ZOOLOGY (2020 SAY)
1. (c) Thorns and tendrils of Bougainvillea and Cucurbita
2. (b) Morula
3. (c) Birds
4. (b) Azospirillum
5. (c) AUG
6. (a) Typhoid.
(b) Salmonella typhi.
(c) Sustained high fever, stomach pain, constipation, head ache etc.
7. a. Vas deferens
8. (a) Allele frequencies in a population are stable and is constant from generation to generation.
(b) Gene migration, Genetic drift, Mutation etc.
9. (a) 44A + XXY
(b) Turner’s syndrome
(c) Sterile female/ ovaries are rudimentary etc.
(d) Down’s syndrome
10. Match the following:
(a) Acetic acid
(b) Citric acid
(c) Cyclosporine A
(d) Lactic acid
(ii) Acetobacter aceti
(iv) Aspergillus niger
(i) Trichoderma polysporum
11. Gametogenesis → Insemination → Fertilisation → Formation of Zygote → Implantation → Gestation → Parturition → Lactation
12. (a) Incomplete dominance
(b) Flower colour in Snap dragon
(c) Phenotypic ratio = 1:2:1
Genotypic ratio = 1:2:1.
I. a. Stabilizing selection.
b. Directional selection.
c. Disruptive selection.
II. The peak is shifted to one direction. i.e., more individuals acquire value other than the mean character value.
14. (a) (i) Digestion of DNA by restriction endonuclease.
(ii) Hybridisation using labelled VNTR probe.
(b) Alec Jeffreys
(c) Variable Number of Tandem Repeats.
15. (a) a. Promoter. b. Structural genes. c. Terminator.
16. (a) Assisted Reproductive Technologies.
(b) i. Artificial insemination (AI) / Intra-Uterine insemination (IUI). Ii. Gamete Intra fallopian Transfer (GIFT).
17. (a) Edward Wilson.
(b) In situ conservation and Ex situ conservation.
(c) Habitat loss & Fragmentation, Overexploitation, Alien species invasion etc.
18. (a) A. Vasectomy B. Tubectomy
(b) Vasectomy: A small part of the vas deferens is removed or tied up through a small incision on scrotum.
Tubectomy: A small part of the fallopian tube is removed or tied up through a small incision in the abdomen or through vagina.
(c) To prevent any more pregnancies.
19. (a) Promoter.
(c) z: β-galactosidase, y: Permease, a: Transacetylase.
20. Avoid undue peer pressure.
Education and counselling.
Seeking help from parents and peers.
Looking for danger signs.
Seeking professional and medical help.