Tag: bio-chemistry

Questions Related to bio-chemistry

The separation of two DNA stands by heating is called

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. melting temperature

  2. annealing

  3. denaturation

  4. boiling

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Correct Option: C
Explanation:

The separation of two DNA stands by heating is called denaturation. The intermolecular hydrogen bonds and disulfde linkages break.

Globular Proteins are present in:

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. Blood

  2. Eggs

  3. Milk

  4. All the above

Show answer
Correct Option: D
Explanation:

Globular Proteins have three dimensional folded structure. These are cross linked proteins, soluble in water.
Globular Proteins are present in blood, eggs and milk.

Which of the following statements are true about (X) and (Y)?
X)  Globular Protein               Y)  Fibrous Protein
a.These are linear condensation polymers.
b. Insoluble in water.
c. These proteins have three dimensional folded structure.
d. These are cross linked protein.
e. Soluble in water
f. These are held together by intermolecular hydrogen bond.

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. X = a, b, c; Y = d, e, f

  2. X = c, d, e; Y = a, b, f

  3. X = b, c, a; Y = c, b, f

  4. X = a, e, f; Y = b, c, f

Show answer
Correct Option: B
Explanation:

Globular Proteins have three dimensional folded structure.
These are cross linked protein.
They are Soluble in water.
Fibrous Proteins are linear condensation polymers.
They are Insoluble in water.
These are held together by intermolecular hydrogen bond.

The secondary structure of a protein refers to:


bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. $\alpha$-helical back bone

  2. hydrophobic interations

  3. Sequence of $\alpha$-amino acids

  4. fixed configuration of the polypeptide backbone

Show answer
Correct Option: A
Explanation:

The secondary structure of a protein refers to either of $\alpha$-helical back bone or $\beta$-sheet.

Which of the following is a globular protein?

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. Collagen

  2. Myoglobin or Haemoglobin

  3. Myosin

  4. Fibroin

Show answer
Correct Option: B
Explanation:

Myoglobin or haemoglobin is a globular protein.


Collagen, myosin and fibroin are fibrous protein.

Option B is correct.

Globular proteins are present in:

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. Eggs

  2. Muscles

  3. Keratin

  4. Blood

Show answer
Correct Option: A,D
Explanation:

 Globular proteins are present in egg albumin, haemoglobin, myoglobin, insulin, serum globulins in blood, and many enzymes.

The main structural feature of proteins is_________.

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. Ether linkage

  2. Ester linkage

  3. Peptide linkage

  4. All the three above

Show answer
Correct Option: C
Explanation:

Proteins are linear polymers formed by linking the -carboxyl group of one amino acid to the -amino group of another amino acid with a peptide bond.

Which structural feature distinguishes proline from other natural $\alpha$-amino acids :

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. It is optically inactive

  2. It contains aromatic group

  3. It is dicarboxylic acid

  4. It has a secondary amine

  5. It contains two amino groups

Show answer
Correct Option: D
Explanation:

Proline is the only proteinogenic amino acid whose side-group links to the -amino group and, thus, is also the only proteinogenic amino acid containing a secondary amine at this position.

The sequence in which amino acids are linked to one another in a protein molecule is called its:

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. Primary structure

  2. Secondary structure

  3. Tertiary structure

  4. Quanternary structure

Show answer
Correct Option: A
Explanation:

Proteins may have one or more polypeptide chains. Each polypeptide in a protein has amino acids linked with each other in a specific sequence and it is this sequence of amino acids that is said to be the primary structure of that protein.

What type of a chemical reaction takes place when,
(i) lime stone is heated?
(ii) proteins are converted into amino acids?

bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

  1. In both (i) and (ii), a combination reaction takes place

  2. In (i), a decomposition reaction takes place while in (ii), a combination reaction takes place

  3. In both (i) and (ii), a decomposition reaction takes place

  4. In (i), a combination reaction takes place while in (ii), a decomposition reaction takes place

Show answer
Correct Option: C
Explanation:

Lime stone is calcium carbonate which, upon heating, decomposes into calcium oxide and carbon dioxide.

$CaCO _3 \rightarrow CaO + CO _2$
 Similarly, proteins also undergo decomposition to form amino acids.
$ (-Amino \ acid-) _n \rightarrow n Amino \ acids$