Infectious Disease

Question 0

Hoe viruses cause harm

Answer 0

Attacking host cell
Investing their DNA into host cell
Host cell copies viral DNA and produces new antigens.
Host cell dies and thousands of new viruses are released.

Question 1

How bacteria cause harm

Answer 1

Releases toxins

Question 2

Preventing the entry of microbes

Answer 2

Skin
Mucous membranes
Acid secretions

Question 3

Phagocytes use in defence against infections

Answer 3

Phagocytes
Engulf pathogens
Produces enzymes to digest pathogen.
Phagocyte cell dies along with the pathogen forming puss.

Question 4

Lymphocytes use in defence against infection

Answer 4

Some respond to bacterial toxins by producing antitoxins to neutralise the toxins.
Many respond to surface antigens found on all pathogens. They produce antibodies which bind to the antigen. It stops the pathogen moving& reproducing but marks the bacteria for destruction by phagocytes.

Question 5

What type of blood cell is a memory cell

Answer 5

Lymphocyte

Question 6

What is a vaccine

Answer 6

A same way of introducing a pathogen and it’s antigens into the body without causing disease

Question 7

4 types of vaccine

Answer 7

Dead pathogen
Small dose of live pathogen
Antigens only
Artificially made antigens

Question 8

4 types of medicines to treat disease

Answer 8

Pain killers
Steroids
Anti-viral drugs, only slow virus reproduction. Eg prolongs the life of HIV patients.
Antibiotics

Question 9

What is an antibiotic

Answer 9

A natural chemical produced by moulds.

They slow/ kill bacteria

Question 10

How does ana antibiotic become resistant

Answer 10

Bacteria reproduce rapidly by asexual reproduction so mutations in genes often occur
Antibiotic which is resistant isn’t killed by antibiotic
Natural selection

Question 11

Ways to prevent antibiotic resistance

Answer 11

Always finish a course of antibiotics
Don’t prescribe for trivial infections
Don’t prescribe for viral
Reduce use of profilactic antibiotics in food chain

Question 12

Why grow bacteria in a lab

Answer 12

To identify the pathogens present in a sample from a patient
To test antibiotic sensitivity
To grow pure uncontaminated samples

Question 13

How to grow cultures

Answer 13

A culture medium- agar jelly containing carbohydrates, minerals, etc
Warmth and oxygen
Incubate at 25 in schools but 35 in labs

Question 14

Why do industrial labs use 35 but schools use 25?

Answer 14

The bacteria will grow at too fast a rate and could be potentially dangerous at school

Question 15

How do we keep the culture pure

Answer 15

Pass a metal loop through a flam to sterilise it
Boil the agar solution to purify it
Use the sterilised inoculating loop to zigzag the bacteria solution across the Petri dish filled with the agar jelly
Replace lid so the microbes don’t escape.