Question 1

A dihybrid cross between two pea plants heterozygous for both seed color (Yy) and seed texture (Rr) is performed. What is the expected phenotypic ratio of the offspring?

Accepted Answer

$$9:3:3:1$$

Question 2

Which of the following statements about dominant alleles is CORRECT?

Accepted Answer

A dominant allele is not necessarily more common in the population.

Question 3

In snapdragons, flower color shows incomplete dominance. If a red-flowered plant ($$RR) is $$crossed with a white-flowered plant ($$rr$$), what will be the phenotype of the $$F_1$$ generation?

Accepted Answer

All pink flowers

Question 4

Which of the following best describes codominance?

Accepted Answer

Both alleles affect the phenotype equally and separately.

Question 5

A woman with blood type $$AB$$ and a man with blood type $$O$$ have a child. What are the possible blood types for their child?

Accepted Answer

A or B

Question 6

Which of the following is an example of a trait with multiple alleles?

Accepted Answer

Rabbit fur color with alleles $$C$$, $$c^{chd}$$, $$c^{ch}$$, and $$c$$

Question 7

Which blood type is considered the universal donor and why?

Accepted Answer

Type O, because it has no antigens on the surface of red blood cells.

Question 8

A woman who is a carrier for hemophilia (an X-linked recessive disorder) has children with a man who does not have hemophilia. What is the probability that their son will have hemophilia?

Accepted Answer

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

Question 9

Which of the following best explains why polygenic traits, such as human skin color, show a continuous range of phenotypes?

Accepted Answer

They are determined by the additive effects of two or more genes.

Question 10

Which of the following is TRUE regarding the inheritance of X-linked traits?

Accepted Answer

Males are more likely to express X-linked recessive disorders because they have only one X chromosome.

Question 11

If two brown-eyed parents (brown is dominant to blue) have a blue-eyed child, what must be the genotype of the parents?

Accepted Answer

Both parents are heterozygous ($$Bb)$$

Question 12

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They have the same genes but may have different alleles.

Question 13

What is the difference between a gene and a chromosome?

Accepted Answer

A gene is a segment of DNA that codes for a trait, while a chromosome is a structure made of DNA and proteins that contains many genes.

Question 14

How many chromosomes are found in a typical human somatic cell?

Accepted Answer

$$46$$

Question 15

What determines genetic sex in humans?

Accepted Answer

The presence of the SRY gene on the Y chromosome.

Question 16

A woman with genotype $$X^C X^c ($$carrier for colorblindness) and a man with genotype $$X^C Y$$ have a son. What is the probability that their son will be colorblind?

Accepted Answer

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

Question 17

Which of the following best describes the difference between polygenic inheritance and multiple alleles?

Accepted Answer

Polygenic inheritance involves multiple genes affecting a trait, while multiple alleles refers to more than two forms of a single gene.

Question 18

If a woman is a carrier for hemophilia and her partner is not affected, what is the probability that their daughter will be a carrier?

Accepted Answer

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

Question 19

Which of the following is a real-life example of codominance in humans?

Accepted Answer

ABO blood group, where both $$I^A$$ and $$I^B$$ alleles are expressed in type AB individuals.

Non-Mendelian Inheritance and Sex-Linked Traits: Advanced Patterns of Heredity

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