Biology GCSE (1) B7

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The Sun - provides geothermal energy helps keep the Earth's atmosphere warm AND provides light energy that green plants use to make food chemicalsLife energy is dependenton the sun. Only the green parts of plants absorb tiny amounts of light energy and use it forPHOTOSYNTHESIS. This produces carbohydrates, fats and proteins which are then used to make new plant cells and any food stores

Autotrophs: anything that makes it's own food for exampl lettuce. Heterotrophs:organisms that can't make their own food for example animals, bacteria or fungi.When ananimal eats a plant = the energy stored in the plant goes to the animal. The chemicals in waste material and dead plants/animals are also an energy store but these go to decomposers.

Pyramind of numbers = shows the number of organisms at each feeding level in an ecosystem. Pyramids of biomass = shows the mass of organisms at each feeding level

There is LESS biomass at each level in a food chain so there is less energy. The energy that is not passed on is uneaten parts, used for life processes, lost to surroundings and in waste products.Soil contains biomass - inorganic particles such as sand, silt and clay - air - water with dissolved mineral ions.

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Plants convert some of the glucose into chemicals (cellulose) needed for growth of plant cells, convert some into starch for storage and use some in respiration.Starch is insoluable and has little effect on the osmotic balance of cells, a higher concentration of glucose causes water to be drawn into cells so starch is better storage molecules than glucose.Energy from respiration is used to synthesise polymers such as STARCHAND CELLULOSE FROM GLUCOSE and AMINO ACIDS AND THEN PROTEINS FROM GLUCOSE AND NITRATES.

Plant roots absorb nitrates by active transport.The rate of photosynthesis varies due to:

  • Temperature
  • Carbon dioxide
  • Light Intensity
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Heterotophic Nutrition

Symbiotic/Mutualism: a relationship that benefits each other (corals and green algae)

Commensalism: a relationship that benefits one but doesn't harm the other (orchid attached to tree branch as orchid gets more light)

Parasitism: a relationship that benefits one but harms the other such as tapeworm in humans

Parasites have to be adapted for finding a host and for living in or on their host. For exampletapeworms have developed suckers to grip to the gut and a thick cuticle to resist enzymes. Malari parasites spread to new hosts by mosiquitoes and live in red blood cells so they are protected from the immune system and have different surface markers at different stages of their lives.

Parasites cause problems such as human disease and reduced food yields.

Sickle cell anaemia is caused by a faulty recessive allele that codes for haemoglobin. It causes the red blood cells to go out of shape and causes symptoms such as:

  • Severe pain
  • anaemia as damged cells can't be replaced fast enough
  • tiredness by shortage of oxygen
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New Technologies


Bacteria and fungi are grown on a large scale in fermentors we can also make:

  • Antibiotics
  • Quorn
  • Cheese
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New Technologies

New Technologies

When a scienist genetically modify an organism they alter its characteristics by transferring genes from another organism into its DNA.

1. They isolate the gene they want to transfer

2. They cut it out using an enzyme

3. They replicate and make copies of the gene

4. The trasfer the copies using a vector, virus or plasmid to transfer the genes

Some genetic modifications are modifiying micro-orgainisms to make drugs and hormones such as insulin or modyifiing crops to make them resistant to pests and diseases.

Scientists can use genetic testing to identify faulty alleles in adults/fetuses/IVF embryos. They use a gene probe which is a single strand of DNA with bases that will pair with the faulty allele

Take a blood sample - isolate white blood cells - extract DNA - heat gently - add gene probe- if faulty allele is present it sticks to gene probe - detect the gene probe using UV light

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Aerobic respiration



 respiration - in this oxygen is neededand energy is released from food chemicals such as glucose. The energy is then used for life processes including movement.

The energy released is first used to make ATP. The energy for the contraction of muscles comes from the breakdown of ATP. ATP is known as the "energy currency" of living things.

When you exercise your muscle cells respire faster to provide additional energy for movement so they need more:

  • Oxygen
  • Glucose
  • Carbon Dioxide REMOVAL
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Respiration - anareobically

Respiration - anareobically

This is the type of respiration that takes place when there is little oxygen, It is a way ofreleasing energy without oxygen.

glucose( lactic acid + Energy

The lactic acid builds up and makes then feel sore and tired.

Oxygen is needed to break down the lactic acid and release the energy from it. The amout of oxygen needed is called the oxygen debt. People also breathe heavily after exercise for this and to remove the carbon dioxide that is built up in their body

Anaerobic respiration is benefical for human beings and other organisms when there is little amounts of oxyge left.

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Human blood contains: Plasma - which contains water, dissolved substances such as glucose, humones and waste products.Red blood cells - to carry haemoglobin.White blood cells - to fight infection. Platelets - to help clot blood at a cut

There are markers called antigens on the surface of cells, if an antibody recognises an antigen it joins with it. The antibodies destroy cells in different way but with foreign antigen, the red blood cells clump together and block the blood vessels so the person dies

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Cirulation Continued

Heartarterysmaller arterycapillariessmall veinsviensheart. Humans have adouble circulatary system. They need it for TWO things:

  • to gain oxygen and lose carbon dioxide in the circulation throught the lungs
  • lose oxgen and gain waste carbon dioxide as it circulates around the rest of the body

( are important. They are one cell wall thick so blood pressure can force water and substances into the tissue. This form tissue fluid. Substance such as oxygen and carbon dioxide can diffuse between the blood and tissues

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Skeletal System

Humans have an internal skeletal of bone and cartilage for SUPPORT and MOVEMENT. Muscles can move bones at a joint only by contraction so they operate in antagonistic pairs. When one muscle contracts, the other relaxes.People injure themselves when exercising. Common injuries are:

  • Sprains - overstretched ligaments
  • Dislocations - bones out of joint
  • Torn ligaments
  • Torn Tendons

For a sprained ankle it will be swollen, red or bruised looking and its difficult to walk.

Rest - not moving the injured

Ice - slows blood flow and reduces pain

Compress - bandage to reduce swelling

Elevate - raise to reduce blood flow and drain fluid

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Skeletal System Continued

Physiotherapy can help get the joint and muscles moving again. Strengthening the muscle also reduces the risk of injuring the joint further.

Doctors/fitness trainers need to know these factors before diagonse:

  • symptoms
  • general health
  • medication
  • previous health problems/treatments
  • alcohol/tobacco consumption

This is to make sure the that the diagonse they give you is safe, that it has realistic targetsand it is a baseline for monitoring your progress. A treatment may need to bo changed because it isn't working and its causing side effects.

Doctors or trainers need to make sure that their way of monitoring their patient or clientproduces reliable data.

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is it just me or does half the text cut off?

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