BIO 110 - EXAM 2

Exergonic

(of a metabolic or chemical process) accompanied by the release of energy.

How many NADH are produced by glycolysis?

2

In glycolysis there is a net gain of ______ ATP.

2

Starting with one molecule of glucose, the energy-containing products of glycolysis are

2 NADH, 2 pyruvate, and 2 ATP

Which of these equations best summarizes photosynthesis?

6 CO2 + 6 H2O → C6H12O6 + 6 O2

In cellular respiration, the energy for most ATP synthesis is supplied by

A proton gradient across a membrane

A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?

A substrate

In glycolysis, what starts the process of glucose oxidation?

ATP

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

The energy required to run the calvin cycle comes from ______ and ______.

ATP, NADPH

The oxygen consumed during cellular respiration is involved directly in which process or event?

Accepting electrons at the end of the electron transport chain

Which of these enters the citric acid cycle?

Acetyl CoA

Which of these is NOT a product of the citric acid cycle?

Acetyl CoA

The primary role of oxygen in cellular respiration is to

Act as an acceptor for electrons and hydrogen, forming water

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

Activation Energy

How does an enzyme increase the rate of the chemical reaction it catalyzes?

An enzyme reduces the free energy of activation of the reaction it catalyzes

Generation of proton gradients across membranes occurs during

Both photosynthesis and respiration

The energy-carrying products of the light reactions, NADPH and ATP, are used by the ______ ________.

Calvin Cycle

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Carbon Dioxide

Carbon from the carbon dioxide is attatched to a 5-carbon molecule called RuBP

Carbon Fixation

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

Catabolic pathways

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

Competitive Inhibition

What is an heterotroph?

Consume organic carbon

What is an autotroph?

Converting inorganic carbon into organic carbon

Which stage of glucose metabolism produces the most ATP?

Electron transport and chemiosmosis

What is the overall reaction for photosynthesis?

Energy + 6 CO2 + 6 H2O ---> C6H12O6 + 6 O2

Which of the following statements regarding enzymes is true?

Enzymes increase the rate of a reaction by lowering the activation energy barrier

Which of these is NOT a product of glycolysis?

FADH2

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as

Feedback Inhibition

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Fermentation

Which molecule is metabolized in a cell to produce energy for performing work?

Glucose

Net input of Glycolysis

Glucose, NAD+, ADP

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

Glycolysis

Which step of the cellular respiration pathway can take place in the absence of oxygen?

Glycolysis

Spontaneous

If it occurs without being driven by some outside force

Where is ATP synthase located in the mitochondrion?

Inner Membrane

Nonspontaneous/Endergonic

Is a chemical reaction in which the standard change in free energy is positive and energy is absorbed.

The active site of an enzyme is the region that

Is involved in the catalytic reaction of the enzyme

What happened to most of the energy that the cell obtains from the oxidation of glucose?

It is stored in NADH and FADH2

What happens to the lactate in skeletal muscle cells?

It is taken to the liver and converted back to pyruvate

Why does the process of photosynthesis require an input of energy?

It takes more energy to break 6 CO2 bonds and energy 6 H2O bonds than formed

Why is glycolysis described as having an investment phase and a payoff phase?

It uses stored ATP and then forms a net increase in ATP

Photosynthesis converts __________ energy to ________ energy.

Kinetic, Potential

In muscle cells, fermentation produces _______.

Lactate and NAD+

Which of the following events occurs in the light reactions of photosynthesis?

Light is absorbed and funneled to reaction-center chlorophyll a

Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?

Localization of enzymes into specific organelles or membranes

The overall function of the calvin cycle is ________.

Making sugar

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?

Mitochondrial intermembrane space

Where are the proteins of the electron transport chain located?

Mitochondrial intermembrane space

Which of the following statements describes NAD+?

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle

Which of the following statements about the electron transport chain is true?

NADH and FADH2 donate their electrons to the chain

Which of the following products of the light reactions of photosynthesis is consumed during the calvin cycle?

NADPH

The splitting of carbon dioxide to from oxygen gas and carbon compounds occurs during

Neither photosynthesis nor respiration

One function of both alcohol fermentation and lactic acid fermentation is to

Oxidize NADH to NAD+

Is oxygen oxidized or reduced?

Oxidized

Which of the following is a product of the light reactions of photosynthesis?

Oxygen, ATP, and NADPH

Reduction of NADP+ occurs during

Photosynthesis

Which of the following statements best describes the relationship between photosynthesis and respiration?

Photosynthesis stores energy in complex organic molecules, whereas respiration releases it

Net output of Glycolysis

Pyruvate, NADH, ATP

In fermentation _______ is reduced and _________ is oxidized.

Pyruvate... NADH

The NADPH required for the calvin cycle comes from

Reactions initiated in photosystem I

Which of the following are directly associated with photosystem I?

Receiving electrons from the thylakoid membrane electron transport chain

Is carbon oxidized or reduced?

Reduced

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes

Reduced

Reduction of oxygen to form water occurs during

Respiration only

What is carbon fixation catalyzed by?

Rubisco

What is the role in the light reactions?

Splits into electrons

When oxygen is released as a result of photosynthesis, it is a direct by-product of

Splitting water molecules

Where in the chloroplast do the reactions of the calvin cycle occur?

Stroma

Where do the enzymatic reactions of the calvin cycle take place?

Stroma of the chlorplast

In glycolysis, ATP molecules are produced by ___________.

Substrate-level phosphorylation

In the citric acid cycle, ATP molecules are produced by _________.

Substrate-level phosphorylation

The ATP made during fermentation is generated by which of the following?

Substrate-level phosphorylation

The ATP made during glycolysis is generated by

Substrate-level phosphorylation

What is the primary function of the calvin cycle?

Synthesize simple sugars from carbon dioxide

Where does the energy from to drive the process of photosynthesis?

The Sun

According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?

The binding of the substrate changes the shape of the enzyme's active site

Which of the following statements best represents the relationships between the light reactions and the calvin cycle?

The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.

When electrons move closer to a more electronegative atom, what happens?

The more electronegative atom is reduced, and energy is released

Where in the chloroplast do the light reactions occur?

Thylakoid discs

In a plant cell, where are the ATP synthase complexes located?

Thylakoid membrane and inner mitochondrial membrane

Where are the molecules of the electron transport chain found in plant cells?

Thylakoid membranes of chloroplasts

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

True

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria

True

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

Two ATP

Which statement about the binding of enzymes and substrates is correct?

When substrate molecules bind to the active site of the enzyme, the enzyme undergoes a slight change in shape

In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during

both photosynthesis and respiration

The light reactions of photosynthesis use _____ and produce _______.

water...NADPH