Question 1

Which of the following best describes an ionic bond?

Accepted Answer

Electrons are transferred from one atom to another, resulting in oppositely charged ions that attract each other.

Question 2

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 3

When ice cubes are added to a drink, which process is primarily responsible for cooling the drink?

Accepted Answer

Heat energy is transferred from the drink to the ice, causing the ice to melt.

Question 4

Which type of bond must be broken for water to vaporize?

Accepted Answer

Hydrogen bonds

Question 5

Why is carbon so important in biology?

Accepted Answer

It can form a variety of bonds with itself and other elements.

Question 6

Serine and leucine are amino acids. If a protein is embedded in a cell membrane, where would you expect to find serine and leucine?

Accepted Answer

Leucine would be in the interior, and serine would be on the exterior of the protein.

Question 7

Which of the following descriptions best fits the class of molecules known as nucleotides?

Accepted Answer

A molecule with a sugar, a phosphate group, and a nitrogenous base

Question 8

Which structure is NOT part of the endomembrane system?

Accepted Answer

Chloroplast

Question 9

Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from:

Accepted Answer

Nearly any eukaryotic organism

Question 10

Which of the following statements BEST describes the fluid mosaic model of biological membranes?

Accepted Answer

That membranes are comprised of a mosaic of proteins embedded in a fluid bilayer of phospholipids

Question 11

Why do unsaturated fatty acids have a lower melting temperature than saturated fatty acids?

Accepted Answer

Double bonds in unsaturated fatty acids create kinks, preventing tight packing of lipids.

Question 12

Which of the following types of reactions would decrease the entropy within a cell?

Accepted Answer

Anabolic reactions

Question 13

Which of the following is true when comparing an uncatalyzed reaction to the same reaction catalyzed in the presence of a catalyst?

Accepted Answer

The catalyzed reaction will have a lower activation energy.

Question 14

Which equation correctly represents the relationship between Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), temperature ($$T$$), and entropy ($$\Delta S$$)?

Accepted Answer

$$\Delta G = \Delta H - T \Delta S$$

Question 15

A scientist discovers a new cell with a cell wall, ribosomes, and no nucleus. Which type of organism is this cell most likely from?

Accepted Answer

A prokaryote

Question 16

Which organelle is primarily responsible for packaging and modifying proteins for secretion?

Accepted Answer

Golgi apparatus

Question 17

Which of the following is a function of the proton pump in plant cells?

Accepted Answer

It uses ATP to actively transport protons ($$H^+) $$across the membrane, creating an electrochemical gradient.

Question 18

Which of the following is NOT a function of the endomembrane system?

Accepted Answer

Energy production via cellular respiration

Question 19

Cellulose and starch are both polymers of glucose. Which statement best explains their difference in digestibility by humans?

Accepted Answer

Cellulose has $$\beta-1$$,4 glycosidic bonds, which human enzymes cannot hydrolyze, while starch has $$\alpha-1$$,4 and $$\alpha-1$$,6 bonds, which can be digested.

Question 20

Which of the following best describes the tertiary structure of a protein?

Accepted Answer

The overall three-dimensional shape formed by interactions among side chains (R groups) of amino acids.

General Biology: Chemical Bonds, Macromolecules, Cell Structure, and Membrane Function

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