ICSE-X-Biology
02 Genetic: Some Basic Fundamentals
- #1Explain the following terms: (a) heterozygous (b) Homozygous (c) pedigree chart.Ans : (a) Heterozygous: The condition in which a pair of homologous chromosomes carries dissimilar alleles for a particular character.
For example -
(i) A daughter (XX°) from a normal homozygous mother for colour vision (XX) and a colour blind father has one normal and one defective allele (X˚Y).
(ii) Certain tongue rollers are heterozygous with Rr genotype. (b) Homozygous: The condition in which a pair of homologous chromosomes carries similar alleles for a particular character.
For example -
(i) A colorblind daughter (XoXo will have both the X chromosomes with defective alleles.
(ii) A non-roller will have rr (homozygous) genotype. (c) Pedigree Chart: A pedigree chart is a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next. In the pedigree chart, males are shown by squares and females by circles.
- #1-aheterozygousAns : Heterozygous: The condition in which a pair of homologous chromosomes carries dissimilar alleles for a particular character.
For example -
(i) A daughter (XX°) from a normal homozygous mother for colour vision (XX) and a colour blind father has one normal and one defective allele (X˚Y).
(ii) Certain tongue rollers are heterozygous with Rr genotype.
- #1-bHomozygousAns : Homozygous: The condition in which a pair of homologous chromosomes carries similar alleles for a particular character.
For example -
(i) A colorblind daughter (XoXo will have both the X chromosomes with defective alleles.
(ii) A non-roller will have rr (homozygous) genotype.
- #1-cpedigree chart.Ans : Pedigree Chart: A pedigree chart is a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next. In the pedigree chart, males are shown by squares and females by circles.