Biology test b1 2010 revision

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Circulatory system- carries oxygen around your blood, to all your cells releasing energy through aerobic respiration.


- it relaxes and fills with blood

- Contracts to squeeze blood into arteries.

Blood is always under pressure so that it reaches all the cells.

Blood pressure is measures in mmhg (millimetres of mercury).

2 measurements of blood pressure are:

-Systolic- pressure in arteries when heart contracts

- Diastolic- pressure in arteries when heart relaxes

Normal blood pressure is around 120/80 mmhg this differs with age and lifestyle.

Aerobic exercise and a healthy diet can help maintain a normal blood pressure.

Factors which can increase blood pressure are:-

-excess weight, high stress levels, smoking, excess alcohol, diet high in salt and a diet high in saturated fat and sugar.

Having prolonged high blood pressure can weaken blood vessels (which can cause them to burst) this can lead to a stroke.

Low blood pressure deprives cells of glucose which can cause:-

- Dizziness, fainting, and cold fingers ad toes.

A normal pulse rate for adults is between 60- 100 beats per minute.

During exercise your breathing rate and pulse rate increase in order to: - - deliver glucose and oxygen to cells more quickly,

Remove carbon dioxide more quickly.

Being healthy means being free from infection.

Being fit relates to how much physical activity you’re capable of doing and how quickly you recover.

Recovery rate is how quickly your pulse rate takes to return to normal after exercise.

Cardiovascular efficiency- how well your heart copes with aerobic exercise and how quickly it recovers afterwards.

Aerobic respiration- the release of energy from glucose in the presence of oxygen. It takes place inside cells.

Glucose + oxygen = carbon dioxide + water, C6 H12 O6= 6CO2 + 6H2O

Anaerobic respiration- takes place with the absence of oxygen. Quickly releases a small amount of energy through the incomplete breakdown of glucose. Glucose= lactic acid

Aerobic respiration with oxygen

Anaerobic respiration without oxygen

Anaerobic respiration occurs when muscles are working to hard for the lungs and circulatory system to deliver enough oxygen to breakdown glucose.

Anaerobic respiration involves the incomplete breakdown of glucose. About a 20th less energy is released than in aerobic respiration.

Lactic acid is toxic to cells it’s produced through anaerobic respiration. It builds up and causes cramps ( fatigue in the muscles).

A balanced diet must contain all of these things:

-carbohydrates, fats, proteins, vitamins, minerals, fibre and water.

How much energy you need depends on your age, gender and levels of activity.

To maintain a healthy body mass you must balance your energy intake with the energy you consume.

Bmi ( body mass index) can be calculated using- mass kg/ height2 (m2)

Obesity can cause:-

- arthritis, heart disease, diabetes and breast cancer

Protein molecules are long strands of amino acids

Essential amino acids can’t be made in the body meaning they have to be taken in by food.

Non- essential amino acids can be made in your body.

Protein deficiency


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