Inheritance: Part 2

The video explains how genes and alleles determine traits, with dominant alleles being expressed even if only one copy is present, while recessive alleles require two copies. Eye color is used as an example, with brown being dominant over blue. Diseases like cystic fibrosis are caused by recessive alleles, requiring both parents to pass on the allele for the child to be affected. Huntington's disease, however, is caused by a dominant allele, meaning only one parent needs to pass it on. The video concludes by noting that most traits are influenced by multiple genes and environmental factors.

What determines if an allele is expressed in an individual?

• The diet of the individual

• The environment

• The age of the individual

• The number of copies inherited

Which of the following is true about recessive alleles?

• They are never expressed

• They require two copies to be expressed

• They can be expressed with one copy

• They are always expressed if present

What is the probability of a child inheriting cystic fibrosis if both parents are carriers?

• 1 in 3

• 1 in 2

• 1 in 4

• 1 in 5

How is Huntington's disease inherited?

• Through a recessive allele

• Through a dominant allele

• Through a viral infection

• Through environmental factors

What influences most human traits besides genetics?

• Environment and lifestyle

• Medication

• Exercise alone

• Diet alone