Topic 4 - Bioenergetics - Respiration and Metabolism Flashcards
What is respiration?
- The process of transferring energy from the breakdown of glucose
- It occurs in every cell in your body continuously
What type of reaction is respiration?
Exothermic
Three ways organisms use the energy transferred by respiration?
- To build up larger molecules from smaller ones (e.g. proteins from amino acids)
- In animals it is used to allow the muscles to contract
- In mammals and birds the enrgy is used to keep their body temperature steady in colder surroundings
- In plants energy from respiration is transferred to move mineral ions from the soil into root hair cells
What is metabolism?
- All the chemical reactions in an organism
- The sum of all the reactions that happen in a cell or the body is called its metabolism
What is aerobic respiration?
- Aerobic respiration is respiration using oxygen
- It is the most efficient way to transfer energy from glucose
- Most of the reactions in aerobic respiration happen in mitochondria
Word equation for aerobic respiration?
Glucose + oxygen —> carbon dioxide + water
What is anaerobic respiration?
- Anaerobic respiration is used if there isn’t enough oxygen
- When you do vigorous exercise and your body can’t supply enough oxygen to your muscles, they start doing anaerobic respiration
- Anaerobic just means without oxygen - it is the incomplete breakdown of glucose, making lactic acid
Word equation for anaerobic respiration in muscle cells?
Glucose —> Lactic acid
Why is aerobic respiration better than anaerobic respiration?
- Anaerobic respiration doesn’t transfer as much energy as aerobic respiration
- This is because the glucose isn’t fully oxidised
Word equation for anaerobic respiration in plants and yeast cells?
Glucose —> Ethanol + Carbon Dioxide
What is anaerobic respiration in yeast cells called?
Fermentation
Why is fermentation by yeast good value
- It is used to make bread and alcoholic drinks
- The carbon dioxide from fermentation makes bread rise
- Fermentation produces alcohol for beer and wine making
How does excercise and aerobic respiration link?
- Muscles need energy from respiration to contract. When you exercise, your muscles contract more frequently than normal, so you need more energy. This energy comes from increased respiration
- The increase in respiration in your cells means you need to get more oxugen into them
- Your breathing rate increases to get more oxygen into the blood, and your heart rate increases to get this oxygenated blood around the body faster. This removes CO2 more quickly at the same time
How does excercise and anaerobic respiration link?
- When you do more vigorous exercise your body can’t supply oxygen to your muscles fast enough, so they start respiring anaerobically
- This causes lactic acid to build up in the muscles
- Long periods of exercise also cause muscle fatigue - the muscles get tired and then stop contracting efficiently
What is muscle fatigue?
- Muscle fatigue is when your muscle fibres become fatigues and stop contracting efficiently
- One cause of muscle fatigue is the build up of lactic acid
What is oxygen debt?
- After anaerobic respiration, you will have an oxygen debt
- This is the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells. Oxygen reacts with lactic acid to form CO2 and water
- This means you have to keep breathing for a while after you stop, to get more oxygen into the blood which ist transported to muscle cells
How does the liver get rid of lactic acid?
- The blood that enters your muscles transports the alctic acid to the liver
- In the liver, the lactic acid is converted back to glucose
