B2.3 - How can we prevent the spread of infection?

Question 1

List 5 ways you can reduce the spreading of diseases

Answer 1

1. cleaning and covering wounds
2. clean water free of pathogens
3. good personal hygiene
4. keeping food in the fridge
5. clean utensils and surfaces

Question 2

What is an epidemic?

Answer 2

If a disease affects many individuals in a population, this is an epidemic.

Only one region e.g ebola in West Africa

Question 3

What is a Pandemic?

Answer 3

If a disease spreads over a very wide geographical area it is a pandemic.

Affects many countries e.g covid 19

Question 4

Why is it important to protect plants from the spread of diseases?

Answer 4

Diseases will kill the plants
Food chain relies on plants.
Plants are habitat for organisms

Question 5

What is polyculture?

Answer 5

Growing a mixture of DIFFERENT plants

Question 6

What is monoculture?

Answer 6

Growing many of the SAME kind of plant close to each other.

Question 7

Is polyculture or monoculture better for preventing the spread of disease in plants?

Answer 7

Polyculture
Disease doesn’t spread as rapidly as different plants are affected differently by certain pathogens.

Question 8

What is crop rotation and how does it prevent the spread of disease in plants?

Answer 8

Growing different plants in the same plot of soil in rotation. eg growing carrots in a certain area then growing potatoes in that same area after the carrots have be harvested.

The soil will contain pathogens from the old crops and can infect the new crop. Growing a different type of crop means there’s a chance it won’t be affected by the pathogen

Question 9

Give an example of chemical control ( Chemical substance used to prevent spreading of disease )

Answer 9

Spraying Pesticide on plant to kill the pathogen

Question 10

Give an example of biological control (Introducing new species into the system)

Answer 10

New species is introduced to the crop.

The new species is a predator of the of the pest that spreads the disease.

e.g using ants to eat the pest

Question 11

What is a vaccine?

Answer 11

Substance that contains dead/inactive pathogens
create immunity to the certain pathogen.

Question 12

How do vaccines work? What do they contain?

Answer 12

Dead pathogen enters body.

White blood cells respond and product specific antibodies to fight pathogen.

White blood cell remembers how to make the antibody and can rapidly produce it if infected by the pathogen before symptoms can show.

Question 13

Are vaccine an example of passive or active immunity

Answer 13

Active ( body creates its own antibodies)

Question 14

What is an example of passive immunity? What is 1 advantage and 1 disadvantage of this

Answer 14

Sick person is injected with antibodies needed.
(antibody is not made in own body)

Quick :)

Immunity doesn’t last long :(

another example is mother breastfeeding milk that contains the antibodies to their baby

Question 15

How do white blood cells respond to vaccines?

Answer 15

Produce antibodies for the pathogen inside the vaccine

Question 16

Advantage and disadvantage of Vaccines?

Answer 16

Long lasting immunity :)

Take long to work :(

Question 17

What is the difference between direct and indirect transmission

Answer 17

Direct - spread from one host to another e.g ill person sneezes on another person and they get ill.

Indirect - a second organism that is unaffected by the pathogen transfers it to a new host e.g mosquito spreading malaria to a human

Question 18

What are disinfectants?

Answer 18

Substance used to kill pathogens on NON-living things
e.g Fairy liquid on plates

Question 19

What is antiseptic

Answer 19

Antimicrobial substances that are applied to LIVING tissue/skin to reduce the possibility of infection

e.g hand sanitiser

Question 20

Name 3 of the antiseptic techniques

Answer 20

1. Sterilising Petri dish before use
2. passing equipment through a Bunsen burner flame to kill bacteria e.g wire loop
3. lifting the lid of the Petri dish as little as possible to prevent unwanted microorganisms entering the dish.

Question 21

How can you tell you’re sick?

Answer 21

You feel symptoms (coughing, sneezing vomiting)

Question 22

If the doctor can’t tell from your symptoms what is wrong, what will they do?

Answer 22

Collect a sample of fluid or tissue from sick person

Sample is tested to identify the pathogen

Question 23

Name 4 of the sampling and identification techniques

Answer 23

1. Counting Cells
2. Microscopy and staining
3. Cell Culture
4. Genome Analysis

Question 24

What is counting cells?

Answer 24

Cells in a sample counted under a microscope using grid method
determine how many cells in sample
compare to healthy amount

Question 25

How can we determine what type of pathogen is present?

Answer 25

Using microscope
compare the shape of the pathogen with a key.

Question 26

What is gram staining? why do we do it?

Answer 26

We dye the pathogen a different colour to make it easier to see.

Question 27

Why is it useful to study and record the genome of particular DNA strands?

Answer 27

to develop vaccines
to develop treatment
for the pathogen

Question 28

Why do we need to sterilise the equipment we use?

Answer 28

avoid contamination
contamination can give incorrect results.

Question 29

what is agar?

Answer 29

jelly that contains nutrients to help the microbes grow.

Question 30

why is the petri dish flat?

Answer 30

large surface area for microbes to grow

Question 31

where is the petri dish places to help the microbes grow?

Answer 31

incubator

Question 32

why do we put a lid on the petri dish?

Answer 32

to stop other microbes from contaminating the culture.

Question 33

In schools, what temperature should the microbe cultures be grown and why?

Answer 33

25 degrees
reduces chances of harmful pathogens from being formed

Question 34

How and why to we sterilise the petri dish?

Answer 34

Heat to high temperatures
to kill the microbes

Question 35

What are monoclonal antibodies?

Answer 35

antibodies clones from single group of identical white blood cells.

They are all identical in structure.

Question 36

How are monoclonal antibodies formed? 6 marks

Answer 36

a mouse is exposed to the antigen

Mouse’s lymphocytes produce antibodies and the antibodies are extracted from the spleen

antibodies mixed with tumour cells

both cells fuse together

cells clone and multiply and produce antibodies

correct cell clone is selected and grown in large scale and antibodies are extracted.

Question 37

List 3 ways monoclonal antibodies can be used

Answer 37

1. Pregnancy test
   (bind to hormones made when pregnant)
2. Diagnosis of Disease
   (antibodies with markers mark the antigen to make it easier for doctors to find)
3. Treatment of disease
   ( carry drugs to tissues )

Question 38

Name the advantages of monoclonal antibodies

Answer 38

They only bind specifically to the cells that need to be treated so healthy cells aren’t affected.

Can be used to treat a wide range of conditions

In time will be cheaper to produce

Question 39

Name the disadvantages of monoclonal antibodies

Answer 39

Are currently expensive to develop

Not as successful as hoped to be. Used mouse cells, which reacted badly in humans – this caused side effects.

Difficult to produce

Question 40

List 3 ways white blood cells protect us against pathogens

Answer 40

1. produce antibodies - (lymphocytes)
2. engulf (eat) pathogen - (phagocytes)
3. produce antitoxins