Biology B1

What is the difference between healthy and fit?
Healthy means being free of any infections or diseases whereas being fit is a measure of how well you can perform physical tasks.
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When is blood pressure at its highest?
When it is its systolic pressure which is when the heart contracts.
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Name four factors that can increase blood pressure?
Smoking, overweight, consuming too much alcohol or being under stress for a long time.
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What happens if blood pressure is too high?
A blood vessel could burst which could lead to strokes, brain damage or kidney damage.
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How can high blood pressure be lowered?
By lifestyle changes, a balanced diet, regular exercise or even drugs.
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What problems can low blood pressure cause?
Poor circulation so tissues don't get all the food and oxygen that they need. this can lead to dizziness and fainting.
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Which two chemicals does cigarette smoke contain?
Carbon Monoxide and Nicotine.
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How does carbon monoxide increase blood pressure?
It combines with haemoglobin in the red blood cells which reduces the amount of oxygen they can carry. In order for the tissues to get all the oxygen they need heart rate has to increase so the heart contracts more frequently-increased blood pressure
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How does nicotine increase blood pressure?
It increases heart rate so the heart contracts more often which increases the blood pressure.
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How do saturated fats put you at risk of heart disease?
They cause a build up of cholesterol which if there is too much can build up in your arteries. it forms plaques in the artery wall which narrow the arteries. These plaques restrict blood flow which can lead to a heart attack.
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How do salt levels increase blood pressure?
Too much salt causes high blood pressure which increases the risk of damaging the arteries. This damage can encourage the build up of plaques which can lead to a heart attack.
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What happens when there is a thrombosis and how are they formed?
A thrombosis is a blood clot which restricts blood flow. if a thrombosis occurs in a narrow coronary artery blood flow to the heart might be blocked off so an area of the heart will be cut off from its oxygen supply leading to a heart attack.
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Name the five nutrients needed for the body and their functions?
Carbohydrates-provide energy; fats-provide energy, act as an energy store and provide insulation, proteins-growth and repair of tissues,provide energy in emergencies, vitamins and minerals-various functions, C prevents scurvy and iron is needed to...
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to make haemoglobin for healthy blood, water-prevents dehydration
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What are carbohydrates made up of and where are they stored?
Simple sugars like glucose, stored in the liver as glycogen or converted to fats.
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What are fats made up of and where are they stored?
fatty acids and glycerol, stored under the skin and around organs as adipose tissue
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What are proteins made from?
amino acids
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How does a balanced diet vary with age?
Teenagers and children need more protein for growth whereas older people need more calcium to protect against degenerative bone diseases like osteoporosis.
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How does a balanced diet depend on gender?
Females need more iron to replace the iron lost in the menstrual blood.
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How does a balanced diet vary with physical activity?
Active people need more protein to develop muscles and more carbohydrates for energy.
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What causes an allergy?
The enzyme needed to digest the food properly cannot be made.
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What are the three types of reasons people choose to have a different diet?
Religious (Hindu), Personal (Vegetarian/healthy), or Medical (intolerance or allergy).
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Name two reasons for people in developing countries having diets which are low in protein?
Overpopulation-there is not enough protein to go around everyone OR Money so there isnt enough money for agriculture so it is hard to produce enough protein rich food
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What is the formula for a persons Estimated Average Daily Requirement (EAR) of protein?
EAR (g) = 0.6 X Body Mass (kg)
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Why do pregnant OR breast-feeding women need extra protein?
To help their baby grow OR to produce milk.
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What is the formula for BMI?
BMI = body mass (kg) / height squared (m)
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Name the four types of pathogens?
Fungi - athletes foot, Bacteria - cholera , Viruses - flu, Protozoa (single celled organism) - dysentery
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Explain how malaria is spread?
It is caused by a protozoan, which is carried by mosquitoes which feed on human blood. the protozoan is a parasite which lives off another organsim (host/us). the mosquitoes are vectors - carry the diesase without getting it themselves.
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they pick up the malarial parasite when they feed on an infected animal. Every time the mosquito feeds on another animal it infects it by inserting the parasite into the animal's blood vessels.
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How can we target mosquitoes to reduce the spread of the infections? (3 points)
