Infection & Response

Question 1

How do fungi cause disease?

Answer 1

Fungi can be single=celled or have a body made of hyphae (thread-like structures).
These hyphae can grow and penetrate human skin & the surface of plants, causing diseases.
These hyphae can produce spores which then spread to other plants & animals.

Question 2

What are drugs tested for at each stage of testing?

Answer 2

Pre-clinical - efficacy & toxicity
Clinical - toxicity (healthy human volunteers) and dosage (patients)

Question 2

What painkiller does aspirin originate from?

Answer 2

Willow

“Aw”

Question 2

Define a monoclonal antibody.

Answer 2

Monoclonal antibodies are produced from lots of clones of a single B-lymphocyte, targeting one specific protein antigen.

Question 2

What painkiller does digitalis originate from?

Answer 2

Foxglove

Question 3

Give 3 ways that monoclonal antibodies can be used.

Answer 3

In labs, research and to treat diseases.

Question 3

How can monoclonal antibodies be used in labs?

Answer 3

Monoclonal antibodies can bind to hormones/chemicals in the blood to measure their levels or test for a pathogen.

Question 3

How can monoclonal antibodies be used in research?

Answer 3

Monoclonal antibody is bound to a fluorescent dye and made to bind to a specific molecule.
If the molecules are present, the monoclonal antibodies will attach to them and can be detected with the dye.

Question 4

How can monoclonal antibodies be used to treat diseases?

Answer 4

Monoclonal antibodies can be made to bind to antigens on the cell you want to target (e.g. tumour markers for cancerous cells) and an anti-cancer drug is attached to the monoclonal antibody.
The antibodies bind to the tumour markers. The drug kills the cancer cells, but not any normal cells near the tumour.

Question 5

Give 3 examples of what an anti-cancer drug could be.

Answer 5

• Radioactive substance
• Toxic drug
• Chemical which stops the cancer cells growing and dividing

Question 6

Explain why plants need magnesium, and what a lack of magnesium ions will cause.

Answer 6

To make chlorophyll for photosynthesis.
Plants without enough magnesium suffer from chlorosis (not enough chlorophyll is made) and have yellow leaves.

Question 7

Explain why plants need nitrates, and what a lack of nitrates will cause.

Answer 7

Nitrates are combined with glucose to make amino acids and then to make proteins for growth.
A lack of nitrates causes stunted growth.

Question 8

Give 3 plant physical defences.

Answer 8

• Leaves & stems have a waxy cuticle, which acts as a barrier agains the entry of pathogens
• Cells have cell walls made from cellulose, which act as a barrier againt pathogens that make it through the waxy cuticle
• Plants have layers of dead cells around their stems (e.g. bark) which act as a barrier to pathogens from entering

Question 9

Give 2 chemical defences.

Answer 9

• Antibacterial chemicals
• Poisons

Question 10

Give 3 plant mechanical defences.

Answer 10

• Thorns and hairs stops animals from touching & eating them
• Leaves that curl when something touches them, knocking off insects or moving away from things
• Plants that mimic other organisms (e.g. the passion flower has spots on its leaves that look like butterfly eggs)

Question 11

Name the 3 different types of plant defences.

Answer 11

Chemical, physical and mechanical.

Question 12

Name 3 (out of 6) signs that a plant has a disease.

Answer 12

• Patches of decay
• Discolouration
• Abnormal growths (e.g. lumps)
• Spots on the leaves
• Stunted growth
• Malformed stems/leaves

Question 13

Explain what happens to a plant when it is in an area of low light intensity for a prolonged period of time.

Answer 13

The chlorophyll in the leaves breaks down.
This means less glucose can be produced from photosynthesis.
This means fewer proteins can be produced by the combination of glucose with nitrate ions, so the plant’s growth is stunted.
It also means less energy is released from respiration.