12. Respiration

Question 1

Respiration

Answer 1

Chemical reactions in cells that break down nutrient molecules to release energy.

Catalyzed by enzymes. Therefore respiration happens fastest at optimum temp bc afterwards enzymes denature.

Question 2

What is energy needed for in the body?

Answer 2

• Muscle contraction
• Protein synthesis (energy needed to link amino acids)
• Cell division and growth (energy needed for growth + repair)
• Active transport (energy needed bc against concentration gradient)
• Passage of nerve impulses (Energy is needed to conduct nerve impulses)
• Maintenance of a constant body temperature (optimum temp needed for enzymes)

Question 3

Aerobic respiration - Def + Formula

Answer 3

Chemical reactions in cells in which nutrient molecules are broken down using oxygen to release energy.

Glucose + Oxygen –> Carbon dioxide + Water

The reaction occurs in the mitochondria

Question 4

Mitochondria

Answer 4

(singular: mitochondrion) Sub-cellular structures that release energy for the cell by aerobic respiration.

Question 5

Aerobic respiration - Balanced chemical equation

Answer 5

C⁶H¹²O⁶ + 6O² → 6CO² + 6H²O

Question 6

Anaerobic respiration - Def + formula

Answer 6

Chemical reactions in cells in which nutrient molecules are broken down to release energy WITHOUT THE USE OF OXYGEN. Releases a lot less energy per glucose than in aerobic respiration.

Glucose –> Lactic acid

Occurs in muscle cells during vigorous exercise bc your cells can’t obtain enough oxygen to get the energy needed through aerobic respiration.

Question 7

Lactic acid

Answer 7

A by-product of anaerobic respiration in muscle cells.

Question 8

Anaerobic respiration in yeast

Answer 8

Glucose → Alcohol + Carbon dioxide

Anaerobic respiration is used in breadmaking and for making bioethanol for use as vehicle fuel.

Question 9

Balanced equation for anaerobic respiration in yeast

Answer 9

C⁶H¹²O⁶ → 2C²H⁵OH + 2CO²

Question 10

Breaking down lactic acid after anaerobic respiration.

Answer 10

Lactic acid is dangerous to the body and must be broken down. Your body takes several actions to remove the lactic acid.

1) Maintaining a higher heart rate for a time after stopping exercise. Causes lactic acid to be transported in the blood from the muscles to the liver.

2) Maintaining deeper and faster breathing for a time after stopping exercise. This provides the oxygen your liver needs to break down the lactic acid.

3) Aerobic respiration in the liver to break down the lactic acid into carbon dioxide and water.

Question 11

Oxygen debt

Answer 11

The amount of oxygen needed after vigorous exercise in order to break down the lactic acid produced by anaerobic respiration.