Pre-Quiz questions

Question 1

The difference between active transport (AT) and facilitated diffusion (FD) is?

Answer 1

AT can move substrate against an electrochemical gradient, FD cannot

Question 2

What distinguishes Primary AT from Secondary AT?

Answer 2

Primary AT makes direct use of ATP, secondary AT does not

Question 3

What distinguishes PMCA from SERCA?

Answer 3

PMCA pumps Ca2+ OUT of cells, whereas SERCA pumps Ca2+ INTO the endoplasmic reticulum

Question 4

Primary P-Type ATPases…

Answer 4

are ions pumps that phosphorylate themselves during the transport reaction cycle

Question 5

If the Na,K-ATPase is inhibited (e.g., by ouabain), you can expect?

Answer 5

Intracellular Na+ to INCREASE and intracellular K+ to DECREASE

Question 6

Rapid, continuous activation of skeletal muscle can result in a gradual increase in cytoplasmic Na+. One regulatory response is the phsophorylation of the gama-regulatory sub unit of the Na,K-ATPase which then exerts a regulatory effect on Na,K-ATPase activity to bring intracellular Na+ back down towards its normal level. What response of the Na,K-ATPase to the phsophorylation of phsopholemman would have this effect?

Answer 6

A decrease in the K0.5 for the Na+ efflux

Question 7

Carrier mediate transport can be distinguished from simple passive diffusion (permeation) by…? (two things)

Answer 7

1. carrier-mediated transport can be competitively inhibited (passive diffusion cannot)
2. Carrier-mediated transport is saturable (passive diffusion is not)

Question 8

In ‘round figures’ the cytoplasm of a ‘typical’ mammalian cell has an osmotic concentration of about 300 mOsM. If you place a cell into a solution with an osmotic concentration of 270 mOsM, it would be reasonable to expect that water, by osmosis, would…?

Answer 8

Go into the cell making it SWELL

Question 9

Synaptic vesicles are generally more acidic than the surrounding cytoplasm. Consequently, by passive forces alone, the concentration within these vesicles of the neurotransmitter, serotonin (which is a weak base), would be expected to be…?

Answer 9

Greater in the cytoplasm

Question 10

The ability of water molecules to ‘solvate’ hydrophilic solute particles and thereby hold them in solution is, in large part, due to the…?

Answer 10

Dipole movement of water

Question 11

Phospholipids are considered to be amphiphilic because?

Answer 11

Their structure includes both hydrophobic, hydrocarbon (alkyl) chains and a hydrophilic phosphate residue bonded to a polar ‘head group.’

Question 12

Phospholipids tend to ‘self-associate’ in water to form a stable ‘bilayer’ structure. In this configuration, the phospholipid…?

Answer 12

The hydrophilic head group faces the two external water compartments

Question 13

Integral membrane proteins are distinguished from peripheral membrane proteins in that…?

Answer 13

Integral MPs have an amphiphilic/amphipathic structure, whereas peripheral MPs generally don’t

Question 14

According to the fluid mosaic model of membrane structure, integral membrane proteins…?

Answer 14

Can diffuse laterally in the plane of the membrane

Question 15

Which generally occurs at rates so low that AT-requiring enzymes are involved in supporting that movement (rotational, lateral, transmembrane)?

Answer 15

Translational diffusion

Question 16

The hydrophic effect … ? (Two things)

Answer 16

Contributes to the stability of the membrane structure

Drives the self-association of non-polar molecules when placed in water

Question 17

The paracellular pathway for transepithelial transport is not freely available to all molecules. This is primarily due to the influence of?

Answer 17

Tight junction proteins that connect adjacent epithelial cells

Question 18

The basolateral side of the eipthelial cell layer that comprises (for example) the renal proximal tubule is exposed to?

Answer 18

The blood

Question 19

Which secretagogues can stimulate zymogen release?

Answer 19

CCK - cholecystokinin
VIP - vasoactive intestine peptide
ACh - acetylcholine
Secretin

Question 20

Synaptotagmin proteins are activated when?

Answer 20

When bound to Ca2+ and then stimulate exocytosis (through the fusion of vesicles with the plasma membrane)

Question 21

Physiologically, the most important secretagogue(s) for stimulation of pancreatic zymogens is/are?

Answer 21

CCK, ACh

cholecystokinin and acetylcholine

Question 22

Acinar cells…(4 things)?

Answer 22

Secrete Na+ and Cl-
Secrete water
Secrete zymogens
Rely on the paracellular pathway for the net transepithelial flux of Na+

Question 23

The permselectivity of tight junctions (TJs) is primarily influenced by?

Answer 23

Which claudin(s) are associated with the TJ complex

Question 24

Carbohydrate and lipid digestion starts?

Answer 24

In the mouth

Question 25

The organ responsible for generation of the digestive enzyme pepsinogen/pepsin is?

Answer 25

The stomach

Question 26

What distinguishes an exocrine gland from an endocrine gland?

Answer 26

Exocrine glands release materials directly to the external environment (outside the body), whereas endocrine glands release materials into the blood stream

Question 27

The duct of an exocrine gland is a site for?

Answer 27

Modificiation of the primary secretion

Question 28

the physiological activation of zymogens typically requires?

Answer 28

The conversion of trypsinogen to trypsin by enteropeptidase

Question 29

Digestion of nucleic acids involves nucleases; digestion of carbohydrates involves ____; digestion of lipids involves ____; and digestion of proteins involves ____?

Answer 29

Amylases digest carbohydrates Lipases digest lipids Proteaes digest proteins