mcb3023 exam 3 modules 3.1-3.4

The biochemical reaction,

PEP + ADP -> Pyruvate +

ATP

is an example of which of these?

Substrate-level phosphorylation.

Which of these is TRUE for a chemoorganoheterotroph?

Uses organic carbon as an electron source and a carbon source.

How many NET molecules of ATP are produced during the Embden-Meyerhof pathway of glycolysis for every molecule of glucose that is converted into two molecules of pyruvate?

two

Fermentation can most accurately be described by which of these?

The direct reoxidation of NADH by an internal organic molecule.

Which of these is NOT an electron carrier used in the electron transport system?

ATPase

How is ATP primarily produced in chemolithotrophs?

Electrons moving through an electron transport system to generate a proton motive force.

Term for the primary pathway for fatty acid oxidation?

β-oxidation pathway

Cyanobacteria use _______ as an electron source for the reduction of NADP+.

water

How many ATP molecules is required to "fix" a molecule of nitrogen?

sixteen

Which amino acids are the primary nitrogen donors for biosynthetic reactions in the cell?

glutamine and glutamate

Which of these best describes assimilatory sulfate reduction?

The reduction of sulfate for incorporation into cellular material.

How do enzymes increase the rate of a biochemical reaction?

By lowering the activation energy.

How is the activity of an allosteric enzyme regulated?

Through the binding of an effector molecule.

Which of these is TRUE for a chemolithoautotroph?

inorganic molecules as energy sources and inorganic carbon as a carbon source.

The products of yeast fermentation, when including the Embden-Meyerhof pathway of glycolysis for one molecule of glucose, are two ethano molecules as well as these others.

two ATP and two CO2

Which statement is TRUE with respect to the electron transport system?

A proton motive force is generated as electrons move through the system to a terminal acceptor.

Which of the following would NOT be appropriate as a terminal electron acceptor during anaerobic respiration?

hydrogen sulfide (H2S)

Enzymes that break down proteins into individual amino acids.

proteases

How is ATP generated during the light-dependent reactions of photosynthesis?

A proton motive force driven ATP synthase.

Nitrogen fixation is the reduction of _______ to ammonia for cell use.

dinitrogen

What is denitrification?

The reduction of nitrate to dinitrogen.

Which of these is the most widely used form of

energy in cell processes?

ATP

Which of these is an example of a coenzyme?

NAD+

When oxygen reacts with hydrogen gas, water is produced as the product in this oxidation-reduction reaction. Hydrogen donates electrons to oxygen in the reaction. Which statement below is true about this reaction?

Oxygen is being reduced in the reaction.

Cyanobacteria carry out oxygenic photosynthesis producing oxygen as a byproduct from the oxidation of water, which serves as the electron donor for the light-dependent reactions. How would cyanobacteria be classified?

photolithoautotroph

What are the NET products of the Embden-Meyerhof pathway, when operating in the catabolic direction?

Two pyruvate, two ATP, and two NADH.

Microorganisms that rely solely on fermentation reactions for energy production make ATP primarily by this method.

substrate-level phosphorylation

When does feedback inhibition of an enzyme occur?

an end product of the pathway binds to the allosteric site of the enzyme.

What can the proton motive force generated by the electron transport system be used for?

ATP synthesis, flagella rotation, and nutrient transport

The product(s) of the light reactions of photosynthesis.

ATP and NADPH

Some anoxygenic photosynthetic bacteria are able to use _______ as an electron source.

H2S

How would the "dark reactions" of photosynthesis best be described?

carbon dioxide fixing reactions

Which nitrogen species is most readily incorporated into an organic molecule in the cell?

ammonia

The most common lipids in the cell are synthesized from ___________ and ____________.

fatty acids and glycerol

What is the oxidation state of carbon in methane?

-4

The main primary producers in aquatic environments are _______, while in terrestrial environments the main primary producers are __________.

microbes, plants

Which carbon reservoir is most actively cycled?

the atmosphere

Which of these is true regarding soil humus?

It is degraded very slowly over time.

Bacteria that rely on methanotrophy for carbon and energy metabolism utilize one of these two unique pathways for carbon assimilation.

Serine pathway and the ribulose monophosphate pathway.

What is the oxidation state of nitrogen in ammonia?

-3

Which of these would occur in an "ideal" food web?

Organic carbon production = carbon dioxide consumption.

Which of these statements is TRUE regarding oxygen use and utilizers of methanogenesis?

It is anaerobic, and carried out by Archaea.

Methanotrophs, in contrast to non-methanotrophic methylotrophs, contain this enzyme.

methane monooxygenase

Which one of the following is NOT a reservoir for oxygen?

ammonia

What is the oxidation state of nitrogen in nitrate?

+5

Which of these summarizes the overall process of denitrification?

