Genetic Combinations Review

Sickle cell anemia is a condition that affects the shape of a red blood cell. An unaffected individual can be represented with the genotype AA. An affected individual can be represented with the genotype SS. Individuals that are carriers have the genotype AS.

Sickle cell anemia is best described by the term

• Co- Dominant

• Incomplete Dominance

• Homozygous Recessive

• Complete Dominance

In mice, a certain species displays incomplete dominance in coat coloring. The offspring of a black (BB) mouse and a white (bb) mouse are gray (Bb) mice. A cross between two gray mice will most likely produce offspring with which percent of coat colors?

• 25% white, 25% black, 50% gray

• 25% gray, 25% black, 50% white

• 25% gray, 75% white

• 25% black, 75% gray

The chart shows a dihybrid cross between pea plants. What are the genotypes of the parents in this cross?

• RrYY and Rryy

• RRYY and rryy

• RrYy and RrYy

• RRyy and rrYY

In the dihybrid cross for pea plants shown below, R is dominant for round peas, r is recessive for wrinkled peas, Y is dominant for yellow peas, and y is recessive for green peas. A student could accurately make which statements about the offspring of this cross?

• There is no chance of having any wrinkled, green peas.

• There is a 100% chance of having round, green peas.

• There is no chance of having any round, yellow peas.

• There is a 50% chance of having round, yellow peas.

A snapdragon plant with red flowers (RR) is crossed with a snapdragon plant with white flowers (WW). Snapdragon flowers show incomplete dominance. A Punnett square of the cross is shown below.

If the cross produces four offspring, how many of each color flower would likely be produced?

• four red flowers

• four pink flowers

• two red flowers and two pink flowers

• two white flowers and two pink flowers

Which biomolecules are found in all organisms?

• glucose, maltose, fructose, sucrose

• adenine, cytosine, thymine, guanine

• chlorophyll, chitin, pepsin, glycogen

• cholesterol, phospholipid, cellulose, gibberellin

Which of these shows the correct order for the central dogma of molecular biology?

• DNA to RNA to protein

• protein to DNA to RNA

• RNA to DNA to protein

• DNA to protein to RNA

Proto-oncogenes code for proteins that stimulate cellular growth and division. What happens when these genes fail to regulate the amount of protein produced?

• Cells stop growing and enter the G₀ phase of the cell cycle.

• Cells continue to grow and divide in an uncontrolled manner.

• Neighboring cells send out chemical signals that start apoptosis.

• Neighboring cells respond to the proteins and begin uncontrolled growth.

In humans, a V-shaped hairline is dominant over a straight hairline. If one parent is homozygous for a V-shaped hairline (HH) while the other parent is homozygous for a straight hairline (hh), what is the probability that the offspring of these parents will have a straight hairline?

**Write your answer with number and %

example: 1%

Genetic crosses involving a particular type of flower exhibit complete dominance with respect to petal color. Red (R) is dominant to white (r).

Using the Punnett square, what is the expected percentage of offspring that will have white flowers from a cross of parent flowers with a genotype of Rr.

**Write your answer with a number and %

EXAMPLE: 1%