Exam 3- Chapter 11

the total of all chemical reactions occurring in a cell is called ______

Metabolism

Although most metabolic reactions are freely reversible, a few irreversible catabolic steps are bypassed during biosynthesis with special enzymes that catalyze the reverse reaction in order to allow for independent regulation of catabolic and anabolic pathways.

True

Metabolic pathways can be either catabolic or anabolic but not both

False

_____ pathways are those that function both catabolically and anabolically

Amphibolic

The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate

True

____ ___ is a process that can completely catabolize an organic energy source to CO2 using the glycolytic pathways and TCA cycle with O2 as the terminal electron acceptor for an ETC

Aerobic respiration

Very few gram positive bacteria utilize the Entner-Doudoroff glycolytic pathway.

True

Some aerobic bacteria lack the Entner-Doudoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis.

False

An organism may use glycolysis and the petnose phosphate pathway simultaneously

True

The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is ______

2

The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is ______

1

The pentose phosphate pathway produces _____

CO2

NADPH

glyceraldehye 3-phosphate

The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called _______ phosphorylation

substrate-level

The most common pathway for conversion of glucose to pyruvate is ______

Embden-Meyerhoff

The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except ______

two ATP or GTP molecules

The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and _____

acetyl-CoA

After glycolysis, pyruvate is oxidize to oneCO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ____ _____ complex

pyruvate dehydrogenase

TCA cycle enzymes are found in the ____ _____ of eukaryotic cells

Mitochondrial matrix

In the TCA cycles, two carbons are removed from citric acid in the form of ____ thereby regenerating oxaloacetate to complete the cycle

Carbon dioxide

In the TCA cycle, two carbons in the form of ______ are added to oxaloacetate at the start of the cycle

acetyl-CoA

The major function of the TCA cycle is _____

energy production and provision of carbon skeletons for biosynthesis of cell components

When mitochondria pass electrons donated by NADH through the electron transport chain to molecular oxygen, a theoretical max of ______ molecules of ATP can be made per oxygen molecule reduced

3

The hypothesis that proton motive force drives ATP synthesis is called the ____ hypothesis

Chemiosmotic

The most commonly accepted hypothesis for the production of ATP that results from electron transport system is called the ____ hypothesis

chemiosmotic

Bacterial ETC may be comprised of fewer components and have lower phosphate to oxygen ratios than mitochondrial transport chans

True

The electron transport systems in eukaryotes and prokaryotes use different electron carriers

True

In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella

True

Differences between mitochondrial and E. Coli electron transport chains include which of the following?

The E. Coli chain contains a different array of cytochromes

Which of the following is NOT true regarding ATP synthases?

The proton flow is outward during ATP synthesis

The theoretical max net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is _____

38

Production of ATP using the energy liberated when electrons from reduced chemical bonds are passed through the electron transport system is generally referred to as ______

Respiration

Mitochondrial electron transport takes place ______

On the inner mitochondrial membrane

In higher eukaryotes, most aerobically generated ATP is produced by _____

A membrane-bound proton translocating ATP synthase during oxidative phosphorylation

The number of ATP molecules generated per atom of oxygen that is reduced when electrons are passed from NADH or reduced FAD to O2 is called ______

P/O ratio

In aerobic conditions, it takes ______ sugar to produce the same amount of ATP when compared to anaerobic conditions

Less

Prokaryotes may use several different terminal oxidases for the electron transport system

True

Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration

True

When cells of a facultative anaerobe such as Paracoccus denitrificans are growing under anaerobic conditions and using nitrate as the terminal electron acceptor, ______________ nitrate reduction is occurring.

dissimilatory

Which of the following can be used as electron acceptors during anaerobic respiration?

All of the choices are correct

Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called ____ fermenters

Heterolactic

Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors

True

In the process of fermentation an organic substrate, such as glucose, is reduced and an intermediate of the pathway, such as pyruvate, is oxidized

False

Organisms that directly reduce almost all of their pyruvate to lactate are called _____ fermenters

homolactic

Oxygen is always required for the regeneration of NAD from NADH

False

Large external polysaccharides are degraded by bacteria and archaea using ________ ________, which secrete these substances outside the cell.

hydrolytic enzymes

Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either ______ or _____

hydrolysis, phosphorolysis

Fatty acids are metabolized by the ____ pathway

beta oxidation

During breakdown of fatty acids, carbons are removed ______ at a time with each turn of the cycles, and two carbon units are released as ______

two, acetyl-CoA

Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called ______

proteases

Amino acids are processed first by the removal of the amino group through ______

deamination

Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.

False

______ is a two-step process that depends on the activity of at least two genera to carry out the oxidation of ammonia to nitrate

Nitrification

Which of the following may be used as sources of energy by chemolithotrophs

Hydrogen gas

reduced nitrogen compounds

reduced sulfur compounds

How many molecules of ATP are needed to reduce one molecule of Co2 to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis

3

How many molecules of NADH are produced during glycolysis?

2

How many quanta of light are needed to reduce one molecule of CO2 to carbohydrate during photosynthesis

10-12

All prokaryotic photosynthesizers are anoxygenic

False

Photosynthetic organisms serve as the base for most food chains in the biosphere

True

All eukaryotic photosynthesizers are oxygenic

True

In the process of noncyclic photophosphorylation, _____

A) water is split to form oxygen gas B) electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH

C) photosystems I and II are both required

D) All of the choices are correct.

