Chapter 4.4

Question 1

Cellular respiration occurs in three series of reactions called

Answer 1

Glycolysis

Citric Acid Cycle

Electron Transport Chain

Question 2

Cellular respiration requires

Answer 2

glucose and oxygen

Question 3

Products of cellular respirationa make

Answer 3

CO2, water, and energy

Question 4

Glycolysis means

Answer 4

the breaking of glucose

Question 5

Glycolysis is a

Answer 5

series of ten enzyme-catalyzed reactions that break down the 6-carbon glucose molecule into two 3-carbon pyruvic acid molecules

Question 6

Glycolysis takes place in

Answer 6

the cytosol

Question 7

Glycolysis involves how many sets of reactions?

Answer 7

Three

Question 8

First Step of Glycolysis

Answer 8

Two phosphate groups are added to a glucose molecule, one at each end, in a step called phosphorylation.

Question 9

How much energy does the first step of glycolysis require?

Answer 9

requires energy from two atps, which are used to “prime” the glucose so that it is activated fro some of the energy-releasing reactions that will happen

Question 10

Second Step of Glycolysis

Answer 10

The 6-carbon glucose molecule is cleaved into two 3-carbon molecules

Question 11

Third Step of Glycolysis

Answer 11

The electron carrier NADH is produced, ATP is synthesized, and two 3-carbon pyruvic acid molecules result

Question 12

During glycolysis, how many ATPs are synthesized directly?

Answer 12

Four

Question 13

Subtracting the two ATPS used in the priming step gives

Answer 13

a net yield of two ATP’s per molecules of glucose from glycolysis

Question 14

For cellular respiration to continue..

Answer 14

NADH + H+ must be able to deliver electrons to the ETC, replenishing the cellular supply of NAD+

Question 15

What acts as the final electron acceptor at the end of the ETC?

Answer 15

Oxygen, which enables the chain to continue processing electrons and recycling NAD+

Question 16

Under anaerobic conditions, the ETC has

Answer 16

no oxygen and therefore nowhere to unload its electrons. As a result, the ETC can no longer accept new electrons from NADH

Question 17

Anaerobic - As an alternative, NADH + H+ can

Answer 17

give its electrons and hydrogen back to pyruvic acid in a reaction that forms lactic acid

Question 18

The buildup of lactic acid evantually

Answer 18

inhibits glycolysis and ATP production declines

Question 19

Pyruvic acid generated by glycolysis can

Answer 19

continue through the aerobic pathways if enough oxygen is available

Question 20

The reactions inside aerobic reactions include

Answer 20

the synthesis of
Acetyl Coenzyme A/Acetyl CoA
the Citric Acid Cycle
ETC

Question 21

How many ATP produced per Glucose molecule in aerobic reactions?

Answer 21

Twenty-Eight ATP molecules per glucose

Question 22

The aerobic reaction begins with

Answer 22

pyruvic acid produced in glycolysis moving from the cytosol into the mitochondria.

Question 23

From each pyruvic acid,

Answer 23

enzymes inside the mitochondria remove two hydrogen atoms, a carbon atom, and two oxygen atoms, generating NADH and CO2 leacing a 2-carbon acetic acid

Question 24

Aerobic Reaction - The Acetic Acid then

Answer 24

combines with a molecule of coenzyme A to form Acetyl Co1.

Question 25

CoA “carries”

Answer 25

the acetic acid into the citric acid cycle

Question 26

Citric Acid Cycle begins when

Answer 26

2-carbon acetyl CoA molecule combines with a 4-carbon oxaloacetic acid molecule to form the 6-carbon citric acid and CoA.

Question 27

The citric acid is changed through

Answer 27

a series of reactions back into oxaloacetic acid.

Question 28

Citric Acid Cycle - The cycle repeats as

Answer 28

long as the mitochondrion receives oxygen and pyruvic acid.

Question 29

The citric acid cycle has how many important consequences?

Answer 29

Three

Question 30

First Important Consequence in Citric Acid Cycle

Answer 30

One ATP is produced directly from each citric acid molecule that goes through the cycle

Question 31

Second Important Consequence in Citric Acid Cycle

Answer 31

For each citric acid molecule, eight hydrogen atoms with high-energy electrons are transferred to the hydrogen carriers NAD+ and the related molecule FAD

Question 32

Third Important Consequence in Citric Acid cycle

Answer 32

As the 6-carbon citric acid reacts to form the 4- carbon oxaloacetic acid, two carbon dioxide molecules are produced

Question 33

What are Oxidation/Reduction Reactions?

Answer 33

That energy is transferred to ATP synthase, an enzyme complex that uses the energy to add a phosphate to ADP to form ATP

Question 34

What two processes do not use oxygen directly?

Answer 34

Neither glycolysis nor the citric acid cycle

Question 35

The final enzyme of the ETC gives up

Answer 35

a pair of electrons that combine with two hydrogen ions and an atom ox oxygen to form a water molecule

Question 36

ETC - Oxygen is therefore the

Answer 36

final electron “carrier”

Question 37

ETC - In the absence of oxygen,

Answer 37

electrons cannot continue to pass through the ETC and the aerobic reactions of cellular respiration stop

Question 38

Excess glucose in cells may

Answer 38

enter anabolic carbohydrate pathways and be linked into storage forms as glycogens

Question 39

Following a meal when glucose concentration is relatively high,

Answer 39

liver cells obtain glucose from the blood and synthesize glycogen. Between meals, when blood glucose concentration is lower, the reaction reverses and glucose is released into the blood

Question 40

GLucose can react to form

Answer 40

lipid molecules, which are deposited in adipose tissue.

Question 41

The most common entry point for aerobic respiration is

Answer 41

into the citric acid cycle as acetyl CoA.