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246 Cards in this Set
- Front
- Back
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What does the circulatory system do? [Respiration]
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It carries oxygen and glucose in your blood to all your body's cells so that energy can be released through aerobic respiration.
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Why does your heart relax?
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To fill with blood.
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Why does your heart contract?
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To squeeze the blood out into the arteries.
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When the heart contracts, the blood is put under pressure and is sent to the x
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Arteries
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What does blood pressure measure?
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The force of blood per unit area as it flies through the arteries.
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What is blood pressure measured in?
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Millimeters of mercury (mm Hg)
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What is systolic blood pressure?
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The pressure in the arteries when the blood contracts. (The first number)
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What is diastolic blood pressure?
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The pressure in the arteries when your heart relaxes. (The device number)
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What is normal blood pressure?
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120/80 mm Hg
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How can you reduce high blood pressure and maintain normal blood pressure?
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By doing regular aerobic exercise to strengthen the heart. A healthy diet can also help my keeping weight steady.
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What are factors that lead to high blood pressure? (5)
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Excess weight
High stress levels. Excess alcohol. A diet high in sat. fats, sugar or salt. Smoking. |
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How does excess weight lead to high blood pressure?
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The circulatory system has to work harder to pump blood around the body.
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How does high levels of saturated fat lead to high blood pressure?
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Saturated fat causes cholesterol to build up in the arteries forming plaques. The plaque bulges into the lumen, restricting or blocking blood flow through the arteries, increasing the risk of heart attack.
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How does smoking lead to high blood pressure?
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Carbon monoxide takes the place of oxygen in the haemoglobin do the oxygen-carrying capacity if the blood is greatly reduced. The pressure increases in older to compensate. Nicotine also increases the heart rate directly.
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Why is high blood pressure dangerous?
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The blood vessels can weaken and eventually burst. If a blood vessel bursts in the brain it may lead to brain damage or stroke. In the kidneys, it may lead to kidney damage.
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Why is low blood pressure dangerous?
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It means the blood doesn't circulate efficiently, so some parts of the body are deprived of glucose and oxygen. This can lead to dizziness, fainting and cold hands and feet. Pressure may drop in the kidneys leading to kidney failiure.
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What are the factors of heart disease? (3)
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High blood pressure
Smoking Too much salt or fat. |
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What can block arteries and cause heart attacks? (2)
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High-fat diets and high cholesterol.
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What makes heart attacks more likely? (2)
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Narrowed coronary arteries and thrombosis.
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What does 'being healthy' mean?
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being free from infection
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What does 'being fit' relate to?
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how much physical activity one is capable of doing and how quickly your body recovers
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What is a better way of measuring someone's fitness?
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Using a combination of tests.
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What is cardiovascular efficiency?
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How well your heart copes with aerobic excercise and how quickly it recovers afterwards.
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What is often used as a measure of general fitness?
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cardiovascular efficiency
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During exercise, a fitter person will have a x x x than a less fit person.
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lower heart rate
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A fit person's heart will return its * * *, * * than a less fit person's heart.
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normal resting rate, much quicker
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What does food supply living organisms with? (2)
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Energy and nutrients
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What 3 nutirients must a balanced diet contain? (3)
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Carbohydrates, Protein and Fats.
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What do carbohydrates and fats provide?
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energy!
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What is protein needed for?
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growth and repair of tissues
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If carbohydrates are in short supply, where else can energy be taken from?
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protein
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What are carbohydrates made of?
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Smiple sugars such as glucose
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What are fats made up of?
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Fatty acids and glycerol.
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What are proteins made up of?
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Amino acids!
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Carbohydrates are stored in the x as x or can be converted into x.
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Carbohydrates are stored in the LIVER as GLYCOGEN or can be converted into FATS.
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What nutrient cannot be stored?
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Protein
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Where are fats stored? (2)
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Under the skin and around organs as adipose tissue.
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What other substances do you need for your body (despite not providing energy)? (4)
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Minerals, Vitamins, FIbre and Water
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Why does the body need water? (2)
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to prevent dehydration and to help remove waste
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Why does the body need fibre? (2)
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to prevent constipation and maintain healthy bowels
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What factors cause diet to vary? (5)
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beliefs, allergies, sex, activity, age,
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What does the amount of energy you need depend on? (3)
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age, sex and activity levels
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How do you maintain a healthy body mass?
