Question 1

Which of the following statements best explains why water has a high specific heat compared to many other substances?

Accepted Answer

Hydrogen bonds between water molecules absorb heat when they break and release heat when they form, buffering temperature changes.

Question 2

A scientist discovers a new element with 15 protons, 16 neutrons, and 15 electrons. What is the atomic mass of this element, and what is its net charge?

Accepted Answer

Atomic mass = $$15 + 16 = 31$$; net charge = 0

Question 3

Which of the following best describes the difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons due to differences in electronegativity, while nonpolar covalent bonds involve equal sharing.

Question 4

Which property of water allows it to move upward through the vessels of a plant against gravity?

Accepted Answer

Cohesion due to hydrogen bonding

Question 5

A solution has a pH of 4. How does its hydrogen ion concentration $$[H^+]$$ compare to a solution with a pH of 7?

Accepted Answer

It is 1,000 times higher.

Question 6

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

Accepted Answer

Buffers maintain constant pH by accepting or donating $$H^+ or$$ $$OH^-$$ ions as needed.

Question 7

Which of the following is true regarding isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 8

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

Accepted Answer

Hydrogen bonds in ice create a lattice that spaces water molecules farther apart, making ice less dense.

Question 9

Which of the following statements about macromolecules is correct?

Accepted Answer

Nucleic acids are polymers made of nucleotides linked by phosphodiester bonds.

Question 10

A dehydration (condensation) reaction is required to build a polymer from monomers. Which of the following best describes what happens during this reaction?

Accepted Answer

A water molecule is removed to form a covalent bond between monomers.

Question 11

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix of nucleotides held together by hydrogen bonds between nitrogenous bases.

Question 12

Which of the following is a correct general formula for a monosaccharide?

Accepted Answer

$$C_{n}H$$_{2n}$$O_{n}$

Question 13

Which of the following best explains why salts dissolve in water?

Accepted Answer

Water's polar molecules surround and separate the positive and negative ions.

Question 14

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

Accepted Answer

Water has a low specific heat, allowing rapid temperature changes.

Question 15

Which of the following best describes the difference between structural and optical isomers?

Accepted Answer

Structural isomers have the same chemical formula but different bonding arrangements, while optical isomers are mirror images of each other.

Question 16

Which of the following statements about acids and bases is correct?

Accepted Answer

Strong acids ionize fully in solution, while weak acids do not.

Question 17

Which of the following best explains why carbon is able to form large, complex molecules?

Accepted Answer

Carbon can form up to four covalent bonds with a variety of atoms, allowing for diverse structures.

Question 18

Which of the following best describes the linkage between nucleotides in a nucleic acid polymer?

Accepted Answer

Phosphodiester bonds between the phosphate group of one nucleotide and the sugar of another

Question 19

A scientist adds a strong acid to a beaker of pure water, causing the pH to drop from 7 to 3. By what factor has the hydrogen ion concentration increased?

Accepted Answer

By a factor of 10,000

Question 20

Which of the following best describes the relationship between genes, DNA, and nucleotides?

Accepted Answer

Genes are made of DNA, which is a nucleic acid polymer made of nucleotide monomers.

Fundamentals of Atoms, Chemical Bonds, Water, and Macromolecules in General Biology

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