NO3→N2

How can denitrification of soil be reduced?

By keeping the soil well aerated.

Why is carbon dioxide considered a greenhouse gas?

It absorbs heat attempting to escape the atmosphere.

Which is the major nitrogen reservoir on Earth?

the atmosphere

Which of these summarizes the overall process of nitrogen fixation?

N2 → ammonia → biomass

Why is the process of denitrification detrimental to the soil?

It leads to loss of utilizable nitrogen from the soil.

Which of these regulates the formation of biofilms?

quorum sensing

Which of these best summarizes the contribution of cyanobacteria in the open ocean?

primary carbon production, oxygenation of the waters, and nitrogen fixation

All of the following but one are xenobiotics that frequently contaminate our terrestrial environments. Which one does NOT represent a xenobiotic?

lignin

In terrestrial environments, where is the greatest microbial diversity found?

soil

What possible sources of energy may be used by microbes living in hydrothermal vents?

methane and sulfide

What is the best classification of primary producers found in hydrothermal vents on the ocean bottom?

chemolithoautotrophs

Today, the most effective technique for analyzing microbial community structure is based on this analysis.

Sequencing small subunit rRNA.

Which elements necessary for microbial life are often limiting in the ocean?

nitrogen and phosphorous

Which of these characterizes dead zones in the ocean?

Being hypoxic.

Lignocellulose is primarily mineralized by this group of organisms during plant decomposition.

fungi

Microbes are able to generate energy through the

oxidation of inorganic and organic compounds

Which of these represents MOST of the ocean's biomass?

microbes

Which of the following groups is the most abundant in the ocean?

viruses

Where is the soil's rhizosphere?

Areas surrounding plant roots.

Which one of the following is an extrinsic factor that affects that rate of food spoilage?

The storage temperature

Lyophilization is

freeze-drying of food

The most common disease associated with improperly canned food is

botulism

Which of the following type of radiation may be used to sterilize food?

Ionizing

All of the following are goals of wastewater treatment except

enhancement of the taste of water.

The release of high levels of nitrogen and phosphorus into streams after wastewater treatment will result in

eutrophication of the stream.

All of the following are processes that may be used in the treatment of drinking water except

activated sludge digestion.

The most common food preservation method used in US households is

refrigeration.

Pasteurization is a method of preservation that involves heating the liquid to _______ °C for 30 min.

63

Pickling is a preservation method that uses __________ to help preserve the food.

acid

Vacuum packaging inhibits the growth of microbes that

rely on aerobic respiration for growth

Fermented soybean products, like miso and tempeh, are produced using

mold

The main goal of the primary treatment phase of wastewater treatment is the

removal of particulate matter.

The activated sludge method of wastewater treatment uses

an inoculum from the previous activated sludge treatment.

Anaerobic digesters at wastewater treatment plants are used to

treat sludge and particulates collected during waste treatment.

Which one of the following foods would have the highest water activity?

apple

When you add salt to meat for preservation you are

decreasing the water activity of the meat

Most milk sold in stores today has an extended shelf life primarily because of

high temperature short term pasteurization

Which one of the following foods is not a fermented milk product?

butter

Vinegar production occurs through the oxidation of ethanol by

acetic acid bacteria.

Which of the following methods use microbial biofilms for secondary phase of wastewater treatment?

trickling filter

The gas __________ is frequently recovered from anaerobic digesters at a waste treatment plant.

methane

Ozonation is a wastewater treatment used to

disinfect wastewater.

The key carbon dioxide fixation reaction in the Calvin Cycle is carried out by which enzyme?

ribulose 1,5-bisphosphate carboxylase (RUBISCO)

Aquatic sulfur is primarily present as:

sulfate

Which of these technologies employs heavy isotopes of nitrogen and carbon to enrich for DNA samples from actively growing organisms?

RNA-SIP

Which of these sets are products of the TCA (Krebs) Cycle?

NADH, FADH2, CO2, and ATP

What is the importance of the Haber-Bosch process

can produce synthetic nitrogen fertilizer

what is a niche?

physiological interactions with its physical habitat and with other co-existing organisms; type, quality, and quantity of sustaining resources defines it

what are biofilms?

structured communities held together by extracellular polysaccharide

types of fungi that specialize in breaking down lignocellulose.

White rot and brown rot basidiomycetes

what are biomes?

Categories of ecosystems based on vegetation characteristics

Temperature and precipitation distinguish them

what are piezophiles?

microbes that can withstand (and sometimes require) these intense pressures to grow.

The standard reduction potential (E0') for ferredoxin (Fdox/Fdred) is (-0.43V). Based on this, which of these would you expect to be true?

Reduced ferredoxin to be a good electron donor

A chemical reaction that has a negative delta G 0'

is an energy yielding reaction