitated diffusion
Diffusion through the bilayer requiring carrier or channel proteins. Req no ATP, req conc gradient
29
Relationship between rate of diffusion and conc gradient?
Directly proportional
30
Active transport?
Movement of ions and other molecules across bilayer, can be from low to high conc against conc gradient req ATP. Occurs via carrier proteins
31
Example of active transport
sodium-potassium pump
32
what movement of particles do both diffusion and facilitated diffusion involve
Random movement
33
Process of active transport?
Molecule or ion combines with a specific carrier protein on outside of membrane ATP transfers a phosphate group to carrier protein on inside of membrane Carrier protein changes shape and transports the substance The molecule or ion is released into the cytoplasm The phosphate ion is released from the carrier protein back to the cytoplasm and combines with the ADP to reform ATP The carrier protein returns to it's original shape
34
The effect of respiratory inhibitors on active transport?
e.g Cyanide, active transport is reduced or stopped
35
Examples of processes involving active transport
Protein synthesis, muscle contraction, absorption of mineral salts by plant roots, absorption of glucose in kidneys
36
Co-transport?
Type of facilitated diffusion where 2 substances are transported in the same direction at the same time
37
Example of co-transport?
sodium-glucose co-transport into the blood in the plenum and kidney nephron
38
Endocytosis?
Bulk movement of substances into the cell requires ATP
39
Phagocytosis?
Process by which cell obtains solid materials too large to enter by diffusion or active transport.
40
Pinocytosis
Entry of liquids into the cell by the same mechanism as phagocytosis but the vesicles produced are smaller
41
Exocytosis?
Bulk removal of substances from the cell after being transported through the cytoplasm in a vesicle
42
Description of the process of phagocytosis
Membrane engulfs material Membrane fuses back together Vesicles is formed
43
Invaginate meaning?
Like caving inwards: cell membrane of phagocyte invaginates to take in pathogens
44
Describe process of phagocytosis of pathogens
Antigens on pathogen bind to receptors on phagocyte Cell membrane off phagocyte invaginates producing a phagosome vesicle Lysosome merges membranes with phagosome to become a phagolysosome Pathogen is digested and contents of phagolysosome are excreted from the cell by exocytosis
45
Osmosis?
movement of H2O from area of high water potential to area of low water potential down a water potential gradient across a partially permeable membrane
46
water potential?
Tendency for water molecules to enter or leave a solution by osmosis.
47
What is the measure for water potential
Kilopascals KPa
48
What represents water potential
Greek letter psi (looks like a pitch fork)
49
What is the water potential of pure water
0KPa, adding solutes reduces it, making it negative
50
Highest possible water potential?
0KPa
51
Hypertonic solution?
Lower water potential than the cell cytoplasm so contains more solutes and water moves out of the cell
52
Isotonic solution
Same water potential as in the cell cytoplasm so zero net movement or water
53
Hypotonic solutions
Higher water potential than cell cytoplasm so contains fewer solutes. Net movement of water is into the cell
54
Process of cells bursting
cytolysis
55
Process of animal cells shrivelling
crenation
56
Equation describing relationship between forces in plant cell
water potential= solute potential+ pressure potential
57
solute potential?
concentration of dissolved solute in cell vacuole
58
Pressure potential?
Opposing force developed as outwards pressure on the cell wall builds due to entrance of water into the cell cytoplasm and vacuole
59
which is the negative and which is the positive component of water potential equation
solute potential is negative, pressure potential is positive
60
Incipient plasmolysis?
Cell membrane must begins to move away from the cell wall. Occured sin isotonic solutions
61
Plasmolysis
Cell membrane shrinks away from the cell wall. When complete the cell is said to be flaccid
62
functions of extrinsic proteins
provide structural support Cell to cell recognition Receptor sites for hormone attachment
63
In which conditions do water molecules move more freely
Water moves more freely in dilute compared to more concentrated
64
why dies increasing conc of ions increase the rate of uptake by active transport
Increases the chance that ion will collide with carrier protein
65
Why does endocytosis require ATP
To provide energy to move membranes to form vesicles to contain entering substances

My bio: Core principles (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions