B7 Revision

Briefly covers some of the topics in B7.

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  • Created by: Pennaling
  • Created on: 10-05-12 19:10


Respiration:- is not breathing!!

- It is the release of energy from glucose, it happens in all cells.

There are 2 types:- anerobic(respiration without oxygen) and aerobic(respiration with oxygen).

  • oxygen + glucose --> carbon dioxide + water

- this occurs in a specific organelle called a mitochondria.

Adinosin Tri-phosphate (ATP) - stores energy(in it's bonds) 

- Energy required for muscle contraction, released by breaking down ATP, then energy is released during respiration, used to convert ADP to ATP.

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Symbiosis:- 'living together'

- Parasitism:- the parasite benefits and the other is harmed (e.g. malaria plasmodium, tapeworm, blood flukes).

- Mutualism:- both benefit (e.g. an ox + ox peckers).

- Commensalism:- parasite benefits and the other is unharmed (e.g. sticky plant getting stuck to you and spreading it's seeds).

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Sickle Cell Anemia

Sickle Cell Anemia:-

- de-oxygenated haemoglobin of sickle cells stick together in a line.

- flexibility of cells is lost leading to clogging in capilleries

- causing extreme pain

- tissue death can occur as a result of reduced blood flow

Sickle Cell Anemia is caused by a faulty recessive gene.

- carriers of this gene have some resistance to malaria as they have some abnormal red blood cells (red blood cells being essential for the malaria life cycle, the malaria plasmid cannot invade sickle cells because of their shape).

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Blood + Blood Types

- Blood is a fluid made up of cells, platelets + plasma.


The gene for blood type has 3 alleles.

- I(o) is the allele for blood type O, I(a) is the allele for blood type A, I(b) is the allele for blood type B.

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The Circulatory System

Humans have a double circulatory system.

- the first one pumps de-oxygenated blood to the lungs to take oxygen in.

- the second one pumps oxygenated blood around the body.

1) The right atrium of the heart recieves de-oxygenated blood from the body (throught the vena cava).

2) The de-oxygenated blood moves through to the right ventricle, which pumps it to the lungs (via the pulmonary artery).

3) The left atrium recives oxygenated blood from the lungs (through the pulmonary vein).

4) The oxygenated blood then moves through to the left ventricle, which pumps it out round the whole body (via the aorta).

5) The left ventricle has a much thicker wall than the right ventricle. It needs more muscle because it has to pump blood around the whole body, whereas the right ventricle only had to pump it to the lungs.

6) The semi-lunar, tricuspid and bicuspid valves prevent the backflow of blood. Veins also have valves to prevent the backflow of blood.

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The Skeletal System

The skeleton:- supports the body + allows it to move, as well as protecting vital organs.

Joints allow the bones to move.

- The bones at a joint are held together by ligaments (they have tensile strength, but are also slightly elastic).

- The ends of bones are covered with a smooth layer of cartilage to stop the bones rubbing together (cartilage can be slightly compressed so it acts as a shock absorber).

- Membranes at some joints release oily synovial fluid to lubricate the joints, allowing them to move more easily.

Muscles pull on bones to move them.

- Muscles are attatched to bones by tendonsTendons can't stretch much so when a muscle contracts it pulls on the bone.

- Muscles can't push on bones to move a joint. This is why muscles usually come in pairs (called antagonistic pairs).

- The muscles move in opposite directions.

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