It functions as an electron carrier.
Correct Answer
c.
It functions as an enzyme.
d.
It is the final electron acceptor for anaerobic respiration.
Step-by-Step AI Explanation
Verified Method
NAD⁺ (Nicotinamide adenine dinucleotide) functions as an electron carrier in cellular respiration. It accepts electrons (and hydrogen) to become NADH during glycolysis and the Krebs cycle, then donates them to the electron transport chain to drive ATP synthesis. It is not an enzyme, not a nucleotide source for ATP, and the final electron acceptor in anaerobic respiration is an organic molecule (e.g., pyruvate), not NAD⁺.
Q2mcq
Oxygen is not produced during photosynthesis by
a.
Cycas
b.
Nostoc
c.
Green sulphur bacteria
Correct Answer
d.
Chara
Step-by-Step AI Explanation
Verified Method
Green sulphur bacteria (e.g., Chlorobium) are anoxygenic photosynthesizers — they use H₂S instead of H₂O as the electron donor, producing sulphur instead of oxygen. Cycas (gymnosperm), Nostoc (cyanobacterium), and Chara (green alga) all perform oxygenic photosynthesis, splitting water and releasing O₂.
Q3mcq
Double fertilization is
a.
Fusion of two male gametes with one egg
b.
Fusion of one male gamete with two polar nuclei
c.
Fusion of two male gametes of a pollen tube with two different eggs
d.
Syngamy and triple fusion
Correct Answer
Step-by-Step AI Explanation
Verified Method
Double fertilization in angiosperms involves two events: syngamy (fusion of one male gamete with the egg cell to form a diploid zygote) and triple fusion (fusion of the second male gamete with the two polar nuclei to form the triploid primary endosperm nucleus). Together these two events constitute double fertilization.
Q4mcq
In which of the following forms is iron absorbed by plants?
a.
Free element
b.
Ferrous
c.
Ferric
d.
Both ferric and ferrous
Correct Answer
Step-by-Step AI Explanation
Verified Method
Plants can absorb iron in both ferrous (Fe²⁺) and ferric (Fe³⁺) forms, though Fe²⁺ is the primary form absorbed. Many plants reduce Fe³⁺ to Fe²⁺ at the root surface before uptake. NCERT notes both forms are absorbed, making option (4) correct.
Q5mcq
Which of the following elements is responsible for maintaining turgor in cells?
a.
Potassium
Correct Answer
b.
Sodium
c.
Magnesium
d.
Calcium
Step-by-Step AI Explanation
Verified Method
Potassium (K⁺) is the most abundant cation in plant cells and plays a key role in maintaining turgor pressure. It is actively transported into guard cells to cause stomatal opening (by increasing osmotic pressure), and is essential for maintaining the osmotic potential that drives water uptake and turgor in all plant cells.
Q6mcq
Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
a.
Banana
b.
Yucca
Correct Answer
c.
Hydrilla
d.
Viola
Step-by-Step AI Explanation
Verified Method
Yucca and the Yucca moth (Tegeticula) share an obligate mutualistic relationship — neither can complete its life cycle without the other. The moth is the sole pollinator of Yucca, and Yucca flowers are the sole site where the moth lays eggs and its larvae feed. This is a classic NCERT example of mutualism/co-evolution.
Q7mcq
Pollen grains can be stored for several years in liquid nitrogen having a temperature of
a.
–196°C
Correct Answer
b.
–80°C
c.
–120°C
d.
–160°C
Step-by-Step AI Explanation
Verified Method
Liquid nitrogen has a temperature of –196°C. Pollen grains can be stored for several years in liquid nitrogen (cryopreservation) at this temperature without losing their viability. This is explicitly stated in NCERT Biology textbook (Class 12, Chapter 2).
Q8mcq
What type of ecological pyramid would be obtained with the following data?
Secondary consumer: 120 g
Primary consumer: 60 g
Primary producer: 10 g
a.
Upright pyramid of numbers
b.
Pyramid of energy
c.
Inverted pyramid of biomass
Correct Answer
d.
Upright pyramid of biomass
Step-by-Step AI Explanation
Verified Method
The data shows: Primary producer (10 g) < Primary consumer (60 g) < Secondary consumer (120 g). Biomass increases from producer to higher trophic levels, which is an inverted pyramid of biomass. This pattern is typically seen in aquatic ecosystems where phytoplankton (producers) have lower standing biomass than the consumers they support due to rapid turnover rates.
Q9mcq
Natality refers to
a.
Number of individuals leaving the habitat
b.
Birth rate
Correct Answer
c.
Death rate
d.
Number of individuals entering a habitat
Step-by-Step AI Explanation
Verified Method
Natality refers to the birth rate in a population — the number of new individuals born per unit time. It is one of the four key parameters (along with mortality, immigration, and emigration) that determine population size and growth.
Q9mcq
Natality refers to
a.
Number of individuals leaving the habitat
b.
Birth rate
Correct Answer
c.
Death rate
d.
Number of individuals entering a habitat
Step-by-Step AI Explanation
Verified Method
Natality refers to the birth rate, i.e., the number of births per unit time in a population. It is one of the factors that increases population size.
