QUESTIONS

Question 1

What coenzyme is required in the mechanism
of a transamination reaction?

Answer 1

Active Vitamin B6

Question 2

Which of the following statements is
INCORRECT

a. Decarboxylation of glutamine
forms the inhibitory
neurotransmitter GABA.
b. Serotonin and melatonin are
metabolites of tryptophan.
c. The concentration of histamine in the
brain hypothalamus exhibits a
circadian rhythm.
d. Histamine arises from the
decarboxylation of histidine.

Answer 2

a. Decarboxylation of glutamine
forms the inhibitory
neurotransmitter GABA.

Question 3

What amino acid is made from pyruvate via
transamination?

Answer 3

Alanine

Question 4

Hydroxylation of tyrosine by the enzyme
tyrosine hydroxylase yields ___________.
Subsequent decarboxylation of the said
product yields _____________.

Answer 4

5-hydroxytryptophan; serotonin

Question 5

Which of the following reactions is highly
active in the liver when large amounts of
amino acids are moving from extrahepatic
tissue to the liver?

Answer 5

oxidation of glutamate by
glutamate dehydrogenase

Question 6

The following enzymes in the urea cycle are
found in the cytosol, EXCEPT:
a) Argininosuccinate lyase
b) None of the above
c) Arginase
d) Ornithine transcarbamoylase

Answer 6

Ornithine transcarbamoylase

Question 7

SITUATION: There are low amounts of
glucose in the body.
Under such conditions, muscle tissue would
be broken down providing a large amount of
ALANINE to the liver. Once the above amino
acid entered the liver, it would undergo
transamination to _____ which would then
undergo ______ to ______ to
enter ________.

Answer 7

pyruvate
carboxylation
oxaloacetate
gluconeogenesis

Question 8

The replication of DNA is made possible by
the presence of _____ strands in the double
helix of DNA.

Answer 8

complementary

Question 9

In DNA, the ribose derivative lacks an _____
on C-_____.

Answer 9

alcohol; 2

Question 10

Nucleotides play a central role in living
organisms because ______.

Answer 10

they function as building blocks for
nucleic acids

Question 11

What is the name of the molecule that is
composed of guanine linked to the C-1ꞌ of
ribose with three phosphate group at C5’?

Answer 11

: guanosine triphosphate

Question 12

The pyrimidine found in both DNA and RNA is
_____.

Answer 12

Cytosine

Question 13

What is the name of the molecule that is
composed of adenine linked to the C-1ꞌ of
ribose with one phosphate group at C5’?

Answer 13

adenosine monophosphate

Question 14

Genomic DNA is _____, resulting in the
production of _____.

Answer 14

transcribed; mRNA

Question 15

What is the name of the molecule that is
composed of adenine linked to the C-1ꞌ of
ribose?

Answer 15

adenosine

Question 16

The triplet code allows many amino acids to
be specified by more than one codon. Such a
code is said to be _____.

Answer 16

degenerate

Question 17

The amino acid would be attached to this
structure at

Answer 17

5

Question 18

Which of the following represents a DNA
mutation in the template strand that would
convert serine to cysteine?

Answer 18

5’-GCT-3’ to 5’-GCA-3’

Question 19

The codon is found _____ while the anticodon
is found _____.

Answer 19

in the mRNA; on the tRNA

Question 20

. The term rRNA refers to ______ RNA.

Answer 20

ribosomal

Question 21

Codons that do not specify amino acids but
signal the ribosome to terminate polypeptide
chain elongation are called

Answer 21

stop codons

Question 22

There is/are ___ start codon(s) and ___ stop
codon(s).

Answer 22

b. 1;3

Question 23

Which of the following best describes a new
strand of DNA relative to the template strand
used to synthesize it?

Answer 23

a negative copy of the template

Question 24

Which lipoprotein carries triacylglycerols
synthesized by the liver during the fasting
state?

Answer 24

VLDL

Question 25

Which enzyme is activated during the fasting state to catalyze the release of free fatty acids from adipose tissue triglycerides?

Answer 25

Hormone-sensitive lipase

Question 26

What is the priority for substrate exchange among tissues during fasting?

Answer 26

Maintaining plasma levels of glucose

Question 27

What is the primary fate of amino acids released during protein degradation in muscles during fasting?

Answer 27

Converted to glucose through gluconeogenesis

Question 28

What does the pancreas secrete in response to elevated glucose and amino acid levels during the absorptive state?

