B5

Question 1

What are communicable diseases?

Answer 1

They are diseases that are caused by microorganisms called pathogens, which include bacteria, viruses, fungi and protists and they can be passed from one person to another. These can cause health issues.

Question 2

What are non-communicable diseases?

Answer 2

They are diseases that cannot be passed from one person to another. These can cause health issues. They can also be passed between different species of organism.

Question 3

What are 3 factors that can affect your health?

Answer 3

1.Diet-it can mean your body lacks in nutrients so that can cause a range of diseases and if you eat too much it can cause obesity, some cancers and type 2 diabetes.
2.Stress-this can cause heart disease, certain cancers and mental health problems
3.Life situations-this can include where you live, your gender, your financial status, amount of children etc.

Question 4

What is a virus?

Answer 4

They are smaller than bacteria and usually have a regular shape. They can cause diseases in every type of living organism.

Question 5

What are communicable diseases caused by?

Answer 5

They can be caused directly from a pathogen or by a toxin made by a pathogen.

Question 6

What is a bacteria?

Answer 6

They are single celled organisms that are used to make some food and medicine, or even are used in your body. The pathogenic bacteria is the minority but they have major impacts.

Question 7

How does bacteria cause disease?

Answer 7

They divide rapidly by splitting in two(binary fission) and may produce toxins that affect your body and make you feel ill. They can sometimes directly damage your cells.

Question 8

How do viruses cause disease?

Answer 8

They take over the cells of your body. They live and reproduce inside the cells, damaging and destroying them.

Question 9

How is a pathogen spread through the air?

Answer 9

Most pathogens are carried in the air. In human diseases droplet infection is common. When you sneeze these droplets full of pathogens exit and other people breathe them in and pick up the pathogen. e.g. common cold

Question 10

How is a pathogen spread through direct contact?

Answer 10

Some diseases are spread by direct contact of an infected organism with a healthy one which is common in plant diseases where one infected plant in a field can pass it on. Also common in people through STDs.

Question 11

What is a vector?

Answer 11

A species that carries the pathogen between infected and uninfected individuals.

Question 12

How is a pathogen spread through water?

Answer 12

Fungal spores can be carried in water which can spread plant diseases down stream. It can also be through eating contaminated foods where the pathogen enters through your digestive system.

Question 13

What is a culture medium?

Answer 13

It is a liquid or gel that provides the environment the pathogen needs to grow. e.g. petri dish

Question 14

How can you grow a microorganism?

Answer 14

Using sterilised Petri dishes and agar. You sterilise the inoculating loop before use and you fix the lid of the Petri dish to prevent unwanted Microorganisms from entering.

Question 15

How can you prevent growth of bacteria?

Answer 15

You can raise or lower the temperature, or use chemicals that stop them growing or kill them.

Question 16

List 4 ways you can prevent the spread of communicable diseases?

Answer 16

1.Hygiene such as hand washing, disinfectants, avoiding cross contamination
2.Isolating infected individuals so it is less likely the pathogen will be passed on and therefore spread
3.Destroying or controlling vectors which can prevent the spread of the disease to be caused.
4.Vaccination where the doctors inject a small amount of the pathogen so your immune system can make antibodies. However it can’t protect plants as they have no immune system

Question 17

What are measles?

Answer 17

They are a viral disease that can cause a fever and red skin/a rash. It was spread by the inhalation of droplets from coughs or sneezes.

Question 18

What is HIV/AIDS?

Answer 18

It starts as a flu-like illness by attacking the immune cells until the immune system is so badly damaged the patient has AIDs. It is spread through direct sexual contact and the exchange of bodily fluids.

Question 19

What is Tobacco mosaic virus?

Answer 19

It is a widespread plant pathogen that affects tomato and tobacco plants. It causes a mosaic pattern on the leaves and discolouration as the virus destroys the cells. It can reduce the yield of a crop as the plant cannot photosynthesise. It is spread through contact of diseased plant material and has no cure. Can be prevented by good field hygiene.

Question 20

What is salmonella?

Answer 20

It is the bacteria that lives in the guts of animals and can be found in raw meat and eggs. When it enters the body it can disrupt the balance of natural gut bacteria and causes food poisoning. One cause is eating uncooked meat where the bacteria has not been killed by heating. The symptoms are diarrhoea.

