Biology: Genetics And Inheritance Flashcards
What is DNA?
Deoxyribonucleic acid.
The chemical molecule in the nucleus that carries our genetic code.
What is a chromosome?
DNA is arranged into strands called chromosomes.
There are 46 in a normal human body cell in 23 pairs.
What is a gene?
A gene is a section of a chromosome that codes for a particular characteristic.
What is an allele?
An allele is a different form of a gene.
For each gene, we inherit two forms of the gene (one from our mother, one from our father).
Each form of the gene is called an allele.
What does recessive mean?
Recessive alleles are only expressed if there are 2 recessive alleles.
What does dominant mean?
Dominant alleles are always expressed even if only one of the alleles is dominant.
What does variation mean?
Variation is the difference between individuals of the same species.
What does genetic variation mean?
The variation has been inherited genetically.
What does environmental variation mean?
The variation hasn’t been passed down through genetics and it is based on your lifestyle.
What is a gamete?
A gamete is a reproductive cell of an animal or plant
What does homozygote mean?
Individual with two identical alleles for a characteristic
What does heterozygote mean?
Individual with different alleles for a characteristic
What does genotype mean?
The genetic makeup of an individual for a particular characteristic, for example hair or eve colour.
What does phenotype mean?
The physical appearance/ biochemistry of an individual for a particular characteristic
