Part 4: 2nd midterm questions (1484 - 1510)

Question 1

Na+-K+ ATPase is electrogenic, because

Select one:
a. It hydrolyses ATP
b. It pumps more K+ into the cell, than Na+ out of the cell
c. Resting membrane potential favors pumping Na+ out of cells
d. Hydrolysing one ATP, 3 Na+ are pumped out and 2 K+ are transported in
e. Pumping out of Na+ causes depolarization

Answer 1

d. Hydrolysing one ATP, 3 Na+ are pumped out and 2 K+ are transported in

Question 2

Which statement is valid for the Na+-K+ ATPase?

Select one or more:
a. It is localized in plasma membrane and intracellular membranes
b. Binding site of Na+ is found intracellularly
c. All conformations can bind Na+ with high affinity
d. When the pump is inhibited, the intracellular Na+ concentration rises e. ATP inhibits the phosphorylation of the enzyme

Answer 2

b. Binding site of Na+ is found intracellularly
d. When the pump is inhibited, the intracellular Na+ concentration rises

Question 3

Which statement is not true for Na+-K+ ATPase?

Select one:
a. Na+-K+ ATPase is a P type ATPase
b. It is composed of alpha and beta subunits
c. ATP inhibits its function
d. Several alpha subunit isoforms exist
e. Na+ and K+ have different binding site on the enzyme

Answer 3

c. ATP inhibits its function

Question 4

Which of the statements are valid in neurons?

Select one or more:
a. Choline is formed from acetylcholine by choline acetyltransferase
b. The choline uptake is mediated by the so called ``high-affinity choline transporter’’
c. Na+-cotransporters inactivate acetylcholine in cholinergic synapses
d. The uptake of acetylcholine into the synaptic vesicles is an ATP-dependent process
e. Acetylcholine esterase can be inhibited by atropine

Answer 4

b. The choline uptake is mediated by the so called ``high-affinity choline transporter’’
d. The uptake of acetylcholine into the synaptic vesicles is an ATP-dependent process

Question 5

Which of the following statements are valid?

Select one or more:
a. The high-affinity choline transporter is found exclusively in cholinergic nerve terminals
b.All types of cholinergic receptors belong to the family of seven- transmembrane domain receptors
c. The nicotinic receptor is an ion channel permeable for Na+ and K+
d. The inhibition of acetylcholine esterase decreases the acetylcholine content of synaptic cleft

Answer 5

a. The high-affinity choline transporter is found exclusively in cholinergic nerve terminals
c. The nicotinic receptor is an ion channel permeable for Na+ and K+

Question 6

Which of the following enzymes participate in the synthesis of dopamine?

Select one or more:
a. Tryptophan hydroxylase
b. Dopamine beta hydroxylase
c. Monoamine oxidase
d. Tyrosine hydroxylase
e. Aromatic amino acid decarboxylase

Answer 6

a. Tryptophan hydroxylase
e. Aromatic amino acid decarboxylase

Question 7

Which statements are valid for the synthesis of norepinephrine?

Select one or more:
a. The rate-limiting step of the synthesis is catalyzed by dopamine beta- hydroxylase
b. All enzymes of the biosynthetic pathway are localized in the cytoplasm of the noradrenergic axon terminals
c. The rate-limiting step of the synthesis is catalyzed by tyrosine hydroxylase
d. Catechol-O-methyl-transferase does not participate in the synthesis

Answer 7

a. The rate-limiting step of the synthesis is catalyzed by dopamine beta- hydroxylase
d. Catechol-O-methyl-transferase does not participate in the synthesis

Question 8

Which metabolite is formed in the course of norepinephrine metabolism in the brain?

Select one:
a. 3-methoxy-4-hydroxymandelic acid
b. homovanillic acid
c. 3-methoxy-4-hydroxyphenylglycol
d. indoleacetic acid

Answer 8

c. 3-methoxy-4-hydroxyphenylglycol

Question 9

Which compound is a substrate of monoamine oxidase?

Select one or more:
a. Glutamate
b. Serotonin
c. Dopamine
d. Norepinephrine
e. Glutamine

Answer 9

b. Serotonin
c. Dopamine
d. Norepinephrine

Question 10

Which molecular events contribute to the positive inotropic and chronotropic effects of norepinephrine?

Select one or more:
a. Activation of cAMP-dependent protein kinase
b. Activation of alpha 2 receptors
c. Dephosphorylation of phospholamban
d. Increase in the intracellular Ca2+ concentration
e. Increased activity of the sarcoplasmic reticulum Ca2+-ATPase

Answer 10

a. Activation of cAMP-dependent protein kinase
d. Increase in the intracellular Ca2+ concentration
e. Increased activity of the sarcoplasmic reticulum Ca2+-ATPase

Question 11

Which molecular events contribute to the epinephrine-induced activation of lipolysis in adipose tissue?