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by balancing the amount of energy you consume with the amount of energy you use up through daily activity
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Formula for calculating BMI:
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BMI = Mass (kg) / Height (m)²
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What happens if you consume too much food than you need?
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You become very overweight or obese.
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What are health problems associated with obesity? (4)
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arthritis, heart disease, type II diabetes and breast cancer
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Protein molecules are long chains of x x
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amino acids
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What are essential amino acids?
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Amino acids that can't be made by the body and therefore must be taken in by eating food.
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What are non-essential amino acids?
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Amino acids that can be made in your body.
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Why is it important for teenagers to eat a high-protein diet?
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Protein supplies the nutrients that enable you to grow.
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Where do first class proteins come from?
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From animals.
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Where do second class proteins come from?
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From plants.
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What do first class proteins contain?
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All the essential amino acids.
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Why is protein deficiency far more common in developing countries? (2)
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Due to overpopulation and limited investment in agricuture.
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In children, protein deficiency results in a disease called x
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kwashiorkor
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How does one calculate one's Estimated Average Requirement for protein (EAR)?
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EAR = 0.6 * Body mass (kg)
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What factors cause EAR for protein to vary?
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age, pregnancy and lactation
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Factors that can lead to under eating: (3)
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Poor self-image or self-esteem, desire for perfection
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Why is under eating very damaging to the body?
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The body does get the balance of energy and nutrients to function correctly. The reproduction system may be affected as well as damage to the bones.
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What is a disease?
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an abnormal condition that affects the body of an organism
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What are the causes of non-infectious diseases? (4)
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Poor diet, Organ malfunction, Genetic inheritance, Cell mutation.
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What is cancer?
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a non-infectious disease, in which cells in an abnormal and uncontrolled way to form lumps of cells called tumours.
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How can one reduce the likelihood of cancer? (4)
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don't smoke,
don't drink excess alcohol avoid getting sunburn eat a healthy diet |
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What is a benign tumour?
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A tumour that grows in one place
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If cells break off and secondary tumours start to grow in other parts of the body, what is the tumour described as?
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Malignant!
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What does a person's chance of survival depend on? (2)
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The type of cancer and how early it is diagnosed (before it becomes malignant)
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What are infectious diseases caused by?
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pathogens
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What are pathogens?
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microorganisms that attack and invade the body
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Give 4 examples of pathogens and the diseases they spread.
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Bacterium - cholera
Fungi - athlete's foot Protazoan - malaria Virus - flu |
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What is a vector?
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an organism that transmits a disease or parasite from one organism to another.
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How is malaria spread? (3 stages)
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1) Mosquito sucks human's blood with Malaria.
2) Malaria parasites mate and move from the gut to the saliviry glands of the mosquito. 3) The mosquito bites another person and passes on the parasites. |
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What helps Malaria to be controlled? (2)
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Knowledge of the disease's life cycle and the way in which vectors spread it.
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How can malaria be prevented? (3)
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Sleeping under mosquito nets
Using insect repellents Killing mosquitos with insecticide |
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State the 4 defences the body has to stop pathogens.
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skin, blood clots, respiratory system and stomach
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How does the body defend itself from pathogens:
skin? blood clots? respiratory system? stomach? |
skin - barrier agains microorganisms
blood clots - prevent microorganisms from entering blood stream respiratory system - lined with cells forming a mucus membrane to trap microorganisms stomach - produces hydrochloric acid, killing microorganisms in the food we eat. |
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If pathogens enter the body, x x x start fighting the invasion.
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white blood cells!
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How are symptoms of a disease caused?
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Pathogens damaging cells and producing toxins before the white blood cells can destroy them.
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What are the two ways white blood cells deal with pathogens?
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By engulfing and digesting them
By making antibodies to attack them. |
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How to antibodies work?
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They recognise markers on the surface of the pathogen and produce antibodies which lock onto the markers, killing the pathogens.
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What is the name given to the markers on the surface of a pathogen?
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Antigens!
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Why do white blood cells make antibodies specifically for a particular antigen?
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Every pathogen has unique antigens.
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Antibodies stay in the blood for years to x x x.
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fight future infections
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What is natural or active immunity?
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An active immunity acquired by experiencing and having recovered from a disease, leading to immunological memory.
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What does immunisation provide?
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Natural immunity from a disease without the individual becoming ill or being infected.
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What are the 3 steps of immunisation/vaccination?
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person injected with a WEAKENED/DEAD strain of the pathogen.
the antigens trigger the production of the necessary antibodies by the white blood cells the white blood cells remain in the blood and memory cells are produced |
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Why is the weakened strain of a pathogen harmless when injected?
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It cannot mulitply.
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How does immunisation/vaccination work?
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The white blood cells remain in the blood and memory cells are produced. Antibodies can be produced very quickly if the same pathogen is detected again.
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What's the difference between natural (active) immunity and passive immunity?
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Antibodies are PUT INTO an individual's body rather than the body producing them itself.
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Why is passive immunity sometimes used? (2)
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Because a very quick response is needed or a person has a weak immune system.
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Why does passive immunity only provide short-term protection?
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The white blood cells didn't produce the antibodies themselves and so after a while, there will be no antibodies in the blood.
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How are diseases caused by bacteria of fungi treated?
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using antibiotics!
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What do antibiotics do?
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The chemicals kill bacteria and fungi.
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How are diseases caused by viruses treated?
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using antiviral drugs!
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What happens if doctors over-prescribe antibiotics?
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All the bacteria in a population are killed off except the resistant ones, wich then spread. So, the antibiotic then becomes useless.
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What is needed to prevent more resistant bacterial infections?
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careful use of antibiotics
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Why do new drugs have to be tested?
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to make sure they are effective and safe before they are made available to the public
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How is a new drug be tested? (4)
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computer models - predict how it will affect cells based on already known information
animals - to see how it affects living organisms human tissue - to see how it affects human cells volunteers - the effects of the drug can then be compared to the effects of taking the placebo |
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In x x, volunteers don't know whether they have been given the new drug or the placebo - why?
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blind trial: to eliminate any psychological factors and provide a fair comparison
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In a x x x, neither the volunteers nor the doctors know which pill has been given - why?
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double blind trial: to eliminate all bias from the test
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how does a double blind trial eliminate all bias from a test?
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the doctors can't influence the volunteers' respons in any way
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What does one's nervous system allow one to do?
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react to one's surroundings and co-ordinate your behaviour.
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What two systems does the nervous system comprise of?
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the central nervous system and the peripheral nervous system
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What is the nervous system made up of? (2)
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receptors and neurones
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How do animals detect stimuli?
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Using receptors (specialised nerve endings that generate nerve impulses)
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What are stimuli?
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Changes in one's environment.
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What receptors do we have as humans? (9)
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Light receptors (in your eyes)
Sound receptors and balance receptors (in your ears) Taste receptors (on your tongue) Smell receptors (in your nose) Touch, pressure, pain and temperature receptors (in your skin) |
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What are neurones?
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specialially adapted cells that can carry a nerve impulse
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What are nerve impulses?
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electrical messages/signals that are carried along the axon.
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What are the 3 types of neurone?
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Sensory neurones, Relay neurones, Motor neurones
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Sensory neurones carry nerve impulses from where to your brain?
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receptors
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What do relay neurones make connections between?
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your spinal cord and neurones in your brain
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Where from and where to do motor neurones carry nerve impulses?
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from your brain to your muscles and glands
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How are neurones adapted to their job?
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an elongated shape - to make connections across the body
an insulating sheath - to speed up the impulse dentrites - to allow a single neurone to act on many muscle fibres |
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What is a synapse?
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a small gap between neurones
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What happens at a synapse? (2)
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When the electrical impulse reaches a synapse, a transmitter substance diffuses across the gap.
The transmitter binds with the molecules on the next neurone, causing an electrical impolite to be initiated. |
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Why do reflex actions bypass your brain?
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to give fast, AUTOMATIC responses to a stimulus, to help protect your body from harm.
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What are the stages of the Reflex Arc and Voluntary Action Pathway? (7)
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Stimulus
Rececptor Sensory Neurone Relay Neurone/Brain Motor Neurone Effector Response |
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What does the iris do?
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It controls the amount of light that enters the eye.
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What does the cornea do?
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It refracts rays of light onto the retina, so the rays converge to produce a clear image.
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What do light-sensitive receptor cells do?
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They cause nerve impulses to pass along sensory neurones in the optic nerve to the brain.
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What does the retina contain?
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light-sensitive receptors with some sensitive to colour
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What is the lens?
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A clear, flexible bag of fluid surrounded by circular ciliary muscles that change the shape of the lens.
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What attaches the lens to the ciliary muscles?
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Suspensory ligaments
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When recieving light rays from a near object… (3)
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The ciliary muscles contract
The suspensory ligaments relax The lens is short and fat to refract a lot of light |
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The ciliary muscles and suspensory ligaments always work in x ways
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opposite
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Name 3 common eye defects.
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long sight
short sight red-green colour blindness |
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What causes red-green colour blindness?
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The person lacks the specialised cells in the retina that detect red and green light.
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What causes long/short sight?
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the eyeball or lens being the wrong shape, so the light rays can't be accurately focused on the retina
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How can long or short sight be corrected? (3)
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By wearing contact lenses, glasses or laser surgery.
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What lens is needed for
short sight? long sight? |
short sight - concave
long sight - convex |
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How does laser eye surgery work? (3)
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By cuting a flap in the cornea, folding it back and using a laser to reshape it.
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What is binocular vision?
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Eyes are positioned close together on the front of the head.
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Name one disadvantage and one advantage of binocular vision.
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ADV. - can judge distance and speed accurately
DISADV. - each eye has a limited field of view |
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Where is binocular vision found?
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On humans and predators
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Where is monocular vision found?
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On prey
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What is monocular vision?
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Eyes are placed on either side of the head.
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Name one disadvantage and one advantage of monocular vision.
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ADV. - each eye has a wide field of view
DISADV. - little overlap makes it difficult to judge distance or speed |
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What are drugs?
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Drugs are chemicals that affect your mind or body.
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What drugs are legal?
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Those that are beneficial
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Why are some drugs only available on prescription?
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because they can have bad side effects if not used correctly
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What drugs are illegal?
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Most harmful drugs
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What affect do stimulants have?
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increase brain activity leading to a feeling of alertness and heightened perception
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What affect do depressants have?
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decrease brain activity which makes you feel tired and slows down your reactions
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What affect do painkillers have?
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reduce pain by blocking nerve impulses
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What affect do performance enhancing drugs have?
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increase muscle development
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What affect do hallucinogens have?
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disortion of vision and hearing
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What is common about stimulants and depressants?
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They both act on the synapses of the nervous system.
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What do stimulants do to synapses?
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They cause more neuro-transmitters to cross the synapse, speeding up the nervous impulses
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What do depressants do to synapses?
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They bind with receptor molecules in the membrane of the next neurone, blocking the transmission of the impulse, slowing everything down.
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What isdrug addiction?
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a state of psychologial of physcial need for a drug
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What happens when an addict's body becomes more used to a drug?
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It develops a tolerance to it and needs higher doses of the drug to get the same effects.
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What can happen when an addict stops taking a drug?
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They suffer from withdrawal symptoms, including:
- psychological problems, e.g. cravings - physical problems, e.g. sweating, shaking, nausea. |
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What is rehabilitation?
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The process by which an addict learns to live without the drug.
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Why does rehabilitation take a long time?
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because the mind and body both have to adapt
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Name 4 short-term effects of drinking alcohol
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lack of balance and muscle control
blurred vision and slurred speech poor judgement and drowsiness vasodilation |
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Name and explain 2 long-term effects of drinking alcohol
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-liver damage: due to the liver working very hard to -remove the toxic alcohol from the body
-brain damage: due to dehydration |
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How is liver damage caused?
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The products of the breakdown of alcohol are toxic.
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What is a common disease against heavy drinkers?