Answer 28

Epinephrine

Question 29

From late fasting into starvation, what key roles do the kidneys play?

Answer 29

Proton excretion as NH4+

Question 30

Which of the following hormones stimulates glucagon secretion?

Answer 30

Low blood glucose

Question 31

What is the significance of C-peptide in insulin synthesis?

Answer 31

It serves as a marker of endogenous insulin production

Question 32

What is a characteristic symptom of hypoglycemia in the central nervous system?

Answer 32

. Confusion and coma

Question 33

allows processive unwinding of DNA

Answer 33

Helicase

Question 34

initiates synthesis of RNA primers

Answer 34

Primase

Question 35

initiates daughter strand synthesis

Answer 35

DNA polymerase

Question 36

bind to ssDNA to prevent premature reannealing of ssDNA to dsDNA

Answer 36

SSBs

Question 37

Prevent extreme supercoiling of the parental helix

Answer 37

Topoisomerases

Question 38

Carboxypeptidase _____ is an enzyme that cleaves aromatic amino acids at the C terminal end of peptides. On the other had Carboxypeptidase ______ cleaves basic amino acids at the same end of the chain. Both enzymes are called ______________.

Answer 38

A; B; Exopeptidase

Question 39

One of the primary routes of ammonia uptake in mammals is

Answer 39

Amination of glutamate to form glutamine

Question 40

Which of the following reactions is highly active in the liver when large amounts of amino acids are moving from extrahepatic tissue to the liver?

Answer 40

oxidation of glutamate by glutamate dehydrogenase

Question 41

What is the primary role of pyridoxal phosphate (PLP) in transamination reactions?

Answer 41

It acts as a carrier of amino groups.

Question 42

The following are purely glucogenic amino acids, EXCEPT: a) Alanine b) Proline c) Glycine d) Phenylalanine

Answer 42

d) Phenylalanine

Question 43

Match the following with their correct specialized conversion product: a) Tryptophan = b) Tyrosine = c) Histidine = d) Glutamine =

Answer 43

Tryptophan = Serotonin b) Tyrosine = Epinephrine c) Histidine = Histamine d) Glutamine = None of the choices

Question 44

The DNA strand that serves as the template for the synthesis of RNA is often called the _____.

Answer 44

noncoding strand

Question 45

RNA occurs primarily as single-stranded molecules that can give rise to _______ structures.

Answer 45

stem-loop

Question 46

Nucleotides contain one or more phosphate groups that are usually attached to the ______.

Answer 46

C-5ꞌ atoms

Question 47

What type of bond is made between nucleotides?

Answer 47

Phosphodiester

Question 48

In most organisms, replication proceeds in a _____ manner from the _____.

Answer 48

bidirectional; replication origin

Question 49

Which strand of DNA is replicated exclusively in a discontinuous fashion?

Answer 49

lagging strand

Question 50

Transfer RNA molecules are involved in ______.

Answer 50

translation

Question 51

The correct amino acid is covalently attached to a tRNA by the corresponding ______ which is specific for each ______.

Answer 51

aminoacyl-tRNA synthetase (aaRS); amino acid

Question 52

Which lipoprotein carries triacylglycerols synthesized by the intestinal mucosal cells during the absorptive state?

Answer 52

Chylomicron

Question 53

What is the primary focus of regulatory mechanisms during the absorptive state?

Answer 53

Storage of nutrients as glycogen, triacylglycerol, and protein

Question 54

What does the pancreas secrete in response to elevated glucose and amino acid levels during the absorptive state?

Answer 54

Insulin

Question 55

What is the sequential order of the cleavage events that convert preproinsulin into insulin?

Answer 55

Cleavage at preproinsulin, then at proinsulin

Question 56

Which cellular organelle is primarily responsible for the synthesis of insulin in pancreatic β-cells?

Answer 56

Rough endoplasmic reticulum

Question 57

In the context of insulin action, what is the primary function of insulinase?

Answer 57

Degradation of insulin

Question 58

What is the primary stimulus for increased insulin secretion?

Answer 58

Glucose

Question 59

How does insulin affect glucose uptake?

Answer 59

Stimulates glucose uptake by muscle and adipose tissue

Question 60

Which hormone opposes the actions of insulin during "survival crises" situations?

Answer 60

Epinephrine

Question 61

During prolonged fasting, which hormone opposes the actions of insulin and promotes lipolysis and ketogenesis?

Answer 61

Growth hormone

Question 62

If you add phosphate group to your nucleoside, it'll become ___?

Answer 62

Nucleotide