[2] class3 Zaidi-transport Thru Membranes

Question 1

Interactions involved in lipid bilayer:

Answer 1

Electrostatic and non covalent

Question 2

These are frequently glycosylated on the extracellular side of the lipid bilayer

Answer 2

Membrane lipids and proteins

Question 3

Integral membranes

Answer 3

All the way transmembrane through lipid bilayer

Question 4

Plasma membrane is semi

Answer 4

Semi-permeable

Question 5

________facilitate movement of specific molecules across the Plasma membrane

Answer 5

Membrane transport proteins

Question 6

Several hydrophobic residues for one protein the enters and leaves PM several times:

Answer 6

polytopic

Question 7

Most transport proteins are:

Answer 7

Polytopic transmembrane integral membrane proteins

Question 8

What is advantage to polytopic membrane proteins?

Answer 8

Allows more diversity in binding and conformational changes

Question 9

What is permeable to PM??

Answer 9

Lipophilic molecules via diffusion - steroid hormones

Question 10

What is impermeable to the PM?

Answer 10

Hydrophilic/ polar substances

Question 11

How can polar/hydrophilic molecules pass through PM?

Answer 11

Needs a specific transport mechanism

Question 12

What is used for specific transport of molecules across PM?

Answer 12

Membrane proteins

Question 13

Polytopic, transmembrane, integral membrane proteins can:

Answer 13

Have multiple transport domains and can shape the cell to allow more substances to pass

Question 14

What determines the ionic composition of the cell?

Answer 14

The activity and protein levels of specific transporters

Question 15

What governs the biochemical/metabolic characteristics of a cell?

Answer 15

Expression of specific transporters

Question 16

One way of regulating metabolism

Answer 16

Alteration in expression levels of transporters

Question 17

Ion gradient are they static?

Answer 17

No dynamic, but they could be thought of static in regard to they are quickly reestablished [in the way they’re maintained]

Question 18

Ion gradient allows for:

Answer 18

Membrane potential for AP

Question 19

Brains uses _____ of energy

Answer 19

20%

Question 20

Molecules move down a [ ] gradient by using energy stored in the gradient: Ex:

Answer 20

Passive transport ; ion channels

Question 21

Molecules move against a gradient by using biochemical energy stored in ATP: EX:

Answer 21

Active transport; pumps/ ATPases

Question 22

Energy independent movement of molecules down a gradient:

Answer 22

Passive transport

Question 23

2 types of passive transport :

Answer 23

Simple diffusion

And

Facilitated diffusion

Question 24

Molecules that are small, nonpolar, and uncharged move freely across PM unaided

Answer 24

Simple diffusion

Question 25

Molecules that're large and charged unable to cross the PM w/o assistance of channel or transporter

Answer 25

Facilitated diffusion

Question 26

____________ of molecules is asso. W. free energy

Answer 26

Unequal distribution

Question 27

What is used to set up an ion gradient across a semi-permeable membrane?

Answer 27

Energy

Question 28

Ion gradients are generated by:

Answer 28

Membrane transporters [energy transducers]

Question 29

Membrane transporters use energy from and store it as free energy of the gradient

Answer 29

ATP

Question 30

Energy is minimum when [ ] across a semi-permeable mebrane is:

Answer 30

Equal

Question 31

Positive free energy =

Answer 31

Active transport

Question 32

- free energy =

Answer 32

Spontaneous

Question 33

Movement of molecules against a gradient

Answer 33

Energy-dependent movement

Question 34

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

Answer 34

P type ATPases ATP binding cassette transporters

Question 35

Ex of P type ATPases

Answer 35

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

Question 36

Ex of ATP binding cassette transporter:

Answer 36

Multi-drug resistance protein

Question 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

Answer 37

P type ATPases

Question 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

Answer 38

Sodium pump

Question 39

Ex of Na pump

Answer 39

Plant steroids- digitoxigenin and ouabain

Question 40

called cardiotonic steroids d/t strong effect on heart

Answer 40

digitoxigenin and ouabain

Question 41

Mixture of cardiotonic steroids

Answer 41

Digitalis

Question 42

Cardiac glycosides that inhibit Na+K+ ATPase activity

Answer 42

ouabain and digitoxigenin

Question 43

How does Digitoxigenin and ouabain work:

Answer 43

- 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

Question 44

Ex of Ca++ pumps:

Answer 44

Plasma mebrane Ca++ ATPase- PMCA Sarco-endoplasmic reticulum Ca++ ATPase- SERCA

Question 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 ```

Answer 45

PMCA

Question 46

Stimulated by the Ca+ binding protein calmodulin (CaM)

Answer 46

PMCA

Question 47

Zaidi research

Answer 47

Structure of PMCA

Question 48

Active site of CaM

Answer 48

ATP binding site

Question 49

PMCA ex:

Answer 49

[CaM] calmodulin

Question 50

Ca++ transport channel open when active or inactive?

Answer 50

Active

Question 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 ```

Answer 51

SERCA

Question 52

Key characteristic of Ca+ pumps SERCA and PMCA

Answer 52

Conformational change

Question 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

Answer 53

ABC transporters

Question 54

ATP binding domain is typically

Answer 54

In cytosol

Question 55

Does ABC transporters have conformational change?

Answer 55

Yes

Question 56

What happens to ATP affinity when substrate binds?

Answer 56

Increases

Question 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

Answer 57

Secondary transporters

Question 58

Ions move in opposite direction

Answer 58

Antiporters

Question 59

Ions move in same direction

Answer 59

Symporters

Question 60

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

Answer 60

Uniporter

Question 61

Ex of antiporter

Answer 61

Sodium calcium exchanger

Question 62

Ex of symporter

Answer 62

Lactose permease

Question 63

Ex of uniporter

Answer 63

Mitochondrial Ca+ transporter

Question 64

Uses a proton gradient generated by oxidation of fuel molecules to drive lactose and other sugars against [ ] gradient Is a symporter

Answer 64

Lactose permease

Question 65

Steps of lactose permease:

Answer 65

``` 1-H+ out 2-lactose out 3-EVERSION 4-lactose in 5- H+ in 6-EVERSION ```

Question 66

Polytopic membrane proteins are often:

Answer 66

Transporters

Question 67

What 2nd structure are proteins that make up polytopic transport proteins in membrane

Answer 67

A helices

Question 68

Sodium pump _____ and K+ pumps in ______

Answer 68

Out; in

Question 69

uses ATP to change conformation for action to occur

Answer 69

Ptype atpase

Question 70

If + ∆G what type of transport

Answer 70

Active transport

Question 71

If -∆G what transport:

Answer 71

Passive: simple or facilitated diffusion

Question 72

Why is P type called P type ATPase?

Answer 72

P=phosphate covalently bonded to protein during process that req's energy. Ex: SERCA Na+/K+ pump / PMCA

Question 73

Where does (Pi) phosphate bind on P type ATPase?

Answer 73

Aspartate residue

Question 74

Inhibit the dephosphorylation of E2P state of the Na+/K+ pump

Answer 74

Digitalis

Question 75

ATP binds to this point________ causing the active for of PMCA

Answer 75

btw 4 and 5 transmembrane domains

Question 76

Abc transporter

Answer 76

MRSA

Question 77

What position SERCA bind a phosphate thus activating its Ca++ transport capabilities

Answer 77

Asp 351