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Genetics & Molecular Biology (Biology) Solved Questions & Notes (2026) - Apex Rankers

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44 Total Solved Questions
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Genetics & Molecular Biology

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Q. 1 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
According to Watson and Crick's model, what type of chemical bonds hold complementary nitrogenous base pairs together in a DNA double helix?
A
Hydrogen Bonds (2 between A-T, 3 between G-C)
✓ Correct
B
Phosphodiester covalent bonds
C
Peptide bonds
D
Disulfide bridges
💡 Step-by-Step Explanation & Concept Rationale
Adenine pairs with Thymine via 2 hydrogen bonds; Guanine pairs with Cytosine via 3 hydrogen bonds.
Q. 2 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
What enzyme is primarily responsible for synthesizing messenger RNA (mRNA) from a DNA template during transcription in eukaryotes?
A
RNA Polymerase II
✓ Correct
B
DNA Polymerase III
C
DNA Ligase
D
Reverse Transcriptase
💡 Step-by-Step Explanation & Concept Rationale
RNA Polymerase II transcribes all protein-coding genes into pre-mRNA in eukaryotic nuclei.
Q. 3 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the universal start codon in mRNA that codes for Methionine in translation?
A
AUG
✓ Correct
B
UAA
C
UAG
D
UGA
💡 Step-by-Step Explanation & Concept Rationale
AUG is the universal initiator codon specifying Methionine (formyl-methionine in prokaryotes). UAA, UAG, and UGA are stop codons.
Q. 4 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the phenotypic Mendelian ratio in the F2 generation of a classic monohybrid cross with complete dominance?
A
3 : 1 (3 Dominant : 1 Recessive)
✓ Correct
B
9 : 3 : 3 : 1
C
1 : 2 : 1
D
1 : 1
💡 Step-by-Step Explanation & Concept Rationale
A monohybrid cross between heterozygotes (Aa x Aa) yields 3 dominant to 1 recessive phenotype (1 AA : 2 Aa : 1 aa genotype).
Q. 5 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
The primary structural component of plant cell walls is:
A
Glycogen
B
Cellulose
✓ Correct
C
Chitin
D
Peptidoglycan
💡 Step-by-Step Explanation & Concept Rationale
Cellulose, a linear polysaccharide of beta-D-glucose units, provides rigidity and tensile strength to plant cell walls.
Q. 6 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #7: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Valine
B
Alanine
C
Methionine
✓ Correct
D
Tryptophan
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 7 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #12: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Tryptophan
B
Alanine
C
Valine
D
Methionine
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 8 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #17: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Methionine
✓ Correct
B
Alanine
C
Valine
D
Tryptophan
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 9 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #22: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Alanine
B
Methionine
✓ Correct
C
Valine
D
Tryptophan
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 10 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #27: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Valine
B
Alanine
C
Methionine
✓ Correct
D
Tryptophan
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 11 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #32: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Tryptophan
B
Alanine
C
Valine
D
Methionine
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 12 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In cell biology & macromolecular biochemistry #37: Which amino acid is the starting codon (AUG) in eukaryotic protein synthesis?
A
Methionine
✓ Correct
B
Alanine
C
Valine
D
Tryptophan
💡 Step-by-Step Explanation & Concept Rationale
AUG codes for methionine in eukaryotes (and formylmethionine in prokaryotes), serving as the universal start codon.
Q. 13 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In a dihybrid cross of heterozygous parents (AaBb x AaBb), the expected phenotypic ratio in the F2 generation is:
A
3 : 1
B
9 : 3 : 3 : 1
✓ Correct
C
1 : 2 : 1
D
9 : 7
💡 Step-by-Step Explanation & Concept Rationale
Mendelian dihybrid phenotypic ratio is 9 (dominant for both) : 3 (dominant 1st, recessive 2nd) : 3 (recessive 1st, dominant 2nd) : 1 (recessive both).
Q. 14 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #7: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Southern Blotting
B
Gel Electrophoresis
C
Polymerase Chain Reaction (PCR)
✓ Correct
D
Northern Blotting
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 15 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #12: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Northern Blotting
B
Gel Electrophoresis
C
Southern Blotting
D
Polymerase Chain Reaction (PCR)
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 16 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #17: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Polymerase Chain Reaction (PCR)
✓ Correct
B
Gel Electrophoresis
C
Southern Blotting
D
Northern Blotting
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 17 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #22: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Gel Electrophoresis
B
Polymerase Chain Reaction (PCR)
✓ Correct
C
Southern Blotting
D
Northern Blotting
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 18 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #27: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Southern Blotting
B
Gel Electrophoresis
C
Polymerase Chain Reaction (PCR)
✓ Correct
D
Northern Blotting
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 19 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #32: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Northern Blotting
B
Gel Electrophoresis
C
Southern Blotting
D
Polymerase Chain Reaction (PCR)
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 20 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In molecular genetics #37: What molecular technique is used to amplify minute quantities of specific DNA segments in vitro?
A
Polymerase Chain Reaction (PCR)
✓ Correct
B
Gel Electrophoresis
C
Southern Blotting
D
Northern Blotting
💡 Step-by-Step Explanation & Concept Rationale
PCR utilizes thermal cycling with Taq polymerase to exponentially amplify targeted DNA sequences.
Q. 21 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which hormone regulates blood glucose levels by facilitating the cellular uptake of glucose?
A
Glucagon
B
Insulin
✓ Correct
C
Thyroxine
D
Cortisol
💡 Step-by-Step Explanation & Concept Rationale
Insulin, secreted by the beta cells of the islets of Langerhans in the pancreas, lowers blood glucose by promoting cellular storage as glycogen.
Q. 22 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In human organ physiology #7: What is the primary digestive enzyme in saliva that begins carbohydrate digestion by breaking starch into maltose?
A
Trypsin
B
Pepsin
C
Salivary Amylase (Ptyalin)
✓ Correct
D
Lipase
💡 Step-by-Step Explanation & Concept Rationale
Salivary amylase hydrolyzes alpha-1,4 glycosidic bonds in starch to initiate carbohydrate digestion in the oral cavity.
Q. 23 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In human organ physiology #12: What is the primary digestive enzyme in saliva that begins carbohydrate digestion by breaking starch into maltose?
A
Lipase
B
Pepsin
C
Trypsin
D
Salivary Amylase (Ptyalin)
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
Salivary amylase hydrolyzes alpha-1,4 glycosidic bonds in starch to initiate carbohydrate digestion in the oral cavity.
Q. 24 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In human organ physiology #17: What is the primary digestive enzyme in saliva that begins carbohydrate digestion by breaking starch into maltose?
A
Salivary Amylase (Ptyalin)
✓ Correct
B
Pepsin
C
Trypsin
D
Lipase
💡 Step-by-Step Explanation & Concept Rationale
Salivary amylase hydrolyzes alpha-1,4 glycosidic bonds in starch to initiate carbohydrate digestion in the oral cavity.
Q. 25 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
In human organ physiology #22: What is the primary digestive enzyme in saliva that begins carbohydrate digestion by breaking starch into maltose?
A
Pepsin
B
Salivary Amylase (Ptyalin)
✓ Correct
C
Trypsin
D
Lipase
💡 Step-by-Step Explanation & Concept Rationale
Salivary amylase hydrolyzes alpha-1,4 glycosidic bonds in starch to initiate carbohydrate digestion in the oral cavity.
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