Exam III Paper Notes

What is the overall purpose of cellular respiration?

To break down glucose and produce ATP

To break down glucose and produce ATP

Glycolysis.

What happens in ATP hydrolysis?

ATP + H₂O → ADP + phosphate group + energy.

What are the 3 types of work ATP powers?

Mechanical work, transport work, and chemical work.

What does NAD stand for?

Nicotinamide Adenine Dinucleotide.

Where does glycolysis occur?

In the cytosol (cytoplasm) of the cell

How many ATP are produced during glycolysis?

Net gain of 2 ATP per glucose.

What is the product of glycolysis?

2 pyruvate molecules.

What is the role of NADH?

Carries high-energy electrons to the Electron Transport Chain.

Where is the Electron Transport Chain located?

In the inner mitochondrial membrane/cristae

What is the final electron acceptor in the Electron Transport Chain?

Oxygen.

What is the matrix of the mitochondria?

The innermost compartment of the mitochondria where the Citric Acid Cycle occurs

What is the intermembrane space?

The space between the inner and outer mitochondrial membranes where H+ ions accumulate.

What enzyme breaks down fats?

Lipase.

What are the products of triglyceride breakdown?

1 glycerol and 3 fatty acids.

Why does fermentation occur?

To regenerate NAD+ so glycolysis can continue when oxygen is unavailable.

What are the products of alcoholic fermentation?

Ethanol, CO₂, and regenerated NAD+.

Where does alcoholic fermentation commonly occur?

Yeast cells.

What are the products of lactic acid fermentation?

Lactate and regenerated NAD+.

Where does lactic acid fermentation occur in humans?

Muscle cells when oxygen is limited.

Example of mechanical work

Muscle contraction, Beating cilia and flagella, Movement of chromosomes during cell division

Transport Work

ATP powers the movement of substances across cell membranes.

Ex of transport work

Sodium-potassium pump (Na⁺/K⁺ pump), Moving ions against their concentration gradient

Chemical Work

ATP powers chemical reactions that build molecules.

Ex of Chemical work

Making proteins from amino acids, Making DNA, Making glycogen

Nicotinamide Adenine Dinucleotide (NAD⁺)

electron carrier that picks up high-energy electrons and hydrogen ions (H⁺) and transports them to the Electron Transport Chain.

Taq DNA requires tiny amounts of ___ cofactor to work

Mg

Mg is common cofactor for

lots of enzymes

Glycolysis makes a lot of

NADH

NADH is located along

the inner membrane

What is the ALDH reaction?

Acetaldehyde + NAD+ → Acetate + NADH

What molecule is reduced in the ALDH reaction?

NAD+ is reduced to NADH.

What molecule is produced along with acetate by ALDH?

NADH

What ETC complex is inhibited by rotenone?

Complex I

What ETC inhibitor was noted with Complex I?

Rotenone

Rotenone is a poison that blocks ___ of ETC

Complex I

What is the pathway of electrons through the ETC?

NADH → Complex I → Complex II → Complex III → Oxygen → Water.

What ETC complex is inhibited by carbon monoxide (CO)?

Complex II and III

What happens if Complex III is blocked?

Electron flow stops and ATP production decreases dramatically.

MPTP

a neurotoxin sometimes discussed with ETC inhibitors

What ETC complex is inhibited by MPTP/MPP⁺

Complex 1

How much ATP is produced during oxidative phosphorylation?

About 28 ATP.

What enters Complex I of the ETC?

Electrons from NADH.

What is the role of Complex I?

Accepts electrons from NADH and pumps H+ ions.

What happens at Complex II?

Electrons enter the ETC from FADH2

How is ATP synthase connected to the Electron Transport Chain?

The ETC creates a proton (H+) gradient, and ATP synthase uses the energy from H+ flowing down the gradient to make ATP.

What is the role of ATP synthase in the ETC?

To make ATP from ADP and phosphate using the proton gradient created by the ETC.

What creates the proton gradient used by ATP synthase?

Complexes I, II, and III of the Electron Transport Chain.

