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Biology - 1 — MH-CET Full Length Paper MCQs with Solutions
Free MH-CET Full Length Paper Biology - 1 MCQs with step-by-step solutions. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — easy
The innermost nutritional layer of the microsporangial wall that nourishes developing pollen grains is:
A. Epidermis
B. Endothecium
C. Middle layers
D. Tapetum ✓ Correct
Solution: The tapetum is the innermost layer of the microsporangial wall, multinucleate with dense cytoplasm, providing nourishment to developing microspores.
Q2 — easy
During ultrafiltration in the human nephron, which component of blood plasma does NOT filter into Bowman's capsule under normal physiological conditions?
A. Glucose
B. Urea
C. Plasma proteins (Albumin) ✓ Correct
D. Inorganic ions ($Na^+, Cl^-$)
Solution: Large colloidal macromolecules like albumin and globulin are retained in the capillary lumen and do not pass through the glomerular filtration barrier.
Q3 — easy
In the lac operon, the structural gene 'y' codes for which of the following enzymes?
A. $\beta$-galactosidase
B. Permease ✓ Correct
C. Transacetylase
D. DNA polymerase
Solution: Gene z codes for $\beta$-galactosidase, gene y codes for $\beta$-galactoside permease (lactose transport), and gene a codes for transacetylase.
Q4 — easy
Which bond links two consecutive adjacent monosaccharide units in a molecule of glycogen or starch?
A. Peptide bond
B. Phosphodiester bond
C. Glycosidic bond ✓ Correct
D. Ester bond
Solution: Monosaccharides are covalently bonded by glycosidic linkages formed via dehydration condensation between hydroxyl groups.
Q5 — easy
A cross between a red-flowered plant ($RR$) and a white-flowered plant ($rr$) in \textit{Mirabilis jalapa} yields pink progeny ($Rr$). This phenotypic pattern exemplifies:
A. Complete dominance
B. Incomplete dominance ✓ Correct
C. Codominance
D. Epistasis
Solution: Incomplete dominance: neither allele is fully dominant, producing an intermediate blending phenotype (pink) in the heterozygote.
Q6 — easy
In the human ECG tracing, the P-wave indicates:
A. Ventricular depolarization
B. Atrial depolarization ✓ Correct
C. Ventricular repolarization
D. Atrial repolarization
Solution: P-wave = atrial depolarization, QRS complex = ventricular depolarization, T-wave = ventricular repolarization.
Q7 — easy
Brunner's glands are histologically confined to which region of the human digestive tract?
A. Stomach mucosa
B. Duodenum submucosa ✓ Correct
C. Ileum muscularis
D. Oesophagus serosa
Solution: Brunner's glands are branched coiled tubular glands in the duodenal submucosa, secreting alkaline mucus to neutralize acidic chyme.
Q8 — easy
A typical mature angiosperm embryo sac of polygonum type at functional maturity is:
A. 7-celled, 8-nucleate ✓ Correct
B. 8-celled, 7-nucleate
C. 7-celled, 7-nucleate
D. 8-celled, 8-nucleate
Solution: 7 cells: 3 antipodals, 1 central cell (2 polar nuclei), 2 synergids, 1 egg = 7 cells, 8 nuclei.
Q9 — easy
The hormone responsible for promoting fruit ripening and triple response in etiolated seedlings is:
A. Auxin (IAA)
B. Gibberellin ($GA_3$)
C. Ethylene ($C_2H_4$) ✓ Correct
D. Abscisic acid (ABA)
Solution: Ethylene is a gaseous phytohormone promoting fruit ripening, abscission, and the triple response in etiolated seedlings.
Q10 — easy
Which of the following is a classical copper-releasing intrauterine contraceptive device (IUD)?
A. Lippes loop
B. Progestasert
C. CuT ✓ Correct
D. LNG-20
Solution: CuT, Cu7, Multiload 375 are copper-releasing IUDs. Lippes loop is non-medicated; Progestasert and LNG-20 are hormone-releasing.
Q11 — easy
A non-protein organic cofactor that is firmly and permanently attached to the apoenzyme moiety is termed:
A. Coenzyme
B. Prosthetic group ✓ Correct
C. Metal activator
D. Apoenzyme
Solution: A prosthetic group is tightly and permanently bound to the apoenzyme (e.g., haem in catalase). Coenzymes are transiently associated.
Q12 — easy
The anatomical structure preventing collapse of the human trachea during expiration consists of:
A. Complete bony rings
B. C-shaped hyaline cartilaginous rings ✓ Correct
C. Elastic circular rings
D. Fibrous connective bands
Solution: The trachea is supported by 16–20 incomplete C-shaped rings of hyaline cartilage positioned anteriorly and laterally.
Q13 — easy
In a terrestrial food chain displaying a pyramid of biomass, the maximum biomass is accumulated at the level of:
A. Primary consumers
B. Secondary consumers
C. Primary producers ✓ Correct
D. Top carnivores
Solution: In terrestrial ecosystems, the pyramid of biomass is upright with primary producers having the highest total biomass.
Q14 — easy
The net number of ATP molecules generated during complete aerobic oxidation of one glucose molecule in eukaryotic systems is:
A. 2
B. 36 or 38 ✓ Correct
C. 4
D. 24
Solution: Complete aerobic respiration yields 36 or 38 ATP per glucose depending on the shuttle system used.
Q15 — easy
The genetic disorder Thalassemia is characterized by abnormal hemoglobin synthesis due to:
A. Deletion or mutation in globin genes ✓ Correct
B. Trisomy of chromosome 21
C. Monosomy of X chromosome
D. Presence of an extra Y chromosome
Solution: Thalassemia results from deletions or point mutations in globin genes on chromosomes 16 ($\alpha$) or 11 ($\beta$).
