Terms Used in Modern Genetics (10.1) Flashcards
Define Genes
Heritable units of information about traits.
What is the locus?
The specific location where a gene occurs on a specific chromosome.
What do cells with a diploid chromosome number (2n) have?
They have a pair of genes, on pairs of homologous chromosomes.
What is a mutation?
A permanent change in a gene and in the information it carries. It may cause a trait to change, such as changing the colour of a flower.
What are all molecular forms of the same gene known as?
Alleles.
What is true-breeding lineage?
When an offspring inherits a pair of identical alleles for a trait generation after generation.
What is a hybrid?
The offspring of a cross between two true-breed individuals. A hybrid inherited two nonidentical alleles for the traits.
When does a heterozygous condition occur?
When there are two different alleles at the same gene locus on homologous chromosomes.
When does a homozygous condition occur?
When the homologous chromosomes carry the same allele.
When is an allele dominant?
When its effect on a trait masks the effect of any recessive allele paired with it.
What is a homozygous dominant individual?
A homozygous dominant individual has a pair of dominant alleles.
What is a heterozygous individual?
A heterozygous individual has a pair of nonidentical alleles.
What is a heterozygous recessive individual?
A homozygous recessive individual has a pair of recessive alleles.
What is gene expression?
Gene expression is the process by which a gene’s information is converted to a structural or functional part of a cell. Expressed genes determine traits.
Define Genotype
Genotype refers to the particular alleles that an individual carries.
