Chapter 5- Microbial Metabolism

Chemical reactions that can proceed in either a catabolic or an anabolic direction are known as _________ reactions

amphibolic

A coenzyme __________. functions as an inhibitor of enzyme function can be derived from a vitamin is an inorganic part of an enzyme is a small accessory enzyme

can be derived from a vitamin

Altering the environmental pH can inhibit microorganism growth due to __________. hydrolysis of enzymatic substrates acidification of carbohydrates denaturation of enzymes chelation of metal ions needed for glycolysis

denaturation of enzymes

Which of the following does NOT affect the activity of an enzyme? temperature pH substrate concentration oxygen concentration

oxygen concentration

Fermentation differs from cellular respiration by __________. producing more molecules of ATP using organic molecules as the final electron acceptor producing only CO2 and water as end products requiring oxygen in order to proceed

using organic molecules as the final electron acceptor

Oxygenic photosynthesis releases oxygen derived from _______.

water

Which of the following is NOT an example of metabolic regulation by a cell? Feedback inhibition prevents cells from producing products that are in abundance. Cells use allosteric sites on enzymes to control enzymatic activity. Cells close all channels in the membrane if no energy sources are needed. If two energy sources are available, cells use the more efficient energy source.

Cells close all channels in the membrane if no energy sources are needed.

ATP is made by substrate-level phosphorylation only during glycolysis.

False: A small amount of ATP is also made by substrate-level phosphorylation during the Krebs cycle.

In feedback inhibition pathways, the end-product of the pathway is usually an inhibitor of the last enzyme in the pathway.

False: End-products that act as inhibitors of enzymes generally inhibit enzymes that are fairly early in the pathway.

Fermentation is more energy efficient than aerobic glucose metabolism

False: Fermentation produces products that have industrial applications, but cells require more glucose to grow when relying on fermentation.

Fermentation results in the production of carbon dioxide and water from pyruvic acid

False: In fermentation, pyruvic acid is generally converted into organic waste products such as alcohol and lactic acid.

The carrier molecules in electron transport chains are all integral membrane proteins.

False:Ubiquinones are electron transport molecules that are lipid-soluble, nonprotein carriers.

What is the major function of fermentation? It regenerates NAD+ for glycolysis. It reduces glucose. It produces ADP. It generates a proton gradient.

It regenerates NAD+ for glycolysis.

___________ phosphorylation is the process in which photosystem I works with photosystem II, and electrons are used to reduce NADP+ to NADPH.

Noncyclic

_______ phosphorylation is the process by which inorganic phosphate is attached to an ADP molecule using the energy produced by redox reactions.

Oxidative

Acidic pH breaks the hydrogen bonds that give enzymes their characteristic shapes, thereby denaturing them.

True- Protons interfere with low energy hydrogen bonds

Carbon dioxide is produced only as a by-product of acetyl-CoA synthesis and the Krebs cycle during cellular respiration.

True: Carbon dioxide is produced whenever decarboxylation occurs in cellular respiration.

A molecule that gains an electron from another molecule will experience __________ in its overall electrical charge. an increase and then a decrease a reduction an increase no change

a reduction

Sulfanilamide is a drug that interferes with bacterial enzymes in which of the following ways? feedback inhibition competitive inhibition noncompetitive inhibition and competitive inhibition end-product inhibition

competitive inhibition

NAD+, FAD, and NADP+ are all examples of __________. cytochromes electron carriers precursor metabolites enzymes

electron carriers

All of the following processes are ways that a cell can use a proton gradient EXCEPT __________. active transport ATP production electron transport flagellar motion

electron transport

Feedback inhibition __________. is not reversible requires a cofactor is a mechanism for controlling the actions of enzymes is always a form of competitive inhibition

is a mechanism for controlling the actions of enzymes

The activation energy of a chemical reaction __________. is lower in the presence of an enzyme is the same for all chemical reactions can be achieved by lowering the temperature of a reaction is eliminated in the presence of an enzyme plus a coenzyme

is lower in the presence of an enzyme

The activation energy of a chemical reaction __________. is the same for all chemical reactions can be achieved by lowering the temperature of a reaction is lower in the presence of an enzyme is eliminated in the presence of an enzyme plus a coenzyme

is lower in the presence of an enzyme

Folic acid is a precursor molecule necessary for the synthesis of which of the following? cholesterol amino acids glycerol nucleotides

nucleotides

All of the following are associated with the process of glycolysis EXCEPT __________. substrate-level phosphorylation production of NADPH phosphorylation of glucose production of pyruvic acid

production of NADPH

Biological oxidations often involve which of the following? the gain of an oxygen atom the gain of an electron e- the loss of a hydrogen atom the loss of an oxygen atom

the loss of a hydrogen atom

he photosynthetic membranes that are similar to mitochondrial membranes in both structure and function are called _______.

thylakoids

Which of following are INCORRECTLY paired? Krebs cycle: three molecules of NADH transition step: two molecules of acetyl-CoA per one molecule of pyruvic acid glycolysis: two molecules of pyruvic acid per one molecule of glucose electron transport chain: three molecules of ATP per molecule of NADH

transition step: two molecules of acetyl-CoA per one molecule of pyruvic acid