Biology 6
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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What is a catalyst ?
A substance which increases the speed of a reaction without being changed or used up in the reaction
What are enzymes ?
Catalysts produced by living things
How do enzymes catalyse reactions ?
They have specific shapes which catalyse their specific substances
What two things are needed for enzymes?
The right temperature and pH
What temperature do enzymes in the human body usually work at ?
37 degrees Celsius
What do digestive enzymes do ?
Break large molecules into smaller molecules
What does Amylase do ?
Convert starch into sugars
What does protease do ?
Convert proteins into amino acids
What does lipase do ?
Convert lipids into glycerol and fatty acids
Why are large molecules broken down ?
Because smaller molecules can pass easily through the digestive system
What does bile do and where is it produced ?
It is produced in the liver and stored in the gall bladder. It neutralizes stomach acids whilst emulsifying fats
True or false - respiration is breathing in and out
False
What is respiration ?
Respiration is the process of releasing energy from glucose, which goes in every cell
What is aerobic respiration ?
Respiring using oxygen
Why is aerobic respiration better than anaerobic respiration ?
Aerobic respiration is more efficient, so more energy is made
Give four examples of what respiration releases energy for ?
• to build larger molecules from smaller molecules • allow muscles to contract • to keep body temperature steady (animals) • to build sugars, nitrates and other nutrients into amino acids (plants
Why does exercise make you breathe deeply ?
The muscle cells require oxygen for respiration. The energy produced is used to contract the muscles. By breathing deeper the demand for oxygen is met
Why does exercise increase the heart rate ?
To remove carbon dioxide from the muscle cell the blood has to flow faster, meaning the heart has to pump harder
What is stored glucose called ?
Glycogen
What is glycogen used for ?
When exercising the glycogen is converted back to glucose to supply enough energy
When does anaerobic respiration take place ?
When doing vigorous exercise and there isn’t enough oxygen
What is the by-product of anaerobic respiration ?
Lactic acid
What is bad about lactic acid ?
It builds up in the muscle which becomes painful. The muscles fatigue and stop contracting properly
What is an advantage of anaerobic respiration ?
You can use your muscles for longer