Chapter 7

Question 1

acetyl CoA

Answer 1

combination of an acetyl group derived from
pyruvic acid and coenzyme A, which is made from
pantothenic acid (a B-group vitamin)

Question 2

aerobic respiration

Answer 2

process in which organisms convert
energy in the presence of oxygen

Question 3

anaerobic

Answer 3

process that does not use oxygen

Question 4

anaerobic cellular respiration

Answer 4

process in which organisms
convert energy for their use in the absence of oxygen

Question 5

ATP synthase

Answer 5

(also F1F0 ATP synthase) membraneembedded
protein complex that adds a phosphate to ADP
with energy from protons diffusing through it

Question 6

chemiosmosis

Answer 6

process in which there is a production of
adenosine triphosphate (ATP) in cellular metabolism by
the involvement of a proton gradient across a membrane

Question 7

citric acid cycle

Answer 7

(also Krebs cycle) series of enzymecatalyzed
chemical reactions of central importance in all
living cells for extraction of energy from carbohydrates

Question 8

dephosphorylation

Answer 8

removal of a phosphate group from a
molecule

Question 9

fermentation

Answer 9

process of regenerating NAD+ with either an
inorganic or organic compound serving as the final
electron acceptor; occurs in the absence of oxygen

Question 10

GLUT protein

Answer 10

integral membrane protein that transports
glucose

Question 11

glycolysis

Answer 11

process of breaking glucose into two threecarbon
molecules with the production of ATP and NADH

Question 12

isomerase

Answer 12

enzyme that converts a molecule into its isomer

Question 13

Krebs cycle

Answer 13

(also citric acid cycle) alternate name for the
citric acid cycle, named after Hans Krebs, who first
identified the steps in the pathway in the 1930s in pigeon
flight muscles; see citric acid cycle

Question 14

oxidative phosphorylation

Answer 14

production of ATP using the
process of chemiosmosis in the presence of oxygen

Question 15

phosphorylation

Answer 15

addition of a high-energy phosphate to a
compound, usually a metabolic intermediate, a protein,
or ADP

Question 16

prosthetic group

Answer 16

(also prosthetic cofactor) molecule bound
to a protein that facilitates the function of the protein

Question 17

pyruvate

Answer 17

three-carbon sugar that can be decarboxylated
and oxidized to make acetyl CoA, which enters the citric
acid cycle under aerobic conditions; the end product of
glycolysis

Question 18

redox reaction

Answer 18

chemical reaction that consists of the
coupling of an oxidation reaction and a reduction
reaction

Question 19

substrate-level phosphorylation

Answer 19

production of ATP from
ADP using the excess energy from a chemical reaction
and a phosphate group from a reactant

Question 20

TCA cycle

Answer 20

(also citric acid cycle) alternate name for the citric acid cycle, named after the group name for citric acid, tricarboxylic acid (TCA); see citric acid cycle

Question 21

ubiquinone

Answer 21

soluble electron transporter in the electron
transport chain that connects the first or second complex
to the third

Question 22

Dinitrophenol (DNP) is an “uncoupler” that
makes the inner mitochondrial membrane “leaky” to
protons. It was used until 1938 as a weight-loss drug.
What effect would you expect DNP to have on the change
in pH across the inner mitochondrial membrane? Why do
you think this might be an effective weight-loss drug?

Answer 22

DNP affects body weight loss by failing the capacity to construct a proton gradient across the mitochondrial inner membrane due to the incapacity to pump hydrogen ions. As a result the weight reduces.

Explanation

DNP affects body weight loss by failing the capacity to construct a proton gradient across the mitochondrial inner membrane due to the incapacity to pump hydrogen ions. Therefore, it leads to the reduction of pH across the inner membrane of mitochondria and accordingly raises intracellular In addition, protons leak through a mitochondrial membrane which influences ATP production and reduces it. So, a person cannot acquire sufficient energy from their food intake, so their needs for food are declined. Because sufficient ATP cannot be formed, sufficient energy is discharged through heat.

Question 23

Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain. If cyanide
poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What
effect would cyanide have on ATP synthesis?

Answer 23

Cyanide attacks reduces cells ability to use oxygen, which would direct to death.

