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Biology - 2 — MH-CET Full Length Paper MCQs with Solutions
Free MH-CET Full Length Paper Biology - 2 MCQs with step-by-step solutions. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — easy
The outer protective exine of an angiospermic pollen grain is composed of which chemically resistant substance?
A. Pectocellulose
B. Sporopollenin ✓ Correct
C. Lignin
D. Suberin
Solution: Sporopollenin is an exceptionally resistant polymer that shields the pollen exine against enzymatic, thermal, and chemical degradation.
Q2 — easy
During human fertilization, the hydrolytic enzymes responsible for dispersing corona radiata and dissolving the zona pellucida are packaged within the:
A. Mitochondrial spiral
B. Acrosome ✓ Correct
C. Centrosome
D. Middle piece
Solution: The acrosome (from Golgi complex) contains hyaluronidase and acrosin for penetrating the egg coats.
Q3 — easy
Which of the following is an example of an autosomal dominant genetic disorder in humans?
A. Sickle-cell anemia
B. Huntington's chorea ✓ Correct
C. Phenylketonuria
D. Cystic fibrosis
Solution: Huntington's chorea is autosomal dominant (chromosome 4). Sickle-cell, PKU, and CF are autosomal recessive.
Q4 — easy
In a plant cell, if osmotic potential ($\Psi_s$) is $-12$ bars and pressure potential ($\Psi_p$) is $+8$ bars, then the water potential ($\Psi_w$) of the cell is:
A. $-20$ bars
B. $-4$ bars ✓ Correct
C. $+4$ bars
D. $-1.5$ bars
Solution: $\Psi_w = \Psi_s + \Psi_p = -12 + 8 = -4$ bars.
Q5 — easy
The physiological role of critical photoperiod perception in plants for inducing flowering is mediated by which pigment?
A. Chlorophyll-a
B. Phytochrome ✓ Correct
C. Carotenoid
D. Anthocyanin
Solution: Phytochrome ($P_r$/$P_{fr}$ interconversion) regulates photoperiodic floral induction.
Q6 — easy
If a person's stroke volume is $70$ mL and the heart rate is $75$ beats/min, their cardiac output is:
A. $4.5$ L/min
B. $5.25$ L/min ✓ Correct
C. $5.0$ L/min
D. $6.0$ L/min
Solution: CO = SV × HR = 70 × 75 = 5250 mL/min = 5.25 L/min.
Q7 — easy
The specific region of the human brain where the primary thermoregulatory center is located is the:
A. Medulla oblongata
B. Pons varolii
C. Hypothalamus ✓ Correct
D. Thalamus
Solution: The hypothalamus is the master homeostatic center controlling body temperature, thirst, hunger, and circadian rhythms.
Q8 — easy
Which cells of the gastric mucosa are responsible for secreting the proenzyme pepsinogen?
A. Oxyntic cells
B. Peptic (chief) cells ✓ Correct
C. Goblet cells
D. Enteroendocrine cells
Solution: Chief (zymogenic/peptic) cells secrete inactive pepsinogen, converted to active pepsin by gastric HCl.
Q9 — easy
The cloning vector $pBR322$ carries resistance genes against which two antibiotics?
A. Ampicillin and Tetracycline ✓ Correct
B. Chloramphenicol and Kanamycin
C. Streptomycin and Neomycin
D. Penicillin and Erythromycin
Solution: pBR322 carries ampᴿ (ampicillin resistance) and tetᴿ (tetracycline resistance) marker genes.
Q10 — easy
The interaction between sea anemone and clownfish residing among its stinging tentacles is a classic example of:
A. Mutualism
B. Parasitism
C. Commensalism ✓ Correct
D. Amensalism
Solution: Commensalism (+/0): clownfish benefits from protection while the sea anemone is unaffected.
Q11 — easy
The annual rate of biomass production per unit area by green plants during photosynthesis, prior to respiratory utilization, is called:
A. Net Primary Productivity (NPP)
B. Gross Primary Productivity (GPP) ✓ Correct
C. Secondary Productivity
D. Net Community Productivity
Solution: GPP = total rate of solar energy capture by autotrophs. NPP = GPP − Respiration.
Q12 — easy
Which of the following is recognized as the single most critical factor driving modern species extinction according to the "Evil Quartet"?
A. Over-exploitation
B. Alien species invasion
C. Habitat loss and fragmentation ✓ Correct
D. Co-extinction
Solution: Habitat destruction and fragmentation is the leading cause of modern biodiversity loss.
Q13 — easy
The anatomical entry of the pollen tube through the micropylar opening of the ovule is designated as:
A. Chalazogamy
B. Porogamy ✓ Correct
C. Mesogamy
D. Herpogamy
Solution: Porogamy: pollen tube enters via micropyle. Chalazogamy = via chalaza. Mesogamy = via integuments.
Q14 — easy
During human embryonic development, the embryonic heart starts beating after how many weeks of gestation?
A. 1 week
B. 4 weeks (1 month) ✓ Correct
C. 8 weeks (2 months)
D. 12 weeks (3 months)
Solution: By the end of week 4, the primitive tubular heart forms and begins rhythmic contractions.
Q15 — easy
In an individual with Klinefelter's syndrome, the total chromosome count and sex chromosome complement are:
A. $45, XO$
B. $47, XXY$ ✓ Correct
C. $47, XYY$
D. $46, XY$
Solution: Klinefelter's: 44 + XXY = 47 chromosomes. Males with hypogonadism and gynecomastia.
