Question 1

Which of the following best describes a characteristic of a good scientific hypothesis?

Accepted Answer

It is a testable and falsifiable statement that explains an observation.

Question 2

A researcher is studying the effect of fertilizer on plant growth. Which variable should be plotted on the x-axis of a line graph?

Accepted Answer

Amount of fertilizer applied (g)

Question 3

Which of the following best explains the role of the independent variable in an experiment?

Accepted Answer

It is the variable that is deliberately changed or manipulated by the researcher.

Question 4

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

Accepted Answer

It allows populations to adapt to changing environmental conditions, supporting species survival.

Question 5

Which of the following best describes the greenhouse effect?

Accepted Answer

The trapping of heat in Earth's atmosphere by certain gases, leading to increased global temperatures.

Question 6

During meiosis I in a cell with $$2n = 2$$, which of the following correctly describes the chromosomal arrangement?

Accepted Answer

Two pairs of homologous chromosomes, each consisting of two sister chromatids, align at the metaphase plate.

Question 7

The experiment with C. elegans grown with or without pathogens supports the changing environment hypothesis for sexual reproduction because:

Accepted Answer

Sexual reproduction increases genetic variation, allowing populations to adapt more quickly to new pathogens.

Question 8

Why is meiosis necessary for sexual reproduction in most organisms?

Accepted Answer

It reduces the chromosome number by half, allowing for genetic diversity when gametes fuse.

Question 9

In peas, tall (T) is dominant over short (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 10

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

Accepted Answer

$$1/4$$

Question 11

In fruit flies, red eyes ($$R) $$are dominant over white eyes ($$r). If a $$heterozygous red-eyed fly ($$Rr) is $$crossed with a white-eyed fly ($$rr$$), what is the expected genotype ratio of their offspring?

Accepted Answer

$$1 Rr$$ : $$1 rr$$

Question 12

In horses, brown coat color ($$B) is $$dominant over chestnut ($$b). If $$two heterozygous brown-coated horses ($$Bb) $$are crossed, what is the expected phenotypic ratio of their foals?

Accepted Answer

$$3$$ brown : $$1$$ chestnut

Question 13

In guinea pigs, the genes for fur color and fur length segregate independently. If a heterozygous black short-furred guinea pig ($$BbLl) is $$crossed with a brown long-furred guinea pig ($$bbll$$), which of the following is a possible phenotype among their offspring?

Accepted Answer

Black, long-furred

Question 14

In fruit flies, the genes for wing shape ($$W/w) $$and eye color ($$E/e) $$are linked on the same chromosome. If a heterozygous winged, red-eyed fly ($$WwEe) is $$crossed with a homozygous wingless, white-eyed fly ($$wwee$$), what is the expected phenotype ratio of their offspring (assuming no crossing over)?

Accepted Answer

1 winged, red-eyed : 1 wingless, white-eyed

Question 15

Which scenario best illustrates the concept of multiple alleles creating a range of phenotypes, as opposed to simple Mendelian inheritance?

Accepted Answer

Human blood type, where alleles $$I^A$$, $$I^B$$, and $$i$$ interact to produce types A, B, AB, and O.

Question 16

How does the phenotypic ratio in a cross exhibiting incomplete dominance differ from that in a cross with complete dominance?

Accepted Answer

Incomplete dominance results in a $$1:2:1$$ phenotypic ratio, while complete dominance results in a $$3:1$$ ratio.

Question 17

Why might genetically identical plants exhibit different phenotypes when grown in different environments?

Accepted Answer

Environmental factors can influence gene expression, leading to phenotypic variation.

Question 18

Which of the following best distinguishes pleiotropy from gene interaction?

Accepted Answer

Pleiotropy occurs when one gene affects multiple traits, while gene interaction involves multiple genes affecting a single trait.

Question 19

Traits governed by quantitative inheritance, such as human height or skin color, often exhibit a bell curve distribution in a population because:

Accepted Answer

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

General Biology Exam 1 Review: Key Concepts and Genetics Practice

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