Respiration Flashcards
Aerobic respiration
The complete break down of glucose molecules using oxygen in order to give us energy.
Symbol equation for aerobic respiration
C₆H₁₂O₆ + 6O2 ——> 6CO₂ + 6H₂O
Word equation for aerobic respiration
Glucose + oxygen ——> carbon dioxide + water (+energy)
Where does aerobic respiration occur?
In the cytoplasm of cells in early stages, but releases energy into the mitochondria.
Anaerobic respiration
The incomplete breakdown of glucose molecules without oxygen to release energy.
Symbol equation for anaerobic respiration
C₆H₁₂O₆ ——> 2C₃H₆O₃
Word equation for anaerobic respiration
Glucose ——> lactic acid (+energy)
Where does anaerobic respiration take place?
Only the cytoplasm in cells
Oxygen debt
The amount of oxygen required remove lactic acid from the body, as it is a poison
How does oxygen remove lactic acid?
Takes it to the liver via blood and:
- oxidises it to carbon dioxide and water
- converted to glucose then glycogen
Metabolism
Term used for the rate of reactions in an organisms body, controlled by enzymes
Why do we need energy?
- growth
- cell division
- muscle contraction
- protein synthesis
- active transport
- nerve impulses
- maintaining body temperature
How are cells adapted for this?
Lots of mitochondria in order to respire more.
Mitochondria has a folded inner membrane to make a larger surface area for enzymes involved.
Muscle fatigue
Using muscle fibres too vigorously for a while stops them contracting efficiently, could be from a build up of lactic acid.
Anaerobic respiration in yeast
Forms ethanol and carbon dioxide, important for making bread and alcohol.
Metabolic reactions examples using glucose
Forming lipid molecules
Synthesis of proteins
Converting to glycogen
(In plants) converting to starch, amino acids and cellulose
What type of reaction is respiration?
Exothermic because it releases energy
Why is anaerobic respiration ‘incomplete breakdown’?
Because the glucose molecules haven’t been fully oxidised: not in the present of oxygen
Why would muscle cells respire anaerobically?
If it’s in certain conditions such as exercising where not enough oxygen is present
Why does anaerobic respiration release less energy?
The oxidation of glucose is incomplete
Fermentation
Anaerobic respiration in yeast to form ethanol and carbon dioxide
Why is fermentation needed for alcoholic drinks?
Makes ethanol, which is used in the drinks such as beer
Why is fermentation needed in bread making?
Makes CO2, as it produces bubbles so the bread rises
Effects of exercise on the body
Needs more energy for muscle contraction
Increase in aerobic respiration = needs more oxygen
Rate of breathing rises
Heart rate increases to pump oxygenated blood to muscles
If not enough O2, increased anaerobic respiration
So lactic acid builds up = muscles fatigued and stop contracting efficiently
Condition known as oxygen debt entered
Storage form of glucose in humans?
Glycogen
Forming a lipid
Using the molecules of glycerol (from converted fat molecules)
+ 3 fatty acid molecules
Forms cell membranes and stores energy
Metabolic reaction for protein
Break down of protein forms urea
