Genetic Diagrams Flashcards
What controls the characteristics you inherit?
Some characteristics are controlled by a single gene, but most are controlled by several genes interacting.
What are alleles?
Different versions of genes, represented as letters in genetic diagrams.
How many alleles of every gene in the body do we have?
Two - one on each chromosome in a pair.
What does homozygous mean?
If an organism has two alleles for a particular gene that are the same.
What does heterozygous mean?
If an organism has two alleles for a particular gene that are different.
How are dominant alleles shown?
With a capital letter (e.g. ‘C’).
How are recessive alleles shown?
With a small letter (e.g. ‘c’).
If an organism has one dominant and one recessive allele, which will determine what characteristic is present?
Dominant allele.
To display a dominant characteristic, what alleles for that gene does an organism need?
Either two dominant alleles for a gene, or one dominant and one recessive allele for that gene.
To display a recessive characteristic, what alleles for that gene does an organism need?
Both its alleles must be recessive.
What is your genotype?
The combination of alleles you have.
What is your phenotype?
The characteristics you have, determined by your alleles.
What is monohybrid inheritance?
The inheritance of a single characteristic.
How many pairs of chromosomes are in every human body cell?
23 pairs.
What is the 23rd pair of chromosomes labelled as?
XX if female.
XY if male.
