Biology-Ideas in Context

Biology Ideas in Context and B7 revision cards

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Respiration-Anaerobic and Aerobic

Respiration is NOT breathing in and out. Respiration happens in every cell of our body. It is the process of releasing energy from glucose. The energy released is used to do things like contract muscles, build up larger moelcules and maintain a steady body temperature.There are two types of respiration: ANAEROBIC and AEROBIC. AEROBIC respiration needs oxygen. ANAEROBIC doesn't use oxygen. Aerobic respiration happens when plenty of oxygen is available. More energy is released per molecule than in anaerobic respiration. Most of the time you're using aerobic respiration: it turns glucose from your food, and oxygen from your lungs into carbon dioxide and water, releasing lots of energy in the process.The word equation for respiration:

glucose + oxygen  -------> carbon dioxide + water (+energy released)

Energy released by respiration is used to make ATP. ATP is a small molecule that is easily transported around the cells. It carries the energy released during respiration to the places where energy is needed. Energy released from both anaerobic and aerobic respiration is used to produce ATP. ATP is the 'energy currency' of living things.

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How ATP is released

ATP is synthesised from another molecule called ADP, using the energy released by the breakdown of glucose during respiration.

ATP moves to the part of the cell that requires energy.

It's then broken down to ADP and this releases energy where it's needed.

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Blood and Blood Typing

Blood transports things around the body. If we lose a lot of blood it has to be replaced, which is where transfusions come in.

RED BLOOD CELLS: They transport oxygen from the lungs to all the cells in the body.

PLASMA: This is the liquid that carries anything about

PLATELETS: These are small fragments of cells that help the blood to clot at the site of a wound.

WHITE BLOOD CELLS: They help to fight infection by protecting your body against attack from microorganisms.

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Blood Type & Transfusions

If you're in an accident or having surgery, you may lose a lot of blood, which will need to be replaced by a blood transfusion. But you can't just use any old blood. People have different blood types or groups-A, B, O or AB. These letters refer to the type of antigens on the surface of a persons red blood cells.

Antigen: A substance that can trigger a response from a persons immune system.

Antibodies: Proteins produced by the immune system.

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Respiration in exercise

You respire more when you exercise. Muscles need ATP for respiration to contract. When you exercise, some of your muscles contract more frequently, so you need more energy. This energy comes from increased respiration. The increase in respiration means you get more oxygen and glucose in the cells. Your breathing rate increases to get more oxygen into the blood. Your heart rate increases to get glucose and oxygenated blood around the body to your muscles quicker, and to remove carbon dioxide at the same time.

HEART RATE: Pulse rate is a measure of heart rate. The normal resting heart range for an adult is 60-80 beats/min, but this will vary between individuals e.g. the fitter you are, the lower your resting heart rate.

BLOOD PRESSURE: When heart rate increases the pressure of blood also increases. The blood pressure is at it's highest when the heart contracts-this is systolic pressure. When the heart relaxes, the pressure is at its lowest-this is the diastolic pressure. Blood pressure is given as a measure of the systolic pressure over the diastolic pressure. The normal range is between 120/80 and 100/60.

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Anaerobic Respiration

''Anaerobic'' just means 'without oxygen'. It is NOT the best way to use glucose because it releases much less energy. The advantage is that at least you can keep on using your muscles. In anaerobic respiration the glucose is only partially broken down and lactic acid is also produced. The word equation for anaerobic respiration:

                           glucose --------> lactic acid (+energy released)

The lactic acid produced builds up in the muscles. After resorting to anaerobic respiration, when you stop exercising you'll have an oxygen debt. This is the amount of extra oxygen you need to break down all the lactic acid that's built up in your muscles. This means you have to keep breathing hard for a while after you stop exercising. The lactic acid is broken down in your muscles and in your liver, so your heart rate has to stay high to carry the lactic acid, and the extra oxygen required to break it down, around your body.

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The skeletal system

The job of a skeleton is to support the body and allow it to move, and to protect vital organs. Fish, amphibians, reptiles, birds and mammals are all vertebrates, they have a backbone and an internal skeleton. Insects have a skeleton on the outside. Joints allow the bones to move. The bones at a joint are held together by ligaments. Ligaments have tensile strength-you can pull them, and they don't snap easily. The end of the bones are covered with a smooth layer of cartilage to stop the bones rubbing together. Cartilage can be slightly compresed so it acts as a shock absorber, like a cushion between two bones. Membranes at some joints release oily synovial fluid to lubricate the joints, allowing them to move more easily. Different kinds of joints move in different ways.

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The Skeletal System

Bones are attatched to muscles by tendons, which also attach muscles to other muscles. Muscles move bones at a joint by contracting. Tendons can't stretch much so when a mucle contracts it pulls on the bone. Muscles can only pull on bones to move a joint-they cannot push. This is why muscles usually come in pairs, called antagonistic pairs. When one muscle in the pair contracts, the joint moves in one direction. When the other muscle contracts, it moves in the opposite direction.

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This is not the whole of B7, its just B7.5

And its not all of B7.5 either.

But the notes so far are so good, just hoped it was on the whole topic with practice questions! 

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