Areas of water where mozzies lay their eggs can be drained or sprayed with insecticides/fish can be introduced into the water to eat mosquito larvae/people can protect themselves with insecticides or mosquito nets.
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Name three ways white blood cells deal with pathogens?
Consuming them (engulf the foreign cells and digest them), Produce Antitoxins (counter the effect of any poisons) OR Producing Antibodies.
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How to antibodies work?
Each pathogen has unique molecules on the surface of the cell/antigens. If the white blood cells come across a foreign antigen they produce proteins called antibodies which lock onto and kill the invading cells.
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The antigens are then produced rapidly and low all around the body to kill all similar bacteria or viruses.
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What are memory cells?
Some white blood cells stay in the blood after the pathogen has been killed - memory cells. if the person is infected with the same pathogen again the cells will remember and immediately make antibodies to kill it - natural immunites.
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How does immunisation work?
Dead pathogens are injected into the body which carry harmless antigens which trigger an immune response. Memory cells will be created so if live pathogens of the same type appear antibodies will be able to kill them immediately.
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What is the difference between active and passive immunity?
Active immunity is where the immune system makes its own antibodies after being stimulated by a pathogen whereas passive immunity is where you use antibodies made by another organism temporarily such as mother to baby through breast milk.
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Name two benefits associated with immunisation?
Stops you from getting ill and if most people are immunised the disease won't be able to spread as easily.
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Name three negatives of immunisation?
Short term side effects - swelling after injection; can't have some vaccines if already ill; some think immunisation can cause other disorders.
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Name two reasons why some bacteria are naturally resistant to antibiotics?
Overprescribing and patients not finishing their course.
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What is a benign tumour?
A tumour which grows until their isn't anymore room. The cells stay where they are. Not normally dangerous.
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What is a malignant tumour?
A tumour which grows and can be spread to other sites in the body. These tumours are dangerous and can be fatal.
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Name the four stages of drug testing?
Computer Models stimulate a humans response, Human Tissue, and then Animal Testing, Human Testing in a Clinical Trial
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Explain the process of a clinical trial?
Two groups of patients, one group given the new drug, the other a placebo (a fake sugar pill), so the scientists can see the actual difference the drug makes - avoiding the placebo effect. Often neither the patient or scientist knowswhichhadwhichdrug
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Define addiction?
A physical need for something, without they get withdrawal symptoms.
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Define withdrawal symptoms?
For example caffeine symptoms include shaky hands or irritability.
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Explain tolerance?
The body gets used to something so you need a higher dose to give the same effect.
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Explain rehabilitation?
Where you can get help and support to try and overcome an addiction.
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What are depressants?
Alcohol, solvents and temazepam which decrease the activity of the brain, slowing down the responses of the nervous system, causing slow reactions and poor judgement of speed and distances
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What are stimulants?
Nicotine, ecstasy and caffeine which increase the brains activity, making you feel more alert and awake, used to treat depression.
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What are painkillers?
Aspirin and paracetamol which work by producing the number of painful stimuli at the nerve endings near an injury.
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What are performance enhancers?
Anabolic Steroids (testosterone) which are taken by athletes to help build muscle and allow them to train but they are banned by most sports organisations.
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What are hallucinogens?
LSD which distorts what is seen and heard by altering the pathways that the brain sends messages along.
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Which class of drugs are the most dangerous?
Class A
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Examples of Class A drugs? (4)
Heroin, LSD, Ecstasy and Cocaine
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Examples of Class B drugs? (2)
Cannabis and Amphetamines
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Examples of Class C drugs? (2)
Anabolic Steroids and Tranquilisers
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Suggest punishments for dealing/using class A and C drugs?
Class A - Lengthy Prison Sentence / Class C - A Warning / Dealing - Worse punishment than just using it yourself
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What is the main effect of consuming alcohol?
Reducing the activity of the nervous system. (Depressant) but helps people to socialise/feel less inhibited.
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Why is alcohol poisonous?
It is broken down by enzymes in the liver and some of the products are toxic. Too much drink over a long time can cause the death of liver cells forming scar tissue that stops the blood reaching the liver - cirrhosis......
