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Biochemistry 5th LE > Biochemistry 5th LE 2017 > Flashcards

Biochemistry 5th LE 2017 Flashcards

1
Q

In pACGUAC, which of the following describes the base of the nucleotide in the 5’ end?

a. its a purine with a hydroxyl at C3’
b. its a purine with a phosphate at C3’
c. its a pyrimidine with hydroxyl at C3’
d. its a pyrimidine with phosphate at C3’

A

b. its a purine with a phosphate at c3

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2
Q

pACGUAC

in the nucleotide sequence above, the phosphodiester bond is made between which pair?

a. 5’hydroxyl: 3’hydroxyl
b. 5’hydroxyl: 3’phosphate
c. 5’ phosphate:3’ phosphate
d. 5’ phosphate:3’ hydroxyl

A

d. 5’ phosphate: 3’hydroxyl

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3
Q

which of the ff. base compositions of nuclear DNA follows chargalf rule?

a. A-15% G-35% C-35% T-15%
b. A-15% G- 35% C-35% T-15%
c. A-35% G-15% C-35% T-15%
d. A-40% B-30% C-20% T-30%

A

a. A-15% G-35% C-35% T-15%

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4
Q

all of the ff. describes B-DNA EXCEPT that the;

a. bases occupy the interior of the helix
b. distance between 2 major grooves is 36A
c. distance per base pair is 3.4A
d. base pair per helical turn is 12

A

d. base pair per helical turn is 12

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5
Q

B-DNA

which of the ff. charachteristics of the structure above is true?

a. C1’ is in alpha configuration
b. glycosidic bond is N9C1
c. the amino group is at C4
d. the pyranose is deoxyribose

A

b. glycosidic bond is N9C1

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6
Q

B-DNA

what glycosyl bond conformation does the structure has?

a. anti
b. syn
c. neither a nor b

A

A. Anti

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7
Q

B-DNA

the glucosyl bend conformation of the structure can be seen in which of the ff?

a. A form
b. B form
c. Z form
d. both a and b

A

c. Z form

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8
Q

which of the ff. are. components of ATP?

a. adenosine,deoxyribose,phosphate
b. adenosine,ribose,phosphate
c. adenosine, deoxyribose,phospate
d. adenosine,ribose, phosphate

A

b. adenosine,ribose,phosphate

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9
Q

the first level of compaction of DNA occur when DNA wind with which basic protein?

a. chromatin
b. coil
c. histone
d. nucleosome

A

c. histone

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10
Q

alluporinol used in treatment of hyperuricemia and gout, has no nitrogen atom in which position in the ring?

a. 1
b. 3
c. 7
d. 9

A

c. 7?

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11
Q

what chemical group is found at the 3’ end of a polynucloetide chain?

a. amino
b. carbonyl
c. hydroxyl
d. phosphate

A

c. hydroxyl

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12
Q

a nucleic acid containing 37% A, 16%G, 22%C and 25% T is most likely a:

a. double stranded dna
b. dsrna
c. single stranded ss DNA
d. ssRNA

A

c. single stranded ss DNA

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13
Q

which of the ff.base side chain is correct?

a. adenine: amino at C4
b. cytosine: amino at C4
c. thymine : methyl at C6
d. uracil :keto at C6

A

b. cytosine: amino at C4

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14
Q

which of the ff. base pairs is not seen in RNA?

a. A-T
b. A-U
c. G-C
d. D-U

A

a. A-T

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15
Q

dTMP has no hydroxyl group at which carbon?

a. C1
b. C2
c. C3
d. C5

A

b. c2

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16
Q

Methotrexate

which of the ff enzymes is inhibited by this drug?

a. dihydrofolate reductase
b. formyltransferase
c. serine hydroxymethyl transferase
d. thymidylate synthase

A

a. dihydrofolate reductase

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17
Q

what is the inhibitory effect of methotrexate on enzymes?

a. allosteric
b. competitive
c. formation of an inactive metabolite
d. non competitive

A

b. competitive

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18
Q

the extracellular domain of the insulin receptor can be characterized as:

a. cysteine-rich
b. igG like
c. leucine rich
d. tyrosine rich

A

a. cysteine-rich

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19
Q

which of the ff. is a feature of the JAK-STAT transduction mechanism?

a. a receptor enzyme system with intrinsic kinase activity
b. binding to a soluble cytosolickinase with formation of H-R complex
c. gene expression is not affected by dimerization of the stat molecule.
d. members of the receptor enzyme systems are enclosed in membrane rafts

A

b. binding to a soluble cytosolickinase with formation of H-R complex

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20
Q

which signaling pathway involves displacement from pseudosubstrate.

a. GPCRs
b. phospholipase c
c. RGCs
d. RTKs.

