Mendelian Review

For a simple dominant and recessive characteristic, a cross between organisms of genotypes AA and aa will produce offspring that ______.

• all have the same genotype

• all have the same genotype as one of the parents

• are 50% AA and 50% aa

• all show the recessive trait

If an organism has two different alleles for a single trait, the organism is said to be _____.

• homozygous

• heterozygous

• recessive

• locus

Sections of a chromosome that code for a trait are called _____.

• genomes

• genes

• allele

• phenotypes

The trait that is masked by the dominant trait is the _____ trait.

• purebred

• cross

• hybrid

• recessive

genetic make-up for a specific trait

• phenotype

• genotype

• allele

• chromosome

physical representation of a trait

• phenotype

• genotype

• allele

• chromosome

The different versions of a trait or gene are called ___.

• phenotype

• genotype

• allele

• chromosome

carries genetic information

• phenotype

• genotype

• allele

• chromosome

In one type of animal, the gene for a long tail (T) is dominant over the gene for a short tail (t). Two animals with long tails are crossed, and 25% of their offspring have short tails. Which diagram correctly shows a Punnett square of this cross?

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If an organism has two different alleles for a single trait, the organism is said to be _______.

• homozygous

• heterozygous

• monohybrid

• dihybrid