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Cirrhosis
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Why is there a blood alcohol limit for driving and what is it set at?
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Alcohol slows reaction times, increasing the chance of accidents. The limit is 80mg of alcohol per 100mg of blood.
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Name 3 diseases smoking can cause.
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mouth/throat/lung cancer
heart disease emphysema bronchitus |
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What does damage of the cilia mean for a smoker?
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The cilia can no longer remove mucus, tar and dirt from the lungs, which leads to a 'smoker's cough'.
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What can excess coughing cause?
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emphysema
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What does the smoke machine experiment show?
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That cigarettes contain tar.
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Why are smokers left feeling breathless?
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Carbon monoxide takes the place of oxygen in the haemoglobin do the oxygen-carrying capacity if the blood is greatly reduced. Heart rate must increase in order to compensate.
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What are two risks of immunisation?
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-An individual could have a bad reaction to that vaccine.
-No vaccination is 100% safe. |
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What are two benefits of immunisation?
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It protects against dieases which could kill or cause disability.
If everybody is vaccinated, the disease can't spread and eventuallt dies out. |
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Tar contains chemicals that are x and x
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irritants and carcinogens (cancer causing chemicals)
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x in cigarette smoke accumulate in living tissue
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particulates
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What does universal indicator show by turning red?
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acidic chemicals are present
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What is homeostasis?
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Your body's automatic control systems that maintain a constant internal environment to ensure cells can function efficiently.
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Your body x inputs and outputs to keep the internal environment steady.
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balance
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At what temperature do enzymes in your body work best?
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37º C
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What is used to maintain body temperature?
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Heat through respiration
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How does the body react when it is too hot?
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-blood vessels widen so blood flows closer to the skin and heat can be transferred to the environment
-sweating cools skin and water evaporates, drawing heat away |
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Why can getting too hot be very dangerous?
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If too much water is lost through sweating, the body becomes dehydrated. This can lead to heat stroke and even death.
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How does the body react when it is too cold?
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-Blood vessels constrict and the blood flow near the skin is reduced.
-Sweating stops and muscles start making tiny contractions (shivers). These contractions need energy from respiration and heat is released as a by product. |
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Why can getting too cold be very dangerous?
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Hypothermia causes unconsciousness and sometimes death.
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At what temperature does hypothermia start?
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35º C
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What organ monitors blood temperature?
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the brain
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What is vasodilation and vasoconstriction?
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The widening and narrowing of the blood vessels close to the skin's surface in order to increase or reduce heat loss by radiation.
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What does negative feedback involve?
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the automatic reversal of a change in condition, occuring frequently in homeostasis.
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If the temperature falls to low, the brain…
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the brain… switches on mechanisms to lower it.
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How does the brain monitor blood temperature?
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by using the nervous system and the hormonal system
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temperature control systems work to…
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keep a constant temperature
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vasodilation happens when…
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the body is too warm
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vasoconstriction happens when…
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the body is too cold
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What are hormones?
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chemical messages released by glands into the bloodstream, traveling around the body to their target organs
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What are the main glands which produce hormones in the body?
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Testes (male)
Ovary (female) Pancreas Thyroid gland Adrenal gland Pituitary gland |
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What does insulin do?
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It helps to regulate a person's blood sugar levels.
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How does insulin help to regulate a person's blood sugar levels?
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It converts excess glucose in the blood to glycogen in the liver.
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Where is insulin released from?
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the pancreas!
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What is Type I diabetes caused by?
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the pancreas failing to produce insulin.
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What does Type II diabetes affect?
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the cells that respond to insulin. They become desensitised to insulin and do not respond.
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What can Type I diabetes cause?
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blood sugars to raise fatally high resulting in a coma or death.
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How can a person with Type I diabetes control their blood sugar levels?
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They can inject insulin into the blood (before meals).
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What does a diabetic person do before injecting?
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test the amount of sugar in their blood with a prick test
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When is a larger dose of insulin required?
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when the food contains a lot of sugar
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How is type II diabetes treated?
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by diet
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What do plant hormones control? (2)
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-the growth of shoots and roots
-flowering and ripening of fruits |
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What is the group of plant hormones called that move through the plant in solution?
