Inheritance

Question 1

What are gene?

Answer 1

Short strand of DNA (Deoxyribonucleic Acid) located on a chromosome. Genes code for a particular characteristics.

Question 2

What are chromosomes?

Answer 2

Long strand of DNA located in the nucleus of a cell.

Question 3

What is an allele?

Answer 3

Alternative form of a gene, e.g. gene for height could have the form tall or dwarf.

Question 4

What are gametes?

Answer 4

Sex cells of an organism, that generally have half a full set of chromosomes (haploid), e.g. a human egg cell has 23 chromosomes and a human sperm cell has 23 chromosomes.

Question 5

What is fertilisation?

Answer 5

Process in which the nucleus of the sperm cell fuses with the nucleus of the egg cell to produce a zygote (restoring the diploid number of chromosomes). Within humans this occurs in the oviduct.

Question 6

What is sex determination?

Answer 6

The gender of offspring is determined by the combination of sex chromosomes, in humans this is the 23rd pair. Female= 2 X sex Chromosomes, male= 1 X and 1 Y sex chromosome. The sex of the offspring is determined by which sperm (X or Y) fertilises the egg. The chances of producing a male child is 50:50.

Question 7

What is recessive?

Answer 7

trait only expressed in the homozygous form (when both alleles are the same, e.g. bb). A recessive allele will be masked by a dominant allele.

Question 8

What is dominant?

Answer 8

Trait expressed in both homozygous (when alleles are the same) and heterozygous (when alleles are different) forms.