A

c. RGCs

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21
Q

a 21 year old medical student had severe diarrhea and dehydration due to E.coli . what molecular mechanism correctly explains the students diarrhea?

a. adp ribosylation- block in GTPase activity - inc adenylate cyclase
b. inc cAMP - inc pka pathway - inc water loss through nacl efflux
c. inc cgmp- inc cl secretion- dec water reabsorption by intestinal epithelium
d. inc cgmp- inc ca removal by ion pumps- dec smooth muscle hyperactivity

A

c. inc cgmp- inc cl secretion- dec water reabsorption by intestinal epithelium

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22
Q

which enzyme cascade phosphorylated residue pair is correct?

a. Grb2:thr
b. IRS-1:cys
c. PKA:ser
d. MAPK:PIP3

A

c. PKA:ser

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23
Q

what membrane receptor is segregated in rafts

a. acetylcholine
b. B-adrenergic
c. glucagon
d. nitric oxide

A

b.B-adrenergic

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24
Q

these signaling systems utilize the protein kinase a pathway, exept.

a. epinephrine
b. light
c. sweet tastant
d. vassopresin

A

b. light

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25
Q

what is the mechanism for a negative feedback circuit for hormones?

a. amplification
b. desensitization
c. integration.
d. specificity

A

b. desensitization

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26
Q

which feature is not common to both by oxytocin and vassopressin.

a. cysteine disulfide bridge structure
b. co-release with neurophysin
c. synthesized as preprohormomes
d. long polypeptide hormones

A

d. long polypeptide hormones

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27
Q

which of the ff statements about the function of calcium is true?

a. calcium mediates the release of the 1st messengers Ca dependent protein kinases.
b. factors 10 and 12 are calcium dependent factors.
c. hypocalcemia manifests as tetany
d. it mediates the conversion of vitamin d in the kidneys

A

c. hypocalcemia manifests as tetany

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28
Q

what is true about the feature of pth?

a. it is secreted as a 34 amino acid single chain polypeptide.
b. its polypeptide chain is composed mainly of basic aa residues.
c. it is dependent on pth
d. the propth is synthesized in the RER

A

b. its polypeptide chain is composed mainly of basic aa residues

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29
Q

which of the ff condition: pth reaction is correct?

a. inc serum ca-inc pth secretion
b. inc serum mg- inc pth
c. dec 1,25 dihydroxyvitamin d- dec pth secretion
d. dec phosphaturia- inc. pth secretion.

A

b. inc serum mg- inc pth

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30
Q

Which of the following is not a purine nucleoside?

a. adenosine
b. cytosine
c. guanosine
d. thymidine

A

b. cytosine

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31
Q 
What hormone is seen in fetal tissues and
reappear during malignancy states?
a. Calcitonin
b. PTH
c. PTHrP
d. Vitamin D
A

c. PTHrP

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32
Q 
The greatest amount of Vitamin D- dependent
calcium absorption is in the;
a. Duodenum
b. Jejunum
c. Ileum
d. colon
A

a. Duodenum

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33
Q 
25(OH)-D3 is a weak agonist that is hydrolyzed for
full biologic activitity at;
a. C1 – C2
b. C2 - C3
c. C3-C4
d. C4 - C5
A

a. C1 – C2

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34
Q 
The probable chemical abnormality in a patient
with Di George Syndrome is:
a. ↓ PTH, ↓ Ca
b. ↑PTH, ↑ Ca
c. ↓PTH, ↑ Ca
d. ↑PTH, ↓ Ca
A

a. ↓ PTH, ↓ Ca

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35
Q 
Which hormone shows similarity in structure with
LH?
a. ACTH
b. GnRH
c. HCG
d. GH
A

c. HCG

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36
Q

Which carbohydrate component of glycoprotein
hormones is critical to its biological half-life?
a. fructose
b. glucosamine
c. Mannose
d. Sialic acid

A

d. Sialic acid

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37
Q

Persistent elevation of serum FSH and LH in a 30
year old infertile female indicates:
a. heralds onset of spontaneous ovulation
within the cycle.
b. persistent negative feedback from ovarian hormones
c. presence of an intra-uterine pregnancy
d. Signals the beginning of menstruation

