week 3

Question 1

what are micro organisms

Answer 1

organisms that are too small to be seen with the naked eye

Question 2

2 types of microrganisms + examples

Answer 2

acellular - pirons / viruses
cellular - prokaryotic / eukaryotic

Question 3

What type of microorganisms are classified as acellular?

Answer 3

Those unable to replicate on their own.

Question 4

State 3 differences between a prokaryotic cell and a eukaryotic cell

Answer 4

Prokaryotic cells have no nucleus whereas eukaryotic cells do have a nucleus.
Prokaryotic cells have a single circular chromosome whereas eukaryotic cells have multiple linear chromosomes.
Prokaryotic cells have a plasmid where as eukaryotic cells have no plasmid
Prokaryotic cells have no membrane bound organelles whereas eukaryotic cells do have membrane bound organelles.

Question 5

viruses

Answer 5

• not living
• not eukaryotic or prokaryotic
• can not carry out metabolic reactions on their own (need a host cell)

Question 6

viruses - structure

Answer 6

1) naked
- nucleic acid enclosed in a protein coat (capsid)
2) enveloped
- have an additional outer layer

Question 7

What is normal microflora?

Answer 7

organisms that live on or in the body but do not cause disease

Question 8

What is the advantage of a virus being enveloped?

Answer 8

Helps adherence

Question 9

What is an advantage of naked viruses?

Answer 9

More resistant to the environment

Question 10

What are the three functions of viral capsid proteins?

Answer 10

• antigenic properties
• helps with attachment
• protects the nucleic acid against inactivation

Question 11

Why do viruses need a host cell?

Answer 11

The don’t have the DNA to replicate

Question 12

viral repication

Answer 12

1. adsorption
   - attachment of viral capsid on receptor site of host
2. penetration
   - virus enters cell via direct penetration, membrane fusion and phagocytosis
3. uncoating
   - capsid is removed so nucleic acid can be released
4. synthesis
   - copying of the nucleic acid
5. assembly
   - nucleic acid and capsid is assembled. The DNA goes to nucleus and the RNA to cytoplasm
6. release
   - naked viruses = released from host cell resulting in cell lysis and death
   - enveloped viruses = bud out through cell membrane acquiring their envelope which has been modified by the insertion of viral glycoprotiens

Question 13

List 5 ways a virus can be transmitted

Answer 13

airborne, faecal-oral, bodily fluids, vectors, foetal and neonatal

Question 14

What is a vector?

Answer 14

Mosquito

Question 15

Which human based diseases are caused by viruses?

Answer 15

Glandular Fever, HIV, Chicken Pox, Hep and Herpes

Question 16

latent viral infections

Answer 16

remain dormant in some host cells and can become reactivated later

Question 17

chronic viral infections

Answer 17

virus remains in host cells - gives rise to continuous low level of viral production and shedding (carrier state)

Question 18

oncogenic viruses

Answer 18

cause tumors

Question 19

Why are antibiotics useless in fighting viral diseases?

Answer 19

viruses have a protective protein that antibiotics can’t attack

Question 20

treatment of viruses

Answer 20

1) vaccines
2) antiviral medications

Question 21

Where in the body does HSV type 2 infect?

Answer 21

usually genitals
occasionaly around skin of mouth

Question 22

Where in the body does HSV type 1 infect?

Answer 22

usually around skin around mouth
occasionally genitals

Question 23

What is vertical transmission?

Answer 23

mother to child

Question 24

What is the transmission route for HPV?

Answer 24

direct contact

Question 25

HPV infects .....

Answer 25

the skin and mucus membrane

Question 26

What are the major properties of bacterial cells?

Answer 26

cell membrane and cell wall

Question 27

What colour do gram positive cells stain?

Answer 27

purple

Question 28

What colour do gram negative cells stain?

Answer 28

pink

Question 29

What is different about gram negative bacteria?

Answer 29

second lipid membrane made from lipopolysaccharides and lipoproteins

Question 30

How is the nucleic acid of bacteria contained within a cell?

Answer 30

plasmids

Question 31

What is the role of flagella?

Answer 31

Move in a watery environment

Question 32

What are pili used for?

Answer 32

transfer of DNA during conjugation

Question 33

What is the role of fimbrae?

Answer 33

allows adherence to host cell

Question 34

What is virulence?

Answer 34

the ability to cause disease

Question 35

What is a slime layer?

Answer 35

glycoproteins and polysaccharides form biofilms on medical devices

Question 36

Are endospores alive?

Answer 36

no but they are resistant to environment

Question 37

What are exotoxins?

Answer 37

a toxin secreted into the environment where bacteria are growing

Question 38

What are endotoxins?

Answer 38

a toxin that forms the outer membrane of gram negative bacteria and it is released when the cell dies

Question 39

What are common forms of bacterial reproduction?

Answer 39

cell division

Question 40

What is the usual habitat for gram positive bacteria?

Answer 40

skin

Question 41

What is the usual habitat for gram negative bacteria?

Answer 41

fluids (water, mucous)

Question 42

How does tuberculosis spread from person to person?

Answer 42

Aerosol Droplets

Question 43

What does a Mantoux test determine?

Answer 43

tuberculosis

Question 44

mad cow disease, kuru, sheep scrapie, fatal familial insomnia are examples of

Answer 44

piron diseases

Question 45

Are prions microorganisms?

Answer 45

no, but they are infectious

Question 46

How are prions different from other infectious agents?

Answer 46

they don't replicate outside the body and the body can't detect them as dangerous

Question 47

What are the common symptoms of someone with prions disease?

Answer 47

damage to the brain tissue

Question 48

What are the transmission routes for human prion disease?

Answer 48

human to human, animal to human

Question 49

distinguish between eukaryotes and prokaryotes

Answer 49

eukaryotes are multicellular and prokaryotes are unicellular

Question 50

How do normal microflora protect against infection?

Answer 50

produces antimicrobial substances to protect from external pathogens