Question 1

In a dihybrid cross involving seed color (yellow vs. green) and seed shape (round vs. wrinkled), the images above represent the four possible phenotypes. If both parents are heterozygous for both traits (YyRr x YyRr), what is the expected proportion of progeny with yellow, round seeds?

Accepted Answer

9/16

Question 2

If you select a seed at random from the progeny of a YyRr x YyRr cross, what is the probability that it is wrinkled, given that it is yellow?

Accepted Answer

$$\frac{1}{3}$$

Question 3

In a cross between two heterozygous plants for seed shape (Rr x Rr), what is the probability that a randomly selected seed is round?

Accepted Answer

$$\frac{3}{4}$$

Question 4

A plant with genotype YyRr is crossed with a plant with genotype yyrr. What is the expected ratio of green, wrinkled seeds in the progeny?

Accepted Answer

1/4

Question 5

Using the multiplicative rule, what is the probability that a seed from a YyRr x YyRr cross is green and wrinkled?

Accepted Answer

$$\frac{1}{16}$$

Question 6

If two events are independent, what is the probability that both occur, according to the multiplicative rule?

Accepted Answer

$$P(A) 	imes P(B)$$

Question 7

In a trihybrid cross (AaBbCc x AaBbCc), what is the probability of obtaining an offspring with genotype aabbcc?

Accepted Answer

$$\frac{1}{64}$$

Question 8

A plant with genotype TTRrGg is crossed with TtRrGg. What is the probability that their offspring will have genotype TTrrGG?

Accepted Answer

$$\frac{1}{8}$$

Question 9

Which probability rule would you use to calculate the chance of obtaining either a round or a wrinkled seed from a cross, assuming these are mutually exclusive events?

Accepted Answer

Additive rule

Question 10

In a two-point test cross (RrGg x rrgg), what is the expected ratio of progeny phenotypes?

Accepted Answer

1:1:1:1

Question 11

If the probability of producing a gamete with allele 'g' from a Gg parent is $$\frac{1}{2}$$, what is the probability of producing an offspring with genotype gg from two Gg parents?

Accepted Answer

$$\frac{1}{4}$$

Question 12

Given a cross between two heterozygous tall plants (Tt x Tt), what is the probability that a randomly selected tall plant is heterozygous?

Accepted Answer

$$\frac{1}{2}$$

Question 13

If you select a plant at random from a Tt x Tt cross, what is the probability that it is tall?

Accepted Answer

$$\frac{3}{4}$$

Question 14

In a cross between RrGg x rrgg, what is the probability of obtaining a progeny with genotype rrgg?

Accepted Answer

$$\frac{1}{4}$$

Question 15

If a fair coin is flipped three times, what is the probability that it lands heads all three times?

Accepted Answer

$$\frac{1}{8}$$

Question 16

Which formula represents the conditional probability of event A given event B?

Accepted Answer

$$P(A \cap B) / P(B)$$

Question 17

In a dihybrid cross, what is the probability of obtaining a progeny with dominant phenotype for both traits?

Accepted Answer

$$\frac{9}{16}$$

Question 18

If two events are mutually exclusive, what is the probability that either one occurs?

Accepted Answer

$$P(A) + P(B)$$

Question 19

In a cross between two heterozygous plants for seed color (Yy x Yy), what is the probability of producing a green seed?

Accepted Answer

$$\frac{1}{4}$$

Question 20

A plant with genotype RrGg is crossed with rrgg. What is the probability of obtaining a progeny with genotype RrGg?

Accepted Answer

$$\frac{1}{4}$$

Probability Rules in Mendelian Genetics: Study Notes

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