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

$$[H^+] = 1 \times 10$$^{-4}$$\ \mathrm{M}$$

Question 1

Which of the following is NOT one of the five fundamental characteristics of life as described in the study guide?

Accepted Answer

Respiration

Question 2

A nitrogen atom has 7 protons. According to the octet rule, how many valence electrons does nitrogen have, and how many more electrons does it need to fill its outer shell?

Accepted Answer

5 valence electrons; needs 3 more

Question 3

Which type of bond is responsible for holding two water molecules together?

Accepted Answer

Hydrogen bond

Question 4

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}$$\ \mathrm{M}$$

Question 5

Which functional group is responsible for forming disulfide bonds in proteins, and which amino acid contains it?

Accepted Answer

Sulfhydryl group (–SH); cysteine

Question 6

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

Accepted Answer

Ice is less dense than liquid water due to hydrogen bonding creating an open lattice structure

Question 7

Which of the following statements about protein structure is correct?

Accepted Answer

Tertiary structure is stabilized by interactions between R-groups, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges

Question 8

A mutation changes a single amino acid in the primary structure of a protein. Which level(s) of protein structure could be affected as a result?

Accepted Answer

All levels: primary, secondary, tertiary, and quaternary

Question 9

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose and thymine; RNA contains ribose and uracil

Question 10

Which property of water is primarily responsible for the phenomenon of surface tension, allowing some insects to walk on water?

Accepted Answer

Cohesion due to hydrogen bonding

Question 11

Which of the following best explains why oil and water do not mix?

Accepted Answer

Oil is nonpolar and hydrophobic, while water is polar and hydrophilic

Question 12

Which of the following is a correct statement about the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein

Question 13

A molecule has both hydrophilic and hydrophobic regions. What is this type of molecule called, and what is a biological example?

Accepted Answer

Amphipathic; phospholipid

Question 14

Which of the following best describes the backbone of a nucleic acid?

Accepted Answer

Alternating sugar and phosphate groups

Question 15

Which of the following is a property of water that helps moderate Earth's climate by absorbing heat with only a slight change in its own temperature?

Accepted Answer

High specific heat

Question 16

If a protein is placed in a solution with a pH much lower than its isoelectric point, what is most likely to happen to its structure?

Accepted Answer

It will denature due to disruption of ionic and hydrogen bonds

Question 17

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

Accepted Answer

They act as catalysts to speed up chemical reactions by lowering activation energy

Question 18

Which of the following statements about peptide bonds is correct?

Accepted Answer

Peptide bonds form between the carboxyl group of one amino acid and the amino group of another via a dehydration reaction

Question 19

Which of the following best explains why sweating cools you down?

Accepted Answer

Evaporation of water from the skin absorbs heat due to water's high heat of vaporization

Question 20

Which of the following is a correct pairing of a nitrogenous base with its nucleic acid and number of rings?

Accepted Answer

Adenine – DNA/RNA – 2 rings (purine)

General Biology I: Study Guide – Chemistry of Life, Proteins, and Nucleic Acids

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