Biology Chapter 9: Cellular Respiration

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Questions and Answers

What is a calorie?

A unit of measurement for distance

The amount of heat produced by food during digestion

The amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius (correct)

The amount of energy needed to raise the temperature of 1 kg of water 1 degree Celsius

What is glycolysis?

The process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid.

What is cellular respiration?

The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

What is NAD+?

An electron carrier that accepts a pair of high-energy electrons; similar to NADP+ in photosynthesis. Signup and view all the answers

What is NADH?

The molecule NAD+ is converted to, holds the electrons until they can be transferred to other molecules; similar to NADPH in photosynthesis. Signup and view all the answers

What is fermentation?

The process that releases energy from food molecules by producing ATP in the absence of oxygen. Signup and view all the answers

Fermentation is said to be ___ because it does not require oxygen.

anaerobic Signup and view all the answers

Pyruvic acid + NADH --> alcohol + CO2 + NAD+ is known as ___ fermentation.

alcoholic Signup and view all the answers

Pyruvic acid + NADH --> lactic acid + NAD+ is known as _ _ fermentation.

lactic acid Signup and view all the answers

The final steps of cellular respiration are ___.

aerobic Signup and view all the answers

What is the Krebs cycle?

The cycle in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. Signup and view all the answers

What compound is formed when Coenzyme A joins a 2-carbon molecule?

Acetyl-CoA Signup and view all the answers

What compound is formed when acetyl-CoA adds the 2-carbon acetyl group to a 4-carbon compound?

Citric acid Signup and view all the answers

What is FAD?

An electron carrier that is changed to FADH2, similar to NAD+. Signup and view all the answers

What is FADH2?

The compound FAD is converted to, similar to NADH. Signup and view all the answers

What does the electron transport chain do?

Uses the high-energy electrons from the Krebs cycle to convert ADP into ATP. Signup and view all the answers

Where does glycolysis take place?

Cytoplasm Signup and view all the answers

Where do the Krebs cycle and the electron transport chain take place?

Mitochondria Signup and view all the answers

What is pyruvic acid?

A 3 carbon compound. Signup and view all the answers

Why is the Krebs cycle also known as the citric acid cycle?

Because citric acid (a 6 carbon molecule) is the first compound formed in this cycle. Signup and view all the answers

In the Krebs cycle, where is pyruvic acid broken down into carbon dioxide?

Mitochondrial matrix Signup and view all the answers

What cell structure is the site for the electron transport chain?

Inner mitochondrial membrane Signup and view all the answers

What substance do the carrier proteins transport across the inner mitochondrial membrane?

Hydrogen ions H+ Signup and view all the answers

What high-energy molecules are formed by the electron transport chain?

ATP Signup and view all the answers

What atom accepts the hydrogen ion at the end of the electron transport chain?

Oxygen Signup and view all the answers

What molecule is formed as a product of oxygen accepting the hydrogen ion?

Water Signup and view all the answers

In cells, the energy available in food is used to make an energy-rich compound called?

ATP Signup and view all the answers

The first step in releasing the energy of glucose in the cell is known as?

Glycolysis Signup and view all the answers

What is the process that releases energy from food in the presence of oxygen?

Cellular respiration Signup and view all the answers

The net gain of energy from glycolysis is?

2 ATP molecules Signup and view all the answers

Where does the Krebs cycle take place?

Mitochondrion Signup and view all the answers

What does the electron transport chain use the high energy electrons from the Krebs cycle for?

To convert ADP to ATP Signup and view all the answers

A total of 36 molecules of ATP are produced from 1 molecule of glucose as a result of?

Cellular respiration Signup and view all the answers

During heavy exercise, the buildup of lactic acid in muscle cells results in?

Oxygen debt Signup and view all the answers

In glycolysis, each glucose molecule is broken down into?

Two molecules of pyruvic acid. Signup and view all the answers

The first set of reactions in cellular respiration is?

Glycolysis. Signup and view all the answers

In the Krebs cycle, what is pyruvic acid broken down into?

CO2 and H2O. Signup and view all the answers

What is the most important product of the electron transport chain in cellular respiration?

ATP. Signup and view all the answers

In cellular respiration, the final electron acceptor is?

Oxygen. Signup and view all the answers

The energy that is released during cellular respiration is stored as?

ATP and NADH. Signup and view all the answers

Study Notes

Key Terms in Cellular Respiration

Calorie: Energy required to raise the temperature of 1 gram of water by 1 degree Celsius.
Glycolysis: Breakdown of a glucose molecule into two pyruvic acid molecules.
Cellular Respiration: Energy release process by breaking down glucose and other molecules in the presence of oxygen.

Electron Carriers

NAD+: Electron carrier accepting high-energy electrons, similar to NADP+ in photosynthesis.
NADH: Formed from NAD+, carries electrons to other molecules; produced during glycolysis.
FAD: Another electron carrier, transforms into FADH2.

Energy Production Processes

Fermentation: Energy release process without oxygen, producing ATP.
Anaerobic: Does not require oxygen, applicable to fermentation.
Aerobic: Requires oxygen for the final steps of cellular respiration.

Types of Fermentation

Alcoholic Fermentation: Converts pyruvic acid and NADH into alcohol, CO2, and NAD+.
Lactic Acid Fermentation: Process in muscle cells that converts pyruvic acid and NADH into lactic acid and NAD+.

Krebs Cycle

Krebs Cycle (Citric Acid Cycle): Pyruvic acid is broken down into carbon dioxide through various energy-extracting reactions.
Acetyl-CoA: Formed when Coenzyme A combines with a 2-carbon molecule.
Citric Acid: The first compound formed in the Krebs cycle, created by the combination of acetyl-CoA and a 4-carbon compound.
Mitochondrial Matrix: Location where pyruvic acid is broken down into carbon dioxide during the Krebs cycle.

Electron Transport Chain

Electron Transport Chain: Uses high-energy electrons from the Krebs cycle to convert ADP into ATP.
Inner Mitochondrial Membrane: Site for the electron transport chain.
Hydrogen Ions (H+): Transported across the inner mitochondrial membrane by carrier proteins.
Oxygen: Final electron acceptor, leading to the formation of water as a byproduct.

ATP Production

Net Gain from Glycolysis: 2 ATP molecules produced.
Total ATP from Cellular Respiration: 36 ATP molecules generated from 1 glucose molecule.
ATP: The primary energy-rich compound produced in cells.

Summary Points on Cellular Respiration

Glycolysis is the initial step, taking place in the cytoplasm, breaking glucose into 2 pyruvic acid molecules.
Krebs cycle occurs in the mitochondria, where pyruvic acid is further processed.
The electron transport chain is the final stage, producing most ATP when high-energy electrons are used.
Lactic acid buildup during intense exercise leads to oxygen debt in muscle cells.

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Explore the key concepts of cellular respiration in this flashcard set. From understanding calories to the intricacies of glycolysis, this quiz reinforces your knowledge of energy processes in living organisms. Perfect for students preparing for exams in biology.