Lipase

enzyme that breaks down fats (triglycerides) into glycerol and fatty acid for cellular respiration

Metabolism

all the reactions that build up and break down molecules in a cell.

What is the role of Complex III?

Transfers electrons and helps pump H+ ions.

Parts of the ETC

I, II, III

What happens to H+ ions during the ETC?

They are pumped across the inner mitochondrial membrane.

What creates the proton gradient in the ETC?

Complexes I, II, and III pumping H+ ions.

What is oxidative phosphorylation?

The process of using the ETC and ATP synthase to produce ATP.

Carbon monoxide binds to ____ in the ETC

Complex II

What ETC complex is affected by carbon monoxide poisoning?

Carbon monoxide blocks oxygen from accepting electrons, stopping the ETC.

Proton gradient consists of _______ to help make ATP

active proteins

PPO requires tiny amounts of ___ cofactor to work in a lab

CU+

Mechanical Work

ATP powers movement.

What is produced when oxygen accepts electrons and H+?

Water (H₂O)

What powers ATP synthase?

A proton (H+) gradient, also called proton motive force.

3rd stage of ETC

Oxidative phosphorylation

What is Oxidative phosphorylation

process where the Electron Transport Chain uses electrons from NADH and a proton (H⁺) gradient to power ATP synthase, which makes ATP, complex III

About how much ATP is produced by ATP synthase during oxidative phosphorylation?

About 28 ATP.

How many Phosphate groups does ADP have

2

how many phosphate groups are in ATP

3

Structure of ATP

Adenine, Ribose, 3 phosphate groups

Where does glycolysis occur?

In the cytoplasm.

NAD+ is sourced from

Normal food consumption

What is the starting molecule for glycolysis?

Glucose.

What is the end product of glycolysis?

Two pyruvate molecules.

How much ATP does glycolysis produce directly?

2 ATP (net)

What happens to pyruvate after glycolysis?

It enters the mitochondrion for further breakdown.

What is the citric acid cycle also called?

The Krebs cycle

What is the main purpose of the citric acid cycle?

To produce NADH and release CO₂

What waste product is released during the citric acid cycle?

Carbon dioxide (CO₂).

What is NADH?

An electron carrier that transports high-energy electrons to the electron transport chain

Where is NADH used?

In the electron transport chain.

What is the electron transport chain (ETC)?

A series of proteins that transfer electrons and pump H⁺ ions across a membrane

What is the role of electrons in the ETC?

They provide energy to pump H⁺ ions.

What is a proton gradient?

A difference in H⁺ concentration across a membrane.

What is the proton-motive force?

The stored energy created by a proton gradient.

What molecule is the final electron acceptor in the ETC?

Oxygen

What is formed when oxygen accepts electrons and H⁺ ions?

Water (H₂O).

What enzyme uses the proton gradient to make ATP?

ATP synthase.

How does ATP synthase work?

H⁺ ions flow through it, driving ATP production.

Approximately how much ATP is produced by oxidative phosphorylation?

About 28 ATP.

Which stage produces the most ATP?

The electron transport chain and ATP synthase

What are the three main stages of cellular respiration?

Glycolysis → Citric Acid Cycle → Electron Transport Chain.

What enzyme converts ethanol into acetaldehyde?

Alcohol dehydrogenase (ADH)

What is the reaction catalyzed by alcohol dehydrogenase?

Ethanol + NAD⁺ → Acetaldehyde + NADH

What enzyme converts acetaldehyde into acetate?

Aldehyde dehydrogenase (ALDH)

What is the reaction catalyzed by aldehyde dehydrogenase?

Acetaldehyde + NAD⁺ → Acetate + NADH

Which molecule is more toxic, ethanol or acetaldehyde?

Acetaldehyde

What does ALDH stand for?

Aldehyde dehydrogenase

What does ADH stand for?

Alcohol dehydrogenase

What is Antabuse (disulfiram)

A drug that inhibits ALDH

What happens when ALDH is inhibited?

Acetaldehyde accumulates in the body.

Why does Antabuse help treat alcoholism?

Buildup of acetaldehyde causes unpleasant symptoms when alcohol is consumed.