[2] class3 Zaidi-transport Thru Membranes Flashcards Preview

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Flashcards in [2] class3 Zaidi-transport Thru Membranes Deck (77)
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31

Positive free energy =

Active transport

32

- free energy =

Spontaneous

33

Movement of molecules against a gradient

Energy-dependent movement

34

2 diff. Types of proteins involved in energy-dependent movement:

P type ATPases

ATP binding cassette transporters

35

Ex of P type ATPases

Na+K+ ATPase
PM Ca++ ATPase [PMCA]
Muscle Ca++ ATPase SERCA
H+ K+ ATPase

36

Ex of ATP binding cassette transporter:

Multi-drug resistance protein

37

Uses energy from ATP hydrolysis to drive transport against gradient

ATP breaks into ADP and phosphate
Transporter forms covalent bond w/ phosphate to form EP intermediate

P type ATPases

38

Makes neurons and muscle cells electrically excitable, controls cell volume, drives the active transport of sugars and amino acids

25-40% of brain ATP used by

3Na+: 2K+ / mole ATP

Sodium pump

39

Ex of Na pump

Plant steroids- digitoxigenin and ouabain

40

called cardiotonic steroids d/t strong effect on heart

digitoxigenin and ouabain

41

Mixture of cardiotonic steroids

Digitalis

42

Cardiac glycosides that inhibit Na+K+ ATPase activity

ouabain and digitoxigenin

43

How does Digitoxigenin and ouabain work:

-Increase Na+ levels in cell: this reduces activity of antiporter Na+Ca++ exchanger
-This increase Ca++ ICF
-This Ca+ increases contractile force of cardiac muscle

44

Ex of Ca++ pumps:

Plasma mebrane Ca++ ATPase- PMCA

Sarco-endoplasmic reticulum Ca++ ATPase- SERCA

45

A protein w/ 10 transmembrane
140kDa
Transports Ca++ from cytosol to extracellular
Maintains 10,000-fold gradient across PM
Uses ATP to pump Ca+ uphill

PMCA

46

Stimulated by the Ca+ binding protein calmodulin (CaM)

PMCA

47

Zaidi research

Structure of PMCA

48

Active site of CaM

ATP binding site

49

PMCA ex:

[CaM] calmodulin

50

Ca++ transport channel open when active or inactive?

Active

51

10 transmembrane domains
110 kDa
Transports Ca+ from cytosol to ER
80% of SR membrane protein
Uses ATP
Plays role in relaxation of contracted muscle

SERCA

52

Key characteristic of Ca+ pumps SERCA and PMCA

Conformational change

53

Human genome has 150 genes
Have common architecture
Multi-drug resistance protein/ P glycoprotein
Pump wide range of small molecules out of cells
Uses ATP as energy source

ABC transporters

54

ATP binding domain is typically

In cytosol

55

Does ABC transporters have conformational change?

Yes

56

What happens to ATP affinity when substrate binds?

Increases

57

Active transport mediators not directly driven by ATP
Thermodynamically unfavorable flow of one species of ion against gradient coupled to favorable flow of another species down gradient

Secondary transporters

58

Ions move in opposite direction

Antiporters

59

Ions move in same direction

Symporters

60

Ions can move in both directions, depending upon the [ ]

Uniporter