Question 1

Which of the following statements best explains why water has a high specific heat?

Accepted Answer

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

Question 2

A scientist is studying a molecule with the formula $C_{12}H_{22}O_{11}$. Which class of macromolecule does this molecule most likely belong to?

Accepted Answer

Disaccharide

Question 3

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

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons between atoms of different electronegativities, while nonpolar covalent bonds involve equal sharing between atoms of similar electronegativities.

Question 4

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

Accepted Answer

Cohesion due to hydrogen bonding

Question 5

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

Accepted Answer

$[H^+] = 1 	imes 10^{-4}$ M

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 7

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

Accepted Answer

Hydrogen bonds in ice create an open lattice structure, making ice less dense than liquid water.

Question 8

Which of the following is a correct statement about the structure of nucleic acids?

Accepted Answer

Nucleic acids are composed of nucleotide monomers linked by phosphodiester bonds.

Question 9

A protein is denatured by a change in pH. Which of the following best explains why this affects the protein's function?

Accepted Answer

A change in pH can disrupt hydrogen and ionic bonds, altering the protein's 3D structure and thus its function.

Question 10

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

Accepted Answer

Buffers maintain a constant pH by absorbing excess $H^+$ or $OH^-$ ions.

Question 11

Which of the following is a property of carbon that makes it especially important in forming large, complex molecules?

Accepted Answer

Carbon can form up to four covalent bonds with a variety of atoms.

Question 12

Which of the following best describes a condensation (dehydration synthesis) reaction?

Accepted Answer

A reaction that joins monomers to form polymers by removing a molecule of water.

Question 13

Which of the following is true about the structure of DNA?

Accepted Answer

DNA is a double-stranded molecule with strands held together by hydrogen bonds between nitrogenous bases.

Question 14

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

Accepted Answer

Water is a polar molecule that surrounds and separates positive and negative ions.

Question 15

Which of the following is a correct match between a macromolecule and its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 16

A molecule of glucose ($C_6H_{12}O_6$) and a molecule of fructose ($C_6H_{12}O_6$) combine to form sucrose and water. What type of reaction is this?

Accepted Answer

Condensation (dehydration synthesis)

Question 17

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is any group of atoms held together by covalent bonds, while a compound is a molecule made up of two or more different elements in a fixed ratio.

Question 18

Which of the following is a function of defensive proteins in organisms?

Accepted Answer

Protecting against disease by helping destroy viruses and bacteria

Question 19

Which of the following best explains why nonpolar molecules such as hydrocarbons are hydrophobic?

Accepted Answer

They do not form hydrogen bonds with water and are repelled by water's polarity.

General Biology Study Notes: Atoms, Chemical Bonds, Water, Macromolecules, and Biological Molecules

Study Guide - Practice Questions

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