MDS PREP
The sulphur containing amino acid is:
1. Cystine
2. Proilne
3. Arginine
4. Isoleucine
Biochemistry
Answer: 1
The correct sulfur-containing amino acid among the options provided is:
1. Cystine
Explanation:
Amino acids are the building blocks of proteins, and they are characterized by
the presence of an amino group (-NH2) and a carboxyl group (-COOH). Some amino
acids also contain a side chain that is unique to each amino acid and determines
its chemical properties. Sulfur is an important element in the structure and
function of certain amino acids.
Cystine is a sulfur-containing amino acid, which is formed by the oxidation of
two cysteine molecules. Cysteine is the amino acid that contains a sulfur atom
in its side chain as a thiol group (-SH). When two cysteine residues are
adjacent in a polypeptide chain and the thiol groups react with each other, they
form a disulfide bond (-S-S-), resulting in the formation of cystine. This
disulfide bond is crucial for the tertiary structure of proteins, contributing
to their stability and function, particularly in the context of protein folding
and maintaining the integrity of protein domains.
The other options listed are not sulfur-containing amino acids:
2. Proline is an imino acid, meaning it contains an -NH group instead of an -NH2
group. Its side chain is a cyclic secondary amine and does not contain sulfur.
3. Arginine is a basic amino acid with a guanidino group in its side chain,
which is composed of nitrogen, carbon, and hydrogen atoms but no sulfur.
4. Isoleucine is a branched-chain amino acid, with a methyl group and an
isobutyl group on its side chain. It is a hydrophobic amino acid and does not
contain sulfur.
Aromatic amino acid is:
1. Tyrosine 2. Histidine
3. Arginine 4. Lysine
Biochemistry
Answer: 1
Tyrosine is Aromatic amino acid
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
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
A component of the coenzyme required in a transamination process is
1. Thiamine
2 Folic acid
3 Pyridoxine
4 Riboflavin
Biochemistry
Answer: 3
A component of the coenzyme required in a transamination process is Pyridoxine
Which of the following dental tissues is most likely to be effected by Vit-A
deficiency
1. enamel
2. dentin
3. cementum
4. pulp
Biochemistry Answer: 1
Enamel most likely effected by deficiency of vitamin A
Urea formation take place in liver by:
1. Salvage pathway
2. Krebs cycle
3. Krebs Henseleit cycle
4. none
Biochemistry
Answer: 3
The synthesis of urea takes place in the liver by the process called ''Ornithine
cycle'' or "Urea cycle"
This cycle was discovered by Hans Krebs and Kurt Henseleit in the year 1932.
The Ornithine cycle is completed in 5 steps:
1. Conversion of ammonia into carbamoyl phosphate
2.The transfer of carbamoyl group from carbamoyl phosphate to ornithine
3. Releasing of the formed citrulline into the cytosol
4. Cleavage of argininosuccinate
5. Hydrolysis of Arginine: The final step involves the hydrolysis of Arginine
into urea and ornithine
Arginase is the sixth and final enzyme of this cycle.
Epinephrine causes increased blood glucose level due to:
1. Increased glycogenolysis in liver and muscle
2. Activation of phosphorylase
3. Inhibition of glycogen synthesis in liver
4. All of the above
Biochemistry
Answer: 4
Epinephrine causes increased blood glucose level due to:
1. Increased glycogenolysis in liver and muscle
2. Activation of phosphorylase
3. Inhibition of glycogen synthesis in liver