Learning Curve

chemoautotroph

Imagine that you discover a microbial deep-sea organism that can derive energy from (inorganic) hydrogen gas (H2). However, this microbe can also synthesize organic compounds from carbon-containing inorganic molecules in the ocean. This microbe is a:

the use of ATP by cells began eons ago and has been conserved over time

Nearly all cells use ATP as their primary energy source. This is evidence that:

exergonic and catabolic

Glycolysis, the breakdown of a glucose molecule to two molecules of pyruvate, is an example of a reaction that is:

inhibited

In the pathway leading from threonine to isoleucine, threonine dehydratase is _____ by an accumulation of isoleucine.

ribose

ATP is a nucleotide composed of adenine, ______, and three phosphate groups

potential; covalent

Organic molecules store _____energy in their _____ bonds.

b.) glucose

Of the following molecules, which has the greatest potential energy?
a.) sodium chloride
b.) glucose
c.) alanine
d.) water
e.) carbon dioxide

heat

In chemical reactions, most of the entropy increase occurs as:

d.) chemoheterotrophs

Escherichia coli bacteria in your colon are categorized as:
a.) chemoautotrophs
b.) photoautotrophs
c.) photoheterotrophs
d.) chemoheterotrophs

second; entropy

You have entered a 5K race. As you finish the last 50 yards, you are breathing harder than at the start of the race and sweating profusely. This is an example of the _____ law of thermodynamics because _____ is increasing.

d.) most bacteria and dogs

Which of the following organisms are considered heterotrophs?
a.) plants
b.) hydrogen bacteria
c.) most bacteria
dogs
d.) most bacteria and dogs

chemoheterotroph

Imagine that you discover a carnivorous deep-sea fish that cannot utilize the carbon in carbonic acid (or any other inorganic molecule) present in seawater to form glucose (or other organic molecules). Living so far beneath the water's surface, this fish

false

As plant cells rely on energy obtained directly from the sun to carry out cellular processes, sugars are only used as backup energy sources for plants on cloudy days.

b.) Even though evolution may decrease the entropy of living organisms, it increases the entropy of the Earth (or the universe) as organisms release heat.

Imagine that you are talking with one of your friends. He states that evolution has actually violated the second law of thermodynamics because complex living organisms are more ordered than the nucleic acids, amino acids, and other molecules that compose

oxidized; reduced

A molecule that is _____ loses electrons, and a molecule that is _____ gains electrons.

b.) anaerobic

Glycolysis is:
a.) aerobic.
b.) anaerobic
c.) aerobic in some organisms but anaerobic in others.
d.) aerobic in some tissues but anaerobic in others.
e.) None of the other answer options is correct.

e.) it links glycolysis with the citric acid cycle

Pyruvate oxidation is an important stage in cellular respiration because:
a.) it is the first step in oxidative phosphorylation.
b.) it eliminates toxic pyruvate from the cell.
c.) it generates ATP by substrate-level phosphorylation.
d.) it transfers larg

c.) bateria and animals

Lactic acid fermentation occurs in: Select all that apply.
a.) animals and fungi.
b.) plants and bacteria.
c.) bacteria and animals.
d.) animals and plants.
e.) fungi and bacteria.

glycogen; starch

_____ is found in animals, and possesses a large, central protein. _____ is found in plants, and lacks a central protein.

b.) reduced (NADH, FADH2)

The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy.
a.) oxidized
b.) reduced
c.) phosphorylated
d.) carboxylated
e.) None of the other answer options is correct.

true

Although glycolysis produces four molecules of ATP by substrate-level phosphorylation, the net gain of ATP for the cell is two molecules. This is due to the fact that glycolysis is�at first�endergonic.

mitochondrial matrix

In eukaryotes, pyruvate oxidation takes place in the:

b.) oxaloacetate

Which of the following is not an end product for an acetyl group that enters the citric acid cycle?
a.) FADH2
b.) oxaloacetate
c.) ATP
d.) NADH
e.) CO2

a.) ATP synthase

For the potential energy of a proton gradient to be converted to the chemical energy of ATP, the movement of protons down their electrochemical gradient must be coupled with ATP synthesis. This coupling is made possible by:
a.) ATP synthase.
b.) cytochrom

a.) fermentation

Which was likely the first of the following metabolic pathways or structures to evolve?
a.) fermentation
b.) the citric acid cycle
c.) electron transport complexes I, II, and III
d.) ATP synthase
e.) All of these choices are correct.

ATP

Beta-oxidation of fatty acids does not directly produce:

c.) many of these bonds are C--C and C--H bonds

The chemical bonds of carbohydrates and lipids have high potential energy because:
a.) they are strong oxidizing agents.
b.) they are strong reducing agents.
c.) many of these bonds are C�C and C�H bonds.
d.) they are easy to hydrolyze.
e.) they are easy

two pyruvate molecules

At the end of glycolysis, the carbon molecules originally found in the starting glucose molecule are in the form of:

false

Like glycolysis, pyruvate oxidation produces both pyruvate and acetyl-CoA. These two products feed directly into the citric acid cycle and are the reactants for the cycle.

a.) the citric acid cycle

Which of the following processes produces the highest number of reduced electron carriers and thus the greatest amount of ATP by oxidative phosphorylation?
a.) the citric acid cycle
b.) glycolysis
c.) pyruvate oxidation
d.) glycolysis and the citric acid

inter membrane space; mitochondrial matrix

Due to the pumping action of the electron transport chain, protons have a high concentration in the _____ and a low concentration in the _____.

It establishes a proton gradient between the cytoplasm and the extracellular fluid.

Some present-day bacteria use a system of anaerobic respiration characterized by an electron transport chain analogous to that found in aerobic organisms. Which of the following correctly characterizes the anaerobic electron transport chain?

Fatty acids cannot be used by some vital tissues in the human body, such as the brain

Recall that fatty acids (like palmitic acid) can yield substantially more ATP when compared with glucose. Why doesn't aerobic respiration rely solely on fatty acids as energy sources, rather than glucose?

The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent.

Which of the following statements is true regarding the equation C6H12O6 + 6O2 ?6CO2+ 6H2O + energy?

phosphorylated sugar molecule is cleaved and the products rearranged.

In the second phase of glycolysis:

It is the catalytic unit that synthesizes ATP.

Which of the following correctly characterizes the F1 subunit of ATP synthase?

through the reduction of acetaldehyde, derived from pyruvate

A beer maker is using yeast to make his favorite brew. How does yeast produce ethanol?

ADP�activator; citrate�inhibitor

The enzyme phosphofructokinase-1 (PFK-1) is thought of as a metabolic "valve" that regulates the rate of glycolysis. Which of the following correctly identifies its allosteric activators and inhibitors and their actions?

oxidized; reduced

In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.

4

After pyruvate oxidation, the chemical energy of how many carbons of the original glucose molecule is converted to chemical energy in the form of ATP in the remaining steps of cellular respiration?

Glucose could move out of the cell, slowing cellular respiration.

Imagine that a eukaryotic cell carries a mutation impairing its ability to phosphorylate glucose during glycolysis. What is a likely result of this mutation?

gains electrons and is an oxidizing agent.

In cellular respiration, oxygen:

This process occurs within the matrix of mitochondria.
This process constitutes the second stage of cellular respiration.
The process produces both CO2 and acetyl-CoA.
The process yields no ATP via substrate-level phosphorylation.

Which of the following statements are true regarding pyruvate oxidation?

less energetic than the acetyl group.

During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is: