Chapter 9 - Summary Questions Flashcards
Write the word equation for aerobic respiration.
Glucose + oxygen —-> carbon dioxide + water.
Energy transferred to the environment
Where does aerobic respiration take place in cells?
In the mitochondria.
Why do muscles respire?
To transfer energy from glucose, to contract.
What is meant by ‘anaerobic’?
No oxygen is used.
In plant metabolism, glucose can be converted into larger molecules. Name two of them.
Two from: cellulose, starch, protein.
State two ways your breathing changes during exercise.
The rate increases, the depth of each breath increases.
Why do muscles store glycogen?
The stored glycogen can be converted to glucose (aerobic) respiration, so muscles have energy to contract.
a) What is fermentation?
b) How do humans benefit from fermentation in yeast cells?
a) anaerobic respiration (in yeast)
b) Carbon dioxide from fermentation is used to make bread (rise); fermentation produces ethanol for alcoholic drinks.
Why do blood vessels in the muscles dilate during exercise?
Allows increased supply of blood to muscle cells to supply more oxygen and glucose more quickly; removes carbon dioxide (more quickly).
What are the disadvantages of anaerobic respiration compared with aerobic respiration?
Less energy is transferred from glucose; lactic acid is produced, which causes muscle fatigue.
Explain what is meant by an oxygen debt.
The amount of oxygen needed to break down the lactic acid from anaerobic respiration.
What measurements would you take to test your level of fitness? Explain how each measurement indicates fitness.
Three measurements and three reasons from: measure breathing rate at rest - this is lower for a fitter person, indicating a larger lung capacity; heart rate at rest - this is lower for a fitter person, indicating that a larger volume of blood is pumped per beat; the increase of both of these during exercise - they are lower in a fitter person; the time taken to return to the resting breathing and heart rates is shorter in a fitter person.
a) Describe how urea is produced.
b) Explain why urea must be excreted and how this is achieved in humans.
a) Excess amino acids are carried to the liver; the amino group is removed in the process of deamination producing ammonia, which is toxic and is converted to urea.
b) Urea in large amounts would be toxic; it is transported by the blood to the kidneys where it is filtered from the blood and passes out in the urine.
