Biology –

 

REPRODUCTION

 

1- Prevention of pregnancy in women is called contraception.

2- Single celled organisms (bacteria, amoeba and paramecium) reproduce by fission.

3- The structure of deoxy ribonucleic acid (DNA) is discovered by Watson & Crick.

4- Reproduction through budding occurs in yeast. Fragmentation occurs in spirogyra, lichens.

5- Mitosis was discovered by Walther Fleming in 1879.

6-Birth control surgery in males called vasectomy and in females called tubectomy.

7- We get seedless fruits due to parthenogenesis (shift from sexual to asexual reproduction).

8-Central cell (secondary cell) in embryo sac contains two polar nuclei.

9- Vegetative reproduction through leaves takes place in Bryophyllum.

10- The second fertilization in plants gives rise to endosperm.

11-Cells that contain only one set of chromosomes are called haploid.

12- Reproduction in fungi (rhizopus, mucor) occurs through spores.

13- No. of cells present in pollen tube are two.

14- Spores containing leaves in fern are called as sporophylls.

15- Bottle guard and papaya are examples for unisexual flowers.

16- External fertilization is common in aquatic animals (fishes and amphibians).

17- The secretion of mammary glands after delivery of baby is called as colostrums.

18- Epididymis (sperms are stored temporarily) is formed by vasefferentia.

19-From the 3rd month of pregnancy the embryo is called as foetus.

20-DNA synthesis takes place in interphase (“S” stage).

21-AIDS (Acquired immuno deficiency syndrome) is caused by HIV.

22-Theodor Boveri confirmed the meiotic division in 1904.

23- The development of male reproductive organs regulated by testosterone.
Johnson and potu Rao revealed the structure of interphase chromosomes.

24- The release of ovum by rupturing of graffian follicle is called ovulation.