Chapter 3: Cell Structure and Function

Chapter 3: Cell Structure and Function

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE

1. Glycolysis is the metabolic process of breaking down a glucose molecule to form

ANS:  B

Glycolysis produces a net gain of 2 ATP molecules and breaks down glucose modules to produce two pyruvate molecules. Oxidative phosphorylation produces CO₂ and H₂O. Oxidative phosphorylation produces 30 ATP molecules. Oxygen is not produced by glycolysis, but it is necessary for oxidative phosphorylation.

REF:   Pg. 34

2. The benefit of glycolysis is that this phase supplies

ANS:  B

The benefit of glycolysis is to supply pyruvate to the citric acid cycle of cellular metabolism, which then produces much ATP. Glycolysis only produces 2 ATP modules, which is insufficient for energy needs. Glycolysis does not supply energy for oxidative phosphorylation. Lactate produced during prolonged anaerobic conditions builds up and can lead to lactic acidosis, which is an undesirable outcome.

REF:   Pg. 34

3. Repolarization of a neuron after a depolarizing action potential is due to

ANS:  C

Repolarization is due to efflux of potassium from the cell. The Na⁺-K⁺ pump maintains cellular volume via osmotic pressure and helps to maintain resting membrane potential. Calcium influx prolongs the action potential. Influx of sodium initiates depolarization.

REF:   Pg. 45

4. Excitable cells are able to conduct action potentials because they have

ANS:  D

Voltage-gated channels respond to changes in membrane potential and are responsible for conducting action potentials. Receptors for neurotransmitters allow neurotransmitters to bind to the cell membrane but are not directly responsible for action potentials in excitable cells. Tight junctions are intercellular connections that help segregate proteins on the cell membrane and are not involved in conducting action potentials. Ligand-gated channels respond to binding of a signaling molecule such as a neurotransmitter, but are not directly responsible for action potentials in excitable cells.

REF:   Pgs. 42-44