Organisation - questons 1-40

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What is the function of the digestive system?

Breaks down large insoluble food molecules into smaller soluble molecules which can be absorbed into the bloodstream at the small intestine.

In which organ does digestion begin?

Mouth

What is an enzyme?

Biological catalysts that speed up reactions without being used up in a reaction.

What are enzymes made up of?

Proteins made from amino acids.

What is the active site of an enzyme?

The specifically shaped part of an enzyme that fits with the substrate.

What does the carbohydrase enzyme do?

Breaks down carbohydrates into glucose.

What does the amylase enzyme do?

Breaks down starch into glucose.

What does the protease enzyme do?

Breaks down proteins into amino acids.

What is different about the pepsin enzyme?

It is a protease enzyme that can withstand low pH in the stomach due to hydrochloric acid.

What does the lipase enzyme do?

Breaks down lipids into fatty acids and glycerol.

Where are all the digestive enzymes made?

The small intestine and the pancreas.

Amylase is produced in which organ?

Salivary glands.

Where is bile made and stored?

Made in the liver and is stored in the gall bladder.

Why is bile alkaline?

To neutralise food from the stomach. A neutral pH will allow lipase to work better.

How does bile help digest fats?

It emulsifies lipids into smaller droplets, increasing the SA meaning lipase works more effectively.

Name 3 ways the small intestine is adapted for absorption of food molecules.

1. folded villi, increases SA.

2. villi are one cell thick, so short diffusion pathway.

3. villi have good blood supply, maintaining a steep concentration gradient.

What is the function of stomach acid?

To kill bacteria.

What reagent is used to test for sugar? Describe positive test.

Benedict’s reagent. Blue → brick red.

What reagent is used to test for protein? Describe positive test.

Biuret reagent. Blue → lilac.

What reagent is used to test for starch? Describe positive test.

Iodine. Orange/brown → blue/black.

What reagent is used to test for fat? Describe positive test.

Ethanol. Clear → cloudy.

Explain why the rate of enzyme action decreases at low temperature.

Enzyme has less kinetic energy, so less enzyme-substrate complexes are formed.

Explain why the rate of enzyme actions decreases at high temperatures.

High temperature denature active site, meaning substrate no longer fits

What is breathing?

The process of inhaling and exhaling.

What is respiration?

A chemical reaction that happens in the mitochondria, releasing energy.

How are the alveoli adapted to gas exchange?

Many alveoli, increasing SA. Alveoli and capillary walls are one cell thick, causing short diffusion pathway. Large capillary network maintains a steep concentration gradient.

Is the blood a tissue or an organ?

Tissue as it is made up of similar cells working together to perform a function.

How are the red blood cells adapted to their function?

Have no nucleus, creating more space to transport oxygen. Have a biconcave shape increasing the SA. Contain a pigment called haemoglobin which oxygen binds to.

What is the function of platelets?

They help blood to clot.

What is plasma?

The liquid part of the blood which transports carbon dioxide, hormones and the products of digestion.

How are arteries adapted to their function?

They transport blood at high pressure. To do this, they have a thick layer of muscle and elastic tissue.

How are veins adapted to their function?

Transport blood at lower pressure , they have a thinner layer of muscle and elastic tissue, they have valves.

What is the function of the valves?

Prevent the backflow of blood.

How are capillaries adapted to their function?

Substances in the blood diffuse into cells through the capillaries, they are one cell thick, so their is a short distance.

Label A-H

A= vena cava

B= pulmonary artery

C= aorta

D= pulmonary vein

E= right atrium

F= left atrium

G= right ventricle

H= left ventricle

Describe the movement of blood in the right side of the heart.

Deoxygenated blood enters the vena cava, it goes into the right atrium, through the valve and into the right ventricle. The cardiac tissue contracts, causing blood to be pumped through the pulmonary artery, where blood is taken to the lungs.

Describe the movement of blood in the left side of the heart.

Oxygenated blood enters the pulmonary vein, into the left atrium, through the valve and into the left ventricle. The cardiac tissue is thicker on the left, blood is pumped with greater force out of the aorta to the rest of the body.

What does the term ‘double circulatory system’ mean?

The right side of the heart pumps blood to the lungs, the left side of the heart pumps blood to the rest of the body.

What are pacemaker cells and where are they found?

These cells control heart rate, found in the right atrium.

What is a non - communicable disease?

A disease that is not caused by a pathogen and cannot be passed from person to person.