Q: Which equation represents the probability of producing a yellow, round offspring from a dihybrid cross ($$YyRr \times YyRr$$)?

$$\frac{3}{4} \times \frac{3}{4} = \frac{9}{16}$$

Question 1

Which of the following best describes Mendel's 'particulate' theory of inheritance?

Accepted Answer

Parents transmit discrete factors (genes) to their offspring that remain unchanged from generation to generation.

Question 2

In Mendel's experiments with pea plants, what was the observed phenotypic ratio in the F2 generation when crossing two heterozygous plants for flower color?

Accepted Answer

3:1

Question 3

Which equation represents the probability of producing a yellow, round offspring from a dihybrid cross ($$YyRr 	imes YyRr$$)?

Accepted Answer

$$\frac{3}{4} 	imes \frac{3}{4} = \frac{9}{16}$$

Question 4

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 5

What is the genotype of a pea plant with a dominant phenotype but unknown genotype, determined by a testcross with a homozygous recessive plant if some offspring display the recessive phenotype?

Accepted Answer

Heterozygous

Question 6

Which law states that alleles for different genes segregate independently during gamete formation?

Accepted Answer

Law of Independent Assortment

Question 7

A child has blood type O. If one parent is blood type AB and the other is blood type O, what is the child's genotype?

Accepted Answer

$$i i$$

Question 8

Which of the following best explains why dominant alleles are not necessarily more common in a population?

Accepted Answer

Dominant alleles can be rare if they do not confer a selective advantage or are introduced by a founder effect.

Question 9

Which genetic principle is illustrated by the fact that skin color in humans is determined by the additive effects of many genes?

Accepted Answer

Polygenic inheritance

Question 10

If a gene at one locus affects the expression of a gene at another locus, this is an example of:

Accepted Answer

Epistasis

Question 11

Which of the following is true about Mendel's use of pea plants in his experiments?

Accepted Answer

He selected traits with discrete character states and controlled crosses by hand pollination.

Question 12

What is the probability that two carriers for a rare recessive genetic disorder will have an affected child?

Accepted Answer

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

Question 13

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple traits.

Question 14

In the context of Mendelian genetics, what is the difference between phenotype and genotype?

Accepted Answer

Phenotype is the physical appearance, genotype is the genetic makeup.

Question 15

Which rule should be used to calculate the probability of two independent events both occurring?

Accepted Answer

Multiplication rule

Question 16

A cross between two yellow mice (with a lethal yellow allele) produces offspring in the ratio 1/3 agouti, 2/3 yellow. What explains the missing 1/4?

Accepted Answer

The yellow allele is dominant and causes lethality in homozygotes.

Question 17

Which of the following is an example of a multifactorial disease?

Accepted Answer

Heart disease

Question 18

Which of the following statements about genetic testing is correct?

Accepted Answer

Genetic testing can identify carriers for both dominant and recessive alleles and help define the odds of inheriting a disease.

Question 19

Which of the following best describes codominance?

Accepted Answer

Both alleles are expressed in the phenotype in separate, distinguishable ways.

Question 20

If a pea plant has genotype $$Pp$$ for flower color, what gametes can it produce?

Accepted Answer

$$P$$ and $$p$$

Mendel and the Gene Idea: Principles of Inheritance

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