EQ'S

Question 1

Why are viruses not classed as living organisms?

Answer 1

They rely on a host cell to survive and reproduce

Question 2

State two ways to prevent the spread of a disease transmitted through the air.

Answer 2

Catch a sneeze/cough in a tissue

Isolate yourself

Question 3

Organisms such as bacteria that cause disease are known as what?

[1 mark]

Answer 3

Pathogens

Question 4

What is a disease called that can be transferred from one person to another?

[1 mark]

Answer 4

Communicable

Question 5

A person suffering from measles travels to work by train.
Explain how 10 days later, other people who were on the train may also be suffering from measles

[3 marks]

Answer 5

1. The infected person coughs or sneezes
2. The virus is transmitted through the air by droplets
3. The are transmitted from the infected person and inhaled by the healthy people, this infects them

Question 6

Measles can be fatal if there are complications.
What can be done to prevent someone from developing measles?

[1 mark]

Answer 6

They can be vaccinated

Question 7

What type of drugs can be used to control HIV

Answer 7

Antiretroviral drugs

Question 8

Outline one why a plant affected by TMV cannot grow properly

2 marks

Answer 8

1. The virus kills cells which causes discolouration in lleaves
2. This stunts growth as it means the plant cannot photosynthesise as well

Question 9

Describe the appearance of leaves with Rose black spot and state what happens to these leaves

[3 makrs]

Answer 9

1. Rose black spot causes black/purple spots to develop on leaves
2. This causes them to turn yellow
3. And drop off

Question 10

A plant has black rose spot.
Explain why it is important for the leaves with black rose spot to be destroyed after being removed

[1 mark]

Answer 10

If they are left, the fungus could be transferred to other living rose plants

Question 11

Explain why it is necessary to vaccinate poultry from Salmonella?

[2 marks]

Answer 11

1. It prevents the spread of the disease among poultry
2. This means that the food humans eat will not be contaminated with salmonella bacteria

Question 12

Name the antibiotic that was originally used to trat people infected with gonorrhoea

[1 mark]

Answer 12

Penicillin

Question 13

Why is penicillin no longer effective against bacterium that cause gonorrhoea?

[1 mark]

Answer 13

Strains of the gonorrhoea bacteria hve become resistant to it

Question 14

Describe how a person develops a natural immunity to a communicable disease like chicken pox

[6 marks]

Answer 14

1. The chicken pox pathogen has protein antigens on its surface
2. These antigens are detected by the immune system and stimulates lymphocyte white blood cells to produce and release antibodies which bind to antigens and cause them to clump together, the antibodies destroy the antigens
3. Then the lymphocytes remain in the blood as memory cells
4. Now, when the case of a secondary infection, the memory cells will be able to produce and release the specific antibodies MORE rapidly to prevent the pathogens from causing cell damage so symptoms of chicken pox do not develop

Question 15

Describe how a vaccine can stop a person from contracting chicken pox in the future

[3 marks]

Answer 15

1. A dead/inactive form of the chicken pox pathogen is injected into the body-the pathogen has protein antigens on it’s surface
2. The lymphocytes detect the antigens and this stimulates them to produce and release the specific antibodies to destroy the pathogens
3. Then the lymphocytes replicate by mitosis and they remain in the blood as memory cells
4. Now when the same pathogen re-enters the body, the lymphocytes can produce and release the specific antibody MORE rapidly and in larger quantities

Question 16

If the mumps pathogen enters the body of someone who has had the mumps vaccination, why would they be unlikely to become ill again with mumps?

[1 mark]

Answer 16

The memory white blood cells would be able to more rapidly produce and release antibodies and in larger quantities

think what do vaccines do in the end?

Question 17

A large population is vaccinated against a particular pathogen.
Suggest why the spread of the pathogen will be very much reduced

[2 marks]

Answer 17

1. People who are vaccinated against the disease will not catch the disease
2. Meaning people who aren’t vaccinated are unlikely to catch the disease as there are less people
   to spread it to

Question 18

A traveller wants to travel to a country where there has been a recent outbreak of a communicable disease
Give two reasons why it would be beneficial that they get a vaccination

[2 marks]

Answer 18

1. It will prevent the traveller from catching the disease when they travel
2. And so they will not spread the disease to other people when they go back to their home country

Question 19

Some countries insist that travellers are vaccinated before they allowed to enter their country

Suggest why

Answer 19

It prevents anyone from brining certain disease to the country

Question 20

Explain why painkillers would not be used to cure a bacterial infection?

[2 marks]

Answer 20

It is unable to kill pathogens
it only treats symptoms by relieving pain

Question 21

What is meant by antibiotic resistant bacteria?

[1 mark]

Answer 21

When an antibiotic is overused and so strains of the bacteria evolve and become resistant
So they are not killed by the antibiotic

Question 22

Suggest two reasons why peer reviewing is done is necessary at the end of a clinical trial?

[2 marks]

Answer 22

1. To help check that the work is valid
2. To prevent false claims

Question 23

Suggest why it is important that the scientists carrying out a peer review of clinical trials have no links to the people who carried out the original trials

[2 marks]

Answer 23

1. To prevent them showing bias in their analysis
2. To prevent them from supporting results that were not valid

Question 24

Explain how increased phagocytosis will help a patient

[2 marks]

Answer 24

The pathogens will be engulfed and ingested by the phagocytes and destroyed by the enzymes that the phagocyte produces more quickly
This means that there will be less damage to cells and so symptoms will not develop

Question 25

**Explain** how **monoclonal antibodies** and **fluorescent dye** can be used to see **pathogens** on a **microscope slide** | [**3 marks**]

Answer 25

**Bind** the **monoclonal antibodies** to the **fluoresenct dye** Then place the **fluorescent monoclonal** onto the **microscope slide** with the **pathogen** The **monoclonal antibodies** are **specific** to the **binding site** on the **protein antigens** on the **pathogen**, so they will **bind** to the **pathogen** and allow it to be seen **under** the **microscope**

Question 26

A **student** has some **chicken for lunch**. The **chicken contains protein** **Describe** how **proteins** are **digested** | [**3 marks**]

Answer 26

1. The **protein** molecules are taken to the **stomach** where the **protease** is **produced** 1. The **protease enzyme** will **break down** the **proteins** into **amino acids** 1. The **protease enzyme** works **optimally** in **acidic conditios**