Redox Reactions

What does ATP stand for?

Adenosine Triphosphate

Why are the phosphate bonds in ATP considered high energy?

Have charge repulsion, making the bonds unstable and easily broken to release energy

What happens during ATP hydrolysis?

ATP reacts with water (ATP + H₂O → ADP + Pi) to release energy in a highly exergonic reaction

What type of cellular reactions does ATP hydrolysis fuel?

Endergonic (energy-requiring) reactions

What does it mean when reactions are “coupled”?

An exergonic reaction (like ATP hydrolysis) releases energy that drives an endergonic reaction

What does "redox" stand for?

Reduction–Oxidation

What happens during oxidation?

An atom or molecule loses electrons; this is an exergonic process.

What happens during reduction?

An atom or molecule gains electrons; this is an endergonic process.

What is the OIL RIG mnemonic used for?

Oxidation Is Loss, Reduction Is Gain (of electrons)

Why do oxidation and reduction always occur together?

When one molecule loses electrons, another must gain them — they’re coupled reactions.

How do cells transfer energy during redox reactions?

By transferring electrons from one molecule to another

What high-energy molecule is converted into ATP during cellular respiration?

Glucose

Why does glucose store a large amount of energy?

Has carbon-hydrogen bonds, which hold electrons that can be transferred to produce ATP

What are the main electron carriers in cellular respiration?

NAD⁺ and FAD

When NAD⁺ and FAD accept electrons, what do they become?

NADH and FADH₂ (reduced forms)

What happens to NADH and FADH₂ later in cellular respiration?

They are oxidized again to release the electrons they carry

What vitamins are precursors to NAD⁺ & FAD electron carriers?

Vitamin B3 (Niacin) for NAD⁺ and Vitamin B2 (Riboflavin) for FAD.

How does ATP hydrolysis drive endergonic reactions in the cell?

By transferring a phosphate group to another molecule (phosphorylation

What kind of reaction is ATP hydrolysis, and what kind is phosphorylation?

ATP hydrolysis is exergonic; phosphorylation is endergonic

Why is coupling oxidation and reduction important for cellular metabolism?

It allows cells to use the energy released from oxidation to power energy-requiring processes through reduction

What is the main function of ATP in cells?
A. Acts as a structural component of cell membranes
B. Provides usable energy for cellular processes
C. Stores genetic information
D. Functions as an enzyme

B. Provides usable energy for cellular processes

Why do the phosphate groups in ATP contain so much potential energy?
A. They attract each other strongly
B. They repel each other due to negative charges
C. They form ionic bonds with oxygen
D. They are surrounded by water molecules

B. They repel each other due to negative charges

What reaction does ATP undergo to release energy?
A. Dehydration synthesis
B. Condensation
C. Hydrolysis
D. Reduction

C. Hydrolysis

The breakdown of ATP into ADP + Pi is considered:
A. Endergonic
B. Exergonic
C. Reversible and energy neutral
D. A dehydration reaction

B. Exergonic

What does it mean when reactions are “coupled”?
A. Two reactions that occur independently
B. An exergonic reaction drives an endergonic reaction
C. Two endergonic reactions occur at once
D. Reactions that occur at different times in the cell

B. An exergonic reaction drives an endergonic reaction

What type of reaction provides the energy to fuel endergonic cellular processes?
A. Oxidation
B. ATP hydrolysis
C. Photosynthesis
D. Condensation

B. ATP hydrolysis

What does the acronym “OIL RIG” stand for?
A. Oxidation Is Lost, Reduction Is Gained
B. Oxidation Is Losing, Reduction Is Gaining
C. Oxidation Is Loss, Reduction Is Gain
D. Oxygen Increases Level, Reduction In Gas

C. Oxidation Is Loss, Reduction Is Gain

During oxidation, a molecule:
A. Gains electrons
B. Loses electrons
C. Is phosphorylated
D. Gains hydrogen

B. Loses electrons

During reduction, a molecule:
A. Loses electrons
B. Gains electrons
C. Breaks down ATP
D. Loses hydrogen atoms

B. Gains electrons

Why do oxidation and reduction reactions always occur together?
A. One produces ATP while the other consumes it
B. Electrons lost by one molecule must be gained by another
C. They both release carbon dioxide
D. They both require water

B. Electrons lost by one molecule must be gained by another

In redox reactions, what form is energy transferred as?
A. Heat
B. Phosphate groups
C. Electrons
D. Ions

C. Electrons

What type of reaction is oxidation considered?
A. Endergonic
B. Exergonic
C. Isotonic
D. Catalytic

B. Exergonic

What type of reaction is reduction considered?
A. Endergonic
B. Exergonic
C. Isotonic
D. Neutral

A. Endergonic

Glucose stores large amounts of energy because it contains:
A. Many nitrogen atoms
B. Strong ionic bonds
C. Many C–H bonds holding high-energy electrons
D. Water molecules bound inside

C. Many C–H bonds holding high-energy electrons

Cellular respiration is an example of what type of chemical process?
A. Photosynthetic
B. Dehydration synthesis
C. Redox reaction
D. Hydrolysis

C. Redox reaction

What is the role of NAD⁺ and FAD in cellular respiration?
A. They directly generate ATP
B. They serve as electron carriers
C. They act as enzymes
D. They store oxygen

B. They serve as electron carriers

What happens when NAD⁺ is reduced?
A. It loses an electron and becomes NADH
B. It gains electrons and hydrogen to become NADH
C. It is converted into ATP
D. It releases oxygen

B. It gains electrons and hydrogen to become NADH

Which vitamin is needed to produce NAD⁺?
A. Vitamin B1 (Thiamine)
B. Vitamin B2 (Riboflavin)
C. Vitamin B3 (Niacin)
D. Vitamin B12 (Cobalamin)

C. Vitamin B3 (Niacin)

Which vitamin is needed to produce FAD?
A. Vitamin B2 (Riboflavin)
B. Vitamin B3 (Niacin)
C. Vitamin C (Ascorbic acid)
D. Vitamin B6 (Pyridoxine)

A. Vitamin B2 (Riboflavin)

What process transfers a phosphate group to another molecule to make it more reactive?
A. Deamination
B. Phosphorylation
C. Reduction
D. Hydrolysis

B. Phosphorylation

The oxidation of ATP is directly coupled with what type of reaction?
A. Reduction of other molecules through phosphorylation
B. Oxidation of glucose
C. Reduction of NADH
D. Electron transport chain activity

A. Reduction of other molecules through phosphorylation

Why are coupled reactions important in biological systems?
A. They prevent ATP from being hydrolyzed
B. They allow energy from one reaction to power another
C. They store glucose in the liver
D. They maintain pH levels

B. They allow energy from one reaction to power another

In the reaction ATP + H₂O → ADP + Pi, which molecule is oxidized?
A. ATP
B. ADP
C. H₂O
D. Pi

A. ATP

What type of energy is released when ATP is hydrolyzed?
A. Potential energy
B. Kinetic energy
C. Chemical energy
D. Nuclear energy

C. Chemical energy

What happens to NADH during its oxidation in cellular respiration?
A. It gains electrons
B. It loses electrons and becomes NAD⁺
C. It breaks down ATP
D. It produces water

B. It loses electrons and becomes NAD⁺