Chapter 9 - Cellular Respiration and Fermentation

What is cellular respiration?

A catabolic process that breaks down glucose to produce ATP (energy)

What is ATP?

Adenosine Triphosphate - ENERGY

What is Aerobic respiration?

Requires oxygen

What is the most efficient way to produce ATP?

Aerobic respiration

What is Anaerobic respiration?

Respiration without oxygen

What is glycolysis?

Breakdown of glucose into pyruvate.

Where does glycolysis occur?

In the cytoplasm

When glycolysis occurs what is gained?

2 ATP (net gain)

2 NADH (electron carriers)

2 Pyruvate

2 H2O

What is catabolism?

Breaking down molecules

What is anabolism?

Building up molecules

What type of respiration is fermentation?

Anaerobic respiration

What is fermentation?

Making ATP w/out oxygen

Breakdown of molecules is ________.

Exergonic

Exergonic

Reactions that release energy

Cellular respiration formula

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy (atp + heat)

Oxidation Phosphorylation (Electron Transport Chain)

Uses high-energy electrons from NADH and FADH₂ to create a proton gradient, which drives ATP synthesis.

Where does oxidative phosphorylation occur?

Cristae

What is the cristae?

Inner membrane folds of the mitochondria

FILL: Transfer of electrons during chemical reactions releases ________ stored in organic molecules, which is ultimately used to synthesize ___.

Energy, ATP

Redox reaction

An oxidation reaction coupled with a reduction reaction

Oxidation

A substance loses electrons, or is oxidized

Reduction

A substance gains electrons, or is reduced (the amount of positive charge reduced)

Citric acid cycle

Complete breakdown of glucose

True or False: Glycolysis is only performed by eukaryotic cells.

FALSE; It is universal for nearly every organism

What are the four defining features of a cell?

1. Cell membrane

2. Cytoplasm

3. DNA

4. Ribosomes

Juicy part of the mitochondria

Matrix

What is the citric acid cycle also called?

Krebs cycle

What happens in the citric acid cycle?

Acetyl-CoA is broken down, releasing energy.

What is gained from the citric cycle?

1 ATP

3 NADH

1 FADH2

2 CO2

(per pyruvate)

Where does the citric(krebs) cycle occur?

Mitochondrial matrix

FILL: The process that generates almost ___% of ATP is called oxidative phosphorylation

90

Three stages of cellular respiration

1. Glycolysis

2. Krebs cycle (Citric Acid Cycle)

3. Electron Transport Chain

Glycolysis produces ______ ATP.

2 ATP

The Krebs Cycle produces ______ ATP.

2 ATP (Krebs)

Oxidative Phosphorylation produces ______ ATP

26 - 28 ATP

In total, cellular respiration makes about ______ ATP per ___ glucose molecule.

30 - 32 ATP, ONE

2 Phases of Glycolysis

Energy Investment phase

Energy Payoff phase

What determines what happens after glycolysis?

Whether or not there is oxygen present

What if oxygen is present after glycolysis?

Pyruvate from glycolysis goes into the mitochondria and becomes acetyl-CoA. This keeps going with aerobic respiration (Krebs cycle and ETC).

How many steps in the Krebs cycle?

8 steps

First step of the Krebs cycle?

Acetyl group combines with oxaloacetate to make citrate

Oxaloacetate

A four-carbon molecule that binds with the two-carbon acetyl unit of acetyl-CoA to form citric acid in the first step of the Krebs cycle.

What is a coenzyme?

A helper molecule that carries and delivers the 2-carbon acetyl group (from pyruvate) to the Krebs cycle.

How many carbons is citrate?

6 carbons

Where do the NADH and FADH2 made by the citric cycle go after?

NADH and FADH₂ donate their high-energy electrons to the electron transport chain(ETC)

TRUE or FALSE: The electron transport chain(ETC) generates ATP.

FALSE; The electron transport chain generates NO ATP, it sets up the conditions to make ATP

When electrons are donated to the Electron Transport Chain (ETC), they pass through and power ______ proton pumps.

Three.