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auxins
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Auxins affect the plant's growth be responding to what? (2)
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gravity (geotropism)
light (phototropism) |
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Shoots grow… (2)
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-towards light (positive phototropism)
-against gravity (negative geotropism) |
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Roots grow…(2)
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-in the direction of gravity (positive geotropism)
-away from light (negative phototropism) |
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Why do plants grow towards light?
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It increases the plant's chance of survival as it can get light for photosynthesis.
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Describe experiment to show shoots grow towards light.
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Get two boxes and cut a hole in the side of each.
Put three cuttings into box a, and three cuttings into box b. Cover the tips of the cuttings in box b with foil. The cuttings in box a detect light and will grow towards it. The cuttings in box b cant't detect light to they grow straight up. |
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Where is auxin made?
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In the shoot tip.
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Why can auxin distribution be unequal?
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Because it its distribution is determined by light.
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What happens when light shines on a shoot? (3)
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-The hormones in direct sunlight are destroyed.
-The hormones on the shaded side continue to function, causing cells to elongate. -The shoot bends towards the light. |
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How can plant hormones be used in agriculture?
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to speed up or slow down plant growth
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What does rooting powder do?
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encourages the growth of roots in stem cuttings, so many plants can be obtained from one plant
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What does fruit-ripening hormone do?
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causes fruit to ripen - important for transportation and storage
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What does control of dormancy do?
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speeds up or slows down plant growth and bud development
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What do selective weedkillers do?
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target larger leaved weeds as they recieve a bigger dose of the hormones and die
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Differences between individuals of the same species are called x.
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Variataions
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Why do genetic variations occur?
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Individuals inherit different combinations of genes.
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What are gametes?
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specialised sex cells (egg and sperm)
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What characteristics are determined by genes? (2)
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Nose shape
Eye colour |
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What characteristics are determined by the environment? (2)
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Language
Scars |
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What characteristics are determined by a combination of genes and the environment? (3)
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Body mass
Intelligence Height |
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What are chromosomes?
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a coil of DNA, made up of genes
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Where are chromosomes found?
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in the nucleus of all body cells
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What is a gene?
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a small section of DNA, in a gene, that determines a particular characteristic
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How many pairs of chromosomes does a person have?
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23 pairs
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Gametes have x the number of chromosomes of normal body cells
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half
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Different versions of genes are called…
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alleles
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Alleles controlling characteristics can either be x or x.
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dominant or recessive
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x alleles control the development of a characteristic even if present on only one chromosome in a pair.
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dominant
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x alleles control the development of a characteristic only if a dominant allele isn't present.
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recessive
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If both chromosomes in a pair contain the same allele of a gene, the person is described as being x for that gene or condition.
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homozygous
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If the chromosomes in a pair contain different alleles, the person is x for that gene or condition.
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heterozygous
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When a characteristic is determined by just one pair of alleles, as with eye colour and tongue rolling, it's called…
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monohybrid inheritance
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What is the phenotype?
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the observable characteristics of a person as a result of a certain genotype
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What is the genotype?
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the letters to describe the genetic make up
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What is gender determined by in mammals?
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sex chromosomes
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What are the female sex chromomes?
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XX
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What are the male sex chromomes?
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XY
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What chromosomes do egg cells carry?
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X chromomes
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What chromosomes do sperm cells carry?
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half carry X and half carry Y.
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What does the sex of an individual depend on?
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Whether the egg is fertilised by an X- or Y-carrying sperm
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An egg fertilised by an X sperm will become a…
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girl
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An egg fertilised by a Y sperm will become a…
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boy
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Why are there approximate numbers of male and female offspring?
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The chances of an egg being fertilised by an X- or a Y-carrying sperm are equal.
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Some diseases are caused by a 'faulty' gene which means they can be…
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inherited
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Inherited disorders (such as cystic fibrosis) are mostly caused by…
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recessive faulty genes
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The gene for cystic fibrosis is recessive, which means that…
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offspring will only have the disorder if both genes are faulty
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Why is it important to know the likelihood that a child could have cystic fibrosis?
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Parents are more informed for thier decisions about whether to have a child
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