Heredity Test - 2

In peas, tall plant trait is dominant over dwarf. If a heterozygous for tall is crossed with one homozygous for dwarf, there will be 50% tall and 50% dwarf appearance of the offspring of a cross of F1.

Human beings have 23 pairs or 46 chromosomes. 22 of these pairs, called autosomes, look the same in both males and females. The 23^rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X chromosome and one Y chromosome.

Gene is a segment of DNA. Genes, which are made up of DNA, act as instructions to make molecules called proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

If father and mother possess blood group A, their children can have blood group A or O.

Identical twins arise when egg divides into two halves which then divides into two separate embryos.

In human beings, an example of a sex linked trait is colour blindness. Color blindness, or color vision deficiency, is the decreased ability or inability to see color, or perceive color differences, under normal lighting conditions.

Deoxyribonucleic acid constitutes a gene in organisms except the virus.

Carriers of genetic information are chromosomes. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA).

The manner of arrangement of genes in a chromosome is linear.

Adenine, thymine, guanine, cytosine are groups of nitrogen bases present in a DNA molecule.