Genetics Flashcards
What is an allele?
Different forms of the same gene. E.g, blue or brown eyes.
What is a gene?
The trait inherited. E.g, eye colour.
What are dominant and recessive alleles?
A dominant allele is an allele that always shows its effect if it is present. A recessive allele is an allele that doesn’t show its effect unless there are no dominant alleles present.
What does genotype mean?
The combination of alleles inherited. E.g, BB, Bb or bb. (Homozygous or heterozygous).
What does phenotype mean?
The characteristics you have visible. E.g, red hair, blue eyes and freckles.
What do homozygous and heterozygous mean?
Homozygous means the same type (type meaning dominant or recessive) of alleles. E.g, BB or bb. Heterozygous means different types of alleles. E.g, Bb or bB.
What is a zygote?
A fertilised egg; the sperm has now entered the egg so it has 46 chromosomes.
What is a gamete?
Any sex cell. E.g, sperm, egg, pollen or ova.
What do the terms haploid and diploid mean?
Haploid means half the normal number of chromosomes are present. E.g, 23 for humans. Diploid means the normal number of chromosomes are present. E.g, 46 for humans.
What is the difference between asexual and sexual reproduction?
Asexual reproduction only needs one parent, and is mainly done by plants. Sexual reproduction however requires gametes coming from two parents, one female and one male to make a zygote.
What is evolution?
Any change in inheritable traits within a population, across generations. Often caused by mutations.
What is the difference between continuous and discreet variation?
Continuous variation means there is a wide spectrum of a characteristic. E.g, things like height or hair colour. Discreet variation means either you have a characteristic or you don’t, there’s no middle ground. E.g, attached or unattached ear lobes.