Q16 — easy
Parietal (oxyntic) cells of the human gastric mucosa secrete:
A. Pepsinogen and mucus
B. HCl and Castle's intrinsic factor ✓ Correct
C. Trypsin and enterokinase
D. Amylase and gastrin
Solution: Parietal cells produce HCl (lowering pH to 1.5–2.0) and Castle's intrinsic factor (essential for vitamin B₁₂ absorption).
Q17 — easy
In an unfertilized ovule, the basal swollen region from where integuments arise is designated as the:
A. Micropyle
B. Funicle
C. Hilum
D. Chalaza ✓ Correct
Solution: The chalaza is the basal region of the ovule opposite the micropyle, from which the integuments originate.
Q18 — easy
Which immunoglobulin class is secreted abundantly in human colostrum providing natural passive immunity to newborns?
A. $IgM$
B. $IgG$
C. $IgA$ ✓ Correct
D. $IgE$
Solution: Colostrum is rich in secretory IgA dimers that coat the GI and respiratory mucosa of neonates.
Q19 — easy
The enzyme that catalyzes the primary fixation of atmospheric $CO_2$ in mesophyll cells of $C_4$ plants is:
A. RuBisCO
B. PEP carboxylase ✓ Correct
C. Carbonic anhydrase
D. Pyruvate dehydrogenase
Solution: In C₄ plants, PEP carboxylase fixes CO₂ to PEP in mesophyll cells to form oxaloacetate.
Q20 — easy
The functional residual capacity (FRC) of human lungs corresponds to the volume of air equal to:
A. $ERV + RV$ ✓ Correct
B. $TV + IRV$
C. $IRV + ERV$
D. $TLC - RV$
Solution: FRC = ERV + RV ≈ 2200–2500 mL, the air remaining after a normal tidal exhalation.
Q21 — easy
Which restriction endonuclease enzyme produces blunt (flush) ends upon cleaving double-stranded DNA?
A. \textit{Eco}RI
B. \textit{Hind}III
C. \textit{Sma}I ✓ Correct
D. \textit{Bam}HI
Solution: SmaI cleaves symmetrically (5'-CCC↓GGG-3') producing blunt ends. EcoRI, BamHI, HindIII produce sticky ends.
Q22 — easy
The resting axonal membrane is comparatively more permeable to which ions?
A. $Na^+$ ions
B. $K^+$ ions ✓ Correct
C. $Ca^{2+}$ ions
D. Negatively charged proteins
Solution: At resting potential (−70 mV), the axonal membrane has many more open K⁺ leak channels, making it 20–100× more permeable to K⁺.
Q23 — easy
The chromosomal constitution of a human patient exhibiting Turner's syndrome is:
A. $44 + XXY$
B. $44 + XO$ ✓ Correct
C. $45 + XX$
D. $44 + XXX$
Solution: Turner's syndrome: 44 + XO (45 chromosomes total). Features include short stature, webbed neck, and sterile streak ovaries.
Q24 — easy
During biological nitrogen fixation, the nitrogenase enzyme is protected from molecular oxygen denaturation by:
A. Chlorophyll
B. Leghaemoglobin ✓ Correct
C. Cytochrome-c
D. Ferredoxin
Solution: Leghaemoglobin scavenges free O₂ in root nodules, maintaining microaerophilic conditions for the oxygen-sensitive nitrogenase.
Q25 — easy
The middle ear ossicle that directly articulates with the oval window (fenestra ovalis) is the:
A. Malleus
B. Incus
C. Stapes ✓ Correct
D. Tympanic membrane
Solution: Sound travels: Malleus → Incus → Stapes; the stapes footplate fits into the oval window of the cochlea.
Q26 — easy
The structural linkage formed between the amino acid carboxyl terminus and the adjacent amino group is a:
A. Glycosidic link
B. Peptide link ✓ Correct
C. Ester bond
D. Disulfide bridge
Solution: Peptide bonds are amide linkages (−CO−NH−) formed by condensation between the α-carboxyl and α-amino groups.
Q27 — easy
Golden rice is an engineered transgenic crop variety enriched primarily in:
A. Vitamin C
B. Vitamin A ($\beta$-carotene) ✓ Correct
C. Vitamin D
D. Iron content
Solution: Golden rice contains phytoene synthase and carotene desaturase genes to synthesize β-carotene (provitamin A).
Q28 — easy
The primary pacemaker initiating electrical impulses across the mammalian heart is the:
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node ✓ Correct
C. Bundle of His
D. Purkinje fibres
Solution: The SA node in the upper right atrium generates self-excitatory action potentials at 70–75 bpm, acting as the primary pacemaker.
Q29 — easy
The specific cell type in human testes that secretes androgens (testosterone) under LH stimulus is:
A. Sertoli cells
B. Leydig (interstitial) cells ✓ Correct
C. Spermatogonia
D. Primary spermatocytes
Solution: Leydig cells in the interstitial spaces between seminiferous tubules synthesize testosterone under LH stimulation.
Q30 — easy
Identify the primary site for the absorption of amino acids and glucose within the human nephron:
A. Proximal convoluted tubule (PCT) ✓ Correct
B. Distal convoluted tubule (DCT)
C. Collecting duct
D. Loop of Henle
Solution: The PCT with brush-border microvilli reabsorbs nearly 100% of glucose and amino acids plus 70–80% of water and electrolytes.