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If the liver can't do its normal job of cleaning the blood, dangerous substances build up and damage the rest of the body. Alcohol also causes dehydration which can damage other body cells even brain cells.
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Name six effects of being drunk and why drink driving is banned?
Impaired judgement, poor balance, poor co-ordination, slurred speech, blurred vision and sleepiness so you aren't allowed to drive, fly planes or operate heavy machinery when drunk.
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How does smoking cause heart disease?
Carbon monoxide is produced when cigarettes are burnt. It reduces the oxygen carrying capacity of the blood. If the heart doesnt receive enough oxygen there can be a heart attack.
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How does smoking cause lung, throat, mouth and oesophageal cancer?
Tar from the smoke collects in the lungs. It is full of toxic chemicals (some carcinogens which cause cancer). Carcinoges make mutations in DNA more likely. So cell division can go out of control and make malignant tumours if mutations occur,
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How does smoking cause a smoker's cough and emphysema (severe loss of lung function)?
It damages cilia on the epithelial tissue lining the trachea, bronchi and bronchioles which encourages mucas to be produced. Excess mucas can't be cleared as cilia are damaged so it sticks to air passages-cough. Alsolungs losing elasicity causing emp
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How does smoking cause low birth weight babies?
Low oxygen in the blood (caused by carbon monoxide) in pregnant women deprives the foetus of oxygen leading to a small baby at birth.
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What does the cornea do?
Refracts light into the eye.
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What does the iris do?
Controls how much light enters the pupil (a hole in the middle).
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What does the lens do?
Refracts light and focuses it onto the retina.
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What is the retina and what does it do?
The retina is the light sensitive part and is covere
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What is the difference between rods and cones?
Rods can't see colour and are more sensitive in dim light, cones are the opposite.
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Why is red-green colour blindness caused?
A lack of certain specialised cone cells.
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What does the optic nerve do?
Carries impulses from the receptors to the brain.
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What is accomodation?
Because the lens is elastic the eye can focus by changing the shape of the lens.
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How do we see distant objects?
The ciliary muscle relaxes which allows the suspensory ligaments to pull tight. This pulls the lens into a less rounded shape so light is refracted less.
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How do we see near objects?
The ciliary muscle contracts which slackens the suspensory ligaments. The lens becomes more rounded so light is refracted more.
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What is being long sighted?
Being unable to focus on near objects.
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When does long sightedness occur?
When the lens is the wrong shape and doesn't bend light enough or the eyball is too short. The images of near objects are brought into focus behind the retina.
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How can you correct being long sighted?
Glasses or contact lenses with a convex lens.
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What is short sightedness?
People who are unable to focus on distant objects.
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When does short sightedness occur?
The lens is the wrong shape and bends the light too much or the eyeball is too long. The images of distant objects are brought into focus in front of the retina.
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How can short sightedness be corrected?
Glasses or contact lenses with a concave lens. Or corneal laser surgery.
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What is binocular vision? One positive and one negative of it?
Two eyes which work together (humans). Your brain compares the images of an object seen by each eye. The more similarities between the images the further away the object. Allows us to judge distances well but gives a narrow field of vision.
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What does the Central Nervous System consist of?
The brain and spinal cord.
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What three type of neurone is the nervous system made up of?
Sensory, motor and relay.
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What is a stimulus?
A change in your environment.
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How does the CNS co-ordinate information?
A receptor detects a stimulus and the sensory neurones carry this information to the CNS. The CNS sends information to an effector by a motor neurone. The effector then creates a response.
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The difference between the nervous system responses and reflex actions?
The nervous system uses electrical impulses whereas reflex actions are automatic.
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How do reflex actions work?
The brain isnt involved. It is a protective role. The sensory neurone connects to a relay neurone in the spinal cord which links to the right motor neurone which tells the muscle to move. No time is wasted thinking about the right response,
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What happens at the axon of a motor neurone cell?
The electrical impulse is passed along it.
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Why do neurones have branched endings or dendrites?
So they can connect with lots of other neurones.
