QUIZ 1. How many pairs of human chromosomes are there? a. 20 b. 23 c. 46 d. 52 Answer: b. Each organism has its own number of chromosomes. Humans have 23 pairs of chromosomes, which add to a total of 46 chromosomes. Of these 22 chromosome pairs are somatic and 1 pair is the sex chromosomes. 2. What is a variation in a gene called? a. Allele b. Chromosome c. DNA d. RNA Answer: a. An allele is a variation in a gene. Different alleles are what makes a person unique because they will encode for different proteins and different traits in a given person. 3. What best defines an asymptomatic carrier for a given trait? a. A person who is homozygous for a dominant trait b. A person who is heterozygous for a dominant trait c. A person who is homozygous for a recessive trait d. A person who is heterozygous for a recessive trait Answer: d. The person who is heterozygous for a recessive trait will not have the disease but will be a carrier for it, meaning they will pass the trait onto half of their offspring. Only if they mate with an individual who has the recessive trait in some form will there be a possibility of having a child who has the recessive disease.
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