Topic 2 Biolgy: Organisation

What are arteries and what is their function?

Arteries carry blood from the heart to the organs in the body.

How are arteries adapted for their function?

Blood runs a high pressure in arteries, therefore they have thick muscular walls to withstand the pressure.

Blood surges every time the heartbeats so they have elastic fibres which stretch when blood passes through and recoil through surges which keeps blood moving.

What are veins and what is their function?

Veins carry blood towards the heart.

How are veins adapted for their function?

They have thin walls as there is no need for thick walls as blood flows at a low pressure.

They have valves to prevent backflow so the blood flows in the right direction.

A bigger lumen to make sure blood flows despite being at low pressure.

What are capillaries and what is their function?

Capillaries are the site of exchange of substances like oxygen glucose and carbon dioxide.

How are capillaries adapted for their function?

They have very thin walls so that substances can diffuse rapidly between blood and body cells.

They have permeable walls which allow for diffusion.

Describe the effects of Ph on enzyme activity?

If the Ph is too acidic the enzyme/ active site denatures.

Optimum Ph is where the fastest rate of enzyme activity happens.

If Ph is too alkaline rate decreases enzyme denatured so the active site changes shape.

Describe the effects of temperature on enzyme activity?

As temperature increases so does enzyme activity.

When optimum temperature is met that is when enzyme activity is at a higher

After optimum temperature, the temperature becomes too hot which start breaking the bonds in the enzymes and making the active site change shape. If this happens too much the active site change shape completely so much so that the substrate can no longer bind and then we call the enzyme denatured.

Describe an example of lock and key

Enzyme: Protease

Substrate: Protein

Protein fits into protease’s active site.

Protease breaks down protein into amino acids.

Amino acids are released.

Describe the lock and key theory

The enzyme has a specific active site.

The substrate is complementary and fits.

The enzyme and substrate bind.

The reaction occurs and products are formed.

Products are released.