Q16 — easy
The sequence of non-coding intervening sequences transcribed in eukaryotic pre-mRNA that must be excised during RNA splicing are called:
A. Exons
B. Introns ✓ Correct
C. Cistrons
D. Promoters
Solution: Introns are non-coding sequences excised during post-transcriptional splicing.
Q17 — easy
The cranial capacity of modern Neanderthal man was approximately:
A. $650$–$800$ cc
B. $900$ cc
C. $1400$ cc ✓ Correct
D. $1650$ cc
Solution: Homo neanderthalensis had cranial capacity ~1400 cc, comparable to modern Homo sapiens.
Q18 — easy
Which mineral element is an indispensable constituent of the ring structure of chlorophyll and activates RuBisCO?
A. Iron ($Fe$)
B. Magnesium ($Mg$) ✓ Correct
C. Manganese ($Mn$)
D. Zinc ($Zn$)
Solution: Mg²⁺ occupies the center of the chlorophyll porphyrin ring and activates RuBisCO and PEPcase.
Q19 — easy
Which endocrine gland undergoes progressive atrophy with advancing age, leading to a weakened immune response in the elderly?
A. Thyroid
B. Thymus ✓ Correct
C. Adrenal cortex
D. Pituitary
Solution: The thymus involutes after puberty, causing declining thymosin and weakened cell-mediated immunity.
Q20 — easy
The biological vector used for introducing foreign recombinant DNA into dicotyledonous plant cells is:
A. \textit{Escherichia coli}
B. \textit{Bacillus thuringiensis}
C. \textit{Agrobacterium tumefaciens} ✓ Correct
D. \textit{Thermus aquaticus}
Solution: Agrobacterium tumefaciens with its Ti-plasmid delivers T-DNA into dicot plant cells.
Q21 — easy
The intermediate host in the life cycle of the human blood fluke (\textit{Schistosoma haematobium}) is:
A. Housefly
B. Freshwater snail ✓ Correct
C. Mosquito
D. Tsetse fly
Solution: Schistosoma requires a freshwater pulmonate snail as intermediate host (miracidia → cercariae).
Q22 — easy
The commercial strain of yeast used extensively in bakeries and brewing industries is:
A. \textit{Saccharomyces cerevisiae} ✓ Correct
B. \textit{Candida utilis}
C. \textit{Aspergillus oryzae}
D. \textit{Rhizopus stolonifer}
Solution: Saccharomyces cerevisiae (baker's/brewer's yeast) ferments sugars to ethanol and CO₂.
Q23 — easy
The logistic population growth model is mathematically represented by the differential equation:
A. $\frac{dN}{dt} = rN$
B. $\frac{dN}{dt} = rN\left(\frac{K-N}{K}\right)$ ✓ Correct
C. $\frac{dN}{dt} = \frac{rN}{K}$
D. $\frac{dN}{dt} = KN$
Solution: Verhulst-Pearl logistic equation with carrying capacity K gives a sigmoid growth curve.
Q24 — easy
The Earth Summit held at Rio de Janeiro in 1992 was primarily convened to address:
A. Ozone layer depletion
B. Conservation of biological diversity and sustainable use ✓ Correct
C. Global warming treaties exclusively
D. Disposal of hazardous nuclear wastes
Solution: The 1992 Rio Earth Summit established the Convention on Biological Diversity (CBD).
Q25 — easy
The development of a fruit directly from an unfertilized ovary without seed formation is termed:
A. Parthenocarpy ✓ Correct
B. Parthenogenesis
C. Apomixis
D. Polyembryony
Solution: Parthenocarpy: fruit development without fertilization, producing seedless fruits (e.g., banana).
Q26 — easy
The primary function of the corpus luteum in human females is to secrete large quantities of:
A. Estrogen
B. Progesterone ✓ Correct
C. Luteinizing hormone
D. Human chorionic gonadotropin
Solution: The corpus luteum secretes progesterone to maintain the endometrium for implantation.
Q27 — easy
Genes located close together on the same homologous chromosome that tend to be inherited together violate:
A. Law of Segregation
B. Law of Dominance
C. Law of Independent Assortment ✓ Correct
D. Law of Purity of Gametes
Solution: Linked genes on the same chromosome co-segregate, violating Mendel's Law of Independent Assortment.
Q28 — easy
The enzyme responsible for unwinding the double-stranded DNA helix at the replication fork is:
A. DNA Topoisomerase
B. DNA Helicase ✓ Correct
C. DNA Ligase
D. RNA Primase
Solution: DNA helicase unzips the double helix by breaking H-bonds between complementary bases at the replication fork.
Q29 — easy
The industrial melanism observed in the peppered moth (\textit{Biston betularia}) in Britain is an evolutionary demonstration of:
A. Artificial selection
B. Natural selection ✓ Correct
C. Genetic drift
D. Adaptive radiation
Solution: Industrial melanism demonstrated directional natural selection favouring dark moths on soot-covered trees.
Q30 — easy
The guttation fluid exuded from the margins of leaves in herbaceous plants escapes through specialized pores termed:
A. Lenticels
B. Stomata
C. Hydathodes ✓ Correct
D. Pneumatophores
Solution: Hydathodes are specialized pores on leaf margins through which guttation fluid (xylem sap) is exuded.