Genotypes and Phenotypes in Genetics

This video tutorial explores key genetic concepts such as genotype, homozygous, heterozygous, dominant, and recessive alleles. Using eye color as an example, it explains how different allele combinations affect phenotype. The video also defines important terms and concludes with a summary of the concepts discussed.

What is the term used to describe an individual with two identical alleles for a trait?

• Recessive

• Dominant

• Homozygous

• Heterozygous

Which of the following best describes a genotype?

• The combination of alleles an individual has

• The dominant trait expressed

• The physical appearance of an organism

• The recessive trait hidden

If an individual has one allele for brown eyes and one for blue eyes, what is their genotype?

• Recessive

• Heterozygous

• Homozygous blue

• Homozygous brown

What does it mean if an allele is dominant?

• It is always hidden

• It is never expressed

• It masks the effect of a recessive allele

• It is only expressed if homozygous

Which genotype would result in a recessive phenotype?

• Capital B, Capital B

• Capital B, Lowercase b

• Capital B, Capital B, Lowercase b

• Lowercase b, Lowercase b

What is the phenotype of an individual with a genotype of capital B, lowercase b?

• Brown eyes

• Hazel eyes

• Blue eyes

• Green eyes

How are dominant alleles expressed in an organism?

• Only if both alleles are dominant

• Only in the absence of other alleles

• Always, if present

• Only if no recessive alleles are present

What is the definition of a recessive allele?

• An allele that is only expressed in heterozygous form

• An allele that can be hidden by a dominant allele

• An allele that is never expressed

• An allele that is always expressed

Which of the following is an example of a homozygous recessive genotype?

• Capital B, Capital B, Lowercase b

• Lowercase b, Lowercase b

• Capital B, Lowercase b

• Capital B, Capital B

What does the term 'phenotype' refer to?

• The genetic makeup of an organism

• The physical expression of a trait

• The combination of alleles

• The presence of a dominant allele