Inheritance and Genetic Crosses Flashcards
What are genetics?
The study of inheritance.
What is inheritance?
The passing on of traits from one generation to the next.
What are traits?
Physical and chemical characteristics that a living organism possesses.
What depends on inheritance?
Continuity of life.
How is continuity of life maintained in single-celled organisms?
Through mitosis.
How is continuity of life maintained in multi-cellular organisms?
Through sexual reproduction.
What are gametes?
Haploid sex cells.
What is a haploid?
One set of chromosomes (23).
In humans, what are the gametes?
The egg cell and the sperm cell.
How are gametes produced?
Meiosis.
How many chromosomes does a gamete contain?
23.
What are 22 pairs of chromosomes called?
Autosomes.
What is fertilisation?
Is the fusion of two haploid gametes to produce a diploid zygote.
What is an allele?
Different forms of the same gene.
Usually, how many forms of the same gene exist?
2.
Where are alleles located?
They are located at the same position or locus on homologous chromosomes.
What is a locus?
Is the position of an allele or gene on a chromosome.
What does the term homozygous mean?
Two alleles are the same e.g. BB, bb, GG.
What does the term heterozygous mean?
Two alleles are different e.g. Bb, Gg.
What is homozygous often referred to as?
Pure-breeding.
Two alleles can be the same (homozygous) or different (heterozygous). True or false?
True.
What does the term dominance, in relation to alleles?
Where one allele (the dominant one) masks the effect of another allele.
What does the term recessive mean, in relation to alleles?
Where one allele’s effect is only expressed when in the homozygous condition.
What do the letters representing alleles make up?
The genotype.
