CBSE Class 12 Biology Human Reproduction Worksheet Set E

Long Short Answer Questions

Question . STDs are a threat to reproductive health. Describe any two such diseases and suggest preventive measures.
Answer. • Infections or diseases that are transmitted through sexual intercourse are collectively called sexually transmitted diseases (STDs) or venereal diseases (VD) or reproductive tract infections (RTI).
• STDs are caused by bacteria (syphilis, gonorrhoea), virus (AIDS, hepatitis B, genital herpes, genital warts), protozoans, nematodes, ectoparasites (trichomoniasis, chlamydiasis) and fungi.
• Early symptoms: Itching, fluid discharge, slight pain and swellings in the genital region. 
• Complications due to chronic STDs: Pelvic inflammatory diseases (PID), abortions, still births, ectopic pregnancies, infertility, or even cancer of the reproductive tract.
• Transmission of hepatitis-B and HIV also occurs by the following ways:
(i) Sharing of injection needles or surgical instruments with infected persons;
(ii) transfusion of infected blood;
(iii) transfer from infected mother to the foetus through placenta.

Question . Name two hormones that are constituents of contraceptive pills. Why do they have high and effective contraceptive value? Name a commonly prescribed non-steroidal oral pill.
Answer. Progestogen-estrogen combination, Progestogen or Progesterone are present in contraceptive pills. They inhibit ovulation, implantation and alter quality of cervical mucus to retard entry of sperm. Saheli is a commonly prescribed oral pill.

Question . (a) Expand IUD.
(b) Why is hormone releasing IUD considered a good contraceptive to space children?
Answer. (a) IUD—Intra uterine devices.
(b) Hormone releasing IUDs are considered a good contraceptives because
(i) they make the uterus unsuitable for implantation.
(ii) they increase the phagocytosis of sperms within uterus and the Cu ions released, suppress sperm motility and the fertilising capacity of sperms.

Question . Name three incurable sexually transmitted diseases and their causative organisms.
Answer. Sexually transmitted disease Causal agent
(i) Hepatitis-B Hepatitis-B virus
(ii) Genital herpes Herpes simplex virus
(iii) AIDS HIV (Human Immunodeficiency Virus)

Please click on below link to download CBSE Class 12 Biology Human Reproduction Worksheet Set E