Stiller Test 4 Cell Bio

Question 1

Phospholipids are…

Answer 1

amphipatic

Question 2

The most common phospholipid(s) on the extracellular side of plasma membranes is/are …

Answer 2

phosphatidylcholine

Question 3

The most common phospholipid(s) on the cytosolic side of plasma membranes is/are …

Answer 3

both c and d -(phosphatidylserine, phosphatidylethanolamine)

Question 4

Which of the following is NOT a type of membrane protein?

Answer 4

all of these are membrane proteins - (transporters, anchors, receptors enzymes)

Question 5

True or false? Channels are transmembrane proteins.

Answer 5

t

Question 6

True or false? Transmembrane proteins are integral proteins.

Answer 6

t

Question 7

Porins are formed by ….

Answer 7

B and C - (multi-pass alpha helices, beta barrels)

Question 8

Exocytosis …

Answer 8

moves molecules out of the cell.

Question 9

Which of the following is MOST LIKELY to cross a membrane by simple diffusion?

Answer 9

oxygen gas

co2, n2, steroids, hormones

Question 10

The following factors will influence the rate of diffusion (from point A to point B) EXCEPT?

Answer 10

all of the above are correct - no exceptions!

Question 11

Active transport involves:

Answer 11

all the above

Question 12

Bacteriorhodopsin ….

Answer 12

is energized by sunlight

Question 13

A large integral protein with a few small sugar side chains is a ….

Answer 13

glycoprotein

Question 14

A small integral protein with a several large sugar side chains is a ….

Answer 14

proteoglycan

Question 15

In a laboratory activity, red-labeled glucose, blue-labeled water, and green-labeled ethanol are added to a solution placed over an artificial, pure phospholipid membrane. Which colors will be observed on the other side of the membrane after 30 minutes?

Answer 15

b and c - (blue, green)

Question 16

Aquaporins are …

Answer 16

water channels.

Question 17

When calculating the osmotic pressure of a glucose solution that must be used instead of KCl, what glucose concentration is the osmotic equivalent of 1 M KCl?

Answer 17

2 M glucose

Question 18

Classes of membrane transport proteins include all of the following EXCEPT:

Answer 18

protein translocons.

Question 19

In which of the following cases is energy NOT needed for transmembrane transport?

Answer 19

b and c - (glucose moves into the cell down its concentration gradient via a glucose uniporter, Potassium ions (K+) move out of the cell via potassium leak channels.)

Question 20

Amino acid entry into cells can occur via uniporters or symporters. If the rate of leucine entry into the cell increases when the pH decreases, this suggests:

Answer 20

leucine is being transported by a H+ symporter.

Question 21

The hypotonic osmotic potential of pond water should cause animal cells to _____________, but frog eggs prevent this by ___________________

Answer 21

burst; not expressing aquaporins

Question 22

The major ATP-powered pump responsible for maintaining ion gradients across the plasma membrane of mammalian cells is:

Answer 22

the plasma-membrane Na+/K+ ATPase.

Question 23

The resting membrane potential in animal cells depends largely on “leaky” _________channels.

Answer 23

K+

Question 24

Transepithelial glucose transport uses a symporter to transport glucose up a concentration gradient by:

Answer 24

coupling glucose transport to Na+ movement.

Question 25

The magnitude of the membrane electrical potential is calculated by:

Answer 25

the Nernst equation.

Question 26

The movement of dietary glucose and sodium from the intestine into the bloodstream relies on which of the following transport mechanisms?

Answer 26

all the above ## Footnote The movement of dietary glucose and sodium from the intestine into the bloodstream relies on secondary active transport via the sodium-glucose symporter (SGLT).

Question 27

All of the following can energize active transport of H+ EXCEPT....

Answer 27

the proton-motive force

Question 28

The plasma-membrane Na+/K+ ATPase is an example for ....

Answer 28

antiport

Question 29

Sound perception via stereocilia involves ....

Answer 29

mechanically-gated ion channels

Question 30

True or false? Plants use (rather slow) action potentials for long-distance signaling

Answer 30

t

Question 31

Action potentials in animals are caused by the flow of _____ into and _____ out of the nerve cell.

Answer 31

sodium; potassium

Question 32

According to the Nernst equation: V = 62 log10 (Cout /Cin), what is the approximate membrane potential of an artificial cell containing 150mM potassium in a beaker containing a 15mM KCl solution?

Answer 32

-62 mV

Question 33

Imagine you added potassium leak channels to the artificial cell membrane in the question above. What would be the resulting membrane potential?

Answer 33

0mV

Question 34

Nerve junctions are called _______________

Answer 34

synapses

Question 35

At the neuromuscular junction, the neurotransmitter _____________ excites the postsynaptic cell by opening ______ channels.

Answer 35

acetylcholine; Na+

Question 36

The neurotransmitter _____________ inhibits synaptic signaling by opening ______ channels.

Answer 36

GABA; Cl-

Question 37

The cool new research approach that introduces and expresses foreign genes for light-gated ion channels in experimental animals is called ______________.

Answer 37

optogenetics

Question 38

Which of the following is NOT a form of cell signaling?

Answer 38

All of these are types of cell signaling ## Footnote paracrine signaling, autocrine signaling, endocrine signaling, and signaling by direct contact.

Question 39

True or false? The same signal molecule can induce a different response in different target cells.

Answer 39

t

Question 40

Which of the following is NOT a steroid hormone?

Answer 40

cholesterol

Question 41

True or False? While cell signaling often involves many steps, some membrane receptors can be cleaved and migrate directly to the nucleus where they act as transcription factors.

Answer 41

t

Question 42

GPCRs are ________________ that ___________________

Answer 42

receptors; activate trimeric G-proteins

Question 43

Activated G-proteins ....

Answer 43

All of the above are correct.

Question 44

A small intracellular signaling molecule:

Answer 44

cAMP

Question 45

Don't get confused: _______ is a small intracellular signaling molecule, whereas _______ is not!

Answer 45

IP3; PI3-kinase

Question 46

True or false? The concentration of free Ca2+ in the cytosol of an unstimulated cell is extremely low so that any pulse of calcium can trigger a response.

Answer 46

t

Question 47

All statements about calmodulin are correct EXCEPT:

Answer 47

All of the above are correct. ## Footnote Ca interacts with it and regulates a whole lot of target proteins

Question 48

True or false? Activated RTK can activate Ras or Akt.

Answer 48

t

Question 49

The enzyme that activates MAP kinase (by adding phosphate) is:

Answer 49

MAP kinase kinase

Question 50

The cytosolic protein that, when activated, encourages a cell to kill itself is ....

Answer 50

Bad | Caspases > Apoptosis

Question 51

Bacteriorhodospin

Answer 51

Pigment that absorbs light energy to transport across the membrane (proton pump)