What is the importance of plants growing photoperiodically?
Plants sense when it is spring and germinate. Plants grow faster in better conditions. Plants also flower in daylight but not at night time. Only produce nectar in daytime so bees will actually come.
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Circadian rhythms in humans
Melatonin levels increase at 10pm for sleep.
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What did Louis Pasteur do?
Louis pasteur showed microorganisms were responsible for food going off. He said people should keep them away from food. Eg, pasteurisation (heating food before storing to kill bacteria).
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How do plants defend themselves?
Young Lupin leaves produce poisonous chemicals called alkaloids to keep pests away.
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Impact of attack of pathogens on food
Potato famine caused by blight killed over 1 million people in ireland 1846.
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What is exponential growth
Rapid growth
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What did Edward Jenner do
He made vaccines for cowpox by giving people small doses of the disease which made them immune.
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The process of immunisation
A weakened pathogen is injected into the body, lymphocyte with antibody that perfectly fits pathogen is activated, lymphocyte divides to produce identical copies
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Carried on
Some of the lymphocytes secrete large amounts of antibodies and destroy the pathogen and some remain in the blood as memory lymphocytes ready to respond if it comes back.
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Risks and Advantages of immunisation
Many children died at childbirth before vaccines, the child can become immune without suffering from it. Children can although get a mild form of the disease, can rarely get allergic reactions and can get swelling.
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Memory lymphocytes and secondary response
Memory lymphocytes stay in the blood incase there is a second attack. Can immediately respond.
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Monoclonal antibodies
Once a lymphocyte has divided a lot, it cannot anymore and becomes a B lymphocyte. To solve this problem it has been fused with a cancer cell which makes it divide more. This is called a Hybridoma. It can produce antibodies.
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How are monoclonal antibodies important
rMonoclonal antibodies are used to detect hCG in pregnant women's urine. hCG binds to monoclonal antibodies on stick and changes colour. Radioactive monoclonal antibodies can pinpoint cancer cells (by sticking to them). Monoclonal antibodies can be
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Carried on
used with drugs (for chemotheraphy eg) and this delivers the drugs. Less of the drug is needed and none is wasted in healthy parts of the body.
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What does cell metabolism do?
Cell metabolism leads to builds up of waste products in the blood such as co2 and urea.
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How is urea produced
From the breakdown of excess amino acids in the liver. It is removed by the kidneys.
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Structure of the urinary system.
Renal arteries and vein, kidneys, ureters, bladder, urethra,
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Kidney failure treatments
Dialysis - machine which removes waste products from blood, although expensive, painful and take up a lot of time. Kidney transplants although kidney could be rejected (antigens must be similar) and will still need lifelong medication.
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Structure of a nephron
glomerulus, bowman's capsule, convoluted tube, lube of henle, collecting duct.
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