Biochemistry of Respiration

Questions and Answers

What is the net gain of ATP from one molecule of glucose during glycolysis?

0 ATP

2 ATP (correct)

6 ATP

4 ATP

The process of glycolysis occurs in the mitochondria and requires oxygen.

False

What byproduct is produced during anaerobic respiration in muscle cells?

lactic acid

The Krebs cycle converts a 6 Carbon compound back to a 4 Carbon compound by losing two _______ and four pairs of hydrogen.

CO2 Signup and view all the answers

Match the following processes with their descriptions:

Glycolysis = Splitting glucose into pyruvate Krebs Cycle = Formation of ATP with the release of CO2 Electron Transport Chain = Use of oxygen to create water and ATP Anaerobic Respiration = Breakdown of sugar in the absence of oxygen Signup and view all the answers

What is the main disadvantage of anaerobic respiration compared to aerobic respiration?

Generates less ATP Signup and view all the answers

Fermentation is a type of aerobic respiration.

False Signup and view all the answers

What do plants and animals use anaerobic respiration for?

Energy in oxygen-deficient environments Signup and view all the answers

During anaerobic respiration, yeast converts glucose into ________ and ethanol.

carbon dioxide Signup and view all the answers

Match the following products to their corresponding fermentation processes:

Alcohol = Produced by yeast fermentation Bread = Leavened by carbon dioxide from yeast Yoghurt = Produced by bacterial fermentation of milk Cheese = Derived from milk through fermentation Signup and view all the answers

Study Notes

ATP Formation

Formation of ATP involves the addition of a third phosphate group to ADP, requiring energy.
This energy is stored in the high-energy bond formed during ATP synthesis.

Waste Removal

Metabolism generates waste products such as urea, carbon dioxide, and water.
The process of eliminating these waste products is known as excretion.

Stages of Respiration

Glycolysis:
- Process of breaking down glucose (6-carbon) into two 3-carbon pyruvate molecules.
- Takes place in the cytoplasm and is anaerobic (does not require oxygen).
- Requires 2 ATP to initiate, resulting in a net gain of 2 ATP per glucose molecule (4 ATP produced).
Krebs Cycle:
- Pyruvate enters the mitochondrion's matrix, releases CO2 and 2 hydrogen atoms.
- Forms acetyl coenzyme A, which enters the Krebs cycle, joining a 4-carbon compound to create a 6-carbon compound.
- The cycle includes a series of reactions, releasing 2 CO2, 4 hydrogen pairs, and 1 ATP.
Electron Transport Chain:
- Occurs in the cristae of mitochondria, utilizing oxygen to produce ATP.
- Electrons from hydrogen atoms are transferred through carrier molecules, generating energy for ATP synthesis.
- Final step involves combining hydrogen ions and electrons with oxygen to create water, which is usable by cells.

Anaerobic Respiration

Takes place without oxygen, leading to the production of lactic acid in certain cells (e.g., muscle cells).
Reduces cellular efficiency, lowers pH, and can cause cramps and stiffness.
Increased breathing post-exercise helps reconvert lactic acid to glucose in the liver.

Aerobic Respiration Equation

Chemical Reaction: C6H12O6 + 6O2 → 6CO2 + 6H2O (Glucose + Oxygen = Carbon Dioxide + Water).

Fermentation

A form of anaerobic respiration utilized for energy production in low-oxygen environments.
Advantages: Provides energy in conditions where oxygen is scarce.
Disadvantages: Limited to 2 ATP production compared to the 38 ATP from aerobic respiration; produces toxic byproducts requiring excretion.
Applications: Alcohol production, bread-making, yogurt, cheese production, and the creation of antibiotics and human growth factors.

Mandatory Practical: Ethanol Production by Yeast

Prepare a 10% w/v glucose solution (400 ml), divide into two flasks (200 ml each).
Add yeast to one flask ('yeast + glucose') and leave the other as a control without yeast.
Use fermentation locks filled with water to monitor gas production.

Overview of Respiration

Process that converts chemical energy in food to usable energy forms for cellular functions.
Types:
- Anaerobic (no oxygen, small energy output).
- Aerobic (requires oxygen, large energy output).

Metabolism

Involves millions of chemical reactions in living cells divided into:
- Anabolic Reactions: Construct complex compounds from simpler ones, requiring ATP for energy.
- Catabolic Reactions: Break down complex molecules into simpler forms, releasing energy for ATP synthesis.

ATP Functions

Stores energy from reactions (e.g., photosynthesis, respiration) in a useable form.
Transfers energy to locations in the cell where it is needed.

Energy Cycle

Respiration provides energy as ATP, which is used by cells and converted back to ADP and inorganic phosphate upon energy release.
ADP and free phosphate can be reassembled into ATP if energy is available, maintaining the cycle.

Description

Explore the key stages of respiration, including glycolysis and ATP formation. Understand the role of energy in the synthesis of ATP and the importance of excretion in metabolic processes. This quiz will challenge your knowledge of biochemical reactions and respiratory pathways.