Biology · Chemistry

Biomolecules and Enzymes

1,501 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

What is Entrez?

  1. A proteomic search engine

  2. A programme key word

  3. Starting code of a sequence analysis

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Entrez is NCBI's integrated search and retrieval system for biological databases. While commonly used for nucleotide/protein sequences, it functions as a comprehensive search engine for proteomic and genomic data.

Multiple choice

Which of the following pathway databases is based on reference pathway maps?

  1. Metacyc

  2. Ecocyc

  3. KEGG pathway

  4. UM-BBD
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

MetaCyc is a curated database of metabolic pathways derived from scientific literature, organized around reference pathway maps that represent consensus metabolic knowledge from diverse organisms. Unlike KEGG's species-specific pathways or EcoCyc's E. coli focus, MetaCyc uses generalized reference pathways as its organizing principle.

Multiple choice

Which of the following statements regarding enzyme inhibition is correct?

  1. Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.

  2. Competitive inhibitors often bind to the enzyme irreversibly.

  3. Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzymes.

  4. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzymes. Most competitive inhibitors function by binding reversibly to the active site of the enzyme. As a result, many sources state that this is the defining feature of competitive inhibitors.

Multiple choice

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals because all of these

  1. are exclusively synthesised in the body of a living organism

  2. enhance oxidative metabolism

  3. are conjugated proteins

  4. help in regulating metabolism
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals because all of these help in regulating metabolism.

Multiple choice

Which of the following statements is/are false?

A. Methionine is an α-amino acid and is polar essential amino acid. B. Alanine is associated with codons- GCU, GCC, GCA, and GCG. C. Alginic acid is a water soluble dietary fiber.

  1. Only A

  2. Only C

  3. A and B

  4. B and C

  5. A and C
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because Methionine is an α-amino acid with the chemical formula HO2CCH (NH2) CH2CH2SCH3. This essential amino acid is classified as non-polar essential amino acid and Alginic acids (Alginates) found in algae is a water insoluble dietary fiber.

Multiple choice

Which of the following is/are essential amino acids for humans?

P. histidine Q. tyrosine R. isoleucine S. glutamic acid

  1. Only P

  2. P and Q

  3. P, Q and R

  4. Q, R and S

  5. Only S
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct statement. P, Q and R all are essential amino acids for humans. The indispensable amino acids or essential amino acids are those amino acids that cannot be synthesized by the organism being considered, and therefore must be supplied in its diet. The amino acids regarded as essential for humans are phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, lysine, and histidine. The amino acids arginine, cysteine, glycine, glutamine, proline, serine and tyrosine are considered as conditionally essential amino acids, meaning they are not normally required in the diet, but must be supplied exogenously to specific populations that do not synthesize them in adequate amounts.

Multiple choice

Match the entries in Group - I (essential amino acids) with those in Group - II (corresponding functional groups/ side chains).

 
Group - I
Group - II
P. Histidine 1. hydroxy
Q. Leucine 2. isobuytyl
R. Threonine 3. imidazole
S. Tryptophan 4. indole

  1. P - 3, Q - 2, R - 1, S - 4

  2. P - 3, Q - 4, R - 1, S - 2

  3. P - 3, Q - 4, R - 2, S - 1

  4. P - 1, Q - 2, R - 3, S - 4

  5. P - 2, Q - 1, R - 3, S - 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option as the correct matching is P - 3, Q - 5, R - 1, S - 4. Histidine is alpha amino acid. The conjugate acid of the imidazole side chain. Leucine is a branched-chain α-amino acid with the chemical formula HO2CCH (NH2) CH2CH (CH3)2.  Leucine is hydrophobic in nature dut to the presence of aliphatic isobutyl side chain. Threonine is an α-amino acid with the chemical formula HO2CCH (NH2) CH (OH )CH3. This essential amino acid is classified as polar. Together with serine, threonine is one of two proteinogenic amino acids bearing an alcohol group (OH group). Tryptophan is one of the 22 standard amino acids and is an essential amino acid in the human diet. It has indole as fuctional group.

Multiple choice

Why are animal proteins called first class proteins?

  1. They release energy in absence of energy in the body.

  2. They repair the damaged tissues in the body.

  3. They contain all the amino acids.

  4. They protect the body from diseases.

  5. They cushion the internal organs.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Animal proteins are called first class proteins because they contain all the amino acids.