Select one:
a. beta 3 receptor activation
b. alpha 2 receptor activation
c. inhibition of hormon sensitive lipase
d. decrease in cAMP level

Answer 11

a. beta 3 receptor activation

Question 12

What is the consequence of alpha1-receptor activation in the arteriolar smooth muscle cells?

Select one:
a. Phosphorylation of myosin light-chain kinase
b. Phosphorylation of voltage-dependent Ca2+ channels
c. Decrease in the cAMP level
d. Activation of myosin light-chain kinase
e. Decrease in the intracellular Ca2+ concentration

Answer 12

a. Phosphorylation of myosin light-chain kinase

Question 13

Which statements are valid for the adrenergic receptors?

Select one or more:
a. All beta receptors activate Gs proteins
b. Alpha 2 receptors act through inhibitory G proteins
c. Alpha 1 receptors act through inhibitory G proteins
d. Alpha 1 receptors mediate decrease in the cytosolic levels of free Ca+2

Answer 13

a. All beta receptors activate Gs proteins
b. Alpha 2 receptors act through inhibitory G proteins

Question 14

Pick the membrane with the lowest protein to lipid ratio!

Select one:
a. Erythrocyte plasma membrane
b. Myelin
c. Mitochondrial outer membrane
d. Mitochondrial inner membrane

Answer 14

b. Myelin

Question 15

Which lipid present in smallest amount in human plasma membrane

Select one:
a. triacylglycerols
b. glycerophospholipids
c. sphingolipids
d. cholesterol

Answer 15

a. triacylglycerols

Question 16

The lipid that contain phosphate is

Select one:
a. ganglioside
b. triacilglycerol
c. cerebroside
d. sphingomyelin

Answer 16

d. sphingomyelin

Question 17

When cholesterol/oxysterol level is high

Select one:
a. ABCA1 transporter is transcribed
b. HMGCoA reductase is active
c. LDL receptors are transcribed
d. IDOL (LDL receptor ubiquitin ligase) is inactivated

Answer 17

a. ABCA1 transporter is transcribed

Question 18

The enzyme that doesn’t participate in serotonine synthesis and degradation is

Select one:
a. MAO
b. tryptophan-hydroxylase
c. tyrosine hydroxylase
d. aromatic aminoacid decarboxylase

Answer 18

tyrosine hydroxylase

Question 19

he serotonine receptor that is a cation-selective member of the pentameric ligand-gated ion channels

Select one:
a. 5HT-1
b. 5HT-2
c. 5HT-3
d. 5HT-4
e. 5HT-5

Answer 19

c. 5HT-3

Question 20

The metabolite of serotonine that can be measured in CSF/blood/urine

Select one:
a. HIAA (5-hidroxyindole acetic acid)
b. VMA (vanillylmandelic acid)
c. HVA (homovallinic acid)

Answer 20

a. HIAA (5-hidroxyindole acetic acid)

Question 21

Pick the right answer!

Select one:
a. The substrate of nitric oxide synthase is citrullin
b. The substrate of nitric oxide synthase is arginine
c. Elevation of nitric oxide cause elevation in intracellular calcium level
d. Elevation of nitric oxide cause inhibition of non-receptor bind guanylate cyclase

Answer 21

b. The substrate of nitric oxide synthase is arginine

Question 22

Pick the right answer!

Select one:
a. endothelial constitutive nitric oxide (NO) synthase is activated by calcium
b. nitric oxide synthase (iNOS) gene expression is inhibited by bacterial lipopolysaccharides
c. Elevation of nitric oxide causes smooth muscle constriction
d. Elevation of nitric oxide promotes vasoconstriction

Answer 22

a. endothelial constitutive nitric oxide (NO) synthase is activated by calcium

Question 23

Identify Enzymes

Answer 23

A= Tyrosine hydroxylase
B= Dopa decarboxylase
C= Dopamine beta- hydroxylase
D= PNMT

Question 24

Identify Enzyme A

Answer 24

A= Tyrosine hydroxylase

B= Dopa decarboxylase
C= Dopamine beta- hydroxylase
D= PNMT

Question 25

Identify Enzyme B

Answer 25

B= Dopa decarboxylase

A= Tyrosine hydroxylase
C= Dopamine beta- hydroxylase
D= PNMT

Question 26

Identify Enzyme C

Answer 26

C= Dopamine beta- hydroxylase

A= Tyrosine hydroxylase
B= Dopa decarboxylase
D= PNMT

Question 27

Identify Enzyme D

Answer 27

D= PNMT

A= Tyrosine hydroxylase
B= Dopa decarboxylase
C= Dopamine beta- hydroxylase

Question 28

The lipid that level elevates in the outer leaflet during apoptosis or platelet activation is

Select one:
a. Phosphatydilcholine
b. Cholesterol
c. Phosphatydilserine
d. Sphingomelin

Answer 28

Phosphatydilserine