$$\text{Mass number} = \text{Number of protons} + \text{Number of neutrons}$$

$$[H^+] = 1 \times 10$$^{-4}$$ \text{ mol/L}$$

Question 1

Which of the following best describes the relationship between energy and matter in an ecosystem?

Accepted Answer

Energy flows in a linear fashion and is not recycled, while matter cycles within the ecosystem.

Question 2

A scientist wants to test the effect of sunlight on plant growth. Which variable should be kept constant to ensure a valid experiment?

Accepted Answer

Type of plant

Question 3

Which statement about water is TRUE and explains why lakes do not freeze solid in winter?

Accepted Answer

Water is less dense as a solid than as a liquid, so ice floats and insulates the water below.

Question 4

Which of the following is a correct formula for calculating the mass number of an atom?

Accepted Answer

$$	ext{Mass number} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 5

A solution has a pH of 4. What is the concentration of hydrogen ions ($$[H^+]) in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ 	ext{ mol/L}$$

Question 6

Which property of water allows insects like water striders to walk on its surface?

Accepted Answer

Water's cohesion due to hydrogen bonding

Question 7

Which of the following best explains why carbon is able to form such a wide variety of organic molecules?

Accepted Answer

Carbon has four valence electrons, allowing it to form four covalent bonds.

Question 8

Which of the following is a correct description of dehydration synthesis?

Accepted Answer

It joins monomers to form polymers and releases water.

Question 9

A molecule of sodium chloride ($$	ext{NaCl}) is $$held together by which type of chemical bond?

Accepted Answer

Ionic bond

Question 10

Which of the following statements about valence electrons is correct?

Accepted Answer

Atoms with a filled valence shell are chemically inert.

Question 11

Which of the following is a correct sequence for the flow of genetic information in the central dogma of molecular biology?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 12

Which of the following best describes a hypothesis in the scientific method?

Accepted Answer

A hypothesis is a testable statement that explains an observation.

Question 13

Which of the following is NOT a property of water that is important for life?

Accepted Answer

Water is nonpolar and does not form hydrogen bonds.

Question 14

Which of the following macromolecules is primarily responsible for storing genetic information?

Accepted Answer

Nucleic acids

Question 15

A polysaccharide is best described as:

Accepted Answer

A polymer made of monosaccharide units

Question 16

Which of the following best explains why water has a high surface tension?

Accepted Answer

Water molecules form hydrogen bonds with each other.

Question 17

Which of the following is TRUE about acids and bases?

Accepted Answer

Acids increase the hydrogen ion concentration of a solution.

Question 18

Which of the following is a correct example of a hydrogen bond?

Accepted Answer

Between the hydrogen of one H$$_2O $$and the oxygen of another H$$_2O$$

Question 19

Which of the following best describes the role of decomposers in the cycling of matter in ecosystems?

Accepted Answer

Decomposers break down dead organisms, returning nutrients to the ecosystem.

General Biology: Foundations, Chemistry of Life, and Macromolecules

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