Topic 3 infection response

Question 1

What is a pathogen

Answer 1

A pathogen is a micro organism that enters the body and causes diseases

Question 2

What is a communicable disease

Answer 2

A disease caused by a pathogen that can spread between organisms

Question 3

Name 4 types of pathogens

Answer 3

Bacteria
Viruses
Protists
Fungi

Question 3

How can pathogens spread

Answer 3

Through dirty water by drinking or bathing in it
Air may be breathed in
Direct contact by touching a contaminated area

Question 4

How do bacteria cause diseases

Answer 4

They release toxins that damage cells and tissues

Question 5

What are the three main viral diseases

Answer 5

Measles
HIV
Tobacco mosaic virus (TMV)

Question 6

what does measles do?
Signs cures symptoms

Answer 6

Measles spread through a sneeze or a cough. People develop a red skin rash can be fatal. Most people are now vaccinated.

Question 7

what does HIV do?
Signs cures symptoms

Answer 7

HIV sexually transmitted disease by exchanging body fluids or sharing needles. develop flu like symptoms and it weakens body’s immune system

Question 8

what does TMV do?
Signs cures symptoms

Answer 8

Effects many species of plants, e.g. tomatoes
Causes a mosaic pattern and discolours leaves
Stops plants from photosynthesizing effecting there growth

Question 9

Name a fungal disease and show its signs cures symptoms

Answer 9

Rose black spot purple or black spots to develop on leaves. The leaves then turn yellow and fall off.
Causing less photosynthesis to take place less growth for the plant. To treat use fungicides or remove effected areas

Question 10

Disease caused by a protist show its signs cures symptoms

Answer 10

Malaria caused by mosquitoes biting an infected person and taking there blood. It then bites another person passing the protist into there blood stream.
Causing repeating episodes of fever. To prevent stop mosquitoes breeding

Question 11

What are the two main bacterial diseases

Answer 11

Gonorrhoea
Salmonella

Question 12

what does salmonella do?
Signs cures symptoms

Answer 12

A bacteria that causes food poisoning
Causes fever, stomach cramps, vomiting and diarrhoea this is caused by toxins that bacteria produce. In the uk most poultry is vaccinated to prevent this

Question 13

what does gonorrhoea do?
Signs cures symptoms

Answer 13

Sexually transmitted passed through sexual contact.
Causes pain during urination. A yellow or green discharge is released from penis or vagina.
To prevent use barrier methods (condoms)

Question 14

How can you reduce or prevent the spread of diseases

Answer 14

Being hygienic
Destroying vectors
Isolating infected individuals
Vaccinations

Question 15

What is our bodies defence system to fight diseases

Answer 15

Skin is a barrier to pathogens
Hair and mucus in se trap pathogens
trachea and bronchi secrete mucus to trap pathogens
Stomach produces hydrochloric acid to kill pathogens

Question 16

What is the role of the immune system

Answer 16

It defends against pathogens using white blood cells

Question 17

How do white blood cells detect pathogens

Answer 17

They patrol the blood stream and respond to foreign microorganisms

Question 18

How do white blood cells attack pathogens

Answer 18

White blood cells engulf foreign cells and digest them (Phagocytosis)
They then produce antibodies which are produced rapidly and antitoxins

Question 19

What do antitoxins do

Answer 19

they neutralise toxins released by invading bacteria

Question 20

White blood cells

Answer 20

Function: Defend against pathogens
It has a nucleus
It has a an irregular shape so it can engulf pathogens
Doesn’t contain haemoglobin
How does it fight infections: Phagocytosis and lymphocytes produce antibodies and antitoxins
Made in the bone marrow
Has a short life span of a few days- weeks
Moves through blood to attack infections

Question 21

Red blood cells

Answer 21

Function: Transports oxygen and removes CO2
It has no nucleus to carry more haemoglobin
It has a biconcave shape larger surface area for oxygen diffusion
Has oxyhaemoglobin
Made in bone marrow
Life span of 120 days
moves only in blood

Question 22

How do vaccinations work

Answer 22

A dead or inactive pathogen is injected for future immunity

Question 23

What is herd immunity

Answer 23

When a large population is vaccinated to reduce spreading of disease or extinct it

Question 24

Pros of vaccinations

Answer 24

Controls spread of communicable diseases Big outbreaks can be prevented such as covid Provides long term immunity

