Communicable disease

Question 1

What is a pathogen

Answer 1

Microorganism that enter the body that cause disease

Question 2

Explain the steps of how vaccines work and are made.

Answer 2

1) pathogen is destroyed/inactive and pathogen carries antigen
3) ingredients added to make vaccine
4) vaccine injected in body
5) antigen stimulates white blood cells into the production of antibodies
6) memory cells remain in the body/produce antibodies rapidly on reinfection for this pathogen and can quickly destroy it

Question 3

What is preclinical testing and what does to test for?

Answer 3

drugs tested on ANIMALS, CELLS,TISSUES in lab, COMPUTER MODELS
- tested for efficacy and toxicity/side effects

Question 4

What is clinical testing and what does to test for?

Answer 4

-drugs is tested on healthy human volunteers with a LOW DOSE that is increased
TEST FOR TOXICITY
-if safe they move on to testing on small no. of PATIENTS

-then move onto large no. of patients , find optimum dosage. Rule out specifics; age, gender

• DOUBLE BLIND TRIALpatients split into 2 group : one given a PLACEBO (double-blind trails)
  TEST FOR TOXICITY AND OPTIMUM DOSAGE
  Jounal- peer review

Question 5

How does the body protect itself from disease

Answer 5

Skin- covers any vulnerable part of the body acting as a barrier
Nose hairs and mucus- trap larger pathogens where it will later be swelled or sneezed .
Trachea and bronchi- lined with cilia (hair like structures) that waft mucus up to the back of the throat where it can be swallowed.
Stomach- hydrochloric acid kills pathogens

Question 6

What drug was found from willow bark

Answer 6

Aspirin

Question 7

What drug was found in foxgloves

Answer 7

Digitalis

Question 8

What is the difference between bacteria and a virus

Answer 8

Virus- smallest in size of all the microbes, uses another organism as a host; it invaded a cell of the body and uses it to multiply itself, eventually causing the cell to burst.They can only survive for seconds to minutes after leaving the host.

Bacteria- much larger than viruses, multiplies by division (if conditions are favourable), can live almost anywhere. Enter cells, reproduce and kill cells
or
Release toxins and paralyse cells’ organelles

Question 9

How are monoclonal antibodies produced? (5)

Answer 9

1) antigen is injected into mouse
2) this stimulates the white blood cells into the production of lymphocytes to produce a particular antibody
3) the antibody is fused together with TUMOR CELLS, producing HYBRIDOMA cells
4) single hybridoma cells DIVIDE to make larger no. IDENTICAL CELLS, that all produce SAME ANTIBODY
5) these antibodies are collected

Question 10

Explain what are monoclonal antibodies? (2)

Answer 10

1)type of antibody which is specific to ONE binding site on ONE ANTIGEN.
2)target particular cells/chemicals in the body

Question 11

uses of monoclonal antibodies and how it works? (4)

Answer 11

PREGNANCY/LFTs tests: Monoclonal antibodies are SPECIFIC to a hormone produced in pregnancy
they will BIND TO THE HORMONE if present/ produce COLOUR CHANGE

DIAGNOSIS/RESEARCH : monoclonal antibodies are SPECIFIC TO ANTIGENS found on pathogens. They contain MARKERS for doctors to locate them
FLUORESCENT DYE can be attached to the antibodies and detect specific molecules

Question 12

advantages of monoclonal antibodies ? (4)

Answer 12

1)only bind to specific molecules so DON’T AFFECT HEALTHY HUMAN CELLS
2)very specific so can be used to TREAT A RANGE OF CONDITIONS
3)hoped to be cheaper in future
4)tried/tested procedure

Question 13

disadvantages of monoclonal antibodies ? (3)

Answer 13

1)caused MORE SIDE EFFECTS than expected at first
2)EXPENSIVE
3)producing specific antibodies is DIFFICULT

Question 14

Why can’t antibiotics work against viruses?

Answer 14

(1)viruses live/reproduce inside cells
- difficult to develop drugs that kill viruses WITHOUT DAMAGING HUMAN CELLS

Question 15

How do antibiotics kill bacteria?

Answer 15

There are different ways depending on the antibiotic:
1) Some antibiotics disrupt the production of the cell wall of the bacteria and they burst
OR
2) Others prevent the bacteria from respiring and they die

Question 16

What are antigens?

Answer 16

Proteins that provoke our body’s immune response ( they are usually on the surface of pathogens).

Question 17

What are the body’s ‘first line of defence’ and how do they defend? (5)

Answer 17

Skin: Stops microbes entering body, scabs
Stomach acid: Kills bacteria
Nose : hair/mucus traps pathogens
Trachea/bronchi : secrete mucus that traps pathogens, cililated cells
Tears: contain anti microbial substances which kill bacteria

Question 18

How does the body defend itself against pathogens? (3)

Answer 18

Using white blood cells, phagocytes and anti toxins.
LYMPHOCYTES-
produce antibodies that target specific bacteria or viruses.
PHAGOCYTES- ingest pathogens and destroy them using enzymes that break down pathogens
ANTITOXINS -
neutralise toxins

Question 19

TBV
(3) symptoms
(2) spread
(2) prevention

Answer 19

VIRUS
-Mosaic pattern
-Discolouration of leaves
-Loss of chlorophyll leads to stunted growth as cannot carry out photosynthesis properly

-Spread through direct contact or tools
- Insects may act as vectors which transfer the virus between different plants.

-Remove infected leaves
-Remove weeds as they can harbour virus

Question 20

Measles
(3) symptoms
Spread
(2) preventions
(2) cures

Answer 20

VIRUS
-Red skin rash
-Fever like symptoms (high temperature)
-Sore eyes

-Spread through droplets when infected person sneezes or coughs

-Vaccination
-Isolation

-Paracetamol for high temperature
-Rehydration

Question 21

Gonorrhoea
(2) symptoms
(2) preventions
cure

Answer 21

BACTERIA
- painful sensation when urinating
- yellow/green discharge

-barrier method contraception
-avoid sex with an infected person

-Antibiotics

Question 22

Rose black spot
(2) symptoms
(1)spread
(2)treatments

Answer 22

FUNGUS
- loss of chlorophyll leads stunted growth due to reduced rate of photosynthesis
- purple/black spots

-Fungal spores are spread by wind and in water

• using fungicides
  -destroying infected leaves

Question 23

How do antibiotics work?

Answer 23

They kills bacterial pathogens inside the body BUT DO NOT KILL HUMANS CELLS.

Question 24

Why do antibiotics not work on viruses?

Answer 24

They have no effect on viral pathogens as viruses LIVE inside the hosts cells. It is difficult to design a drug that would kill virus without destroying human cells

Question 25

What is antibiotic resistance?

Answer 25

This occurs when a MUTATION leads to an individual bacteria becoming resistant to an antibiotic. This bacteria is able to survive antibiotic treatment and will reproduce, passing on its alleles onto the next generation. This leads to a greater proportion of antibiotic-resistant bacteria.

Question 26

How can antibiotic resistance be prevented?

Answer 26

By avoiding overuse/ unnecessary use of antibiotics.
By finishing antibiotic courses to ensure all bacteria is killed.

Question 27

Why do antibiotics work on bacteria but not viruses?

Answer 27

Viruses do not have cell wall as that can be attacked by antibiotics like bacteria does.