Chapter 9

Question 1

Energy enters an ecosystem as ____ and exits as ______

Answer 1

sunlight; heat

Question 2

What releases the energy stored in glucose during cellular respiration? What is this released energy used for?

Answer 2

• The transfer of electrons

- Used to synthesize ATP

Question 3

Cellular respiration is a ______ reaction

Answer 3

exergonic

Question 4

Redox reaction

Answer 4

Reaction with transfer of electrons between reactants

Question 5

Oxidation

Answer 5

A substances loses electrons and is oxidized

Question 6

Reduction

Answer 6

A substance gains electrons and is reduced.

Question 7

In this equation: Na + Cl = Na+ + Cl- Which is oxidized and which is reduced?

Answer 7

-Na is oxidized, Cl is reduced
Remember that Na loses electrons, and therefore has more protons. It has a positive charge. Cl gains electrons and has less protons that electrons. Its charge is reduced to negative.

Question 8

Reducing agent

Answer 8

Electron donor; this would be the substance that is oxidized

Question 9

Oxidizing agent

Answer 9

Electron receptor; this would be the substance that is reduced

Question 10

Some redox reactions do not transfer electrons but change _______

Answer 10

electron sharing in covalent bonds

Question 11

In cellular respiration, which is oxidized and which is reduced?

Answer 11

• Glucose is oxidized

- Oxygen is reduced

Question 12

In a molecule of H2O, which atom is reduced?

Answer 12

Oxygen is reduced as electrons of covalent bonds tend to gravitate towards it more

Question 13

Oxidation of glucose transfers electrons to a ____ free energy level

Answer 13

Lower; they lose potential energy along the way

Question 14

What is NAD+

Answer 14

An electron carrier coenzyme

Question 15

NAD+ functions as a _____ agent during cellular respiration

Answer 15

Oxidizing

-Remember that NAD+ receives electrons, therefore it is reduced. So, it is an oxidizing agent.

Question 16

What does NADH represent?

Answer 16

Stored energy that is tapped to synthesize ATP

Question 17

What electron transfer is coupled with the reduction of NAD+?

Answer 17

The oxidation of glucose
(Dehydrogenase enzymes remove 2 hydrogen atoms from glucose, thus oxidizing it, and then delivers 2 electrons and 1 proton to NAD+)

Question 18

What do dehydrogenase enzymes do?

Answer 18

Oxidize glucose by removing 2 hydrogen atoms and delivers it to NAD+

Question 19

The Electron Transport Chain passes electrons down the chain until it meets _____, which is the stable and electron acceptor

Answer 19

O2

Question 20

The energy yielded from which process is used to generate ATP?

Answer 20

Electron Transport Chain

Question 21

Which process generates the most ATP and why?

Answer 21

Oxidative phosphorylation and because it is powered by redox reactions

Question 22

Which 2 processes generate the least ATP and why?

Answer 22

Glycolysis and Citric Acid Cycle because it is fueled by substrate-level phosphorylation

Question 23

What is substrate-level phosphorylation?

Answer 23

Transfer of phosphate group from organic substrate to ADP

Question 24

Glycolysis breaks glucose into __(number)__ molecules of _____

Answer 24

2 molecules of pyruvate

Question 25

Where does glycolysis occur and what are its phases?

Answer 25

In cytoplasm, energy investment phase and energy payoff phase

Question 26

What are the products of glycolysis?

Answer 26

-2 pyruvate and 2 H2O, 2 ATP, 2 NADH and 2 H+ | The 2 ATP is produced by substrate-level phosphorylation and the NAD+ is reduced to NADH

Question 27

What does the Citric Acid Cycle ultimately do?

Answer 27

Completely oxidizes glucose in the presence of oxygen

Question 28

What happens before Krebs cycle begins and after glycolysis?

Answer 28

Carbon is lost as carbon dioxide, 2-carbon molecule combines with CoA to form acetyl CoA

Question 29

What is the final electron acceptor in oxidative phosphorylation?

Answer 29

Oxygen

Question 30

More H+ ions = _____ pH

Answer 30

Lower

Question 31

The electron transport chain sends H+ from where to where?

Answer 31

Matrix to intermembrane space

Question 32

How does the exergonic flow of H+ ions create ATP?

Answer 32

Catabolic pathway of H+ across membrane through ATP synthase conforms ADP and phosphate group

Question 33

What is chemiosmosis?

Answer 33

Use of energy in an H+ gradient to drive work

Question 34

What are the types of fermentation? What happens in these?

Answer 34

- Alcohol: CO2 released from pyruvate, then that is oxidized. Ethanol is final. - Lactic: Pyruvate oxidized right away, creating lactate

Question 35

Obligate anaerobe

Answer 35

Carry out fermentation and cannot survive in O2

Question 36

What three organic molecules are often utilized to make ATP by cellular respiration?

Answer 36

Proteins, fats, carbohydrates

Question 37

Why don't cells catabolize carbon dioxide?

Answer 37

CO2 is already completely oxidized