Infection and Response

Question 1

How do diseases caused by viruses, bacteria, protists and fungi spread

Answer 1

Droplet infection, direct contact, water and food or vectors(carriers like mosquitoes)

Question 2

What is a pathogen

Answer 2

A microorganism that causes a disease

Question 3

How do viruses reproduce in the body

Answer 3

The virus infects a host cell and replicates itself many times by changing the DNA inside of the cell. The host cell then bursts and releases lots of the replicated virus cells which then infect other host cells.

Question 4

How do bacteria reproduce in the body

Answer 4

Through binary fission where their offspring are identical to the parent cell with the the same genetic material

Question 5

Symptoms of measles

Answer 5

A high fever and skin rashes

Question 6

Effects of HIV

Answer 6

Weakens the immune system and leaves it more vulnerable to other infections and diseases

Question 7

How is HIV transmitted

Answer 7

Through bodily fluids(unprotected sex) but also through cuts and injecting drugs using shared needles

Question 8

Describe tobacco mosaic virus

Answer 8

Infects tobacco through contact with other plants(either naturally or by the hands of the farmers). It infects the chloroplasts and turns it from green to a yellow/white mosaic pattern. This reduces the plants ability to photosynthesize and grow properly. There is no cure for this disease.

Question 9

How is Salmonella spread

Answer 9

By bacteria ingested in food or on food prepared in unhygienic conditions

Question 10

Symptoms of salmonella

Answer 10

High fever, stomach ache , headache, loss of appetite and rashes

Question 11

How is gonorrhoea transmitted

Answer 11

It is sexually transmitted

Question 12

How can gonorrhoea spread be reduced

Answer 12

Not have anal or use protection

Question 13

Cause of gonorrhoea

Answer 13

Caused by a bacterium

Question 14

Symptoms of gonorrhoea

Answer 14

Burning pain when urinating and forms a yellow or green discharge

Question 15

How is gonorrhoea treated

Answer 15

Through antibiotics

Question 16

Describe rose black spot

Answer 16

Caused by a fungus that which infects roses and causes black/purple spots on the leaves. Reduces the plants ability to photosynthesize. Transmitted through the air of the water and also through contact of gardeners.

Question 17

How does rose black spot spread

Answer 17

From leaf to leaf and plant to plant through the wind

Question 18

How is malaria spread

Answer 18

Spread by mosquitoes which carry a protist which are found in higher temperature areas. Suck blood containing the protists from an infected person and pass the protist to other people they suck blood from.

Question 19

Describe malaria and its causes

Answer 19

Caused by mosquitoes that carry protists. Can cause fever, sweating, vomiting and headaches. No vaccination for malaria. Mosquito nets and insect repellents can prevent bites. Antimalarial drugs can prevent symptoms and infection.

Question 20

How does skin defend you

Answer 20

It is a physical barrier that prevents microbes from entering.
Also produces anti-microbial secretions to destroy pathogenic bodies

Question 21

How does respiratory system defend you

Answer 21

Nose is full of hairs to trap pathogens . Produces mucus that trap pathogens. Cells that live in the trachea and bronchi are covered in cilia that move the waft the pathogenic mucus to the back of the throat

Question 22

How does digestive system defend you

Answer 22

Produces hydrochloric acid to destroy the micro-organisms in the mucus that you swallow.

Question 23

How does immune system defend you

Answer 23

Your white blood cells try to destroy the pathogenic cells that get inside your bodies. Some white blood cells ingest the pathogens to digest and destroy them through phagocytosis

Question 24

Role of white blood cells

Answer 24

To ingest micro organisms through phagocytosis, produce antibodies and produce antitoxins

Question 25

Process of vaccination

Answer 25

Inject a dead or weakened pathogen. B cells will start producing antibodies and some of them will become memory B cells. If you are exposed to the pathogen, your body will remember how to fight of it and produce large amounts of antibodies very quickly.

Question 26

What is herd immunity

Answer 26

If enough people are vaccinated, the disease cannot spread to those who aren’t. The whole population becomes protected. This is how to protect people with vulnerable immune systems

Question 27

What can antibiotics treat

Answer 27

They can treat or prevent some types of bacterial infection. They kill bacteria and prevent them from reproducing and spreading

Question 28

Explain the development of antibiotic resistance bacteria

Answer 28

A random mutation occurs in the DNA of individual bacterial cells. This protects the cell from the effects of the antibodies.

Question 29

What are painkillers

Answer 29

They are chemicals which relieve the symptoms but do not kill the pathogen

Question 30

Why are anti-viral drugs so hard to develop

Answer 30

This is because the virus infects a cell and hijacks the cell’s machinery in order to create more copies of itself. Destroying the virus will often mean destroying the cell that the virus is inside of.

Question 31

Explain the stages of preclinical and clinical trials

Answer 31

Phase 1 - Testing the drug on a small number of healthy people to test for side effects

Phase 2 - Test it on a small number of people with the disease to see if the drug works

Phase 3 - Test it on a large number of people with the disease to see if it is cost effective and to compare with other drugs

Question 32

What is a placebo

Answer 32

A substitute with no effect that looks like the drug. Patients often feel better/reassured when they are given treatment and say they feel better

Question 33

What is double blind trials

Answer 33

Both the doctors nor the patients know if they are given the real or placebo drug. This avoids patient and scientist bias

Question 34

How are monoclonal antibodies produced

Answer 34

They are produced by fusing antibodies ,which are taken from mice that have been stimulated to produce a certain type of antibody, with tumour cells which have been grown in tissue culture to produce hybridomas. These are then screened for antibody productions and then cloned. These monoclonal antibodies are then isolated for cultivation

Question 35

Uses of monoclonal antibodies

Answer 35

Pregnancy test kits, Cancer diagnosis and treatment.
Can also bind to antigens on blood clots. Can also be attached to fluorescent dye that makes the process of locating the clot much easier and can speed up the amount of time to treat a patient.

Question 36

How plant disease is detected and identified

Answer 36

Visual inspections, laboratory tests, microscopes and culture tests

Question 37

Explain plant physical defence responses

Answer 37

Cellulose wall form a physical barrier between the cells and the pathogens, protecting it from infection

Question 38

Explain chemical plant defence responses

Answer 38

Produce compounds that have anti-microbial properties that can defend the plant from disease causing agents.

Question 39

Explain plant mechanical defence adaptations.

Answer 39

A impenetrable barrier of bark and waxy cuticle. Others include hard shells thorns and spines.