Brainscape's Knowledge GenomeTM

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


See full index

Cell Biology Exam 2 > Membrane transport Part 1 > Flashcards

Membrane transport Part 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Rate of diffusion is affected by

A

hydrophobicity and size

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

Hydrophobic molecules and synthetic lipid bilayer

A

moves fast

ATP O2 CO2 N2 steroid hormones

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

small uncharged polar molecules and synthetic lipid bilayer

A

at slower rate

H2O urea glycerol NH3

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

Large uncharged polar molecules and synthetic lipid bilayer

A

v slow rate

glucose sucrose

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

ions and synthetic lipid bilayer

A

hydration schell - impermiable to membrane

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

two main classes of transport proteins

A

Transporters and Channels

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

difference between enzymes/substrate and transport cycle (transporter and solute)

A

solute is not altered/changed

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

Transporters

A

carriers, permeases

possess solute binding sites: Solute binds to binding site

Conformational change is transporter after solute binds

same still apply from enzime substrate - Vmax max rate of transport, rate when fully saturated - Km, binding affinity, solute and solute binding

open and close randomly but concentration gradient makes solute more likely to bind and cause change

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

Channels

A

interact with solutes more weakly
no energy requirement
no binding site
all channels alow solutes to cross the membrane passivly downhill
formation of pores do not exibit solute binding sites

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

which has fater rate of tansport, chanel or transporters

A

chanel because does not have to change conformations

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

Passive transport

A

Movement of solutes “down” their concentration gradient (High concentration to Low concentration)

If solute is charged, movement also dependent on electrical gradient (membrane potential).

Concentration + charge=“electrochemical gradient”

no energy requirement

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

Active transport

A

Movement of solutes “against” their concentration gradient. Always mediated by transporters

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

Primary Active transport

A

Free energy of ATP hydrolysis used to drive “uphill” movement of solutes.

direct energy reqirement - from ATP hydrolosis

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

Secondary Active transport

A

Ion gradient generated by ATPase elsewhere (indirect requirement of ATP).

Secondary active transport harnesses energy released from ion gradient by one molecule going down its electrochemical gradient to drive a different molecule against its gradient

indirect energy requirement - stored energy in gradent - used in second active transport

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

Gradients across the membrane (with and without charge_

A

without charge difference - move across gradient

with charge opposite - move faster

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

Uniports

A

unidirectional
one solute movement

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

Symports

A

simultaneous movement of more than one solute in one direction

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

Antiports

A

simultaneous movement of more than one solute in opposite directions

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

GLUT

A

glucose transporter - passive, facilitated - when concentration gradients change - moves opposite ways

Glc fits into GLUT binding site.

Glc binding drives conformational change.

Dissociation driven by low [Glc].

GLUT bounces back to original conformation.

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

Classes of ATP-driven pumps

A
  1. P type pumps
  2. ABC (ATP binding cassette) transporters
  3. V type pumps

all use ATP - bind to transporter (hydrolized-> energy)

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

P-type pumps

A

Formation, maintenance of

Na+, H+, and Ca2+ gradients.

Self-phosphorylate during cycle.

Mantain order in body, maintaion ion gradents, mediate cellular processes

22
Q

ABC (ATP-Binding Cassette) transporters

A

Transport variety of nutrients, toxins, ions.

most abundant
medical relevance - drug resistance - involve in removing drugs

23
Q

V-type pumps

A

Acifigy vaculoar compartments

use engery from ATP hydroslos - move H across - more acific enviorment (ex/ use in digestion)

24
Q

Ca2+ pump

in eukaryotic cells

A

(P-type ATPase)

Eurcharylotic cells - (invest a lot of energy to) maintain very low concentrations of Ca2+ in their cytosol and very high extracellular Ca2+

Steep gradient maintained (Ca2+pumped out by Ca2+ pump and Na+Ca2+ Exchanger) at plasma membrane

25
Q

When action potential depolarizes the muscle cell plasma membrane __

A

Ca2+ is released into cytosol from the sarcoplasmic reticulum through Ca2+ release channels, which stimulates muscle to contract

26
Q

Sarcoplasmic Reticulum

A

Specialized Endoplasmic reticulum in muscle cell cytoplasm, intracellular storage of Calcium ions

27
Q

Ca2+ pump in the Sarcoplasmic Reticulum

A

moves Ca2+ from cytosol back to sarcoplasmic reticulum, end of muscle contraction

28
Q

Structure of Ca2+ Pump

A
29
Q

Ca2+ cycle

A
  1. ATP bound Ca2+ (two) can bind
  2. binding causes conformational change, passage way is closed
  3. ATP is hydrolyzed (ATP to ADT and P) Phosphate transfer reaction
  4. ADP excanged for ATP - conformational change - passage is opened to lumen
  5. proton (two) is picked up (also with water) to stabalize empty binding site - passage is closed to lumen
  6. hydrolosis of phosphate, pack to orional conformation, so Ca2+ can be transpoted again (and again)
30
Q

Why are the maximum rates of transport by transporters and channels thought to be so different.

