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Biology & Medical Sciences (Biology) Solved Questions & Notes (2026) - Apex Rankers

Natural & Physical Sciences > Biology > Biology & Medical Sciences

278 Total Solved Questions
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Biology & Medical Sciences

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Q. 1 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the primary function of Hemoglobin in human red blood cells (erythrocytes)?
A
Reversible transport of molecular Oxygen (O2) via four iron-containing heme prosthetic groups
✓ Correct
B
Synthesis of plasma clotting factors
C
Phagocytosis of invading bacterial pathogens
D
Production of circulating antibodies
💡 Step-by-Step Explanation & Concept Rationale
Hemoglobin is a tetrameric allosteric protein binding up to 4 O2 molecules for systemic respiratory delivery.
Q. 2 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which blood group is universally termed the 'Universal Donor' for red blood cell transfusions?
A
O Negative (O-)
✓ Correct
B
AB Positive (AB+)
C
A Positive
D
B Negative
💡 Step-by-Step Explanation & Concept Rationale
O Negative erythrocytes lack A, B, and Rh (D) antigens, minimizing risk of hemolytic transfusion reactions in recipients.
Q. 3 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which blood group is universally known as the 'Universal Recipient' for plasma and whole blood?
A
AB Positive (AB+)
✓ Correct
B
O Negative
C
A Negative
D
B Positive
💡 Step-by-Step Explanation & Concept Rationale
AB Positive individuals have A, B, and Rh antigens on their cells and lack anti-A, anti-B, and anti-Rh antibodies.
Q. 4 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the main nitrogenous waste product excreted by the human urinary system?
A
Urea
✓ Correct
B
Uric acid
C
Ammonia
D
Creatine phosphate
💡 Step-by-Step Explanation & Concept Rationale
Humans are ureotelic organisms; ammonia produced from amino acid deamination is converted to less toxic urea in the liver via the urea cycle.
Q. 5 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which enzyme in human saliva begins the chemical digestion of dietary starch into maltose?
A
Salivary Amylase (Ptyalin)
✓ Correct
B
Pepsin
C
Trypsin
D
Lingual Lipase
💡 Step-by-Step Explanation & Concept Rationale
Ptyalin breaks alpha-1,4 glycosidic bonds in starch inside the oral cavity at near-neutral pH.
Q. 6 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
Which cells in the stomach gastric mucosa secrete Hydrochloric acid (HCl) and Intrinsic Factor?
A
Parietal (Oxyntic) Cells
✓ Correct
B
Chief (Peptic) Cells
C
Goblet (Mucous) Cells
D
G Cells
💡 Step-by-Step Explanation & Concept Rationale
Parietal cells use H+/K+ ATPase proton pumps to secrete gastric acid, activating pepsinogen secreted by chief cells.
Q. 7 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What vector transmits the Plasmodium protozoan parasite causing Malaria in humans?
A
Female Anopheles mosquito
✓ Correct
B
Male Anopheles mosquito
C
Aedes aegypti mosquito
D
Culex mosquito
💡 Step-by-Step Explanation & Concept Rationale
Female Anopheles mosquitoes require blood meals for egg development and transmit Plasmodium sporozoites.
Q. 8 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What disease is caused by the flavivirus transmitted by the daytime-biting Aedes aegypti mosquito?
A
Dengue Fever
✓ Correct
B
Malaria
C
Cholera
D
Typhoid
💡 Step-by-Step Explanation & Concept Rationale
Aedes aegypti is the primary vector for Dengue, Chikungunya, Yellow Fever, and Zika viruses.
Q. 9 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the fundamental unit of biological classification and taxonomy?
A
Species
✓ Correct
B
Genus
C
Family
D
Order
💡 Step-by-Step Explanation & Concept Rationale
Species is the basic biological taxonomic rank consisting of individuals capable of interbreeding and producing fertile offspring.
Q. 10 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
What type of nucleic acid genome is found in the Human Immunodeficiency Virus (HIV)?
A
Single-stranded positive-sense RNA (Retrovirus with Reverse Transcriptase)
✓ Correct
B
Double-stranded circular DNA
C
Single-stranded DNA
D
Segmented double-stranded RNA
💡 Step-by-Step Explanation & Concept Rationale
HIV is an enveloped lentivirus possessing two identical copies of single-stranded positive-sense RNA.
Q. 11 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which mineral ion is essential for normal thyroid hormone (T3 and T4) synthesis?
A
Iodine (I-)
✓ Correct
B
Iron (Fe)
C
Calcium (Ca)
D
Zinc (Zn)
💡 Step-by-Step Explanation & Concept Rationale
Iodine is incorporated into tyrosine residues of thyroglobulin to synthesize triiodothyronine (T3) and thyroxine (T4).
Q. 12 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Deficiency of Vitamin C (Ascorbic acid) impairs collagen synthesis and causes which clinical condition?
A
Scurvy (bleeding gums, skin petechiae, poor wound healing)
✓ Correct
B
Rickets
C
Night Blindness (Nyctalopia)
D
Beri-beri
💡 Step-by-Step Explanation & Concept Rationale
Vitamin C is a required cofactor for prolyl and lysyl hydroxylases in collagen biosynthesis; deficiency results in scurvy.
Q. 13 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
