B2 - Detecting Disease

Question 1

Why is it important to work out what disease an organism has?

Answer 1

In order to treat it properly.

Question 2

What can observing an organism symptoms indicate?

Answer 2

What disease it has.

Question 3

What is a plant pathologist?

Answer 3

Expert in plant diseases.

Question 4

What might the symptoms of a high and a spotty rash show?

Answer 4

Chicken pox

Question 5

What do the symptoms of growths on roots, stem or branches indicate to a plant pathologist?

Answer 5

Crown gall disease

Question 6

How does a fever help the body fight infection?

Answer 6

By killing the pathogens or reducing the speed at which they can multiply.

Question 7

Why Do we need to use laboratory techniques to identify some diseases?

Answer 7

If the symptoms are uncommon or if they could indicate many different diseases.

Question 8

Why is it important to identify the disease and the pathogen causing it using laboratory techniques?

Answer 8

So the most appropriate treat meant can be given.

Question 9

What do laboratory techniques analyse?

Answer 9

Samples of tissue or body fluids e.g. blood, urine or faeces.

Question 10

List the ways that samples can be analysed using laboratory techniques? (6)

Answer 10

Counting the number of cells
Viewing using a microscope
Growing a sample in a culture
Testing microorganisms with antimicrobial compounds
Sequencing and analysing the genetic material
Isolation and reinfection (in plants)

Question 11

What does a number of white blood cell outside the normal range indicate?

Answer 11

The body is fighting an infection.

Question 12

Why does counting the number of red blood cell help identify a disease?

Answer 12

Some disease change the number of red blood cells in a given volume of blood.
So a red blood cell count may help to identify the presence of a particular disease

Question 13

How can viewing a sample using a microscope help to identify a disease?

Answer 13

Scientists can identify some microorganisms from their appearance.
Staining the sample can help as some species of bacteria absorb a dye while other won’t.

Question 14

Why may it be necessary to grow a sample in a culture when trying to identify a disease?

Answer 14

Some time there may not be enough of a pathogen in a sample to be identified under a microscope.

Question 15

Why can testing microorganisms found in a sample with antimicrobial compounds help to identify a disease?

Answer 15

The effectiveness of different antimicrobials e.g. antibiotics, in killing the microorganisms may help to identify it.

Question 16

When trying to identify if as specific pathogen is present in a sample how can adding complement sections of DNA be used?

Answer 16

Scientists have works out the genomes of many different pathogens.
If the pathogen is present the DNA stands will bind to the pathogens DNA and allow it to be identified.

Question 17

How do scientists isolate a microorganisms they suspect is causing a disease?

Answer 17

A section of disease plant tissue is added to a growth medium in the lab this will encourage the microorganisms to grow
Scientists can then identify the microorganisms they suspect is causing the disease.

Question 18

What do scientists do with a microorganisms they have isolated (plant)?

Answer 18

Infect healthy plants with it to see if the plants develop the same Symptoms as the diseased plant.

Question 19

Why is it important that aseptic techniques are used in all laboratory tests?

Answer 19

To ensure samples don’t get contaminated with other microorganisms.
This could lead to the wrong microorganisms being detected as the pathogen causing the disease.

Question 20

Describe how staining can help to identify a bacterial species in a sample under a microscope. (2 marks)

Answer 20

Only certain bacterial species will absorb the dye. (1 mark)

So they can be more easily identified when viewed under a microscope. (1 mark)