Explanation:
Cyanide attacks the electron conveyance chain of mitochondria within cells and controls deriving of energy from oxygen.

Thus, pH of the intermembrane space would rise due to the incapacity of pumping electrons into the intermembrane space. Therefore, ATP synthesis would arrest, cells would be incapable to use oxygen, which would direct to death.

Question 24

Tremetol, a metabolic poison found in the white snake root plant, prevents the metabolism of
lactate. When cows eat this plant, tremetol is concentrated in the milk they produce. Humans who
consume the milk can become seriously ill. Symptoms of this disease, which include vomiting, abdominal pain, and tremors, become worse after exercise. Why do you think this is the case?

Answer 24

Tremetol, a metabolic toxin found in the white snakeroot plant, forestalls the digestion of lactate. When humans drink milk, the lactate is then transferred to the human body. Then humans become unhealthy.

Explanation

The milk includes lactate. When humans drink milk, the lactate is then transferred to the human body. Since the milk already included the metabolic poison, humans become unhealthy. After exercising, the lactate level increases. This would induce the signs of the illness to worsen.

Question 25

The energy currency used by cells is ________.

Answer 25

ATP

Question 26

A reducing chemical reaction ________.

Answer 26

adds an electron to the substrate

Question 27

During the second half of glycolysis, what occurs?

Answer 27

ATP is made.

Question 28

What is removed from pyruvate during its conversion into an acetyl group?

Answer 28

carbon dioxide

Question 29

What do the electrons added to NAD+ do?

Answer 29

They go to another pathway for ATP production.

Question 30

GTP or ATP is produced during the conversion of
________.

Answer 30

succinyl CoA into succinate

Question 31

How many NADH molecules are produced on each turn
of the citric acid cycle?

Answer 31

Three molecules of NADH are created during two oxidative decarboxylation stages and one dehydrogenation stage.

Question 32

What compound receives electrons from NADH?

Answer 32

FMN

Question 33

Chemiosmosis involves ________.

Answer 33

the movement of hydrogen ions across a mitochondrial membrane

Question 34

Which of the following fermentation methods can occur
in animal skeletal muscles?

Answer 34

lactic acid fermentation

Question 35

A major connection for sugars in glycolysis is ________.

Answer 35

glucose-6-phosphate

Through triosephosphate isomerase, dihydroxyacetone phosphate is converted to glyceraldehyde-3-phosphate, however it does not come into contact with sugars during glycolysis.

Phosphoenolpyruvate (PEP) is converted to pyruvic acid by pyruvate kinase and also produces ATP (adenosine triphosphate).

Hence, fructose-1,6-bisphosphate, dihydroxyacetone phosphate, and PEP are not the major contacts for sugars in glycolysis. So, the options b, and d are incorrect.

Glucose-6-phosphate is a sugar molecule that is naturally found in cells as most of the glucose that joins the cell is phosphorylated to create glucose-6-phosphate. Thus, in glycolysis, the main relation for sugars is glucose–phosphate.

Question 36

Beta-oxidation is ________.

Answer 36

the breakdown of fatty acids

Beta-oxidation is a catabolic method that appears in the mitochondrial matrix and concerns the breakdown of fatty acids utilizing two-carbon fragments from the carboxyl end of greasy acids.

Question 37

The effect of high levels of ADP is to ________ in cellular
respiration.

Answer 37

increase the activity of specific enzymes

The impact of significant degrees of ADP is to expand the movement of the protein.

Question 38

The control of which enzyme exerts the most control on
glycolysis?

Answer 38

phosphofructokinase

Question 39

Why is it beneficial for cells to use ATP rather than
energy directly from the bonds of carbohydrates? What
are the greatest drawbacks to harnessing energy directly
from the bonds of several different compounds?

Answer 39

nucleotide (ATP) is that the wellspring of energy to be used and capacity in cells.

Question 40

Nearly all organisms on Earth carry out some form of glycolysis. How does this fact support or not support the assertion that glycolysis is one of the oldest metabolic
pathways?

Answer 40

Glycolysis is that the initial introduce the breakdown of glucose to separate energy for cell digestion. Glycolysis comprises an energy-requiring stage followed by an energy-delivering stage.