D) All of the choices are correct

In the process of ____, ATP is synthesized when excited electrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700

Cyclic photophosphorylation

Photosynthetic electron transport in cyanobacteria takes place _____

on the thylakoid membranes

Select the terms that describe an organism's carbon source

A) Heterotroph

B) Lithotroph

C) Chemotroph

D) Autotroph

E) Organotroph

A, D

The terms phototroph and chemotroph refer to an organism's source of ______

energy

A newly described bacterial species has been shown to use CO2 as its carbon source. Its energy source and its source of reducing power (electrons) are inorganic chemicals. Which term would best describe this nutritional type?

Chemolithotroph

Which nutritional classification would you predict to fit most of the well-known members of the human microbiome?

Chemoorganohetertrophs

Processes that supply ATP, reducing power, and precursor metabolites are collectively referred to as ____ reaction

Fueling

In most cases, fueling reaction are _____ reactions

Catabolic

An organism can it into only one nutritional patter, such as photoheterotrophy, and cannot change if the environmental conditions change

False

An organism can take advantage of energy available from both light and from organic molecules and exhibit both phototrophy and chemoorganotrophy

True

Indicated the processes below that represent the basic types of chemoorganotrophic metabolism

A) Photosynthesis

B) Aerobic respiration

C) Fermentation

D) Oxidation-reduction

E) Anaerobic respiration

B, C, E

Aerobic respiration, anaerobic respiration, and fermentation are the three basic types of ________

Chemoorganoheterotrophic metabolism

Glycolysis and the TCA cycle are two of the most important catabolic pathways in chemoorganotrophs

True

What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?

The presence of an ETC

The six carbons of the glucose molecule that enter the cell respiration pathway end up in/as _____ _____ by the end of the process

carbon dioxide

Indicate the products of aerobic respiration

Water, CO2, ATP

Which of the following produces the most ATP during aerobic respiration?

ETC and chemiosmosis

During glycolysis, ATP is produced when 1, 3, bisphosphoglycerate transfers a phosphate to ADP forming ATP. This is an example of _____

Substrate-level phosphorylation

In order for a substance to transfer a phosphate to ADP in substrate-level phosphorylation reaction , which of the following must be true?

The phosphate donor may have a high phosphate transfer potential than ATP

Where the embden-Meyerhof pathway produces two molecules of pyruvate for each glucose, the Entner-Doudoroff pathway produces one molecule each of ____ and _____

pyruvate, glyceraldehyde

Which of the following is the major glycolytic pathway used by plants and animals?

Embden-Meyerhof pathway

The pentose phosphate pathway is the major glycolytic pathway used by archaea?

False

Which of the following names refer to the tricarboxlic acid cycle?

Krebs cycle, citric acid cycle

Which of the following is produced in largest numbers by the TCA cycle?

NADH

The TCA cycle is located in the ____ of bacteria, and in the _____ of eukaryotes

cytoplasm; mitochondrial matrix

The major difference between aerobic and anaerobic respiration is the final electron acceptor at the end of the ETC

True

When nitrate is used as a final acceptor by bacteria growing in anoxic soils, the nitrogen is no longer available for the construction of precursor metabolites. This Is referred to as ______

dissimilatory nitrate reduction

The amount of ATP produced during anaerobic respiration is _____ that produced during aerobic respiration, because the difference in the standard reduction potential between NADH and the final electron acceptor is ________

Less than; smaller

Which of the following are consequences of anaerobic respiration?

A) Some bacteria are able to readily survive in both well-oxygenated as well as anoxic environments.

B) Some bacteria may cause denitrification.

C) Some bacteria are able to perform nitrogen fixation.

D) Bacteria are able to reduce the levels of NO3− in sewage plant effluents

A, B, D

How is ATP produced during fermentation?

Substrate-level phosphorylation

How does a fermenter generate PMF to drive active transport?

Fermenters can reverse the direction of the ATP synthase to generate PMF

How does the phosphorylation of galactose differ from the phosphorylation of glucose, mannose, and fructose prior to catabolism?

Phosphorylation of galactose requires UTP to phosphorylate galactose-1-phosphate

Complete catabolism of lactose requires ______

ATP, UTP, NAD, and appropriate enzymes

What enzymes hydrolyze proteins, releasing amino acids?

Proteases

A ______ hydrolyzes a protein into its constituent amino acid monomers and a ______ enzyme removes amino groups from the amino acids

Protease; deaminase

______ refers to the removal of an amino group from an amino acid. One mechanism for this removal is ______, in which the amino group is transferred to an acceptor molecule

Deamination; transamination

The substance that donate electrons to the electron transport chains of chemolithotrophs are _____

inorganic compounds

Most chemolithotrophs have ETC that terminate with O2 as the final electron acceptor

True

Many chemolithotrophs are able to produce more ATP from oxidation of their inorganic energy source than chemoheterotrophs produce from the aerobic oxidation of glucose

False

Chemolithotrophs generally derive ____ ATP from oxidation of inorganic substrates because the reduction potentials of those substrates are much more _____ than the reduction potential of organic substrates

less; positive