Topic 2 - Organisation

Question 1

What is a tissue?

Answer 1

A group of similar cells that work together to carry out a particular function.

Question 2

Explain what is meant by the term ‘organ system’

Answer 2

A group of organs working together to perform a particular function e.g. Digestive system

Question 3

Name 3 types of tissue

Answer 3

• Muscular tissue, which contracts to move whatever it’s attached to
• Glandular tissue, which makes and secretes chemicals like enzymes and hormones
• Epithelial tissue, which covers some parts of the body

Question 4

Why can enzymes be described as biological catalysts?

Answer 4

They help speed up useful chemical reactions in the body and reduce the need for high temperatures.

Question 5

Why do enzymes only usually catalyze one reaction?

Answer 5

In order for the enzyme to work, the substrate has to fit into the active site. If the substrate doesn’t match the active site, the reaction won’t be catalyzed.

Question 6

What does it mean when an enzyme has been ‘denatured’?

Answer 6

When the shape of an enzyme’s active site has been changed, so the substrate won’t fit in anymore. This can be caused by either a high temperature or a pH level that is too high or low of it’s optimum.

Question 7

Describe how you could investigate the effect of pH on the rate of amylase activity (6)

Answer 7

• Put a drop of iodine solution into every well of a spotting tile
• Set up your Bunsen burner, put a tripod and gauze over it
• Place a beaker full of water on top and heat it until it is your desired starting temp., make sure the keep the temperature of water constant throughout the experiment
• Use a syringe to add 1cm^3 of amylase solution and 1cm^3 of buffer solution with a pH of 5 in a boiling tube. Put the tube into the beaker of water and wait for 5 minutes.
• Next use a different syringe to add 5 cm^3 of a starch solution to the boiling tube
• Immediately mix the contents of the boiling tube and start a stop watch
• Repeat.

Question 8

Name the formula for rate of reaction

Answer 8

Rate = 1000 ÷ Time

Question 9

List 3 places where amylase is made in the human body

Answer 9

• Salivary glands
• Pancreas
• The small intestine

Question 10

List 3 places where protease is made in the body

Answer 10

• The stomach (called pepsin)
• The pancreas
• The small intestine

Question 11

List 2 places where lipases are made in the body

Answer 11

• The pancreas
• The small intestine

Question 12

Name the roles of amylase, protease, and lipase

Answer 12

• Amylase breaks down carbohydrates into simple sugars
• Protease breaks down proteins into amino acids
• Lipase breaks down lipids into glycerol and fatty acids

Question 13

Where is bile stored?

Answer 13

Gall bladder

Question 14

Why does bile neutralise the stomach acid?

Answer 14

The hydrochloric acid in the stomach makes the pH too acidic for enzymes to work properly. Bile is alkaline and neutralises the acid to make it alkaline. The enzymes work best under alkaline conditions.

Question 15

Name the solution that you would use to test for the presence of lipids in a food sample

Answer 15

Sudan III stain solution

Question 16

Name the solution for testing sugars in a food sample

Answer 16

Benedict’s solution

Question 17

Name to solution for testing starch in a food sample

Answer 17

Iodine solution

Question 18

Name to solution for testing proteins in a food sample

Answer 18

Biuret solution

Question 19

What are the colour changes in all 4 solutions?

Answer 19

• Benedict’s: From blue to either green, yellow or red depending on how much sugar is in the sample
• Iodine: Brown/Orange to Blue/Black
• Biuret: Blue to Purple
• Sudan III: clear to a separate red top layer

Question 20

Name the tubes that split off the trachea.

Answer 20

Bronchi (sing. term is bronchus)

Question 21

Explain the role that alveoli play in gas exchange

Answer 21

Oxygen diffuses out of the alveolus (high concentration) into the blood (low concentration). Carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out.

Question 22

Explain why the circulatory system in humans is described as a ‘double circulatory system’

Answer 22

Two circuits joined together

Question 23

Why does the heart have valves?

Answer 23

Makes sure that blood flows in the right direction - prevents it from flowing backwards

Question 24

Name the 4 chambers of the heart

Answer 24

• Right Atrium
• Left Atrium
• Right Ventricle
• Left Ventricle

Question 25

How is the resting heart rate controlled in a healthy heart?

Answer 25

It is controlled by a group of cells in the right atrium wall that act as a pacemaker. They produce a small electric impulse which spreads the surrounding muscle cells, causing them to contract.

Question 26

How are arteries adapted to carry blood away from the heart?

Answer 26

- Strong and elastic walls to withstand high blood pressure

Question 27

How are capillaries adapted to efficiently exchange materials at the tissue?

Answer 27

- Thin wall: only one cell thick - Very small lumen

Question 28

How are veins adapted to carry blood to the heart?

Answer 28

- Thinner walls than arteries due to a lower blood pressure - Bigger lumen to help blood flow despite low pressure - Valves to keep blood flowing in the right direction

Question 29

Why do red blood cells not have a nucleus?

Answer 29

Allows more room to carry oxygen

Question 30

Give 4 examples of cells in your blood and their roles.

Answer 30

- Red blood cells - carries oxygen - White blood cells - defend against infections / pathogens - Platelets - Help blood clots - Plasma - Liquid that carries everything in the blood

Question 31

Give 2 advantages and disadvantages of statins.

Answer 31

Advantages: - Reduces the risk of strokes, CHD and heart attacks - Can increase the amount of HDL (beneficial) cholesterol Disadvantages: - Long-term and have to be taken regularly - Negative side effects such as kidney failure

Question 32

Give 2 examples of methods of preventing cholesterol buildup in the arteries

Answer 32

- Stents: Tubes that are inserted in the arteries and keep them open to make sure blood passes through. - Statins: Drugs that can reduce the amount of 'bad' cholesterol present by slowing down the rate of fatty deposits forming.

Question 33

Define Coronary Heart Disease (CHD).

Answer 33

CHD is when the Coronary arteries are blocked by layers of fatty material building up. The lack of oxygen in the heart muscle causes heart attacks.

Question 34

What is the difference between biological and mechanical replacement heart valves?

Answer 34

Biological heart valves are taken from either humans or other mammals. Mechanical heart valves are man-made.

Question 35

What is meant by a non-communicable disease?

Answer 35

Diseases that cannot be spread between other organisms.

Question 36

Give an example of where different types of disease might interact in the body.

Answer 36

Pathogens can sometimes trigger allergic reactions such as skin rashes.

Question 37

What is meant by a risk factor of disease?

Answer 37

Things linked to an increase in the chance that a person will develop a certain disease during their lifetime.

Question 38

Which type of tumour is cancerous?

Answer 38

Malignant.

Question 39

What are tumours the result of?

Answer 39

Uncontrolled cell growth and division.

Question 40

List the tissues that make up a leaf.

Answer 40

- Epidermal tissue: Covers the plant - Palisade mesophyll tissue: Part of the leaf where most of photosynthesis occurs - Spongy mesophyll tissue: Part of the leaf which contains air spaces to allow gases to diffuse in and out of cells - Xylem and Phloem: Transport water, mineral ions and roots - Meristem tissue: Differentiates into different types of plant cells, allowing plants to grow.