Question 25

Cons of vaccinations

Answer 25

Don't always work May have a bad side effect

Question 26

What do antibiotics do Give examples

Answer 26

They kill or prevent the growth of bacteria. penicillin, amoxicillin

Question 27

What do Painkillers do Give examples

Answer 27

They relieve pain however they don't tackle the actual pain Aspirin, ibuprofen

Question 28

Are antibiotics always useful

Answer 28

As bacteria can mutate they can become resistant to antibiotics if over used

Question 29

Why don't antibiotics work on viruses

Answer 29

Viruses live inside a host cell making it harder to target them

Question 30

What plant produces Aspirin and Digitalis

Answer 30

Aspirin is produced from the willow tree Digitalis in found in foxgloves

Question 31

Why are drugs tested before use

Answer 31

Check for safety, effectiveness and to know the correct dosage

Question 32

What are the three main stages of drug testing?

Answer 32

1. Preclinical Testing 2. Clinical Trials 3. Peer Review & Licensing

Question 34

What happens in preclinical testing? Stage 1

Answer 34

Drugs are tested on cells, tissues, and live animals. Checks toxicity, efficacy, and dosage. Ensures the drug is safe before human trials.

Question 35

What happens in clinical trials? Stage 2

Answer 35

Drugs are tested on humans in three phases: Phase 1: Small group of healthy volunteers – checks safety & side effects. Phase 2: Larger group of patients – tests effectiveness & correct dosage. Phase 3: Very large group – detects rare side effects and compares with existing treatments. Double-blind trials are used (some get a placebo to prevent bias).

Question 36

What happens Peer Review & Licensing? stage 3

Answer 36

Results are peer-reviewed to check for accuracy and reliability. The drug is approved and licensed for public use.

Question 37

What are monoclonal antibodies?

Answer 37

Identical antibodies produced from a single type of white blood cell. Designed to target one specific antigen.

Question 38

How are monoclonal antibodies produced?

Answer 38

1. A mouse is injected with an antigen. 2. The mouse’s B-lymphocytes (antibody-producing cells) are extracted. 3. B-lymphocytes are fused with a tumour cell to create a hybridoma cell. 4. Hybridoma cells divide rapidly and produce monoclonal antibodies. 5. Antibodies are collected and purified for use.

Question 39

Why are tumour cells used in monoclonal antibody production?

Answer 39

Tumour cells divide rapidly, ensuring a large supply of antibodies.

Question 40

What are monoclonal antibodies used for?

Answer 40

✅ Pregnancy tests – detect hormone hCG in urine. ✅ Cancer treatment – attach to cancer cells and stop growth. ✅ Medical diagnosis – detect infections or diseases. ✅ Locating blood clots – antibodies stick to clots, visible on scans.

Question 41

advantages of monoclonal antibodies?

Answer 41

Highly specific (only bind to the target antigen). Can be used for targeted treatments (e.g., cancer therapy).

Question 42

disadvantages of monoclonal antibodies?

Answer 42

Expensive to produce. • Can cause side effects like fever and vomiting. • Ethical concerns (use of mice in production).

Question 43

What are the main causes of plant diseases?

Answer 43

1. Pathogens (viruses, bacteria, fungi) 2. Insects (e.g., aphids) 3. Nutrient deficiencies (e.g., lack of magnesium causes yellow leaves)

Question 44

What are the common plant diseases?

Answer 44

Tobacco Mosaic Virus (TMV) – viral, causes mosaic pattern & stunts growth. Rose Black Spot – fungal, black spots on leaves, reducing photosynthesis.

Question 45

How can plant diseases be identified?

Answer 45

1. Visual symptoms (discolouration, spots, stunted growth) 2.Lab testing for pathogens 3.Testing soil for nutrient deficiencies

Question 46

What are plant physical defences?

Answer 46

Waxy cuticle – prevents pathogens entering. Cell walls – tough barrier against infection. Layers of dead cells (e.g., bark) – fall off with pathogens.

Question 47

What are plant chemical defences?

Answer 47

Antibacterial chemicals – kill bacteria (e.g., mint, witch hazel). Poisons – deter herbivores (e.g., tobacco, foxgloves).

Question 48

What are plant mechanical defences?

Answer 48

Thorns & hairs – stop animals eating them. Leaves that droop or curl – move away from danger. Mimicry – some plants look like unhealthy ones to avoid pests.