Expand the abbreviation — DNA.

Haploid number of chromosomes are found in: (a) Nephrons (b) Neurons (c) Skin cells (d) Sperms

Differentiate between Karyokinesis and Cytokinesis.

Name the following: (i) The organelle that forms the aster during cell division. (ii) A genetic disorder in which the blood does not clot. (iii) The permanent stoppage of menstruation in human females around the age of 45 years. (iv) The openings on the barks of trees through which transpiration occurs. (v) A gaseous plant hormone which promotes ripening of fruits.

Choose the odd one out from the following terms and name the category to which the others belong: (a) Used bandages, Pesticides, Face masks, Syringes. (b) Dust, Smoke, Carbon monoxide, Effluents (c) Uterus, Urethra, Urinary bladder, Ureter (d) Menstrual phase, Telophase, Follicular phase, Luteal phase (e) Malleus, Incus, Cochlea, Stapes

Duplicated chromosomes are joined at a point termed: (a) Centrosome (b) Centromere (c) Centriole (d) Chromatid

What is the structure of DNA as proposed by Watson and Crick?

A male gorilla has 48 chromosomes in each body cell. How many chromosomes will be present in each of its sperms? (a) 24 (b) 48 (c) 12 (d) 16

Which is the resting but metabolically active stage of the cell cycle?

A phase of cell division where the spindle fibres disappear is: (a) Telophase (b) Prophase (c) Metaphase (d) Anaphase

Mention the two pairs of nitrogenous bases that are present in a DNA strand and pair with each other by hydrogen bonds.

Draw a neat, labelled diagram of an animal cell showing Metaphase with four chromosomes.