Biology

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  • Created by: Rachel
  • Created on: 27-05-13 18:48
Pathogens
Bacteria and viruses are the main types of pathogen.
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Bacteria
food poisoning, cholera, typhoid. whooping cough.
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viruses
Viruses can only reproduce inside host cells and they damage the cell when they do this. A virus can get inside a cell and, once there, take over and make hundreds of thousands of copies of itself.
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White blood cells
ingest pathogens and destroy them, produce antibodies to destroy particular pathogens,produce antitoxins that counteract the toxins released by pathogens.
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Antibodies
bind to pathogens and damage or destroy them,coat pathogens, clumping them together so that they are easily ingested by white blood cells called phagocytes
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Painkillers
Painkillers helps to relieve the symptoms of an infectious disease, but they do not kill the pathogens involved. For example, paracetamol, aspirin and morphine block nerve impulses from the painful part of the body, or block nerve impulses.
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Antibiotics
Antibiotics are substances that kill bacteria or stop their growth. They do not work against viruses because they live and reproduce inside cells. It is difficult to develop drugs that kill viruses without also damaging the body’s tissues.
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Cells
Most animal cells have a nucleus, cytoplasm and cell membrane. Light receptors have these cell components too.
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The human central nervous system
consists of the brain and spinal cord. When a receptor is stimulated it sends a signal along the nerve cells, also called neurones, to the brain. The brain then coordinates the response.
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Neurones
Neurones are nerve cells that carry information as tiny electrical signals. There are three different types of neurones, each with a slightly different functions: sensory neurones carry signals from receptors to the spinal cord and brain, relay
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Receptors
Receptors are groups of specialised cells that can detect changes in the environment called stimuli. Receptors are often located in the sense organs, such as the ear, eye and skin. Each organ has receptors sensitive to particular kinds of stimulus
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realay, motor
relay neurones carry messages from one part of the CNS to another, motor neurones carry signals from the CNS to effectors.
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Synapses
Where two neurones meet there is a tiny gap called a synapse. Signals cross this gap using chemicals. One neurone releases the chemical into the gap. The chemical diffuses across the gap and makes the next neurone transmit an electrical signal.
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Extremophiles
Extremophiles are organisms that live in very extreme environments and can survive conditions that would kill most other organisms.
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The carbon cycle
Removing carbon dioxide from the atmosphere,Returning carbon dioxide to the atmosphere, respiration Passing carbon from one organism to the next
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Chromosomes and genes
Chromosomes, found in the cell nucleus, contain many genes. A gene is a section of DNA, which carries coding for a particular protein. Different genes control the development of different characteristics of an organism. many genes needed
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Cuttings
The simplest way to clone a plant involves taking a cutting. A branch from the parent plant is cut off, its lower leaves removed and the stem planted in damp compost. Plant hormones are often used to encourage new roots to develop.
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Tissue culture
Another way of cloning plants is by tissue culture, which works not with cuttings but with tiny pieces from the parent plant. Sterile agar jelly with plant hormones and lots of nutrients is needed.This makes tissue culture more expensive and difficul
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Embryo transplants
A developing embryo is removed from a pregnant animal at an early stage, before the embryo’s cells have had time to become specialised. The cells are separated from one another. They are then grown for a while in a laboratory and then into the host
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Genetic modification
Genetic modification, or GM for short, is not the same as cloning. Although cloning techniques are used in genetic engineering, the two things should not be confused.
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Darwin’s theory
Charles Darwin was an English naturalist. He studied variation in plants and animals during a five-year voyage around the world in the 19th century. He explained his ideas about evolution in a book called On the Origin of Species.
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Lamarck’s theory
1.A characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used eventually disappears,2.Any feature of an organism that is improved through use is passed to its offspring.
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Natural selection
Individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed on to the next generation. Given enough time, a species will gradually evolve.
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Antibiotic-resistant bacteria
Microorganisms such as bacteria and viruses reproduce very rapidly. They can evolve in a relatively short time. One example is the bacterium E. coli. Its DNA can be damaged or changed when it reproduces. death
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Other cards in this set

Card 2

Front

Bacteria

Back

food poisoning, cholera, typhoid. whooping cough.

Card 3

Front

viruses

Back

Preview of the front of card 3

Card 4

Front

White blood cells

Back

Preview of the front of card 4

Card 5

Front

Antibodies

Back

Preview of the front of card 5
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