Microbio Ch 5

During the light-independent reactions of photosynthesis, organisms __________.

synthesize sugars

Enzymes work most effectively at their optimal __________.

temperature amount of substrate pH

Streptococci lack an electron transport chain. How many molecules of ATP can a Streptococcus cell net from one molecule of glucose?

2

Which one molecule could provide the carbon source, the energy source, and the electron source for a chemoheterotroph?

Glucose

Which of the following molecules traps energy released during oxidation-reduction reactions?

ATP

Which of the following statements accurately describes the difference between aerobic and anaerobic respiration?

Aerobic respiration uses oxygen as the final electron acceptor, and anaerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or an organic molecule, such as an acid or alcohol.

Which of the following terms refers to pathways that can function in both anabolism and catabolism?

Amphibolic pathways

Which group of organisms has members representing each of the following nutritional classifications: chemoheterotrophs, chemoautotrophs, photoheterotrophs, and photoautotrophs?

Bacteria

At the completion of the Krebs cycle, the carbons from glucose are found in __________.

CO2

Which of the following is true of catabolism?

Catabolic reactions are exergonic; they break down complex organic molecules into simpler ones.

Which of the following statements is correct about enzymes?

Each enzyme has a characteristic three-dimensional shape.

A coenzyme assists an enzyme by accepting or donating matter. What does NAD+ transfer?

Electrons

All of the following steps are involved in the aerobic electron transport chain. Which step happens last?

Electrons are transferred to O2.

The complete oxidation of glucose in aerobic and anaerobic respiration involves which three stages?

Glycolysis, Krebs cycle, and the electron transport chain

One of the sites of allosteric regulation of the Krebs cycle is the conversion of pyruvic acid to acetyl CoA. Which of the following conditions would you expect to inhibit the conversion of pyruvic acid to acetyl CoA?

High ATP and high NADH

__________ may serve as substrate(s) of glycolysis.

Lipids Proteins Sugars

During glycolysis, electrons from the oxidation of glucose are transferred to __________.

NAD+

In an enzymatic reaction involving oxidation of a substrate, which of the following would be required?

NAD+

Which of the following molecules carry electrons during various stages of glucose catabolism?

NADH and FADH2

Which of the following are products of noncyclic photophosphorylation reactions in oxygenic organisms?

O2, ATP, and NADPH

Which of the following pairs is NOT correctly matched?

Oxidation; reaction in which electrons are gained

Which of the following four stages of glucose oxidation during aerobic respiration requires molecular oxygen?

Oxidative phosphorylation

Which organism is NOT correctly matched to its energy source?

Photoautotroph; CO2

Which of the following statements is accurate concerning glucose metabolism?

Pyruvic acid, the product of glycolysis, is the starting block for both the Krebs cycle and fermentation.

Which of the following mechanisms does NOT generate ATP using an electron transport chain?

Substrate-level phosphorylation

The complete oxidation (catabolism) of glucose typically involves three stages. The greatest number of ATPs is produced in which stage?

The electron transport chain

When fermentation tests are used to help identify bacteria, which of the following end-products is typically detected by a color change?

acid

The proton motive force is __________.

an electrochemical gradient formed across a membrane

The chemical reactions involved in synthesizing proteins and cell wall peptidoglycan are examples of __________ reactions.

anabolic

Enzymes are important in living organisms because they __________.

bring together reactants or properly orient a molecule for a reaction

Like glucose, amino acids are catabolized for energy, but these must be converted to a form in which they can enter the Krebs cycle for oxidation. All of the following reactions occur in the catabolism of amino acids EXCEPT __________.

carbon fixation

A Thiobacillus bacterium uses the Calvin-Benson cycle to reduce CO2 and the oxidation of sulfide ions for energy. This organism is a __________.

chemoautotroph

Nitrobacter bacteria use carbon dioxide for their carbon source and nitrate ions as an energy source. This organism is a __________.

chemoautotroph

Organisms that use carbon dioxide as a carbon source and ammonia or hydrogen sulfide as energy sources are called __________.

chemoautotrophs

An organism uses glucose as energy source and respires O2. This organism is known as a(n) __________.

chemoheterotroph

Competitive inhibition of enzyme action involves __________.

competition with the substrate for binding at the active site

All of the following are required for the generation of ATP by chemiosmosis EXCEPT __________.

conversion of pyruvic acid to lactic acid

You inoculate a bacterial culture into a tube containing glucose and peptides. The pH indicator shows that the pH decreased after 24 hours and then increased at 48 hours. What has caused the increase in pH?

deamination

In __________ an end-product of an anabolic pathway inhibits the activity of one or more enzymes in a pathway.

feedback inhibition

Unlike chemiosmosis in eukaryotes, prokaryotes chemiosmosis __________.

occurs at the plasma membrane and not the mitochondria

All of the following pairs are correctly matched EXCEPT __________.

oxidation—reaction in which electrons are gained

NADH molecules formed during glycolysis and in the Krebs cycle are __________.

oxidized when electrons are passed to the electron transport chain

Heterotrophs use organic molecules as energy and carbon sources. To produce five-carbon intermediates needed for synthesis of nucleic acids, the cell utilizes the __________.

pentose phosphate pathway

Carbon fixation occurs during __________.

photosynthesis

All of the following are potential end-products of fermentation EXCEPT __________.

pyruvic acid

Glycolysis produces ATP through __________.

substrate level phosphorylation

Fermentation differs from anaerobic respiration in that fermentation does NOT __________.

use an electron transport chain