Question 1

Which of the following best describes an emergent property in biological systems?

Accepted Answer

A property that arises from the interaction of simpler components, such as consciousness emerging from neural networks.

Question 2

A scientist is testing the effect of a new fertilizer on plant growth. She sets up two groups: one receives the fertilizer, and the other does not. She measures the height of the plants after four weeks. In this experiment, what is the dependent variable?

Accepted Answer

The height of the plants

Question 3

Which of the following is NOT one of the three domains of life?

Accepted Answer

Protista

Question 4

Which of the following statements about natural selection is FALSE?

Accepted Answer

Natural selection causes individuals to evolve new traits during their lifetime.

Question 5

Which of the following best explains why ice floats on water?

Accepted Answer

Ice is less dense than liquid water because its hydrogen bonds form a stable, open lattice.

Question 6

A radioactive isotope of carbon ($$^{14}\mathrm{C}) is $$used in medical imaging. What property makes radioactive isotopes useful for this purpose?

Accepted Answer

They emit detectable radiation as they decay, allowing tracking within organisms.

Question 7

Which of the following best describes a buffer in biological systems?

Accepted Answer

A substance that minimizes changes in pH by accepting or donating $$\mathrm{H}^+$$ ions.

Question 8

Which of the following is a correct comparison between DNA and RNA?

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar.

Question 9

Which of the following best describes the process of dehydration synthesis?

Accepted Answer

A reaction in which two monomers are joined together by removing a molecule of water.

Question 10

A population of insects is exposed to a pesticide. After several generations, most of the population is resistant to the pesticide. Which concept does this scenario best illustrate?

Accepted Answer

Natural selection

Question 11

Which of the following is a trace element essential for human health, and what is its primary biological role?

Accepted Answer

Iodine; required for the synthesis of thyroid hormones

Question 12

Which of the following best explains why O$$_2$$ would have been problematic for the formation of the first organic molecules on early Earth?

Accepted Answer

O$$_2 is $$highly reactive and would have broken down organic molecules before they could accumulate.

Question 13

Which of the following is a correct sequence for the four stages of the origin of life, as described in the study materials?

Accepted Answer

Abiotic synthesis of monomers → Formation of polymers → Formation of protocells → Origin of self-replicating molecules

Question 14

Which of the following best describes the relationship between structure and function in proteins?

Accepted Answer

The specific sequence of amino acids determines the protein's three-dimensional shape, which determines its function.

Question 15

Which of the following is an example of a polar covalent bond?

Accepted Answer

The bond between oxygen and hydrogen in a water molecule ($$\mathrm{H}_2\mathrm{O})$$

Question 16

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

They lower the activation energy required for reactions to proceed.

Question 17

Which of the following statements about macromolecules is TRUE?

Accepted Answer

Proteins are polymers made of amino acid monomers.

Question 18

Which of the following best explains why whales have vestigial pelvic bones?

Accepted Answer

They are remnants of ancestral structures that were functional in whale ancestors.

Question 19

Which of the following is a correct statement about the pH scale?

Accepted Answer

A solution with pH 4 is ten times more acidic than a solution with pH 5.

Question 20

Which of the following best describes the Miller-Urey experiment and its significance?

Accepted Answer

It demonstrated that organic molecules could form spontaneously under conditions thought to resemble those of early Earth.

BIO 121 Unit 1 Exam Review: Foundations of Biology, Evolution, and the Chemistry of Life

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