A

b. persistent negative feedback from ovarian hormones

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38
Q 
Prolactin and growth hormone utilize this signal
transduction pathway:
a. JAK-STAT
b. protein kinase A
c. MAPK
d. Protein kinase G
A

a. JAK-STAT

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39
Q 
Which is TRUE of mitochondrial CP450 enzyme
system?
a. NADPH CP450 reductase is the
obligatory flavoprotein electron donor.
b. NADPH donates electrons to FAD and
FMN serves as the exit flavin.
c. transfers 2 electrons from NADPH
directly to CP450 enzyme
d. Uses adrenodoxin that shuttles
electrons via its iron-sulfur cluster
A

d. Uses adrenodoxin that shuttles

electrons via its iron-sulfur cluster

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40
Q 
Which is characteristic of the structure of
estradiol?
a. has an angular methyl group at C19
b. the A ring contains 3 double bonds
c. The D-ring is a cyclohexane
d. Has a hydroxyl group at C11
A

b. the A ring contains 3 double bonds

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41
Q

Aromatase catalyzes which reaction?

a. androstenedione -> testosterone
b. DHEA -> androstenedione
c. Testosterone -> estradiol
d. Testosterone -> Estrone

A

c. Testosterone -> estradiol

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42
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

Her normal blood glucose is maintained by which
of the following hormones?
a. cortisol
b. epinephrine
c. glucagon
d. insulin
A

d. insulin

43
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

An increased intracellular concentration of which
of the following molecules is the primary trigger
for the release of this hormone from its source?
a. ATP
b. Ca2+
c. glucose
d. K+

A

b. Ca2+

44
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

This hormone promotes the storage of which of
the following molecules, EXCEPT?
a. carbohydrates
b. fats
c. ketone bodies
A

c. ketone bodies

45
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

An increase of which of the following inhibits the
release of this hormone?
a. amino acids
b. cathecolamines
c. fatty acids
d. Glucose
A

b. cathecolamines

46
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

Which of the following statements is TRUE of the
signaling pathway of this hormone?
a. ERK activating Raf-1 in an upstream
manner promotes binding of GTP to Ras
via Raf-1
b. Grb2 serves as docking point for
activation of a complex of proteins in
the cascade
c. phosphorylation of the B-subunit of
the receptor triggers further
phosphorylation of other proteins
d. Phosphorylated MEK is responsible for
phosphorylation of nuclear transcription
factor
A

c. phosphorylation of the B-subunit of
the receptor triggers further
phosphorylation of other proteins

47
Q

MM, 18 yr old female, came in for her annual
examination. Her parents and an older brother are on oral
hypoglycemic drugs. Her random blood sugar is 80 mg/dl.

Which of the following is TRUE of the receptor of
this hormone?
a. forms a complex with its hormone in the
cytosol
b. the alpha subunit contains the ligandbinding
site
c. The B-subunits activate the trimeric Gproteins
d. The 2 subunits are phosphorylated by
MAPK

A

b. the alpha subunit contains the ligandbinding

site

48
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

Which of the following is the predominant
hormone released at the time of his rescue?
a. cortisol
b. glucagon
c. growth hormone
d. norepinephrine

A

b. glucagon

49
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

This hormone increases blood sugar during
periods of energy deficits via which of the
following?
a. activation of phosphofructokinase 1
b. conversion of amino acids -> glucose
c. inactivation of glycogen phosphorylase
d. ↓ Carboxylation of pyruvate Acetyl CoA

A

b. conversion of amino acids -> glucose

50
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

Which of the following metabolic pathways is
stimulated by this hormone?
a. ↓ oxidation of acetyl CoA to ketone
bodies
b. fatty acid conversion to TAG
c. fatty acid oxidation to acetyl CoA
d. Glucose oxidation to pyruvate
A

c. fatty acid oxidation to acetyl CoA

51
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

The effect of this hormone on fuel metabolism is
mediated via which of the following reactions?
a. activation of G proteins by GTP binding
to the alpha subunit of the receptor
b. autophosphorylayion of serine residues
upon hormone-receptor formation
c. Dimerization and activation of
membrane-bound adenylate cyclase
d. Inositol triphosphate-mediated
phosphorylation of inactive target
enzymes

