Question

genes
definition
what are alleles?
how are alleles passed on to the offspring?
homozygous heterozygous dominant recessive

Explanation:

1. What are alleles?: Alleles are variant forms of a single gene that occupy the same position (locus) on a chromosome, leading to different trait expressions.
2. How are alleles passed on to the offspring?: During sexual reproduction, each parent produces gametes (sperm/egg) that carry one copy of each allele. Offspring inherit one allele for each gene from each parent, combining to form their genotype.
3. Homozygous: A genotype where an individual has two identical alleles for a single gene (e.g., AA or aa).
4. Heterozygous: A genotype where an individual has two different alleles for a single gene (e.g., Aa).
5. Dominant: An allele that is expressed in the phenotype even when only one copy is present (paired with a recessive allele).
6. Recessive: An allele that is only expressed in the phenotype when two copies are present (homozygous recessive genotype).

Answer:

1. What are alleles?

Alleles are variant forms of a single gene that occupy the same locus on homologous chromosomes, determining different variations of a trait.

1. How are alleles passed on to the offspring?

Parents produce gametes (sperm/egg) via meiosis, each carrying one allele per gene. Offspring inherit one allele from each parent at fertilization, forming their genotype.

1. Homozygous

A genotype with two identical alleles for a gene (e.g., AA or aa).

1. Heterozygous

A genotype with two different alleles for a gene (e.g., Aa).

1. Dominant

An allele that is expressed in the phenotype even in a heterozygous genotype.

1. Recessive

An allele that is only expressed in the phenotype when in a homozygous genotype.