What is the active form of Vitamin D synthesized following sunlight exposure on skin?
A
Calcitriol (1,25-dihydroxycholecalciferol)
✓ Correct
B
Cholecalciferol (D3)
C
Ergocalciferol (D2)
D
Calcidiol (25-OH-D3)
💡 Step-by-Step Explanation & Concept Rationale
The kidneys convert 25-hydroxyvitamin D into active 1,25-(OH)2-D3 (Calcitriol) to regulate calcium absorption.
Q. 14 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which photoreceptor cells in the human retina are responsible for color vision and visual acuity in bright light?
A
Cone cells (Cones)
✓ Correct
B
Rod cells (Rods)
C
Bipolar cells
D
Amacrine cells
💡 Step-by-Step Explanation & Concept Rationale
Cones (containing photopsins for Red, Green, and Blue) provide high-acuity photopic color vision (Rods mediate low-light scotopic vision).
Q. 15 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
What is the primary excitatory neurotransmitter in the human central nervous system?
A
Glutamate
✓ Correct
B
GABA (gamma-aminobutyric acid)
C
Glycine
D
Endorphin
💡 Step-by-Step Explanation & Concept Rationale
Glutamate is the major fast excitatory neurotransmitter; GABA is the chief inhibitory neurotransmitter.
Q. 16 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the primary function of Hemoglobin in human red blood cells (erythrocytes)?
A
Reversible transport of molecular Oxygen (O2) via four iron-containing heme prosthetic groups
✓ Correct
B
Synthesis of plasma clotting factors
C
Phagocytosis of invading bacterial pathogens
D
Production of circulating antibodies
💡 Step-by-Step Explanation & Concept Rationale
Hemoglobin is a tetrameric allosteric protein binding up to 4 O2 molecules for systemic respiratory delivery.
Q. 17 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which blood group is universally termed the 'Universal Donor' for red blood cell transfusions?
A
O Negative (O-)
✓ Correct
B
AB Positive (AB+)
C
A Positive
D
B Negative
💡 Step-by-Step Explanation & Concept Rationale
O Negative erythrocytes lack A, B, and Rh (D) antigens, minimizing risk of hemolytic transfusion reactions in recipients.
Q. 18 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which blood group is universally known as the 'Universal Recipient' for plasma and whole blood?
A
AB Positive (AB+)
✓ Correct
B
O Negative
C
A Negative
D
B Positive
💡 Step-by-Step Explanation & Concept Rationale
AB Positive individuals have A, B, and Rh antigens on their cells and lack anti-A, anti-B, and anti-Rh antibodies.
Q. 19 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the main nitrogenous waste product excreted by the human urinary system?
A
Urea
✓ Correct
B
Uric acid
C
Ammonia
D
Creatine phosphate
💡 Step-by-Step Explanation & Concept Rationale
Humans are ureotelic organisms; ammonia produced from amino acid deamination is converted to less toxic urea in the liver via the urea cycle.
Q. 20 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
Which enzyme in human saliva begins the chemical digestion of dietary starch into maltose?
A
Salivary Amylase (Ptyalin)
✓ Correct
B
Pepsin
C
Trypsin
D
Lingual Lipase
💡 Step-by-Step Explanation & Concept Rationale
Ptyalin breaks alpha-1,4 glycosidic bonds in starch inside the oral cavity at near-neutral pH.
Q. 21 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
Which cells in the stomach gastric mucosa secrete Hydrochloric acid (HCl) and Intrinsic Factor?
A
Parietal (Oxyntic) Cells
✓ Correct
B
Chief (Peptic) Cells
C
Goblet (Mucous) Cells
D
G Cells
💡 Step-by-Step Explanation & Concept Rationale
Parietal cells use H+/K+ ATPase proton pumps to secrete gastric acid, activating pepsinogen secreted by chief cells.
Q. 22 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What vector transmits the Plasmodium protozoan parasite causing Malaria in humans?
A
Female Anopheles mosquito
✓ Correct
B
Male Anopheles mosquito
C
Aedes aegypti mosquito
D
Culex mosquito
💡 Step-by-Step Explanation & Concept Rationale
Female Anopheles mosquitoes require blood meals for egg development and transmit Plasmodium sporozoites.
Q. 23 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What disease is caused by the flavivirus transmitted by the daytime-biting Aedes aegypti mosquito?
A
Dengue Fever
✓ Correct
B
Malaria
C
Cholera
D
Typhoid
💡 Step-by-Step Explanation & Concept Rationale
Aedes aegypti is the primary vector for Dengue, Chikungunya, Yellow Fever, and Zika viruses.
Q. 24 Biology & Medical Sciences
Difficulty: EASY (1 Mark)
What is the fundamental unit of biological classification and taxonomy?
A
Species
✓ Correct
B
Genus
C
Family
D
Order
💡 Step-by-Step Explanation & Concept Rationale
Species is the basic biological taxonomic rank consisting of individuals capable of interbreeding and producing fertile offspring.
Q. 25 Biology & Medical Sciences
Difficulty: MEDIUM (1 Mark)
What type of nucleic acid genome is found in the Human Immunodeficiency Virus (HIV)?
A
Single-stranded positive-sense RNA (Retrovirus with Reverse Transcriptase)
✓ Correct
B
Double-stranded circular DNA
C
Single-stranded DNA
D
Segmented double-stranded RNA
💡 Step-by-Step Explanation & Concept Rationale
HIV is an enveloped lentivirus possessing two identical copies of single-stranded positive-sense RNA.
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