A

because transportors binding of solvent on specific site (with weak ineractions) - slower

31
Q

The permeability of a protein-free lipid bilayer to various molecules depends on their properties. Sort the following in order of low to high permeability from left to right.

A. O2
B. ATP
C. Na+
D. Glucose

A

B
C
D
A

32
Q

Na+K+ Pump, concentration of K+ ions and Na+ ions

A

Concentration of K+ ions higher inside cells than outside, reverse is true of Na+ ions

33
Q

Na+ gradient (in Na+K+ pump) drives

A

transport of most nutrients into animal cells (1/3 animal cells energy devoted to this pump)

34
Q

Na+K+ pump is ___

A

electrogenic- volated difference across membrane (membrane potental) - when charges do not balansse out.

also antiporter

35
Q

Na+K+ pump cycle

A
  1. Na binds to pump
  2. pump phosporilates itself (ATP to ADP and P)
  3. phosporlation triggers conformational change, Na is ejected
  4. K binds
  5. pump is dephosporlated
  6. pump returned to orional conformation, K is ejected
36
Q

ABC Transporter family

A

Largest family of Membrane Transport Proteins

37
Q

ABC transporter bacterial vs eukaryotic

A

bacterial - import process - to inside cell
eukaryotic - export - to out of cell

38
Q

ABC transporter steps

A

2 ATP added (each own domain), small soluble molecule binds
hydrolized (2ATP to 2ADP and phospate) - opens

39
Q

Clinical importance of ABC transporters in Eukaryotic cells

A

Multi-drug resistance (MDR) protein, also called P-glycoprotein: high levels in cancer cells, makes cells resistant to cytotoxic drugs (chemo).

Plasmodium falciparum (causes Malaria): transporter pumps out Chloroquine (drug resistance)

40
Q

V type Pump

A

Present in vacuolar compartments.
(Lysosomes, endosomes, Golgi.)

Uses deltaG of ATP hydrolysis to make H+ gradient.

41
Q

F type ATPases

A

Structurally related to V type pumps (exact opposite, protein gradient to make ATP)

Instead of using ATP hydrolysis to drive H+ transport, they use the H+ gradient across the membrane to drive the synthesis of ATP

is still considered primary active transport

42
Q

Uncouplers

A

collapse proton gradient by equalizing proton concentrations on both sides of the membrane

43
Q

Dinitrophenol (DNP)
Caused ___

A

Diet pill in 1920s

Caused increased oxygen consumption and an increased metabolic rate, but a decline in ATP production

Can be fatal, liver failure

lipid soluble picked up proton and diffuse to other side.

UNCOUPLER - collapse protein gradient

44
Q

why was DNP effective for weight loss

A

not generated from carbohydrate metabolism,
get from fat (energy)

45
Q

How did DNP cause hyperthremia

A

(rapid increase in body temp)

energy was released as heat (what not used)

46
Q

Symporter cooperative binding

A

because ion gradient, favorable for Na to bind, promoting glucose to bind (what drives glucose against gradient) - called cooperative binding

47
Q

Symporter occluded

A

not open to either side
either completely empty or full

48
Q

Symporter steps

A

secondary active transport

49
Q

___ facilitates the uptake of nutrients (in intestinal epithelial cells)

A

Asymmetric distribution of Transporters in plasma membrane

50
Q

Transcellular Transport in Intestinal Epithelial Cells

A

intestinal lumen (atypical domain) - Na driven glucose symport (Na in and glucose into cell)

extracellular fluid (basal domain) - facilitate diffusion (no energy requirement) - carrier protein mediating

Na out- keeps gradient going (Na+K+ pump)

51
Q

structural polarity in Transcellular Transport in Intestinal Epithelial Cells

A

two sides are different - distribution of transporters

Cell Biology Exam 2 (6 decks)

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