A

a. activation of G proteins by GTP binding

to the alpha subunit of the receptor

52
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

The emaciation seen in Luis is due to:

a. catabolism of TAGs
b. conversion of stored fats to glucose
c. degradation of glycogen
d. proteolysis of muscle proteins

A

d. proteolysis of muscle proteins

53
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

His acetone breath is due to increased activity of
which of the following enzymes?
a. acetyl CoA carboxylase
b. carnitine acyltransferase I
c. HMG-CoA reductase
d. Pyruvate carboxylase
A

b. carnitine acyltransferase I

54
Q

Luis, a well-built 20 yr old male, washed
ashore at the height of typhoon Yolanda, was plucked out
from the sea after 3 days without food. Upon rescue, he
was dehydrated, weak, emaciated, tachypneic, with
acetone breath. Blood exam showed increased free fatty
acids and low blood glucose.

The increased fatty acids is secondary to:
a. ↓ beta oxidation of fatty acids into
acetyl CoA
b. ↓ utilization of fatty acids as muscle
energy source
c. ↑ degradation of TAGs into FAs and
Glycerol
d. ↑ Fatty acid synthesis from glucosederived
Acetyl CoA

A

c. ↑ degradation of TAGs into FAs and

Glycerol

55
Q

The anti-cancer drug Sorafenib inhibits which of
the following components of the insulin signaling
pathway?
a. ERK
b. MEK
c. RAF-1
d. Ras

A

c. RAF-1

56
Q 
A decrease of the following reactions/
phenomena explains the hyperglycemia in
gestational diabetes:
a. insulin receptor kinase activity
b. MAPK phosphorylation cascade
c. number of membrane insulin receptors
d. No. of membrane glucose transporters
A

a. insulin receptor kinase activity

57
Q 
Choose the correct hormone: effect on glucose
metabolism pair in the liver:
a. cortisol: ↑ gluconeogenesis
b. glucagon : ↓ gluconeogenesis
c. epinephrine : ↓ glycogenolysis
d. Insulin: ↓ glycogenesis
A

a. cortisol: ↑ gluconeogenesis

58
Q 
Choose the correct hormone: effect on protein
metabolism in the muscle:
a. Cortisol: increase protein synthesis
b. Glucagon: decrease proteolysis
c. Growth Hormone: Negative N2 balance
d. Insulin: Increase protein synthesis
A

d. Insulin: Increase protein synthesis

59
Q 
Choose the correct enzyme deficiency: hormonal
level pair
a. 3 BHSD:increase aldosterone
b. 11BSD: decrease cortisol
c. 17 alpha-hydroxylase: Increase
deoxycortisol
d. 21 apha-hydroxylase: Decrease
testosterone
A

b. 11BSD: decrease cortisol

60
Q

a 21 year old female consulted because
of 3 months duration of gradually enlarging anterior
neck mass. She is fond of salad greens mixed with
radish. She has gained weight, easily gets tired and
constipated. Her physician ordered thyroid function
tests

What would be the level of TSH in this patient?

a. increase
b. decrease
c. Normal

A

a. increase

61
Q

a 21 year old female consulted because
of 3 months duration of gradually enlarging anterior
neck mass. She is fond of salad greens mixed with
radish. She has gained weight, easily gets tired and
constipated. Her physician ordered thyroid function
tests

Which display the observed TSH level?
a. autonomous TSH secretion of anterior
pituitary gland
b. compensatory stimulus of APG by
increase T3 secretion
c. Compensatory stimulators of the APG
by decrease T3
d. decrease TRH release from
hypothalamus
A

c. Compensatory stimulators of the APG

by decrease T3

62
Q

a 21 year old female consulted because
of 3 months duration of gradually enlarging anterior
neck mass. She is fond of salad greens mixed with
radish. She has gained weight, easily gets tired and
constipated. Her physician ordered thyroid function
tests

The goitrins present in green salads decrease
thyroid hormone synthesis by inbibiting which
of the following step?
a. coupling
b. iodine trapping
c. Iodination
d. Uptake

A

c. Iodination

63
Q

a 21 year old female consulted because
of 3 months duration of gradually enlarging anterior
neck mass. She is fond of salad greens mixed with
radish. She has gained weight, easily gets tired and
constipated. Her physician ordered thyroid function
tests

The patient's state is mediated by this T3
mechanism of action
a. coupling
b. iodine trapping
c. HRE induced protein by the nuclear
machinery
d. LATS-associated inhibition of
transcription and translation
A

c. HRE induced protein by the nuclear

machinery

64
Q

PY,female, 50 years old came to your clinic
due to increasing adipose tissue mass. She claims to have a
“healthy lifestyle” but is fond of ice cream, soda and pasta.
No significant past history nor intake of drugs but with a
strong family history of obesity.

