Microbiology and the Immune System

Question 1

What is a micro-organism?

Answer 1

A living organism which is so small that it can only be seen with a microscope

Question 2

What are the 4 types of microorganisms?

Answer 2

Viruses
Bacteria
Fungi
Protists

Question 3

What are protists?

Answer 3

one cell
from the kingdom Protista
eukaryotic (contains a nucleus)

Question 4

Features of bacteria?

Answer 4

• cell wall made of merien and not cellulose
• cell membrane
• DNA floats in cytoplasm
• cytoplasm in middle

Question 5

What are the features of viruses?

Answer 5

• protein coat
• coiled up genes in middle
• even smaller than bacteria

Question 6

What is bacterial growth dependant on?

Answer 6

Temperature
Warm temps are ideal
Too cold and the growth will be slow
Too high and the bacteria will die

Question 7

What is agar?

Answer 7

Jelly that contains nutrients that can grow bacteria

Question 8

What is a large group of bacteria called?

Answer 8

Colonies

Question 9

Explain the process of aseptic technique

Answer 9

1 - loop is flamed to kill bacteria
2 - stopper is removed from bacterial tube
3 - mouth of tube is flamed, no bacteria drifts out of tube
4 - loop is dipped in bacteria
5 - mouth of tube is flamed again, stopper is replaced, stops bacteria getting into the tube
6 - lid of petri dish is raised slightly so traces can be put on, plate is not completely off to prevent bacteria in the air getting onto the agar
7 - loop is flamed again, repeat process if necessary

Question 10

What is penicillin?

Answer 10

It is an antibiotic that treats bacteria, it is a fungus.

Question 11

What is an antibiotic?

Answer 11

A chemical used in medicine to destroy bacteria.

Question 12

What are the 3 conditions for optimum penicillin growth?

Answer 12

• Temperature between 23-28*
• pH of 6.5
• correct oxygen level (fungus is aerobic so needs oxygen for respiration and growth)

Question 13

Why are the nutrients added to the fermenter until growth has actually started?

Answer 13

Fungus only produces penicillin when nutrient levels are low

Question 14

What happens after the penicillin has been brewing for 200hrs?

Answer 14

The liquid is drained, filtered and chemically treated to extract the penicillum.

Question 15

What does the stirrer in a fermentor do?

Answer 15

Mixes ingredients, otherwise they settle at the bottom

Question 16

Why is a cooling jacket used in a fermentor?

Answer 16

The reaction produces heat, but we need the conditions to stay within 23-28*

Question 17

Why is a pressure relief valve used in a fermentor?

Answer 17

Otherwise pressure would increase to dangerous levels and growth of fungus would stop.

Question 18

What is a pathogen?

Answer 18

An organism that causes disease.

Question 19

5 ways pathogens can spread?

Answer 19

• direct contact or bodily fluids
• aerosol infection
• water
• insects
• contaminated food

Question 20

What is AIDS?

Answer 20

acquired immune deficiency syndrome, caused by human immune deficiency virus.

Question 21

How is AIDS spread and what can we do to prevent it?

Answer 21

- spread by bodily fluids
We can prevent it by
- safe sex
- avoid sharing needles
- wear surgical gloves when dealing with bleeding

Question 22

What is chlamydia?

Answer 22

Chlamydia trachomatis

• transmitted by unprotected sex
• treated by antibiotics

Question 23

What is malaria?

Answer 23

A tropical disease spread by flies or mosquitoes

Question 24

What is the name of the parasite responsible for malaria?

Answer 24

Plasmodium

Question 25

How can we prevent malaria?

Answer 25

• use mosquito nets
• draining swampy areas
• treating homes with insecticides
• taking anti-malarial tablets

Question 26

What are pathogens killed by?

Answer 26

white blood cells

Question 27

What are phagocytes?

Answer 27

Ingest micro-organisms and digest them, they will attack any cell.

Question 28

What are lymphocytes?

Answer 28

They produce antibodies that destroy micro-organisms, antitoxins neutralise any poison produced by the pathogen. (antibodies are specific to pathogens)

Question 29

What are antigens?

Answer 29

They are in white blood cells

• recognise foreign bodies
• we have identical antigens

Question 30

What happens when a pathogen is detected?

Answer 30

1 - antigens detected by white blood cells
2 - phagocytes attack, lymphocytes develop antibodies (pathogens will grow in this time, worsening symptoms)
3 - lymphocytes produce right antibodies + memory cells that will produce the antibody if pathogen repeats
4 - antibodies usually wipe out pathogen
5 - memory cells = response will be more rapid, person will be immune to the disease

Question 31

What are vaccines?

Answer 31

Vaccines protect us from bacterial and viral diseases

Question 32

How do vaccines work?

Answer 32

• They are made of dead or weakened pathogens with antigens
• Lymphocytes will react and build up memory cells +immunity
• to build up more memory cells, boosters are sometimes needed

Question 33

Disadvantages of vaccines?

Answer 33

• vaccination involves injection, which can hurt and panic young children
• usually some have side effects, even though they are minor they may put people off the idea of having them

Question 34

What are superbugs?

Answer 34

Evolved resistance to antibiotics (eg MRSA)

Question 35

How do you slow the natural selection/mutation of superbugs?

Answer 35

• doctors to avoid prescribing antibiotics when possible

- vary the types of antibiotics

Question 36

How do you prevent the spread of superbugs in hospitals?

Answer 36

• patients screened for MRSA
• rigorous with personal hygiene
• visitors wash hands and use hand sanitisers
• safety measures when dealing with open wounds

Question 37

How are monoclonal antibodies made?

Answer 37

1- the antigen that the antibody is to be used is injected into the mouse
2- the mouse white blood cells will produce antibodies specific to that antigen
3- spleen tissue containing white blood cells is collected from mouse
4- they are fused with myeloma (cancer cells) to form hybridoma cells, which divide and grow
5- hybridoma cells are collected and grown in a culture medium
6 - hybridoma cells grow and divide indefinitely and produce large amounts of the monoclonal antibody specific to the original antigen
7- antibodies extracted from culture medium by centrifugation (spinning), filtration and chromatography

Question 38

4 ways monoclonal antibodies can be used?

Answer 38

• more specialised/safe chemotherapy treatment
• helps diagnose AIDS
• allowing malaria to be detected before symptoms show, to help track spread of disease
• used to identify tissue type for transplants

Question 39

What are the 4 processes in pre-clinical testing?

Answer 39

1- the drug is tested on human cells outside the body
2- the drug is tested on animals
3- tested on healthy volunteers
4- tested for optimum dosage

Question 40

What is clinical testing?

Answer 40

The drug is trialled on those with said disease, to see if the new drug is more effective than current treatments