Terms in this set (15)
State the uses of energy in the body of humans
-Passage of nerve impulses
-The maintenance of a constant body temperature
What does respiration involve
The action of enzymes in cells
The chemical reactions in cells that use oxygen to break down nutrient molecules to release energy.
Aerobic respiration word equation
Glucose + oxygen --> carbon dioxide + water
Aerobic respiration chemical equation
C6H12O6 + 6O2 --> 6CO2 + 6H2O
-It is in the mitochondria that aerobic respiration takes place.
-Generate ATP compound, which is used by the cell as the source of energy for driving other chemical reactions in the cytoplasm and nucleus.
Investigate the uptake of oxygen by respiring organisms, such as arthropods and germinating seeds
-Locust (invertebrate) or woodlice, placed in boiling tube. Organism protected from soda lime by cotton wool or wire gauze (soda lime is caustic)
-Drop of water introduced in the capillary tube by touching it against the liquid
-The capillary tube is rested against a ruler and the position of the water drop is noted.
-After 1 minute the new position of the water drop is recorded.
-Results: water drop moves towards the organism. If diameter of bore in capillary tube measured, volume of air taken in my organism can be calculated: volume=piexr^2xl (l=distance travelled by bubble)
-Interpretation: movement of water goes towards organism shows it is taking in air. Rates can be compared with a range of organisms -locust, woodlice, germinating seeds. Control = glass beads. (bubble may move as soda lime will absorb CO2 in air in boiling tube, but should be less than that of organism)
Investigate the effect of temperature on the rate of respiration of germinating seeds
-Put boiling tube (with soda lime, cotton wool or wire gauze, germinating seeds) with capillary tube coming out of (through bung), in beaker of water acting as a water bath with a thermometer.
-Use wheat grains or pea seeds that have been soaked for 24 hours and rinsed in 1% diluted domestic bleach for 5 minutes. These solutions will kill any bacteria or fungi on the surface of the seeds.
-Kill an equal quantity of soaked seeds by boiling them for 5 mins.
-Cool the boiled seeds in cold tap water; rinse them in bleach for 5 mins as before -these are the control
-Start with a water bath at about 20 degrees and allow the seeds to acclimatise to that temp for a few mins before taking any readings.
-The initial and final readings recorded on the capillary tube with a permanent marker. Distance travelled then measured with ruler.
-Repeat, introducing a new bubble each time, at a range of temps, remembering to allow time for the seeds to acclimatise to new conditions.
-Results: as temp increased, the rate of movement of water bubble towards seeds increased. Movement may stop at higher temps -rate of rest increases as enzymes more reactive at higher temps but may stop around 40 degrees due to denaturation.
The chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
Anaerobic word equation in muscles during vigorous exercise
glucose --> lactic acid
Anaerobic word equation in microorganism yeast
glucose --> alcohol + carbon dioxide
Anaerobic chemical equation for yeast
C6H12O6 --> 2C2H5OH + 2CO2
Anaerobic respiration releases.............. per glucose molecule than aerobic respiration
-Much less energy
-So much less efficient
(i) .......... builds up in muscles and blood during vigorous exercise causing (ii) ............
(i) Lactic acid
(ii) an oxygen debt
How is the oxygen debt removed during recovery?
-Aerobic respiration of lactic acid in the liver
-Continuation, after exercise, of fast heart rate to transport lactic acid in blood from muscles to liver
-Continuation, after exercise, of deeper breathing supplying oxygen for aerobic respiration of lactic acid.