The release of energy from food when oxygen is available. The process is

controlled by enzymes

Make a table to show the advantages and disadvantages of using enzymes

Advantages Diadvantages

Work at low temperatures so cheap to run process

Denatured at high temperatures

Work at relatively low pressures

Sensitive to pH changes

Efficient catalystsMicrobes can be used to make enzymes

If produced by microbes need to provide these with food, oxygen and remove waste

Note if the enzymes are derived from microbes they may well have optimum temperatures different from mammals- higher than 37

Glucose + Oxygen Carbon dioxide + Water+ Energy

This process occurs in the Mitochondria

To build larger molecules from small ones

To enable muscle contraction in animals

To maintain a constant body temperature in mammals and birds

To build sugars, nitrates and other nutrients into amino acids and then proteins

Where does aerobic respiration take place?

What is needed for muscles to contract?

What are amino acids built up into?

This means keeping conditions inside the body constant

The conditions include

Temperature Blood glucose levels Water Urea Carbon dioxide

Carbon Dioxide- every cell in your body respires producing carbon dioxide, so it is vital that carbon dioxide it is removed.

If it remained dissolved in the cells it affects pH. It is acidic in solution and this

would affect the enzymes in the cells

Urea is made in the liver from the breakdown of amino acids not needed if you have eaten more protein than you need or when body tissues are worn out. Urea is poisonous so must be removed

The urea passes into the blood and filtered out of the blood by the kidneys

The urea is removed with water as urine along with excess water and salts

Urine is produced all the time by the kidneys and stored in the bladder

Water and ions enter your body when you eat or drink

Water is lost through breathing, sweating and in urine

If the water or ion content is wrong too much water may move in and out of your sells by osmosis

Carbon dioxide is the waste product of respiration

Some amino acids are not used they are converted to urea by the liver and excreted as urine by the kidneys

Water and ion content of cells must be controlled or too much or too little water may move in or out of cells

List the 2 main waste products of the body

State how each of them is formed and how they are removed from the body

The brain has a thermoregulatory centre to detect body temperature

Also the skin detects changes in temperature

Blood vessels near the surface of the skin DILATE (get wider) so more blood flows through the capillaries near the skins surface Heat is lost by RADIATION

Sweat glands produce more sweat . This evaporates on the skins surface The energy for evaporation comes from the skins surface so we cool down

Blood vessels near the surface of the skin constrict so less blood flowsthrough the skin capillaries

Less heat is radiated We shiver. Muscles contract quickly this

needs respiration Some of the energy produced from

respiration is released as heat

Which 2 parts of the body detect changes in body temperature?

Where is sweat produced?

Why does shivering make you feel warmer?