B3 - Energy And Respiration Flashcards
Why do living organisms needs energy?
- to build large molecules from smaller ones
- for muscle contraction in animals
- to control body temperature in mammals and birds
How do plants and animals make large molecules from smaller ones?
- plants use sugars, nitrates and other nutrients to make amino acids which are joined together in long chain during protein synthesis.
- all living things need to make proteins ( e.g. Enzymes, structure )
- plants join sugar molecules together to make starch
- animals join sugar molecules together to make glycogen
- living organisms join fatty acids and glycerol together to make lipids
What is ATP?
The energy released from glucose during respiration is used to make molecules of ATP. It is used as the energy source for all processes in cells that need energy.
How is energy released from food molecules?
- respiration in cells released energy from glucose molecules.
- aerobic respiration uses oxygen. Happens continuously.
- anaerobic respiration is respiration without oxygen. Doesn’t happen continuously, only when cells aren’t getting enough oxygen.
What is the word and symbol reaction for respiration? Where does it take place?
Glucose + oxygen -> carbon dioxide + water
C6H12O6 + 6CO2 -> 6CO2 + 6H20
Takes place in the mitochondria.
How do you work out a respiratory quotient?
Volume CO2 produced / Volume O2 consumed
Why do you respire more during exercise?
Why does your heart and breathing rate go up?
During exercise your muscles need more energy, so your rate of respiration increases. You use more oxygen per minute and produce more carbon dioxide per minute. Your heart rate goes up to deliver more oxygen and glucose to your muscles. Your breathing rate goes up to remove the extra carbon dioxide more quickly.
What is metabolic rate?
As respiration uses oxygen, it’s rate of oxygen consumption indicates its metabolic rate. The metabolic rate is a measure of how quickly all the chemical reactions are going on in the organisms body.
Why do you sometimes anaerobically respire? Word equation?
When your start hard exercise, your heart rate does not go up quickly enough to supply the extra oxygen. To make up for this your muscle cells use anaerobic respiration as well as aerobic respiration. Glucose is incompletely broken down to lactic acid.
Glucose -> lactic acid (+ energy)
It cannot go on for long as lactic acid is toxic, causing pain and fatigue.
How is rate of respiration influenced by temperature and pH?
Temp - when the muscles are warmed , respiration is faster and can release more energy.
pH - the increased lactic acid from anaerobic respiration lowers the pH. This reduces enzyme activity, and so reduces the rate of respiration. Muscles get fatigued.
What happens when you stop exercising? What is oxygen debt?
- your heart rate stays high so the blood can quickly carry lactic acid to the liver
- you continue to pant to breathe in extra oxygen to deal with the lactic acid in the liver
The amount of oxygen needed to do this is called the oxygen debt.
