Chapter 5

What provides electrons for the light reactions?

H2O

According to the animation, where would you find the lowest pH?

In the thylakoid spaceIn the thylakoid space

According to the animation, which compounds provide electrons to the system?

NADH and FADH2

Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?

glucose

The molecule that an enzyme acts upon is known as its

substrate

What is the function of GTP?

An energy carrier

What is the correct general equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP energy Cellular respiration extracts energy from glucose (C6H12O6) to produce smaller energy packets (ATP).

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?

Carbon dioxide (CO2)

What occurs at the bridge step?

Decarboxylation of pyruvic acid

What is meant by the statement "Enzymes are biological catalysts"?

Enzymes speed up the chemical reactions in living cells

Why does FADH2 yield less ATP than NADH?

FADH2 electrons enter the electron transport chain at a lower energy level

What is the key product formed by the Calvin-Benson cycle?

G3P

Which of the following statements concerning glycolysis is TRUE?

Glucose is activated by substrate-level phosphorylation

Which of the following statements about glycolysis is true?

Glycolysis is also called the Embden-Meyerhof pathway

Which of the following equations represents photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2

What connects the two photosystems in the light reactions?

An electron transport chain

Which energy-rich molecule directly powers cell work?

ATP

What two molecules are produced by the light reactions and used to power the Calvin cycle?

ATP and NADPH

Why is ATP required for glycolysis?

ATP makes it easier to break apart glucose into two three-carbon molecules

Where would you expect to find electron transport chains in a prokaryote?

Along the plasma membrane

Noncyclic photophosphorylation employs which photosystem(s)?

Both photosystem I and photosystem II

Where does the energy required for anabolic reactions come from?

Catabolic reactions

What molecule is used to capture light energy?

Chlorophyll

In which of the following organelles does photosynthesis take place?

Chloroplast

Why do all enzymatic reactions need activation energy?

Energy is required to disrupt a substrate's stable electron configuration

Why are enzymes important to biological systems?

Enzymes decrease the amount of activation energy required for chemical reactions to occur

Which of the following statements about fermentation is true?

It is an alternative way to return electron carriers to their oxidized state

What is the role of water in noncyclic photophosphorylation?

It provides electrons and protons.

What is the fate of the NAD+ newly regenerated by fermentation?

It returns to glycolysis to pick up more electrons

What is the role of pyruvic acid in fermentation?

It takes the electrons from NADH, oxidizing it back into NAD+

Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium?

Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields

Which of the following is an acid produced by fermentation?

Lactic acid and propionic acid

Drag the labels onto the diagram to identify the inputs and outputs of the two stages of photosynthesis. Use labels of Group 2 for targets of Group 2.

Light > light reactions > O2 CO2 > Calvin cycle > glucose

According to the animation, what is the net total (gain or loss) of ATP after one cycle?

Loss of nine

What is the source of the electrons that reduce 1,3-bisphosphoglyceric acid?

NADPH

What transports electrons from the light reactions to the Calvin cycle?

NADPH

How many of the six G3P's produced in one cycle are used to make one molecule of glucose?

One

Label the scheme of glucose catabolism

Respiration > glycolysis > Acetyl-CoA > Krebs cycle > High-energy electrons Fermentation > Pyruvic acid (for derivative) > Fermentation end-products > Electron transport chain > Final electron acceptor

What is the role of light energy in photosynthesis?

To produce a proton gradient to make ATP

What drives the production of ATP in cyclic photophosphorylation?

Proton gradient

How does the proton gradient help ATP synthase to make ATP?

Protons move from outside the membrane to inside the membrane

What carbon molecules remain at the end of glycolysis?

Pyruvic acid

What is the fate of electrons in noncyclic photophosphorylation?

Reduce NADP+ to NADPH

Where does the energy to excite the electrons in photosystem I come from?

Sunlight

Why is the Calvin-Benson cycle also termed the "light independent reactions" of photosynthesis?

Sunlight is not directly needed to carry out this process.

According to the animation, what does the electron transport chain do to the concentration of hydrogen ions (protons)?

The concentration of protons is higher outside the membrane than inside

What is the fate of metabolites during respiration?

They are oxidized completely to carbon dioxide and water

What is the fate of the NADPH molecules created during noncyclic photophosphorylation?

They are used in the Calvin-Benson cycle.

Where do the electrons from photosystem I ultimately go after they are passed through the electron transport proteins?

They return to photosystem I.

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

What is one difference between ubiquinones and cytochromes?

Ubiquinones are not made of protein; cytochromes are

Which of the following is used in photosynthesis by both plants and cyanobacteria?

Water, sunlight, and carbon dioxide

What is the intermediate product formed by pyruvic acid during alcoholic fermentation?

acetaldehyde

Chemical reactions that can proceed toward either anabolism or catabolism are called

amphibolic.

The reactions involved in producing larger compounds from smaller compounds is called

anabolism

Sulfanilamide is an antimicrobial drug that mimics the shape of an important substrate for a particular bacterial enzyme, thereby inhibiting the enzyme. This type of inhibition is known as

competitive inhibition

Fatty acids are catabolized into two carbon molecules during the process of __________.

beta-oxidation

According to the animation, the reactions that occur between glucose and pyruvic acid

can either be anabolic or catabolic.

The process of generating ATP using a proton gradient is referred to as

chemiosmosis

The conversion of pyruvic acid to acetyl-CoA can be described as ________, because a molecule of CO2 is produced as a by-product.

decarboxylation

In E. coli, the presence of isoleucine shuts down the enzymatic pathway that results in the synthesis of isoleucine. This is an example of __________.

feedback inhibition

Anabolic reactions may be characterized as

forming large molecules from smaller molecules

Based on the animation, how many electron carriers are reduced in the Krebs cycle only?

four

Pyruvic acid is a product of

glycolysis

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis Glycolysis, the breakdown of glucose into two molecules of pyruvic acid, takes place in the cytosol, outside the mitochondria.

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain Glycolysis produces pyruvic acid, which enters the mitochondrion. There, it is converted to acetyl CoA, which enters the citric acid cycle. Electron carriers bring electrons from the first three steps to the electron transport chain, and ATP is made.

Match the metabolic process to the region in the mitochondrion where the process occurs.

glycolysis, electron transport, krebs cycle

Which of the following is an active enzyme?

holoenzyme

Label the compounds produced in each step of the Krebs cycle.

image

According to the animation, oxidative phosphorylation

is a catabolic process.

The use of amino acids to make proteins

is an example of anabolism

The Pentose Phosphate Pathway

is an example of anabolism.

In metabolism, energy that is not used

is given off as heat

Lipases break down

lipids

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion All of the steps of cellular respiration except glycolysis take place in the mitochondrion.

Which of the following can be used as a final electron acceptor for aerobic respiration?

molecular oxygen

The electron transport chain provides the energy for

oxidative phosphorylation

Glycolysis literally means

sugar splitting

Which of the following is NOT a catabolic pathway or reaction?

the conversion of glucose to starch

The energy captured by photophosphorylation is used to produce glucose

through the Calvin-Benson cycle.

The light reactions take place in the _________ and the Calvin cycle takes place in the _________.

thylakoids; stroma

Reactions that are both catabolic and anabolic are amphibolic.

true

How many net ATPs can be made from one molecule of glucose in glycolysis?

two

According to the animation, what does oxygen get reduced to at the end of the electron transport chain?

water