Respiraiton

Question 1

State 7 uses of energy in the body

Answer 1

Protein synthesis 
Muscle contractions 
Cell divisions
Active transport
Growth
Nervous transmission 
Maintaining a constant internal environment

Question 2

Define aerobic respiration

Answer 2

Chemical reactions in cells that use oxygen to break down molecules to release energy

Question 3

Aerobic respiration

Word equation

Answer 3

Glucose + oxygen —> carbon dioxide + water (+energy)

Question 4

Define anaerobic respiration

Answer 4

Chemical reactions in the cells that break down nutrients molecules to release energy without using oxygen

Question 5

Word equation for anaerobic in muscle cell

Answer 5

Glucose —> lactic acid + energy

Question 6

Which type produce more energy

Answer 6

Aerobic

Question 7

Which produce energy quicker

Answer 7

Anaerobic

Question 8

Aerobic properties

Answer 8

Respire in oxygen

Release more energy

Need ATP

Question 9

Anaerobic properties

Answer 9

Don’t require oxygen

Don’t release as much glucose

Release small amount of energy

Question 10

Anaerobic respiration in animals

Answer 10

Anaerobic respiration mainly takes place in muscle cells during vigorous exercise
When we exercise vigorously, our muscles have a higher demand for energy than when we are resting or exercising normally. Our bodies can only deliver so much oxygen to our muscle cells for aerobic respiration
In this instance, as much glucose as possible is broken down with oxygen, and some glucose is broken down without it, producing lactic acid instead
There is still energy stored within the bonds of lactic acid molecules that the cell could use; for this reason, less energy is released when glucose is broken down anaerobically

Question 11

Oxygen debt

Answer 11

Lactic acid builds up in muscle cells and lowers the pH of the cells (making them more acidic)
This could denature the enzymes in cells so it needs to be removed
Cells excrete lactic acid into the blood. When blood passes through the liver, lactic acid is taken up into liver cells where it is oxidised, producing carbon dioxide and water (Lactic acid reacts with oxygen - this is actually aerobic respiration with lactic acid as the nutrient molecule instead of glucose)
So the waste products of lactic acid oxidation are carbon dioxide and water
This is the reason we continue to breath heavily and our heart rate remains high even after finishing exercise - we need to transport the lactic acid from our muscles to the liver, and continue getting larger amounts of oxygen into the blood to oxidise the lactic acid
This is known as ‘repaying the oxygen debt’