Question 21

What is Gonorrhoea?

Answer 21

It is an STD spread by unprotected sex with an infected person. It’s symptoms are a thick yellow discharge coming from the genitals and pain while pissing. It can be treated with antibiotics and prevented through the use of a condom.

Question 22

What is rose black spot?

Answer 22

It is a fungal disease of rose leaves which causes purple or black. It can be a nuisance in gardens and commercial flower growers. The leaves often turn yellow and drop off, so the plant cannot flower well. It is spread in the environment, carried by the wind. It can be prevented through burning affected leaves and chemical fungicides can also prevent it.

Question 23

What is malaria?

Answer 23

It is a disease cause by the protist-a mosquito. It is caused by the bite of female mosquitos that damages blood and liver cells, causes fever and shaking and can be fatal. Some drugs can be effective if given early but the protists are becoming more resistant. It can be reduced by preventing the vectors from breeding and by using mosquito nets to prevent people from being bitten.

Question 24

What is a parisite?

Answer 24

An organism that lives and feeds off other living organisms.

Question 25

How is your skin made to protect against pathogens?

Answer 25

It covers the body cand acts as a barrier from pathogens. When you are cut it forms a scab to prevent pathogens from entering. Your skin also produces antimicrobial secretions to destroy bacteria.

Question 26

How does your nose protect against pathogens?

Answer 26

It is full of hair and produces mucus that traps particles in the air that may contain pathogens or irritate your lungs.

Question 27

How does your trachea and bronchi protect against pathogens?

Answer 27

They secrete mucus that traps pathogens from the air. The lining is also coated in cilia that beat to waft the mucus up into the throat.

Question 28

How does your stomach protect against pathogens?

Answer 28

It produces acids and destroys the microorganisms in the mucus you swallow as well as some of the pathogens you eat.

Question 29

How does a white blood cell ingest microorganisms?

Answer 29

They ingest pathogens, digesting and destroying them so they can’t make you ill.

Question 30

How does a white blood cell produce antibodies?

Answer 30

Some white blood cells produce special chemicals called antibodies. These target particular bacteria or viruses and destroy them. Each pathogen has it’s own antibody so when it is produced, they can be made very quickly if the pathogen gets into your body again.

Question 31

How does a white blood cell produce antitoxins?

Answer 31

These counteract the toxins released by pathogens when the toxin joins to the antitoxin produced by the bacterium.

Question 32

What are aphids?

Answer 32

They have sharp mouthparts that penetrate into the phloem vessels of the plants so they can feed on the sap. They can also transport viruses, bacteria and fungi from plant to plant through their mouths. They can be prevented through pesticides and can be killed by releasing insects that eat them.

Question 33

How can plants be damaged by a mineral defficiency?

Answer 33

They need minerals to allow for growth in the plant. When the chlorophyll is not made due to a lack of magnesium ions, it can cause yellowing of leaves called chlorosis.

Question 34

What are symptoms of disease in plants?

Answer 34

Stunted growth, spots on leaves, decay, growths, malformed areas, discolouration and presence of visible pests. They can be seen detected due to gardening manuals, lab tests and monoclonal antibodies.

Question 35

What are 4 physical barriers a plant has to reduce the invasion of pathogens?

Answer 35

The cell walls can reduce invasion of microorganisms so there is no way into the cells, there is a tough waxy cuticle, there is bark on trees, and leaves fall so any pathogens that are in the leaves will be lost.

Question 36

What are chemical barriers a plant has to stop pathogens?

Answer 36

These include antibacterial chemicals and poisons to deter herbivores.

Question 37

How can a plant defend itself against herbivores?(5)

Answer 37

1.Can use poisons so the animal learns not to eat it to avoid being unwell.
2.Thorns can make it painful for large herbivores to eat it however they don’t deter insects.
3.Hairy stems deter insects and larger animals from feeding off them or laying eggs on their stems. They can also be infused with poison.
4.Curling leaves when touched, which can frighten the insects or animals or dislodge them
5.Mimicry where some plants mimic unhealthy plants by drooping so animals don’t eat them. They can also mimic eggs on the surface so other insects don’t lay eggs on to avoid competition.