Variation and Inheritance Flashcards
MEMORISE
discrete inheritance is controlled by:
a single gene
Continuous variation is controlled by:
By many genes
Allelle
the different forms of a gene
Homozygous
Both alleles of a gene are the same
Heterozygous
Both alleles of a gene are the same
Dominant
The allele which shows in the phenotype when it is present and can mask a recessive form.
Recessive
The allele are not shown in the phenotype unless both alleles are recessive as it is masked by a dominant form.
Genotype
Alleles present in an organism
Phenotype
An organism’s appearance which has resulted from genetic info
Reasons for sample error in Genes:
- Fertilisation is a random process
2. Sample size is small
Sex cells are called:
Gametes
Gametes are made in specialised organs called:
Gonods
Diploid cells:
- It has two sets of chromosomes
2. TWO sets of 23 chromosomes
Haploid cells:
- Has ONE set of chromosome
- GAMETES are haploid
- ONE of 23 chromosomes
Male gametes:
- produced in testes
2. sperm are motile ans has tail for swimming to the ovum