Zusammenfassung der Ressource
GCSE AQA Biology 2 Respiration & Exercise
- Respiration
- Involves reactions catalysed by enzymes
- All living things respire to
release energy from food
- Respiration: The process of
releasing energy from glucose,
which goes on in every cell
- Aerobic respiration
- Respiration using oxygen
- Most efficient way to
release energy from glucose
- Goes on all the time in plants & animals
- Most reactions happen
inside mitochondria
- Glucose + oxygen ---> carbon dioxide + water + ENERGY
- Energy released is used to...
- Build up larger molecules
from smaller ones
Anmerkungen:
- Like proteins from amino acids
- (In animals) allow muscles to contract
Anmerkungen:
- Which allows them to move about
- (In mammals & birds)
keep body temp. steady
- (In plants) build sugars, nitrates & other
nutrients into amino acids, then proteins
- Exercise increases heart rate
- Muscles made of muscle cells -
aerobically respire to contract muscles
- Increase in muscle activity requires more glucose
& oxygen to be supplied & extra carbon dioxide
to be removed - blood has to flow at faster rate
- Physical activity increases...
- Breathing rate & makes you breathe more
deeply - to meet demand for extra oxgen
- Speed at which heart pumps
- Glycogen is used during exercise
- Some glucose from food stored as glycogen
- Glycogen mainly stored in liver
- each muscle has own store
- During vigorous exercise, muscles use glucose
rapidly - some of the glycogen is converted back
to glucose (to provide more energy)
- Anaerobic respiration
- Respiration without oxygen
- Doesn't release as much energy as aerobic
- Incomplete breakdown of glucose
- Glucose ---> ENERGY + lactic acid
- Causes lactic acid build up in muscles
- painful & causes muscle fatigue
Anmerkungen:
- Muscle fatigue: when muscles get tired & stop contracting efficiently
- Can allow use of muscles for longer
- Leads to oxygen debt
- Have to 'repay' oxygen that
didn't reach muscles in time
- Have to breathe hard for a while
after stopping to get more oxgygen
into blood - blood flows through
muscles to remove lactic acid by
oxidising it to carbon dioxide & water
- While high levels of carbon
dioxide & lactic acid detected -
pulse & breathing rate stay high