Topic 3 - Infection and response

Question 1

What is bacteria?

Answer 1

• Very small cell which rapidly reproduces in your body and produces toxins that make you feel ill by damaging your cells and tissues

Question 2

What is a virus?

Answer 2

• They are NOT cells
• They live inside your cells and rapidly reproduce causing cells to eventually burst
• It is cell damage that makes you fell ill

Question 3

What is a protist?

Answer 3

• A single celled Eukaryota

* Parasites are an example of protist. They are carried by a vector (eg mosquito for malaria)

Question 4

What is a fungus?

Answer 4

• Some are single cells
• Some are bodies made up of hyphae
• Cause damage by penetrating the surface of your skin or plant surface

Question 5

What are the three main ways pathogens are spread?

Answer 5

• Water (eg cholera)
• Air (eg influenza)
• Direct contact (eg athlete’s foot)

Question 6

What is measles? (Type, symptoms, prevented)

Answer 6

• Type - Virus
• Symptoms - Rash, fever, can lead to pneumonia or encephalitis,
• Prevention - Most children are vaccinated

Question 7

What is HIV? (Type, symptoms, transferred, treated)

Answer 7

• Type - Virus
• Symptoms - Initially flu like symptoms, many years later weakened immune system, can develop into AIDs
• Transferred - Exchange in bodily fluids (eg blood or sexual fluid)
• Treated - Antiretroviral drugs

Question 8

What is tobacco mosaic virus? (Type, symptoms and effect)

Answer 8

• Type - Virus
• Symptoms - Mosaic patterns on leaves and discoloration
• Effect - Limited photosynthesis and stunted growth

Question 9

What is malaria? (Type, symptoms, transferred, prevented)

Answer 9

• Type - Protist
• Symptoms - Repeating fever
• Transferred - Mosquitoes
• Prevented - Reduce mosquito breeding, insecticides and mosquito nets

Question 10

What is gonorrhoea? (Type, symptoms, transferred, treated, prevented)

Answer 10

• Type - Bacteria
• Symptoms - Painful urination, thick green or yellow vagina discharge
• Transferred - Unprotected sex
• Treated - Antibiotics, used to be penicillin however many strains have become resistant
• Prevented - Condoms

Question 11

What is salmonella? (Type, symptoms, transferred, prevented)

Answer 11

• Type - Bacteria
• Symptoms - Fever, stomach cramps, vomiting, diarrhoea
• Transferred - Eating contaminated food ie raw chicken, egs
• Prevented - Most UK poultry is given a vaccine for it

Question 12

What is rose black spot? (Type, symptoms, transferred, treated)

Answer 12

• Type - Fungus
• Symptoms - Purple or black spots on leaves that cause them to yellow and drop off
• Transferred - Spreads through wind or water
• Treated - Fungicide or striping effected leaves

Question 13

What four ways can disease be reduced or prevented?

Answer 13

• Being hygienic
• Destroying vectors
• Isolating infected individuals
• Vaccinations

Question 14

What is a pathogen?

Answer 14

• A microorganism that enter the body and causes communicable diseases in plants and humans

Question 15

What are the three main ways your immune system attacks pathogens?

Answer 15

• Phagocytes engulf white blood cells
• Lymphocytes produce antibodies
• Immune system produces antitoxins which counteract toxins by invading bacteria

Question 16

How do antibodies fight disease?

Answer 16

• B-lymphocytes produce proteins called antibodies
• All pathogens have unique antigens on their surface
• White blood cells produce the specific antigens that lock onto the bacterium or virus so they can be destroyed by other white blood cells

Question 17

How is the skin designed to prevent disease?

Answer 17

• It acts as a barrier

* Secretes antimicrobial substances

Question 18

How is the nose designed to prevent disease?

Answer 18

• Hairs and mucus trap particles that could contain pathogens

Question 19

How are the trachea and bronchi designed to prevent diseases?

Answer 19

• Secretes mucus to rap pathogens

* Lined with cilia to waft mucus up to the back of the throat where it can be swallowed

Question 20

How is the stomach designed to prevented diseases?

Answer 20

• Produces HCl to kill pathogens

Question 21

Pros of vaccinations?

Answer 21

• Controls and gets rid of communicable diseases

* Epidemics (big disease outbreaks) can be prevented if a lot of the population is vaccinated

Question 22

Cons of vaccinations?

Answer 22

• Don’t always work

* Some people have bad reactions to vaccines (eg swelling, fevers, seizures)

Question 23

How does a vaccination work?

Answer 23

• By injecting a small amount of a weakened strand of a disease into a person whose white blood cells will produce a new antibody for the disease so if they are reinfected, their body can fight of the disease