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Why is there a sheath along the axon?
It acts as an electrical insulator which speeds up the electrical impulse.
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Why are motor neurone cells long?
To speed up the impulse - connecting neurones slows the impulse down so one long impulse is better than lots of short ones joined together.
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What is a synapse?
The connection between two neurones - a tiny gap.
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What happens at the synapse?
The electrical impulse triggers the release of transmitter chemicals which diffuse across the gap. The chemicals bind to receptor molecules in the membrane of the next neurone, starting a new electrical impulse.
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How do stimulant drugs affect the amount of transmitter chemical at synapses?
They increase the amount of transmitter chemicals so the frequency of impulses along neurone two is increased.
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What happens when depressant drugs are present at the synapse?
They bind with the receptor molecules on the membrane of the neurones which blocks the electrical imupulse. Overall it decreases brain activity.
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Which conditions in the body need to be kept steady (3) and why?
CO2 levels (respiration produces co2 which needs to go), water content (the water you gain and the water you lose must be balanced) and body temperature (need to lose excess body heat when hot but retain it when cold).
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What is negative feedback?
Changes in the environment trigger a response that counteract the changes. This means the internal environment tends to stay where the cells work best. This only works in certain limits sometimes it is not possible to counteract extreme circumstances
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What and where is your thermoregulatory centre?
Your personal thermostat in the brain.
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How does your thermoregulatory centre work?
It contains receptors which are sensitive to blood temp in the brain and receives impulses from the skin about skin temp. The brain responds to this info and brings changes in the bodys temperature using the nervous and hormonal systems
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Name three temperature control mechanisms for when you are too hot?
Flat hairs, lots of sweat and blood vessels widen (vasodilation).
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How does sweating cool you down?
When sweat evaporates it uses heat from the skin which transfers heat from your skin to the environment which cools you down.
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How does vasodilation cool you down?
Blood vessels close to the skins surface widen which allows more blood to flow near the surface so it can radiate more heat into the surroundings.
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What are the effects of being too hot?
You can get dehydrated and get heat stroke which can kill you.
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What happens in a heat stroke?
Sweating stops because you are so dehydrated and there is a big rise in body temp. ENzymes can't work properly and important reactions are disrupted. If you don't cool down you could collapse and die.
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Name four temperature control mechanisms for being too cold?
Hairs on end, very little sweat produced, vasoconstricion/constricted blood vessels and shivering.
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How do hairs standing on end warm you up?
They trap an insulating layer of air which helps keep you warm.
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Describe how vasoconstriction keeps you warm?
Blood vessels near the surface of the skin constrict so that less heat can be transferred from the blood to the surroundings.
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How does shivering keep you warm?
The movement generates heat in the muscles.
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What are the effects of being too cold?
Your body temperature can drop to dangerous levels if exposed to very low temperatures for a long time - hypothermia. You can die if you don't get help fast enough.
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Name one way insulin is glucose gets into the blood and two ways it is removed naturally?
Eating carbohydrates puts glucose into the blood from the gut. Respiration in cells and vigourous exercise removes glucose from the blood.
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What happens if blood glucose level is too high.
INSULIN IS ADDED. Insulin is released by pancreas so there is too much glucose but also insulin in the blood. Glucose is then removed by the liver because insulin makes the liver turn glucose into glycogen.
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What happens if blood glucose level is too low?
INSULIN IS NOT ADDED. Glucose is added to the blood by the liver as the liver can turn glycogen into glucose so blood glucose increased.
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How do hormones like insulin work?
They travel in the blood which can take a while to get them to where they are needed in the body.
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Does it take the body longer to respond to a hormone or nervous impulse?
Electrical impulses sent along the nerves travel much faster than hormones so it takes the body longer to respond to a hormone.
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What is diabetes?
A condition which affects your ability to be able to control blood sugar level.
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What is type 1 diabetes?
Where the pancreas produces little or no insulin so the person's blood glucose level can rise to a level that can kill them.
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How is type 1 diabetes controlled?