Which of the following adipokines would be
increased in this patient?
a. adiponectin
b. Ghrelin
c. Leptin
d. PYY
A

c. Leptin

65
Q

PY,female, 50 years old came to your clinic
due to increasing adipose tissue mass. She claims to have a
“healthy lifestyle” but is fond of ice cream, soda and pasta.
No significant past history nor intake of drugs but with a
strong family history of obesity.

Which of the following is the correct sequence of reactions in this leptin signaling pathway?

a. demirization of receptors > leptin receptor> phosphorylation of receptor JAK> phosporylation of STAT> nuclear transport of STAT
b. leptin receptor> demirization of receptors > phosphorylation of receptor JAK> phosporylation of STAT> nuclear transport of STAT
c. Leptin-receptor binding > dimerization of receptor > phosphorylation of STAT > phosphorylation of receptor by JAK > nuclear transport of STAT
d. Leptin-receptor binding > dimerization of receptor > phosphorylation of JAK > phosphorylation of receptor by STAT > nuclear transport of STAT

A

d. Leptin-receptor binding > dimerization of receptor > phosphorylation of JAK > phosphorylation of receptor by STAT > nuclear transport of STAT

66
Q 
The ff. are features of Ras protein in the active
conformation, EXCEPT:
a. Favored when GDP is bounded
b. GTP phosphatease bind to p loop
c. H bonds in switch regions are intact
d. Switch I & II regions are expose
A

a. Favored when GDP is bounded

67
Q 
Hormones that bind intracellular receptors exhibit
this property
a. use of second messengers
b. require plasma transport proteins
c. Short half-life
d. Hydrophilic
A

b. require plasma transport proteins

68
Q 
The phosphate group of cAMP is linked to which
of the ff. carbon atoms?
a. C1&C3
b. C2&C5
c. C3’ & C4’
d. C3’ & C5’
A

d. C3’ & C5’

69
Q

Dihydrofolate reductase

What is the effect of the inhibition of this enzyme?

a. accumulation of FH2 > toxicities anapoptosis of cancer cells
b. increase convertion
c. Increase conversion of FH2 to N10-formyl FH4 > death of cancer cells
d. Non-regeneration of FH4 > no DNA synthesis

A

d. Non-regeneration of FH4 > no DNA synthesis

70
Q 
Choose the correct donor of carbon and nitrogen
atoms in the purinr ring
a. C2- CO2
b. C6-N10 formyl FH4
c. N1-aspartate
d. N3-glycine
A

c. N1-aspartate

71
Q

Which of the following participates in the
biosynthesis of both purine and pyrimidine
nucleotides, EXCEPT:
a. aspartate
b. Glycine
c. PRPP
d. FH4

A

b. Glycine

72
Q

The coenzyme involved in the oxidation of succinate to fumarate is formed when adenosine diphosphate is linked to which vitamin?

a. niacin
b. panthothenate
c. Riboflavin
d. Thiamine

A

c. Riboflavin

73
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
The release of the following hormones is inhibited
by somatostatin 
1. GH
2. TSH
3. Insulin
4. Glucagon
A

E

74
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct

Somatostatin analogs are used in the treatment of
gigantism at their inhibitory effects on which of
the ff. hormones?
1. TSH
2. GH
3. CRH
4. GHRH

A

C

75
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct

The conversion of cholesterol to prenenolone
involves which of the following?
1. formation of isocapric aldehyde
2. sequential hydpoxlation of carbon22 and 20
3. 3 NADPH & 3 O2 mol
4. Formation of aromatic ring

A

A

76
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which receptor system/s is/are desensitized by
associating with arrestin? 
1. ACTH receptor
2. B adrenergic receptor
3. Insulin receptor
4. Transducin receptor
A

C

77
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Theses secondary messengers contribute to
activation of protein kinase C 
1. CAMP
2. diacyglycerol
3. cGMP
4. Inositol triphosphate
A

C

78
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Theses secondary messengers contribute to
activation of protein kinase C 
1. CAMP
2. diacyglycerol
3. cGMP
4. Inositol triphosphate
A

