MHT CET Biology (Zoology) Flashcards

24 sample cards from the Biology (Zoology) deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. State the sliding filament theory of muscle contraction.

   During contraction, the thin actin filaments slide over the thick myosin filaments by cross-bridge formation, shortening the sarcomere (H-zone and I-band shorten while A-band remains constant). It requires Ca2+ and ATP.

2. Name the contractile proteins of muscle and the regulatory proteins.

   Contractile proteins: actin (thin) and myosin (thick). Regulatory proteins: troponin and tropomyosin.

3. What is the role of calcium ions in muscle contraction?

   Ca2+ released from the sarcoplasmic reticulum binds to troponin, removing the blocking effect of tropomyosin so that myosin heads can bind actin and form cross-bridges.

4. Differentiate between the axial and appendicular skeleton.

   Axial skeleton (80 bones): skull, vertebral column, ribs and sternum. Appendicular skeleton (126 bones): bones of limbs and their girdles (pectoral and pelvic).

5. Name the parts of the human male reproductive system that produce sperm and secrete fluids.

   Testes (seminiferous tubules) produce sperm; seminal vesicles, prostate gland and bulbourethral (Cowper's) glands secrete the seminal fluid.

6. What is spermatogenesis and where does it occur?

   Spermatogenesis is the formation of haploid sperm from diploid spermatogonia by meiosis; it occurs in the seminiferous tubules of the testes and is stimulated by FSH and testosterone.

7. Describe the hormonal changes during the menstrual cycle that trigger ovulation.

   Rising estrogen from the maturing follicle causes a surge of LH (and FSH) around day 14, which triggers ovulation (release of the secondary oocyte). The ruptured follicle becomes the corpus luteum secreting progesterone.

8. What is the function of the placenta during pregnancy?

   The placenta connects the foetus to the uterine wall and enables exchange of nutrients, gases and wastes between mother and foetus; it also secretes hormones such as hCG, estrogen and progesterone.

9. At which stage does the embryo implant in the uterus and what is this structure called?

   The embryo implants as a blastocyst (about 7 days after fertilization); the trophoblast layer of the blastocyst attaches to the endometrium.

10. Define fertilization and state where it normally occurs in humans.

    Fertilization is the fusion of a haploid sperm with a haploid ovum to form a diploid zygote; it normally occurs in the ampulla (junction of ampulla-isthmus) of the fallopian tube.

11. Classify contraceptive methods with one example of each major type.

    Natural (periodic abstinence/rhythm method), Barrier (condom, diaphragm), IUDs (Copper-T), Hormonal (oral pills like Saheli/Mala-D), Surgical/sterilization (vasectomy in males, tubectomy in females).

12. What does the full form ART stand for and name two ART techniques.

    ART = Assisted Reproductive Technologies. Examples: IVF-ET (in vitro fertilization-embryo transfer / test-tube baby), ZIFT (zygote intra fallopian transfer), GIFT (gamete intra fallopian transfer), ICSI, and IUI.

13. Differentiate between a pathogen-based innate and acquired immunity.

    Innate (non-specific) immunity is present from birth and provides general defence (skin, phagocytes, inflammation). Acquired (specific) immunity develops after exposure to a pathogen and is antigen-specific with memory (antibody-mediated and cell-mediated).

14. Name the antibody classes (immunoglobulins) found in humans.

    IgG, IgM, IgA, IgE and IgD.

15. Name the causative organism, vector and one symptom of malaria.

    Causative organism: Plasmodium (e.g. P. vivax, P. falciparum); vector: female Anopheles mosquito; symptom: recurring high fever with chills (and headache).

16. What is the difference between active and passive immunity?

    Active immunity: the body produces its own antibodies after exposure to antigen/vaccine; slow but long-lasting. Passive immunity: ready-made antibodies are given from outside (e.g. mother's milk, antitoxin); fast but short-lived.

17. Name the cells of the immune system attacked by HIV and the disease it causes.

    HIV attacks helper T-lymphocytes (CD4+ T-cells) and macrophages, causing AIDS (Acquired Immuno Deficiency Syndrome).

18. State the difference between benign and malignant tumours.

    Benign tumours remain confined to their original site (do not spread) and are generally harmless. Malignant tumours grow rapidly, invade surrounding tissues and spread to other parts (metastasis) - they are cancerous.

19. State Darwin's theory of evolution and the key mechanism he proposed.

    Darwin proposed the theory of evolution by natural selection: organisms with favourable variations (fitness) survive and reproduce more, passing traits to offspring ('survival of the fittest'), causing gradual change in populations over time.

20. What does the Hardy-Weinberg principle state and give its equation.

    It states that allele and genotype frequencies in a population remain constant across generations in the absence of evolutionary influences. Equation: p2 + 2pq + q2 = 1, where p + q = 1.

21. Name the restriction enzyme commonly used in genetic engineering and its function.

    Restriction endonucleases (e.g. EcoRI); they act as 'molecular scissors' cutting DNA at specific recognition sequences (palindromes), often leaving sticky ends for recombination.

22. What is a cloning vector and name a commonly used one.

    A cloning vector is a DNA molecule that carries a foreign gene into a host cell and can replicate inside it; commonly used vectors are plasmids (e.g. pBR322) and bacteriophages.

23. What is Bt cotton and which gene is used to make it?

    Bt cotton is a transgenic crop resistant to certain insect pests; it contains the cry gene (e.g. cryIAc) from the bacterium Bacillus thuringiensis, which produces an insecticidal protein (Bt toxin).

24. Name two microbes used in welfare and their products: one for curd/dairy and one for antibiotics.

    Lactobacillus (lactic acid bacteria) converts milk to curd; Penicillium (Penicillium notatum/chrysogenum) produces the antibiotic penicillin.

What this deck covers

Biology (Zoology) flashcards FAQ