B1.3

Question 1

Describe cellular respiration

Answer 1

• Universal chemical process
• continuous
• supplies ATP

Question 2

Is cellular respiration endothermic or exothermic

Answer 2

• Exothermic reaction

Question 3

What is respiration

Answer 3

• Respiration is a process of transferring energy from the breakdown of glucose
• It is controlled by enzymes takes
• rate of respiration is effected by both temperature and pH

Question 4

Describe the process of aerobic respiration

Answer 4

• Aerobic respiration happens when there is plenty of oxygen available in the mitochondria
• It’s the most efficient way to transfer energy from glucose
• Aerobic respiration produces lots of ATP-32 molecules per molecules of glucose
• it’s the respiration that we use the most

Question 5

Recall the equation for aerobic respiration (word and symbol)

Answer 5

• Glucose + oxygen → carbon dixode+water
• C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Question 6

describe the process of anaerobic respiration

Answer 6

• Anaerobic respiration happens when there is no oxygen available
• it takes place the cytoplasm in cells
• It’s a less efficient way to transfer energy from glucose
• just 2 molecules of ATP per molecule of glucose which is less than aerobic

Question 7

describe anaerobic respiration in animals

Answer 7

• vigorous exercise= body cant supply enough oxygen to your muscles for aerobic respiration
• Muscles have to start respiring anaerobically, heart rate and breathing rate increase
• glucose is only partially broken down and lactic acid is produced in anaerobic respiration
• lactic acid builds up in muscles=pain + muscle fatigue

Question 8

what is the equation for anaerobic respiration

Answer 8

glucose → lactic acid

Question 9

explain what is meant by oxygen debt

Answer 9

• after respiring anaerobically there is an oxygen debt
• extra oxygen is needed to break down the lactic acid that’s built up
• in order for aerobic respiration to take place
• that why we breath heavy after vigorous exercise

Question 10

describe anaerobic respiration in plants and fungi

Answer 10

• in conditions like waterlogged soil where there is littlie or no oxygen plants respire anaerobically
• fungi respire anaerobically too
• in yeast anaerobic respiration is known as fermentation

Question 11

recall the word and symbol equation for anaerobic respiration in plants and fungi

Answer 11

• Glucose → ethanol + carbon dioxide
• C₆H₁₂O₆ → 2C₂H₅OH(aq) + 2CO₂(g)

Question 12

explain the importance of sugars in the synthesis and breakdown of carbohydrates

Answer 12

1. monomers are simple sugars eg glucose
2. monomers can be joined to make polymers in long chains to make large complex carbohydrates eg starch which is too large to be absorbed by the walls digestive system
3. polymer molecules can be broken down back into simple sugar monomers which can be absorbed into the blood stream
4. when chemical bonds between monomers are broken by enzymes in the mouth and intestine

Question 13

explain the importance of amino acids in the synthesis and breakdown of proteins

Answer 13

1. proteins are polymers made up of long chains of monomers amino acids
2. they are too large to pass though the gut wall
3. they have to be broken down by enzymes in the stomach and small intestine back into monomers
4. then the amino acids are used for protein syntheses

Question 14

explain the importance of fatty acids and glycerol in the synthesis and breakdown of lipids

Answer 14

• lipids are esters of glycerol and three fatty acids
• they are not polymers because they don’t form a long chain of repeating units
• in the body lipids are broken down by enzymes in the small intestine
• they contain carbon hydrogen and oxygen