Question 1

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes have the same genes at the same loci but may have different alleles, while sister chromatids are identical copies of a chromosome with the same alleles.

Question 2

A plant with genotype $$Pp ($$where $$P is $$dominant for purple flowers and $$p is $$recessive for white flowers) is self-crossed. What is the expected phenotypic ratio in the offspring?

Accepted Answer

$$3:1 (3 $$purple : 1 white)

Question 3

According to Mendel's law of segregation, what happens during the formation of gametes?

Accepted Answer

Alleles for each gene separate so that each gamete receives only one allele for each gene.

Question 4

In a dihybrid cross between two individuals with genotype $$AaBb$$, what is the expected phenotypic ratio in the F2 generation if the genes assort independently?

Accepted Answer

$$9:3:3:1$$

Question 5

A test cross is performed between a plant with an unknown genotype for a dominant trait (A__) and a homozygous recessive plant (aa). If all offspring display the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant ($$AA)$$

Question 6

Which phase of meiosis is responsible for the segregation of alleles according to Mendel's first law?

Accepted Answer

Anaphase I

Question 7

If a child is born with an autosomal recessive disorder, but both parents are unaffected, what can you conclude about the parents' genotypes?

Accepted Answer

Both parents are heterozygous carriers.

Question 8

In a pedigree, if two unaffected parents have an affected child for an autosomal recessive trait, what is the probability that a normal (unaffected) sibling is a carrier?

Accepted Answer

$$\frac{2}{3}$$

Question 9

Which of the following best explains why the 9:3:3:1 ratio is observed in a dihybrid cross?

Accepted Answer

The genes are located on different chromosomes and assort independently during meiosis.

Question 10

A plant with genotype $$AaBb$$ produces which of the following gamete combinations, assuming independent assortment?

Accepted Answer

$$AB$$, $$Ab$$, $$aB$$, $$ab$$

Question 11

If a gene for flower color is located on chromosome 1 and a gene for seed shape is on chromosome 2, what is the probability that a gamete from a $$YyRr$$ plant will contain the $$y$$ and $$r$$ alleles?

Accepted Answer

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

Question 12

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are alternative versions of a gene found at the same locus on homologous chromosomes.

Question 13

A pea plant with genotype $$Aa is $$crossed with another $$Aa$$ plant. What is the probability that an offspring will be homozygous recessive?

Accepted Answer

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

Question 14

Which of the following best describes the phenotype of an individual?

Accepted Answer

The observable traits expressed by the individual.

Question 15

During which stage of meiosis does the law of independent assortment occur?

Accepted Answer

Metaphase I

Question 16

If a plant with genotype $$AABb is $$crossed with a plant with genotype $$aaBb$$, what proportion of the offspring will have the genotype $$AaBB$$?

Accepted Answer

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

Question 17

A pedigree shows a trait that skips generations and appears equally in males and females. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 18

If a gene is located far from another gene on the same chromosome, what is the most likely outcome during meiosis?

Accepted Answer

Crossing over is likely to separate the alleles, allowing them to assort independently.

Question 19

Which of the following is a correct statement about a monohybrid cross?

Accepted Answer

It is a cross between two individuals heterozygous for one trait.

Question 20

In a dihybrid cross, what is the probability that an offspring will be homozygous recessive for both traits ($$aabb) if $$both parents are $$AaBb$$?

Accepted Answer

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

Mendelian Genetics: Principles, Laws, and Applications

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