Question 1

Which of the following best describes the monomer unit that makes up nucleic acids such as DNA and RNA?

Accepted Answer

Nucleotide

Question 2

A nucleotide, the building block of nucleic acids, is composed of which three components?

Accepted Answer

A phosphate group, a pentose sugar, and a nitrogenous base

Question 3

In DNA, the four different nucleotides differ in which specific part of their structure?

Accepted Answer

The nitrogenous base

Question 4

Why are nucleotide bases in DNA described as 'complementary'?

Accepted Answer

Because each base pairs with a specific partner according to base-pairing rules

Question 5

DNA serves as a code to generate which type of molecule, and what is a codon?

Accepted Answer

Protein; a codon is a sequence of three nucleotides that codes for an amino acid

Question 6

Which of the following best defines a gene in the context of a genome?

Accepted Answer

A segment of DNA that codes for a specific protein or functional RNA

Question 7

Which statement correctly contrasts transcription and translation in eukaryotic cells?

Accepted Answer

Transcription occurs in the nucleus and produces mRNA; translation occurs in the cytoplasm and produces proteins

Question 8

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA contains uracil, while RNA contains thymine

Question 9

Which historical figure is correctly matched with their contribution to evolutionary theory?

Accepted Answer

Jean-Baptiste Lamarck: Proposed inheritance of acquired characteristics

Question 10

Darwin’s hypothesis for evolution can best be summarized as:

Accepted Answer

Species evolve through natural selection, where individuals with advantageous traits survive and reproduce

Question 11

Which scenario best illustrates natural selection?

Accepted Answer

A population of moths becoming darker in color due to increased predation on lighter moths in polluted environments

Question 12

How can a beneficial allele enter a population?

Accepted Answer

Through mutation, genetic drift, or migration

Question 13

Which of the following best compares natural selection and artificial selection?

Accepted Answer

Natural selection is driven by environmental pressures, while artificial selection is driven by human choices

Question 14

Which of the following is NOT considered evidence supporting the theory of evolution?

Accepted Answer

Identical DNA sequences in all living organisms

Question 15

How does sexual selection contribute to fitness in a population?

Accepted Answer

By increasing the likelihood that individuals with certain traits will reproduce

Question 16

Which of the following is the best definition of a biological species?

Accepted Answer

A group of organisms that can interbreed and produce fertile offspring

Question 17

Which of the following is an example of a prezygotic reproductive isolation barrier?

Accepted Answer

Mating occurs at different times of the year

Question 18

Which scenario best illustrates allopatric speciation?

Accepted Answer

A population is divided by a geographic barrier, leading to the formation of two distinct species

Question 19

Which of the following best contrasts convergent and divergent evolution?

Accepted Answer

Convergent evolution results in unrelated species developing similar traits; divergent evolution results in related species developing different traits

Question 20

Which statement correctly distinguishes between gradualism and punctuated equilibrium?

Accepted Answer

Gradualism suggests evolution occurs slowly and steadily; punctuated equilibrium suggests long periods of stability interrupted by rapid change

Question 21

Which of the following lists the components of the biological classification system in the correct order from broadest to most specific?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Unit III Biology Study Guide – Step-by-Step Guidance

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