How many protein complexes are there in cristae?

Four.

What happens to the energy released as electrons move through the Electron Transport Chain (ETC)?

The energy is used to pump H⁺ (protons) from the mitochondrial matrix into the intermembrane space, creating a proton gradient.

What is a proton gradient?

A higher concentration of protons outside the inner membrane of the mitochondria than inside the membrane

ATP synthase

A molecular motor that uses the H+ proton gradient to phosphorylate ADP into ATP.

Chemiosis

The use of energy in a H+ gradient to drive cellular work

Proton motive force

Emphasizes the capacity of the gradient to perform work.

Most ATP comes from

oxidative phosphorylation

What is the final electron acceptor?

Oxygen is the final electron acceptor, forming water (H₂O) by combining with H+

What is the sequence of energy during cellular respiration?

1. Glucose

2. NADH and FADH2

3. Electron transport chain (ETC)

4. Proton-motive force

5. ATP

Only 34% of the energy is captured from the bonds stored in glucose. What happens to much of the energy originally stored in glucose?

Much of it is released as heat.

Two most common types of fermentation

Alcoholic(ethanol) and Lactic acid

Alcohol fermentation

1. Glycolysis makes 2 pyruvate

2. Pyruvate is then converted into alcohol

In alcoholic fermentation, what happens when pyruvate loses a CO2 molecule?

It turns into acetaldehyde

FILL: Acetaldehyde acts as the ____ ______ in fermentation.

Final acceptor

How is pyruvate converted to ethanol?

In the absence of oxygen pyruvate can be converted to CO2 and ethanol

Release of what creates ethanol?

Carbon dioxide (CO2)

What molecule donates electrons to acetaldehyde in alcohol fermentation?

NADH

What does acetaldehyde become after accepting electrons from NADH?

Ethanol (alcohol)

What is regenerated when NADH donates its electrons to acetaldehyde?

NAD⁺

Why is NAD⁺ important for glycolysis?

NAD⁺ is required to accept electrons during glycolysis, allowing the process to continue and produce ATP.

What is the main difference between alcohol fermentation and the ETC?

Alcohol fermentation does not require oxygen and produces ethanol, while the ETC requires oxygen and produces water.

Products of alcohol fermentation

alcohol, CO2 and 2 ATP

In alcohol fermentation you start with ____ carbons in pyruvate, and end with ___ carbons in ethanol(alcohol)

Three, Two

What does alcoholic fermentation?

Yeasts, bacteria, or other fungi

What fermentation process is used to make alcoholic beverages like beer and wine?

Alcoholic fermentation

Lactic acid fermentation

1. Glycolysis occurs

2. Pyruvate is reduced by NADH to make lactate and NAD+

What reduces pyruvate to lactate?

NADH

TRUE or FALSE: The lactic acid cycle does NOT release CO2.

TRUE

In lactic acid fermentation you start with ___ carbons in pyruvate, and end with ____ carbons in LACTATE with NO CO2.

Three, Three.

What makes yogurt sour?

Lactic acid

During strenuous exercise, what cells use the lactic acid cycle to generate ATP when oxygen is low?

Muscle cells

Shared characteristics between Fermentation and Anaerobic/Aerobic respiration.

1. All use glycolysis (2 ATP) to oxidize glucose

2. All use NAD⁺/NADH.

Use NAD⁺ as the oxidizing agent that accepts electrons during glycolysis

Obligate anaerobes

Organisms that cannot live where molecular oxygen is present

Facultative anaerobes

Can make enough ATP to survive using using fermentation or respiration.

What is the "fork" in the metabolic "road" that leads to two catabolic routes?

Pyruvate

TRUE or FALSE: These catabolic pathways ONLY accept glucose.

FALSE; They funnel electrons from many kinds organic molecules

Beta oxidation

Reaction that converts fatty acids to acetyl CoA to enter the Krebs cycle

An oxidized gram of fat produces more than ____ as much ATP as an oxidized gram of carbohydrate

Twice

Which makes more ATP, aerobic or anaerobic respiration?

Aerobic respiration