This document discusses respiration and gas exchange. It explains that aerobic respiration uses oxygen to break down glucose, releasing carbon dioxide and water. Anaerobic respiration in yeast breaks down glucose into alcohol and carbon dioxide without oxygen. Anaerobic respiration in humans produces lactic acid instead of alcohol when oxygen cannot be supplied fast enough to muscles during vigorous exercise.

1. Respiration and Gas
Exchange

2. Respiration
• Why do organisms need energy?
• Muscle contraction. Why?
• Making protein molecules. How?
• Cell division. Why?
• Active transport. What?
- movement of molecules and ions in or out of a cell, across a
membrane, from lower concentration to higher against concentration
gradient.
• Nerve impulses. Why?
• Internal heat. Why?

3. How do we get this energy?
• Food is ingested (eaten)
• Food is digested (broken down into smaller molecules)
• Molecules absorbed (from intestines into the blood)
• Blood transports nutrients to the body
• Cells take up the nutrients as needed

4. What is the main nutrient for energy?
GLUCOSE
C6H12O6
How does our body make use of glucose?
A series of metabolic reactions (respiration) break down the glucose to
release its chemical energy

5. Aerobic Respiration
• By combining glucose with oxygen
Glucose + Oxygen = Carbon dioxide + Water
Balanced Equation (same number of elements on each side)
C6H12O6 + 6O2 = 6CO2 + 6H2O
Most of the steps of Aerobic Respiration takes place in mitochondria

6. Anaerobic Respiration
• An = without so Anaerobic = without air (oxygen)
• Yeast breaks glucose down to alcohol (beer)
Glucose = Alcohol + Carbon dioxide
C6H12O6 = 2C2H5OH + 2CO2
• The energy released is low per glucose molecule

7. Humans can respire Anaerobically
• If produces poor energy/glucose molecule, why?
• During vigorous exercise, muscles are using oxygen faster than it can
be supplied.
• For short periods
• Instead of alcohol and CO2, Lactic Acid is produced
• Glucose = Lactic Acid

8. Draw 3 columns
Aerobic
Respiration
Anaerobic
Respiration in
Yeast
Anaerobic
Respiration in
Humans

9. Mini Test