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I: a. Herbarium, b. Key, c. Museum, d. Catalogue
Column II: i. It is a place having a collection of preserved plants and animals. ii. A list that enumerates methodically all the species found in an area with brief description aiding identification. iii. Is a place where dried and pressed plant specimens mounted on sheets are kept. iv. A booklet containing a list of characters and their alternates which are helpful in identification of various taxa.
a.
a-ii, b-iv, c-iii, d-i
b.
a-iii, b-ii, c-i, d-iv
c.
a-i, b-iv, c-iii, d-ii
d.
a-iii, b-iv, c-i, d-ii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I: a. Tidal volume, b. Inspiratory Reserve volume, c. Expiratory Reserve volume, d. Residual volume
Column II: i. 2500–3000 mL, ii. 1100–1200 mL, iii. 500–550 mL, iv. 1000–1100 mL
a.
a-i, b-iv, c-ii, d-iii
b.
a-iii, b-i, c-iv, d-ii
c.
a-iii, b-ii, c-i, d-iv
d.
a-iv, b-iii, c-ii, d-i
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I: a. Tricuspid valve, b. Bicuspid valve, c. Semilunar valve
Column II: i. Between left atrium and left ventricle, ii. Between right ventricle and pulmonary artery, iii. Between right atrium and right ventricle
a.
a-i, b-ii, c-iii
b.
a-i, b-iii, c-ii
c.
a-iii, b-i, c-ii
d.
a-ii, b-i, c-iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Tricuspid valve i. Between left atrium and left ventricle
b. Bicuspid valve ii. Between right ventricle and pulmonary artery
c. Semilunar valve iii. Between right atrium and right ventricle
a b c
a.
i ii iii
b.
i iii ii
c.
iii i ii
d.
ii i iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Proliferative Phase i. Breakdown of endometrial lining
b. Secretory Phase ii. Follicular Phase
c. Menstruation iii. Luteal Phase
a b c
a.
ii iii i
b.
i iii ii
c.
iii ii i
d.
iii i ii
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Which of the following structures or regions is incorrectly paired with its function?
(1) Hypothalamus: production of releasing hormones and regulation of temperature, hunger and thirst.
(2) Limbic system: consists of fibre tracts that interconnect different regions of brain; controls movement.
(3) Medulla oblongata: controls respiration and cardiovascular reflexes.
(4) Corpus callosum: band of fibers connecting left and right cerebral hemispheres.
a.
Hypothalamus : production of releasing hormones and regulation of temperature, hunger and thirst.
b.
Limbic system : consists of fibre tracts that interconnect different regions of brain; controls movement.
c.
Medulla oblongata : controls respiration and cardiovascular reflexes.
d.
Corpus callosum : band of fibers connecting left and right cerebral hemispheres.
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Glycosuria i. Accumulation of uric acid in joints
b. Gout ii. Mass of crystallised salts within the kidney
c. Renal calculi iii. Inflammation in glomeruli
d. Glomerular nephritis iv. Presence of glucose in urine
a b c d
a.
ii iii i iv
b.
i ii iii iv
c.
iii ii iv i
d.
iv i ii iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Glycosuria i. Accumulation of uric acid in joints
b. Gout ii. Mass of crystallised salts within the kidney
c. Renal calculi iii. Inflammation in glomeruli
d. Glomerular nephritis iv. Presence of glucose in urine
a b c d
a.
ii iii i iv
b.
i ii iii iv
c.
iii ii iv i
d.
iv i ii iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I (Function) Column II (Part of Excretory System)
a. Ultrafiltration i. Henle's loop
b. Concentration of urine ii. Ureter
c. Transport of urine iii. Urinary bladder
d. Storage of urine iv. Malpighian corpuscle
v. Proximal convoluted tubule
a b c d
a.
v iv i ii
b.
iv i ii iii
c.
iv v ii iii
d.
v iv i iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I (Function) Column II (Part of Excretory System)
a. Ultrafiltration i. Henle's loop
b. Concentration of urine ii. Ureter
c. Transport of urine iii. Urinary bladder
d. Storage of urine iv. Malpighian corpuscle
v. Proximal convoluted tubule
a b c d
a.
v iv i ii
b.
iv i ii iii
c.
iv v ii iii
d.
v iv i iii
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Fibrinogen i. Osmotic balance
b. Globulin ii. Blood clotting
c. Albumin iii. Defence mechanism
a b c
a.
i iii ii
b.
i ii iii
c.
iii ii i
d.
ii iii i
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Match the items given in Column I with those in Column II and select the correct option given below:
Column I Column II
a. Eutrophication i. UV-B radiation
b. Sanitary landfill ii. Deforestation
c. Snow blindness iii. Nutrient enrichment
d. Jhum cultivation iv. Waste disposal
a b c d
a.
iii iv i ii
b.
i iii iv ii
c.
ii i iii iv
d.
i ii iv iii
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Which of the following characteristics represent 'Inheritance of blood groups' in humans?
a. Dominance
b. Co-dominance
c. Multiple allele
d. Incomplete dominance
e. Polygenic inheritance
a.
b, d and e
b.
a, b and c
c.
b, c and e
d.
a, c and e
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