Biology · Chemistry

Biomolecules and Enzymes

1,432 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice drug-target interaction pharmaceutical products and drug action medicinal chemistry chemistry in everyday life chemistry body defense system

Which of the following statements is not true about enzyme inhibitors?

  1. Inhibit the catalytic activity of the enzyme.

  2. Prevent the binding of substrate.

  3. Generally a strong covalent bond is formed between an inhibitor and an enzymes.

  4. Inhibitors can be competitive or non-competitive.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Generally a weak bond such as H-bonding, van der Waals interaction etc. is formed between an inhibitor and an enzyme.

Multiple choice drug-target interaction pharmaceutical products and drug action medicinal chemistry chemistry in everyday life chemistry body defense system

Which of the following statements is not true about enzyme inhibitors?

  1. Inhibit the catalytic activity of the enzyme.

  2. Prevent the binding of substrate.

  3. Generally, a strong covalent bond is formed between an inhibitor and an enzyme.

  4. Inhibitors can be competitive or non-competitive.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Enzyme inhibitors bind reversibly and irreversibly.
They bind reversibly with non-covalent bond, whereas, they bind irreversibly with covalent bond where they change the key amino acid residues needed for enzymatic activity.
Hence, option C is correct.
Multiple choice drug-target interaction pharmaceutical products and drug action medicinal chemistry chemistry in everyday life chemistry body defense system

Which site of an enzyme is called allosteric site?

  1. which binds to the cell wall

  2. where drugs bind to an enzyme

  3. which is not the active site, where some drugs bind to an enzyme

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 The allosteric site is the site, which is not the active site, where some drugs bind to an enzyme. Due to this, the shape of the enzyme changes, it becomes difficult for the substrate to recognize the active site of the enzyme. This represents non-competitive inhibition.

Multiple choice drug-target interaction pharmaceutical products and drug action medicinal chemistry chemistry in everyday life chemistry body defense system

The bond formed between an enzyme and an inhibitor:

  1. can be broken easily

  2. cannot be broken easily

  3. is a weak bond

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
If the bond formed between an enzyme and an inhibitor is a strong covalent bond, it cannot be broken easily. Then the enzyme is blocked permanently and the body degrades the enzyme-inhibitor complex and synthesizes the new enzyme.
Multiple choice evs - i constituents of food simple test for nutrients test for nutrients protein and its function nutrients and foodstuffs

Which of the following is made up of amino acids?

  1. Amylase

  2. Glycogen

  3. Phospholipid

  4. Polysaccharide

  5. Ribonucleic acid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Amylase is a protein enzyme, a polymer of amino acids. Glycogen is homopolysaccharide of D-glucose with highly branched structure (every 8-12 residues as compared to presence of branches in starch for every 24-30 residues). Phopholipids have phosphate and lipids (carbon and hydrogen atoms) while polysaccharides are polymer of simple sugars. RNA is polymer of ribonucleotides. 

Therefore, the correct answer is option A.

Multiple choice evs - i constituents of food simple test for nutrients test for nutrients protein and its function nutrients and foodstuffs

The different amino acids are joined together by peptide bonds to form

  1. Lipids

  2. Proteins

  3. Carbohydrates

  4. Nucleic acids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Proteins are the building blocks, which takes part in several metabolic reaction. They have four different levels of structure primary, secondary, tertiary and quaternary. There are 20 different standard L-α-amino acids used by cells for protein construction. Amino acids contain both a basic amino group and an acidic carboxyl group. This difunctionality allows the individual amino acids to join together in long chains by forming peptide bonds: amide bonds between the -NH2 of one amino acid and the -COOH of another. Sequences with fewer than 50 amino acids are generally referred to as peptides, while the terms protein or polypeptide are used for longer sequences. A protein can be made up of one or more polypeptide molecules. The end of the peptide or protein sequence with a free carboxyl group is called the carboxy-terminus or C-terminus. The terms amino-terminus or N-terminus describe the end of the sequence with a free α-amino group. The amino acids differ in structure by the substituent on their side chains. These side chains confer different chemical, physical and structural properties to the final peptide or protein.
So, the correct answer is option B.

