Science Review Genetics

One trait that is ALWAYS present and causes the other traits to disappear is a ________________________

• recessive trait
• aggressive trait
• absent trait
• dominant trait

What does heterozygous mean?

• An organism that has the same genes for a trait (TT or tt)
• An organism that has different genes for a trait (Tt)
• When neither gene is fully dominant; offspring is a mixture of both
• the different forms of a trait (hair color--> brown, blonde, red

What is a phenotype?

• The expression of a trait; physical appearance.
• refers to the genetic makeup of an individual
• An organism that has the same genes for a trait (ex. TT or tt)
• the passing of traits from parent to offspring

Two heterozygous (Tt)tall pea plants are crossed. Which describes their offspring?

• 50% tall and 50% short
• 75%tall and 25% short
• 100%short

A human usually has _____ total chromosomes.

• 6
• 22
• 4
• 46

Which of the following alleles is homozygous recessive?

• Tt
• tt
• TT
• T

In fruit flies eye color is carried on the X chromosome. RED is dominant to WHITE. What is the sex and color of the following: X^RX^R

• female red
• female white
• male red
• male white

What determines gender in humans? 

• the X and Y chromosome
• chromosome 21
• codominance
• epistasis

Two brown eyed parents (Bb) have a baby. What is the chance the baby is blue eyed?

• 0 %
• 25%
• 50%
• 75%

This type of inheritance pattern is a MIXTURE of both traits.

• incomplete dominance
• co-dominance
• complete dominance
• recessive pattern