MDS PREP
After fasting for 24 hours, the major source of glucose for the whole body is
1. amino acids from muscle protein degradation.
2. ketone bodies from muscle triglycerides.
3. glycogen stored in the muscle.
4. creatine phosphate
Biochemistry Answer: 4
Creatine Phosphate is the major source of glucose for the whole body during starvation
The immunoglobulin secreted in Bile is
1. IgG
2. 1gM
3. IgA
4. IgE
Biochemistry
Answer: 3
The immunoglobulin secreted in Bile is IgA
An important rate limiting step of Kreb's cycle is catalysed by
1. pyruvate dehydrogenase
2. isocitrate dehydrogenase
3. succinate dehydrogenase
4. citrate synthetase
Biochemistry Answer: 2
Rate limiting step of Kreb's cycle is catalysed by isocitrate dehydrogenase
All of the following statements are true for the acetylcholinesterase receptor
EXCEPT that it
1). opens an ion channel.
2). binds to succinylcholine.
3). undergoes irreversible conformational changes when exposed to carbamates
4). is inactivated in myasthenia gravis
Biochemistry
Answer: 2
Acetylcholinesterase receptor opens an ion channel, undergoes irreversible conformational changes when exposed to carbamates , it is inactivated in myasthenia gravis
Site of â-oxidation of fatty acid Is:
1. Cytoplasm
2. Mitochondria
3. Both cytoplasm and mitochondria
4. Lysosomes
Biochemistry
Answer: 2
â-oxidation of fatty acid occursin Mitochondria
Iodine is a characteristic component of
1. Cysteine
2. Tyrosine
3. Thyroxine
4. Thiamin
Biochemistry
Answer: 3
odine is a characteristic component of Thyroxine
The essential. sulphur containing amino acid is:
1. Methionine 2. Cystetne
3. Cystine 4. Valine
Biochemistry
Answer: 1
Methionine is sulphur containing AminoAcid
Which of the following amino acids is a
precursor for epinephrine?
1. Valine
2. Leucine
3. Tyrosine
4. Cysteine
Biochemistry
Answer: 3
Epinephrine, also known as adrenaline, is a hormone and neurotransmitter that
is synthesized in the body from the amino acid tyrosine. Tyrosine is a
non-essential amino acid, which means that it can be synthesized in the body
from phenylalanine, another essential amino acid. The synthesis of epinephrine
occurs in two main steps:
1. Hydroxylation of tyrosine: Tyrosine is converted into dihydroxyphenylalanine
(DOPA) by the enzyme tyrosine hydroxylase. This is the rate-limiting step in the
synthesis of epinephrine.
2. Decarboxylation and further hydroxylation: DOPA is then decarboxylated to
form dopamine, which is further hydroxylated to produce norepinephrine.
Norepinephrine is the immediate precursor of epinephrine.
3. Formation of epinephrine: Norepinephrine is methylated by the enzyme
phenylethanolamine N-methyltransferase (PNMT) and converted into epinephrine.
The other amino acids listed are not directly involved in the synthesis of
epinephrine:
1. Valine and Leucine are branched-chain amino acids that are primarily involved
in the metabolism of muscles and energy production.
2. Cysteine is a sulfur-containing amino acid that is important for the
synthesis of proteins with disulfide bridges and is a precursor for other
molecules like glutathione and taurine, but not directly involved in the
synthesis of epinephrine.