Glycolysis

The destruction of carbohydrates and energy expended into system is identified as glycolysis. Many physiological heart rates be using the energy provided. The metabolism of the glucose unit sugar included most of the energy expended in metabolic activities.

Glucose and Carbon

Fermentation involves two stages. Its initiative are to gather material’s glucose molecules and wear them down as two sugar molecules, each with carbon rings.

The energy from a number of these molecules is taken within the kind of ATP and NADH within the two stages (Reduced Nicotinamide Adenine Dinucleotide).

Cryptoplasm

Glycolysis takes place within the cytosol both of prokaryotes and eukaryotes, although even the steps remain varied in each animal. The organisms that ruled the world eons ago used pyruvate as element of their lifecycle.

Within the lack of oxygen, ,the tactic isdole out . These have revealed that the glucose see another and has evolved. As a result, it effects all bacterial and eukaryotic species. Other key metabolic processes in other species are thought to arise after this glycogen synthesis process

Question 41

Because they lose their mitochondria during
development, red blood cells cannot perform aerobic
respiration; however, they do perform glycolysis in the
cytoplasm. Why do all cells need an energy source, and
what would happen if glycolysis were blocked in a red
blood cell?

Answer 41

All cells need an energy source to have enough energy to perform some actions in essential processes (e.g. synthesis of macromolecules, pumping ions across membranes).
Red blood cells don’t have mitochondria and they are completely dependent on glycolysis for ATP. Therefore, if the process of glycolysis was blocked in a red blood cell, loss of its membrane potential would occur and that would lead to death.

Question 42

What is the primary difference between a circular
pathway and a linear pathway?

Answer 42

The difference between a circular pathway and a linear pathway is that in a circular pathway, the reactant and the item are equivalent while in a linear pathway, they are unique.

Additionally, circular pathways contain a solitary chemical reaction while linear pathways can have various others which are autonomous of each other.

Question 43

How do the roles of ubiquinone and cytochrome c differ
from the roles of the other components of the electron
transport chain?

Answer 43

Ubiquinone andcytochrome are electron carriers that participate justwithin the exchange of electrons between complex proteins.

Question 44

What accounts for the different number of ATP
molecules that are formed through cellular respiration?

Answer 44

The electron transport chain differs in composition between species, so different organisms will make different amounts of ATP using their electron transport chains.

Explanation

Few tissues except muscle produce the maximum possible amount of ATP from nutrients. The intermediates are used to produce needed amino acids, fatty acids, cholesterol, and sugars for nucleic acids.

When NADH is transported from the cytoplasm to the mitochondria, an active transport mechanism is used, which decreases the amount of ATP that can be made.

The electron transport chain differs in composition between species, so different organisms will make different amounts of ATP using their electron transport chains.

Question 45

What is the primary difference between fermentation
and anaerobic respiration?

Answer 45

Fermentation is the chemical breakdown of an organic substrate like glucose by microorganisms like bacteria and yeast, typically giving off effervescence and heat.

Respiration is the set of chemical reactions involved in the production of energy by completely oxidizing food.

Question 46

Would you describe metabolic pathways as inherently
wasteful or inherently economical? Why?

Answer 46

As a result, one pathway is utilized as the substrate for another lastly this keeps the general metabolism of the body adjusted.

Question 47

How does citrate from the citric acid cycle affect glycolysis?

Answer 47

Citrate can inhibit phosphofructokinase by feedback regulation and this affects glycolysis.

Explanation

A citrate in the citric acid cycle is formed from oxaloacetate and acetyl-CoA. The citrate can go from the mitochondria to the cytosol. Citrate in the cytosol is a known inhibitor of phosphofructokinase-1, the rate-limiting enzyme in glycolysis. The inhibition of phosphofructokinase-1 by citrate signals enough energy in the system. Therefore, it signals the pathway that it can slow down the oxidation of glucose molecules for energy purposes.

Question 48

Why might negative feedback mechanisms be more common than positive feedback mechanisms in living cells?

Answer 48

Negative feedback components really control a cycle; it can switch it off, though positive feedback speeds up the interaction, permitting the cell zero influence over it.

Explanation

Negative feedback switches the framework off, making it insufficient in specific substances.

Positive feedback adjust these shortfalls. Positive feedback takes substance sums back to balance while negative feedback produces overabundance measures of the substance.