Chapter B3: Organisation and Digestive system

Question 1

What is tissue?

Answer 1

Formed by lots of similar cells working together to perform the same function e.g. muscle tissue, blood tissue.

Question 2

What is an organ?

Answer 2

Formed by lots of tissues working together e.g. heart lungs, brain.

Question 3

What is an organ system?

Answer 3

Lots of organs working together in a system e.g. circulatory system, digestive system, nervous system.

Question 4

What is the role of the small intestine?

Answer 4

To absorb nutrients and minerals from food.

Question 5

What does bile do?

Answer 5

It helps digest food.

Question 6

What is protein needed for?

Answer 6

They are needed for growth and repair of body tissues. They are made up of long chains of amino acids.

Question 7

What are carbohydrates needed for?

Answer 7

They are needed to give us energy. There are 3 types of carbohydrates; starch, sugar and fibre. Starch and sugar gives us energy and fibre prevents constipation. They are made up of simple sugars e.g. glucose.

Question 8

What are lipids needed for?

Answer 8

For energy and insulation. They’re made up of one molecule of glycerol and three attached fatty acids.

Question 9

What are enzymes?

Answer 9

A biological catalyst that speeds up the rate of reactions in living things. They can only catalyse (break down) one substrate molecule because they have a specific shape called the active site.

Question 10

What is a substrate molecule?

Answer 10

Where an enzyme acts. The substrate can bond with the enzyme active site and an enzyme substrate complex is formed.

Question 11

What is the active site?

Answer 11

A place where an enzyme binds to a protein or other substance during a reaction.

Question 12

What do protease enzymes do?

Answer 12

They break down proteins into amino acids.

Question 13

What do lipase enzymes do?

Answer 13

They break down fats/lipids into fatty acids and glycerol.

Question 14

What do carbohydrase enzymes do?

Answer 14

They break down carbohydrates into simple sugars.

Question 15

What is a denatured enzyme?

Answer 15

When the enzyme’s active site starts to change shape when the temperature goes above 40 degrees.

Question 16

What does plasma do in your body?

Answer 16

It transports dissolved substances around the body such as digested foods, gases, wastes and hormones. It also transports heat around the body.

Question 17

What do red blood cells do in the body?

Answer 17

They carry oxygen around the body as oxyhemoglobin.

Question 18

What do white blood cells do around the body?

Answer 18

They fight off diseases. For example, there are phagocytes which engulf/eat pathogens. And there are lymphocytes which create antibodies which kill pathogens.

Question 19

What do platelets do in the body?

Answer 19

They help to clot blood and they make a scab.

Question 20

What are arteries?

Answer 20

A tube where usually oxygenated blood is conveyed from the heart to all parts of the body.

Question 21

What are veins?

Answer 21

Tubes that carry usually de-oxygenated blood towards the heart.

Question 22

What are capillaries?

Answer 22

Tubes that link arteries and veins. They are only one cell thick.

Question 23

What is a stent?

Answer 23

A metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open.

Question 24

What is a pacemaker?

Answer 24

A medical device which uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart.

Question 25

What are statins?

Answer 25

They are a class of drugs often prescribed by doctors to help lower cholesterol levels in the blood.

Question 26

What are adaptations of the alveolus?

Answer 26

• alveoli have a very large surface area which provides maximum diffusion of gases.
• each alveolus is surrounded by a network of capillaries near the surface which maintains a steep concentration gradient, this means a faster rats of diffusion.
• the alveoli have thin moist walls which provides a short diffusion pathway for gases.