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How many different chemicals are there is cigarettes?
- about 4,000
- many are harmful
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What is the addictive substance in cigarettes?
Nicotine
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What does nicotine do to the body?
increases the heart rate
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What does the carbon monoxide in cigarettes do?
- Carbon monoxide reduces the oxygen-carrying capacity of the blood
- It combines with haemoglobin in red blood cells, preventing oxygen combining with the haemoglobin.
- This causes an increase in heart rate to compensate for the reduced amount of oxygen carried in the blood.
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What is fitness?
fitness is the ability to do physical activity
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What is health?
health is the amount of freedom from disease.
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name 6 ways to measure fitness?
- strength
- stamina – endurance or staying power
- flexibility
- agility – how easily someone moves
- speed
- cardiovascular efficiency – how well a person's circulatory system works
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What immediate effect does exercise have on the respiratory system?
- It causes an increase in the
- breathing rate
- tidal volume (the volume of air breathed in or out in one breath)
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What effect does regular exercise have on the respiratory system?
- an increase in the
- strength of the diaphragm and intercostal muscles
- vital capacity (volume of air that can be forcibly exhaled after inhaling fully)
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how many adult deaths are linked to smoking?
It’s estimated that nearly one in every five deaths (of adults aged over 35 in England) is connected to smoking
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name four harmful substances in cigarettes?
- tar
- nicotine
- carbon monoxide
- smoke
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What does tar from cigarettes do?
- Tar causes cancer of the lungs, mouth and throat
- It coats the inside of the lungs, including the alveoli, causing coughing
- It damages the alveoli, making it more difficult for gas exchange to happen
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What does the smoke from cigarettes do?
- Cells in the lining of the trachea, bronchi and bronchioles produce sticky mucus.
- This traps dirt and microbes.
- Cells with tiny hair-like parts, called cilia then move the mucus out of the lungs.
- However, hot smoke and tar from smoking damages the cilia.
- As a result of this, smokers cough to move the mucus and are more likely to get bronchitis.
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What are the cells with tiny hair-like parts in the lungs called?
cilia
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What does nicotine do?
- Nicotine is addictive.
- It causes a smoker to want more cigarettes.
- Nicotine also increases the heart rate and blood pressure, and makes blood vessels narrower than normal.
- This can lead to heart disease
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Name four organs of the digestive system, in order?
- oesophagus or gullet
- stomach
- small intestine
- large intestine
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describe four stages of digestion?
- food is digested in the mouth, stomach and small intestine
- digested food is absorbed into the bloodstream in the small intestine
- excess water is absorbed back into the body in the large intestine
- any undigested food passes out of the anus as faeces when we go to the toilet
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What does the liver do?
The liver produces bile, which helps the digestion of lipids (fats and oil).
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What does the pancreas do?
The pancreas produces biological catalysts called digestive enzymes which speed up the digestive reactions
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What are enzymes?
- Enzymes are not living things.
- They are just special proteins that can break large molecules into small molecules.
- Different types of enzymes can break down different nutrients
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what do amylase and other carbohydrase enzymes do?
amylase and other carbohydrase enzymes break down starch into sugar
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what does protease do?
protease enzymes break down proteins into amino acids
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what does lipase enzymes do?
lipase enzymes break down lipids (fats and oils) into fatty acids and glycerol
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How are carbohydrates digested?
- Carbohydrates are digested in the mouth, stomach and small intestine.
- Carbohydrase enzymes break down starch into sugars.
- The saliva in your mouth contains amylase, which is another starch digesting enzyme.
- If you chew a piece of bread for long enough, the starch it contains is digested to sugar, and it begins to taste sweet
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How are proteins digested?
- Proteins are digested in the stomach and small intestine.
- Protease enzymes break down proteins into amino acids.
- Digestion of proteins in the stomach is helped by stomach acid, which is strong hydrochloric acid.
- This also kills harmful microorganisms that may be in the food
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How are lipids (fats and oils) digested?
- Lipase enzymes break down fat into fatty acids and glycerol.
- Digestion of fat in the small intestine is helped by bile, made in the liver.
- Bile breaks the fat into small droplets that are easier for the lipase enzymes to work on.
- Bile is not an enzyme.
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What are not digested?
- Minerals, vitamins and water are already small enough to be absorbed by the body without being broken down, so they are not digested.
- Digestive enzymes cannot break down dietary fibre, which is why the body cannot absorb it
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What is the respiration?
- Respiration is a chemical reaction that happens in all living cells, including plant cells and animal cells.
- It is the way that energy is released from glucose so that all the other chemical processes needed for life can happen.
- Do not confuse respiration with breathing (which is properly called ventilation).
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What is aerobic respiration?
- Glucose and oxygen react together in cells to produce carbon dioxide and water and releases energy.
- The reaction is called aerobic respiration because oxygen from the air is needed for it to work.
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What is the word equation for aerobic respiration?
glucose + oxygen → carbon dioxide + water
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Where does most respiration happen?
The mitochondria, found in the cell cytoplasm, are where most respiration happens
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When does anaerobic respiration happen?
- During hard exercise, not enough oxygen can reach your muscle cells.
- So, aerobic respiration is replaced with anaerobic respiration.
- This does not need oxygen for it to happen
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What is lactic acid?
- Anaerobic respiration produces much less energy than aerobic respiration.
- The waste product, lactic acid, builds up in the muscles causing pain and tiredness
- This leads to cramp. Lactic acid is only broken down when you start aerobic respiration again.
- Anaerobic respiration happens in microorganisms such as bacteria because they need to release energy from glucose too
- Yeast, which are unicellular fungi, can carry out an anaerobic process called fermentation.
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What is the windpipe called?
trachea
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The windpipe divides into two...what?
bronchi
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What are the smaller tubes in each of the two bronchi called?
bronchioles
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what are at the end of the bronchioles?
- group of tiny air sacs
- these air sacs have bulges called alveoli to increase their surface area.
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Features of the alveoli?
- The alveoli are adapted to make gas exchange in lungs happen easily and efficiently.
- they give the lungs a really big surface area
- they have moist, thin walls (just one cell thick)
- they have a lot of tiny blood vessels called capillaries
- The gases move by diffusion from where they have a high concentration to where they have a low concentration
oxygen diffuses from the air in the alveoli into the blood carbon dioxide diffuses from the blood into the air in the alveoli
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