A carefully controlled diet alongside insulin therapy which involves injecting insulin into the blood several times a day to make sure that glucose is removed from the blood quickly once food has been digested. This stops the level of glucose in ....
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in the blood from getting too high and is very effective treatment. The amount of insulin needed depends on a person's diet and how active they are.
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What is type 2 diabetes?
Where a person becomes resistant to insulin and their body cells don't respond to the hormone properly. It cal also cause blood sugar level to rise to a dangerous level.
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How is type 2 diabetes controlled?
By limiting the intake of foods rich in simple carbohydrates and sugars which cause glucose levels to rise rapidly.
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What are auxins and what do they do?
Auxins are plant hormones which control growth at the tips of shoots and roots. They move through the plant in solution. (dissolved in water)
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Where are auxins produced and how do they help plants grow?
In the tips but diffuses backwards to stimulate the cell elongation process which occurs in the cells just behind the tips.
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Where do auxins promate and inhibit growth?
Promotes growth in the shoot but inhibits growth in the root.
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Explain shoots and how phototropism affects their growth?
Shoots are positively phototrophic so grow towards the light. When a shoot tip is exposed t olight it accumulates more auxin on the side in the shade. This makes the cells grow faster on the shaded side so the shoot bends towards the light.
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Explain shoots and how geotropism affects their growth?
Shoots are negatively geotrophic so grow away from gravity. When a shoot grows sideways gravity produces an uneven distribution of auxin in the tip with more auxin on the lower side. This causes the lower side to grow faster, bending the shoot upward
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Explain roots and how geotropism affects them?
Roots are positively geotrophic so grow towards gravity. A root growing sideways will have more auxin on its lower side but in a root the extra auxin inhibits growth so the cells on top elongate faster and the root bends downwards.
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Explain roots and how phototropism affects them?
Roots are negatively phototrophic so grow away from light. If a root is exposed to light more auxin accumulates on the shaded sight. The auxin inhibits cell elongation on the shaded side so the root bends downwards.
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How do selective weedkillers work?
They are developed from plant growth hormones which only affect broad leaved plants. They disrupt their normal growht patterns which kills them whilst leaving grass and crops untouched.
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How do growing cuttings with root powder work?
If rooting powder is added to a cutting it will produce roots rapidly and start growing as new plants. This enables growers to produce lots of clones of a good plant quickly.
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How can the ripening of fruit be controlled?
Plant hornones can delay the ripening of fruit while they are on the plant or travelling to the shops. This allows fruit to be picked while it is unripe and therefore firmer and less easily damaged. Ripening hormone is added and the fruitripensintime
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How can dormancy be controlled?
A homone called gibberellin breaks down dormancy and allows seeds to germinate. COmmercial growers can treat seeds with gibberellin to make them germinate at times when they wouldnt normally. It also helps to make all the seeds in 1 batch growtogethe
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What does the nucleus contain?
Your genetic material in the form of chromosomes. (chromosomes came in pairs).
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What do chromosomes contain/do?
They carry genes. Different genes control the development of different characteristics.
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What is an allele?
Different forms of the same gene.
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What are gametes?
Sperm and egg cells formed in the ovaries or testes.
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What is fertilisation?
When the sperm and the egg with 23 chromosomes each join to form a new cell with the full 46.
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What are the three sources of genetic variation?
Gamete formation, fertilisation and mutations
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What is a mutation?
A gene may mutate occasionally - it changes. This can create new characteristics increasing variation.
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What is being homozygous?
Having two alleles the same for that particular gene.
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What is being hetrozygous?
having two different alleles for that particular gene.
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What is your genotype?
Your genetic makeup - the alleles that you have for a particular gene.
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What is your phenotype?
The characteristics that your alleles produce.
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Which chromosomes cause male and female characteristics?
XY - Male / XX - Female
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When is blood pressure at its highest?

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Card 3

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Name four factors that can increase blood pressure?

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Card 4

Front

What happens if blood pressure is too high?

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Card 5

Front

How can high blood pressure be lowered?

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