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Bio344-Cell and Molec > Bio344-Exam#1 (Q's & A's) > Flashcards

Bio344-Exam#1 (Q's & A's) Flashcards

1
Q

In order to maintain osmotic balance and maintain cell volume, what would the Na+/K+ pump do if the cell is exposed to pure water?

A

Start pumping faster because 3 ions are pumped out for two that come in and the cell needs to get rid of as many ions as possible.

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2
Q

How are glucose transporters distributed around an intestinal epithelial cell, which is a conduit for glucose into the rest of the body?

A

Active transporters take up glucose into the cell from the intestine and passive transporters move the glucose from the cell into the extracellular fluid

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3
Q

What process below will be facilitated by active transport?

A

Movement of glucose into an intestinal epithelial cell.

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4
Q

The Na+/K+ pump is a

A

antiport

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5
Q

What molecule contributes to the negative charge on the cytosolic side of the membrane?

A

phosphatidyl serine

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6
Q

What gives a cell its strength and its shape?

A

the cytoskeleton.

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7
Q

How can ABC transporters interfere with cancer treamtent?

A

by Pumping chemotherapy durgs out of cancer cells

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8
Q

What is the function of a dendrite on a nerve cell?

A

They receive signals from the axon terminals of other nerve cells

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9
Q

What causes the kink in one of the phospholipids fatty acid tails?

A

a cis double bond.

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10
Q

Why do phospholipids in water spontaneously organize into spheres?

A

So the fatty acids do not have to associate with water

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11
Q

Where are the glycolipids in an animal cell?

A

On the extracellular side of plasma membranes

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12
Q

What is the primary function of membranes?

A

They are a barrier to polar and charged molecules

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13
Q

What energy source is used to transport glucose from inside an intestinal epithelial cell to the outside?

A

glucose is exported passively from intestinal epithelial cells and therefore no energy source is required.

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14
Q

If K+ ions rush out of a cell what will happen to the electrochemical gradient of Na+ in an animal cell?

A

The electrochemical gradient will increase promoting transport of Na+ across the membrane.

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15
Q

Which molecule below is polar?

A

H2O

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16
Q

What does it mean if during a FRAP (Fluorescenc Recovery After Photobleaching) experiment the bleached area rapidly regains fluorescence?

A

That the fluorescent protein is moving rapidly in the membrane

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17
Q

What is an important property of a phospholipid?

A

It is a molecule that is polar on one end and nonpolar on the other end.

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18
Q

How can a protein be removed from a membrane?

A

By rupturing and dissolving the membrane with a detergent.

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19
Q

How are ion channels, that are the first to open, gated in muscle cells at the neuromuscular junction?

A

by neurotransmitters

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20
Q

What is the anion transporter in red blood cells used for?

A

It removes CO2 from the body in the form of HCO3-.

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21
Q

What is a synaptic cleft?

A

It is the space between the axon terminal of a nerve cell and neighboring muscle or nerve cells.

22
Q

Why does an action potential not move backwards towards the dendrites of a nerve cell?

A

Because the membrane potential is restored when an ion channel is inactivated so that after inactivation the channel remains closed

23
Q

How are sodium channels that allow an action potential to travel along the axon of a nerve cell gated?

A

voltage

24
Q

Which of the molecules below will cross the lipid bilayer, without the aid of a protein, fastest?

A

O2

25
Q

Why does one of the fatty acid chains in a phospholipid have a kink?

A

The kink gives the phospho lipid the shape of a sphere so that it forms sheets instead of micelles.

26
Q

What would a large positive peak on a hydropathy plot signify?

A

That the protein is likely to have a membrane spanning region

27
Q

How is a lipid raft different from the rest of the membrane?

A

It is enriched in sphingomyelin.

28
Q

In a human cell, most of the phospholipids are usually part of which membrane?

A

the membrane of the Endoplasmic Reticulum.

29
Q

Where does the energy to transport glucose into a cell against the glucose concentration gradient come from?

A

Na+ gradient

30
Q

How many Na+ ions does the Na+/K+ pump transport during each cycle?

A

3

31
Q

What happens to the membrane potential when a potassium leak channel opens up during an action potential?

A

The membrane potential will be restored with a negative charge on the cytosolic layer of the membrane.

32
Q

What are the four parts of phosphotidyl choline?

A

choline, phosphate, glycerol, and fatty acids.

33
Q

What is a neurotransmitter?

A

It is a ligand than can bind ion channels.

34
Q

What is a difference between active transport and passive transport?

A

Passive transport goes from high concentration to low concentration while active transport goes from low concentration to high concentration

35
Q

Why can a sodium ion not pass through a potassium leak channel?

A

The sodium ion cannot interact correctly with the oxygen atoms of the selectivity filter of the potassium leak channel.

36
Q

What kind of ATP driven pump is the Na+/K+ pump?

A

P-type pump

37
Q

What is acetyl choline?

A

ATP

38
Q

What is the energy source for the Na+/K+ pump?

A

ATP

39
Q

How could one test if sodium ions can pass through a lipid bi-layer without the aid of proteins?

A

By testing if sodium ions can enter liposomes.

40
Q

What does the influx of Ca2+ into an axon terminal cause?

A

It causes synaptic vesicles to fuse with the membrane.

41
Q

The Na+/glucose transporter is a?

A

symport

42
Q

What is a property of the membrane spanning region of a membrane protein?

A

It contains amino acids with non-polar side chains.

43
Q

What is a characteristic of axon terminals on a nerve cell?

A

They contain vescicles with neurotransmitters

44
Q

How do most proteins span the membrane?

A

In the form of alpha-helices.

45
Q

What is Sodium Dodecyl Sulfate?

A

detergent

46
Q

What process below is facilitated by a channel protein?

A

Transport of Na+ ions into the cell

47
Q

What is the consistency of the phospholipid bilayer?

A

fluid

48
Q

How can proteins move in the membrane?

A

Proteins diffuse laterally in the membrane.

49
Q

Which of the following ions is present in high concentration in the cytosol but at low concentrations extracellularly?

A

K+

50
Q

Most membrane proteins in a human red blood cell are…

A

Associated with the cytoskeleton

Bio344-Cell and Molec (6 decks)

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