Unit 3

Question 1

Do bacteria and viruses reproduce quickly in the body

Answer 1

Yes

Question 2

Viruses reproduce inside cells. Describe what problem this can cause the cells

Answer 2

They can burst

Question 3

House flies have legs covered in tiny hairs, mouthparts that secrete saliva, wings, and produce faeces. How does the House fly transmit disease to humans. Include details of how the housefly can pick up pathogens and spread them to humans

Answer 3

The house fly uses its wings to fly to dirty places
Pathogen stick to the Flies body
Pathogen stick to hairs on the Flies legs
Pathogens are eaten by The Fly

The fly uses its wings to travel to a human food source
The fly secretes saliva on a human food source along with pathogens that the fly ate
The housefly deposit species on to a human food source
Humans then eat the contaminated food and taking the pathogen

Question 4

What type of drug can be used to control HIV

Answer 4

antiretroviral drugs

Question 5

What system in the body does HIV attack

Answer 5

The immune system

Question 6

What species of plant is often attacked by tmv

Answer 6

Tomato plants

Question 7

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

Answer 7

Purple or black spots develop on the Leaves. These leaves can then turn yellow and drop off.

Question 8

A gardener notices one of her rose plants with Rose black spot. Worried about the rest of her rose plants becoming infected. Why are the other rose plants in the garden at risk.

Answer 8

It can spread to other plants by water or wind

Question 9

Why is it necessary to vaccinate poultry

Answer 9

It prevents the spread of disease in poultry. It means to poultry won’t be contaminated with the salmonella bacteria so they are safe for humans.

Question 10

How is gonorrhea spread from person to person

Answer 10

Sexual contact

Question 11

State two symptoms of gonorrhea in women

Answer 11

Pain whilst urinating. Green discharge from vagina

Question 12

Name the antibiotic that used to treat people with gonorrhea

Answer 12

Penicillin

Question 13

Why is penicillin no longer effective against gonorrhea

Answer 13

Strains of the bacteria have become resistant to it

Question 14

Describe two ways the skin defend against the bodies pathogens

Answer 14

It acts as a barrier to stop pathogens getting in

It secretes antimicrobial substances which kill pathogens

Question 15

What is injected into the body during a vaccination

Answer 15

A small amount of dead or weakened pathogen

Question 16

How does vaccination work

Answer 16

It allows the body to be able to rapidly produce antibodies which defend against the pathogen

Question 17

If a large proportion of population is vaccinated against the pathogen, why will the spread of the pathogen be reduced?

Answer 17

The large proportion of the population who have been vaccinated against the pathogen when catch the disease. This means that the people who aren’t vaccinated are unlikely to catch the disease because they’re a few of people able to pass it on

Question 18

Why is a painkiller not able to cure bacterial infection

Answer 18

Because it’s unable to kill pathogens

Question 19

Suggest why very low doses are given at the start of clinical trials

Answer 19

In case the drug has harmful effects

Question 20

Why clinical trials carried out using a double blind method

Answer 20

It allows for the placebo effect and eliminates the fact that treatment may not be working even though the patient feels it is

Question 21

why is it important that scientists to peer review have no link to the original trials

Answer 21

To prevent them showing bias in the analysis of their results, and giving support to the results when in fact they werent valid

Question 22

Explain how monoclonal antibodies can be used to treat cancer

Answer 22

An anticancer drug is attached to the monoclonal antibody. The monoclonal antibody targets to cancer cells and deliver the substance without killing any normal body cells near the tumour.

Question 23

Give three uses of monoclonal antibodies

Answer 23

Pregnancy test, pectin pathogens, measuring hormone levels

Question 24

Describe the process of making monoclonal antibodies

Answer 24

1. Inject the antigen into the mouse
2. Extract the lymphocytes from the mouse and select the correct one
3. Combine this with a tumour cell to produce a hybridoma cell that reproduces rapidly
4. Allow this hybridoma cells are produced by mitosis
5. The antibodies are then collected and purified

Question 25

Name one insect that can cause damage to plants

Answer 25

Aphids

Question 26

List four signs that a plant has a disease

Answer 26

Discolouration
Stunted growth
Pictures of Decay
Malformed stems/ leaves

Question 27

How can a gardener identify disease that’s infected a plant

Answer 27

Laboratory
Testing kit
Gardening manual

Question 28

How does cellulose cell walls protect a plant from microorganisms

Answer 28

Cellulose acts of physical barrier to stop pathogens entering

Question 29

Give two types of chemical that plants can produce for Defence. For each type of chemical, explain how it helps the plant survive.

Answer 29

Antibacterial chemicals kill pathogens that could damage the plant
Poisons deter herbivores from eating the plant

Question 30

State two types of mechanical adaptations that help plants protect themselves

Answer 30

Thorns or hairs stop animals touching and eating the plant

Drooping and curling leaves knock microorganisms off

Question 31

A plant has stunted growth suggest what mineral it is deficient in

Answer 31

Nitrates

Question 32

Why does a nitrate deficiency cause stunted growth

Answer 32

Nitrates are needed to make protein which plants need to grow

Question 33

Name another mineral that plants require for healthy growth

Answer 33

Magnesium ions

Question 34

How does a deficiency in magnesium ions affect a plant

Answer 34

The plant will have a lack of chlorophyll and will have yellow leaves