Infection and response

Question 1

What are pathogens?

Answer 1

Microorganisms that enter the body and cause disease

They cause communicable/infectious disease.

Question 2

What is bacteria?

Answer 2

Very small living cells.

Question 3

What does bacteria do?

Answer 3

It reproduces rapidly and produces antitoxins that damage your cells and tissues.

Question 4

Viruses are NOT cells.

What can viruses do?

Answer 4

Reproduce rapidly and replicate themselves using the cells machinery.
The cell usually bursts, releasing new viruses.

Question 5

Fungi come in different shapes.

List them.

Answer 5

Some fungi are single-celled

Others have a body made of hyphae (thread-like structures)

Question 6

What are protists?

Answer 6

Single-celled eukaryotes.

Question 7

Some protists are parasites.

Define parasites.

Answer 7

An organism which lives in or on another organism- its host and it can cause them to damage.

Question 8

Pathogens can be spread in different ways.

List the ways.

Answer 8

Water- by drinking or bathing in drinking water. e.g. cholera.
Air- when breathed in or when someone coughs/sneezes
Direct contact- touching contaminated surfaces including the skin.

Question 9

List 3 viral diseases.

Answer 9

Measles
HIV
tobacco mosaic virus.

Question 10

Describe the Measles viral disease.

Answer 10

It is spread by droplets of an infected persons sneeze/cough
People that have it have a red skin rash-signs of fever
It can be very serious or even fatal. E.G. it can lead to pneumonia- a lung infection or encephalitis- a brain infection.
You can get vaccinated to prevent it.

Question 11

Describe HIV viral disease.

Answer 11

It is spread by sexual contact or by exchanging body fluids such as blood or sharing needles when taking drugs
it cause flu-like symptoms for a few weeks, usually the person doesn’t experience the symptoms for several years
HIV can be controlled with antiretroviral drugs- these stop the virus replicating in the body
HIV damages the immune system and is also know as AIDS.

Question 12

Describe tobacco mosaic virus.

Answer 12

It affects many species of plants like tomatoes
It causes a mosaic pattern on the leaves of a plant, parts of the leaves become discolored.
This means they can’t carry out photosynthesis- their growth is affected.

Question 13

What is rose black spot?

Answer 13

A fungal disease that causes purple or black spots to develop on the leaves of rose plants.
The leaves can then turn yellow and drop off.
This means that less photosynthesis can happen- its growth is affected.
It can spread through water and wind.
Gardeners can treat the disease by using fungicides- a chemical that destroys fungus and by stripping down the leave so the disease doesn’t spread.

Question 14

What is malaria?

Answer 14

A disease caused by protist and it takes place inside the mosquito.
They pick up the malarial protist when they feed on an infected animal
Every time a mosquito feeds on another animal it infects it
Malaria causes fever and it can be fatal
The spread of malaria can be stopped by stopping the mosquitoes from breeding
People can be protected from mosquitoes by using insecticides or mosquito nets.

Question 15

List 2 bacterial diseases.

Answer 15

Salmonella

Gonorrhoea.

Question 16

Describe salmonella bacterial disease.

Answer 16

It causes food poisoning
Infected people can suffer from fever, stomach cramps, vomiting and diarrhoea.
These symptoms are caused by toxins that the bacteria produce.
You can get salmonella food poisoning by eating food that’s been contaminated with salmonella bacteria e.g.eating a chicken that caught the disease when it was alive
In the Uk most poultry- chickens and turkeys are given vaccines to control the spread of the disease.

Question 17

Describe Gonorrhoea bacterial disease.

Answer 17

It is a sexually transmitted disease-STD
they are passed on by sexual contact like having unprotected sex
it is caused by bacteria
A person with the disease will get pain when they urinate.
Another symptom is thick yellow or green discharge from the vagina or penis.
It used to be treated with antibiotic- penicillin but this has become tricker because bacteria have become resistant to it.
to prevent the spread of the disease, people can be treated with antibiotics and should use barrier methods of contraception such as condoms.

Question 18

How can the spread of disease be prevented or reduced?

Answer 18

Being hygienic
Destroying vectors- using insecticides
isolating infected individuals- stay away from people with communicable disease
vaccination- to prevent

Question 19

How can you fight disease?

Answer 19

The skin acts as a barrier to pathogens- it also secretes antimicrobial substances which kill pathogens.
Hairs and mucus in your nose trap the particles that could contain pathogens
The trachea and bronchi secrete mucus to trap pathogens
They are line with cilia- hair like structures which waft the mucus up to the back of the throat where it can be swallowed.
The stomach produces hydrochloric acid which kills pathogens that make it past the mouth.

Question 20

Your immune system can attack pathogens.

How?

Answer 20

Through white blood cells, they travel around the blood and constantly look for microbes and when they come across one, they invade it.
They engulf foreign cells and digest them-phagocytosis
They also produces antibodies
When a wbc comes across a foreign antigen, they produce proteins called antibodies to lock onto the invading cells so that they can be found by other wbc.

Question 21

How does vaccination fight disease?

Answer 21

It prevents you from future infections
It involves injecting dead/inactive pathogens
They carry antigens which cause your body to produce antibodies to attack them even though the pathogen is harmless but this makes the immune system recognize antigens so when active antigens enter the wbc know what to do.

Question 22

List pros and cons of vaccination.

Answer 22

PROS-It helps control communicable diseases.
E.G. polio infections have fallen by 99%
epidemics can be prevented
CONS- they don’t always work
you can sometimes have a bad reaction e.g. swelling or fever or seizures.

Question 23

List drugs that relieve symptoms.

Answer 23

Painkillers- e.g. aspirin- can kill pathogens
antibiotics-e.g.penicillin- kill bacteria- different antibiotics kill different bacteria
they don’t destroy viruses
it reduced the number of deaths from communicable diseases.

Question 24

Bacteria can become resistant to antibiotics.

How?

Answer 24

they can mutate(change)- this can cause them to be resistant to an antibiotic-not get killed by an antibiotic
if u have an infection and the bacteria is resistant to antibiotics, only the non-resistant strains of bacteria will be killed.
The resistant strain could cause an infection that can’t be treated e.g. MRSA
to slow down the rate of development of resistant strains, its important to avoid over-prescribing antibiotics so you won’t get them for a sore throat.

Question 25

What are 2 things tested on in preclinical testing?

Answer 25

Human cells and tissues.

Question 26

What is a placebo?

Answer 26

A medicine/procedure prescribed for a psychological benefit- it doesn’t actually do anything.