Multiple choice evs - i constituents of food simple test for nutrients test for nutrients protein and its function nutrients and foodstuffs

Choose the correct answer from the alternatives given:
Amino acids are building blocks of

  1. Carbohydrates

  2. Nucleic acids

  3. Lipids

  4. Proteins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amino acids are the building blocks of polypeptide chain or proteins. These are encoded by the triplet codons of mRNA. Each codon synthesizes a specific amino acid. Example: AUG for methionine, UUU for phenylalanine and so on. Amino acids are connected via the peptide bonds to form the proteins.

Hence, the correct answer is 'Proteins'

Multiple choice evs - i constituents of food simple test for nutrients test for nutrients protein and its function nutrients and foodstuffs

Proteins are a polymerisation product of 

  1. Monosaccharides

  2. Muramic acid

  3. Amino acids

  4. All the above.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Amino acids are Linked by peptide bonds to form polypeptide chains. Proteins are linear polymers formed by linking the α-carboxyl group of one amino acid to the α-amino group of another amino acid with a peptide bond (also called an amide bond).

So, the correct answer is option C.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

Today, it is most appropriate to state that a gene controls

  1. one enzyme

  2. one protein

  3. one polypeptide chain

  4. one amino acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

One gene one enzyme hypothesis had many defects so it changed to one gene-one polypeptide.  According to one gene-one polypeptide hypothesis, the information enclosed in one gene is sufficient to form one polypeptide only. Genes control the synthesis of all proteins. Some proteins are enzymes and some are hormones.  Hemoglobin molecule consists of two different polypeptides alpha and beta which are formed by two different genes.

So, the correct option is 'one polypeptide chain'.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

Absorption of amino acid is dependent upon

  1. Sodium gradient

  2. ATP

  3. Protein gradient

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Amino acids together constitute the proteins. They are absorbed in the blood by active transportation mechanism. They are transported from the lumen into the cells by Na+ amino acid co-transporter using ATP in apical membrane energy by sodium gradient. 
So the correct answer is 'All of the above'.
Multiple choice different stages of growth reproductive system in humans division for growth and reproduction human system biology

Enzyme which becomes more active in aged person is _____________.

  1. Malate dehydrogenase

  2. Aldolase

  3. Lactate dehydrogenase

  4. Acetylcholinestrase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When ageing is progressing in the human body, different types of oxidising enzymes activity increases because of decreased rate of metabolism.

So, the correct option is ‘Malate dehydrogenase’.

Multiple choice different stages of growth reproductive system in humans division for growth and reproduction human system biology

Protein which plays a significant role in ageing is

  1. Actin

  2. Myosin

  3. Collagen

  4. Elastin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A. Actin - plays an important role in embryogenesis, the healing of wounds and the invasivity of cancer cells.

B. Myosin – plays an important role in muscle contractions and  a variety of movements of nonmuscle cells, including cell division,

C. Collagen – plays a significant role in ageing.

D. Elastin - plays an important role in the biomechanical function of vital body tissues and organs such as the heart, lungs, skin and the vocal folds.

So, the correct option is ‘Collagen’.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

Simple proteins bonded with a non-protein prosthetic group (acting as a cofactor) are called:

  1. Simple proteins

  2. Conjugated proteins

  3. Proteonic proteins

  4. All the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Simple proteins bonded with a non-proteinic prosthetic group (acting as cofactor) are called conjugated proteins.
Examples include  Glycoprotein, Lipoprotein, and Phosphoprotein.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

A holoenzyme contains apoenzyme and ____________ .

  1. isoenzyme

  2. cofactor

  3. inhibitor

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Holoenzyme = Apoenzyme+ Cofactor.

Apoenzyme:-An apoenzyme is an inactive enzyme, activation of the enzyme occurs upon binding of an organic or inorganic cofactor.
Cofactor:-A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's activity