Question 1

Which of the following is NOT a characteristic of a good scientific hypothesis?

Accepted Answer

It is stated as a question rather than a statement.

Question 2

A student is designing an experiment to test the effect of light intensity on plant growth. Which of the following is the best example of an independent variable for this experiment?

Accepted Answer

The intensity of light the plants receive

Question 3

How does genetic diversity contribute to overall biodiversity in an ecosystem?

Accepted Answer

It allows populations to adapt to changing environments, supporting species survival.

Question 4

During meiosis, what is the chromosomal makeup of a cell at the end of meiosis I, assuming the original cell is diploid with $2n = 6$?

Accepted Answer

Each cell has $n = 3$ chromosomes, each consisting of two sister chromatids.

Question 5

Which of the following best explains why sexual reproduction can increase genetic diversity in a population?

Accepted Answer

It combines genetic material from two parents, resulting in new allele combinations.

Question 6

In pea plants, the allele for tall stems (T) is dominant over short stems (t). If a heterozygous tall plant ($Tt$) is crossed with a homozygous short plant ($tt$), what is the expected phenotypic ratio of their offspring?

Accepted Answer

1 tall : 1 short

Question 7

In guinea pigs, black fur (B) is dominant over brown fur (b). If two heterozygous black-furred guinea pigs ($Bb$) are crossed, what is the probability of them having a brown-furred offspring?

Accepted Answer

$\frac{1}{4}$

Question 8

In a dihybrid cross between two pea plants heterozygous for both seed shape (R = round, r = wrinkled) and seed color (Y = yellow, y = green), what is the expected phenotypic ratio of their offspring?

Accepted Answer

9 round yellow : 3 round green : 3 wrinkled yellow : 1 wrinkled green

Question 9

A cross between a homozygous dominant red-flowered plant ($RR$) and a homozygous recessive white-flowered plant ($rr$) produces all pink-flowered offspring. Which inheritance pattern does this demonstrate?

Accepted Answer

Incomplete dominance

Question 10

Which of the following scenarios best illustrates Mendel’s law of independent assortment?

Accepted Answer

A plant with round, yellow seeds produces offspring with round, yellow; round, green; wrinkled, yellow; and wrinkled, green seeds.

Question 11

In a human pedigree, a trait appears in every generation and affects both males and females equally. What is the most likely mode of inheritance for this trait?

Accepted Answer

Autosomal dominant

Question 12

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple, seemingly unrelated phenotypic traits.

Question 13

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

Accepted Answer

A or B

Question 14

Which of the following is an example of epistasis?

Accepted Answer

A gene for pigment deposition masks the expression of a gene for pigment color in Labrador retrievers.

Question 15

Which of the following best explains why traits governed by quantitative inheritance, such as human height, often show a bell curve distribution in a population?

Accepted Answer

They are influenced by multiple genes and environmental factors, resulting in continuous variation.

Question 16

A geneticist crosses two plants and observes a 9:7 ratio in the offspring for a particular trait. Which genetic interaction is most likely responsible for this ratio?

Accepted Answer

Complementary gene interaction

Question 17

Which of the following best describes codominance?

Accepted Answer

Both alleles are fully expressed in the heterozygote, resulting in a phenotype that shows both traits distinctly.

Question 18

In a cross between two heterozygous individuals for a gene showing incomplete dominance, what is the expected genotypic ratio among the offspring?

Accepted Answer

1:2:1

Question 19

Which of the following scenarios best illustrates polygenic inheritance?

Accepted Answer

Human skin color, which is determined by the additive effects of several genes.

Question 20

A researcher observes that a certain trait in mice is only expressed when two different genes both have at least one dominant allele present. What type of gene interaction is this?

Accepted Answer

Complementary gene interaction

Genetics and Scientific Method: Study Notes for General Biology

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