C

79
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct

21 year old female has episodes of carpopedal
spasms after thyroidectomy. She has decreased
levels of which of the following?
1. magnesium
2. calcium
3. Phosphate
4. PTH

A

C

80
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Incomplete reabsorption of Ca in the intestines
is due to? 
1. Lack of vitamin D
2. magnesium in the body
3. Formation of insoluble salts
4. Production of NADPH
A

B

81
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the following statements is true of
calcium sensing receptors? 
1. There are 7 hyrophobic helixes that
ran around the plasma membrane
2. Intracellular domain is identical in
their integration with extracellular Ca
3. The intracellular domain is a potential
protein kinase phosphate site
4. The receptor has 20 AA cytosolic tail
located at the extrace
A

B

82
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the ff. are the effects of PTH in the
kidney? 
1. increase tubular calcium
reabsorption
2. increase urine phosphate excretion
3. Decrease in urine Ca excretion
4. Decrease in Ca filtration
A

A or C

83
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the following are non collagen
structural proteins seen in bone remodelling?
1. Proteoglycan
2. Sialoproteins
3. Osteocalcin
4. Osteonectin
A

E

84
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Vitamin D supplementation is recommended
among which population? 
1. patient taking steroid
2. malabsorption syndrome
3. Patients with ERSD
4. All newborn
A

A

85
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the following are transcripts of DNA
template? 
1. mRNA
2. rRNA
3. tRNA
4. snRNPS
A

E

86
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the ff are metabolic
precursors/activators of purone and pyrimidine necleoide
synthesis? 
1. amino acid
2. ATP
3. CO2
4. Folic acid
A

E

87
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct

Inhibitors of the CPS2 include the following:

  1. ATP
  2. CTP
  3. UTP
  4. PRPP
A

A

88
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the following reactions utilize PRPP as
a ribosylating agent? 
1. nucleotide synthesis
2. NAD synthesis
3. Salvage Pathway
4. Coenzyme A synthesis
A

A

89
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct

Which of the following enzymes is the primary target in
CA chemotherapy during the inhibition of DNA
precursor synthesis by rapidly dividing cancer cells?
1. CTP synthase
2. dehydrofolate reductase
3. xanthine oxidase
4. thymidylate synthase

A

C

90
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
Which of the following describes the formation of
position 8 of the purine ring? 
1. C-N bond formation
2. formyl group transfer
3. single carbon donor required
4. ATP hydrolysis required
A

E

91
Q 
A- 1,2,3 are correct
B- 1 and 3 are correct
C- 2 and 4 are correct
D- if only choice 4 is correct
E- all choices are correct
B-Mercaptopurine inhibits which of the following
enzymes? 
1. IMP dehydrogenase
2. adenylosuccinate synthase
3. PRPP amide transferase
4. GMP synthase
A

A

92
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Leptin
A- increase appetite
B- stimulates anorexigenic neurons

A

C

93
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Ghrelin
A- stimulate orexigenic neurons
B- signalling via JAK STAT pathway

A

A

94
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Adiponectin
A- stimulate appetite
B- signalling via AMPK pathway

A

C

95
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Thymine synthesis
A- N10-formyl FH4
B- N5, N10-methylene FH4

A

B

96
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Pyramidine synthesis
A- more energy consumed
B- Ring is built on a ribose structure

A

D

97
Q

A = if item is related to A
B = if item is related to B
C - if item is relted to A and B
D = if item is not related to A and B

Purine synthesis
A- inhibited by 1.6 mercaptopurine
B- inhibited by 5-Fluorouracil

A

A

98
Q

Oxidises D-glucose into gluconic acid

A

Glucose oxidase)

99
Q

Standard glucose concentration

A

100 mg%)

100
Q

Catalyzes hydrolysis of H202 to H20 and O2

A

Peroxidase

101
Q

color reagent

A

4-aminophenazone

102
Q

renal threshold for sugar

A

170-180 mg%

103
Q
  1. The primary mechanism of the body to maintain normal blood glucose during the first 3-6 hours of fasting is gluconeogenesis
  2. A normal person has high glucose tolerance
  3. There will be glucosuria if the blood glucose is 150 mg%
  4. FBS is still the best screening test to detect the presence of diabetis
A
  1. False
  2. True
  3. False
  4. False

Biochemistry 5th LE (4 decks)

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