Viral and Bacterial Infections

Question 0

What are viruses?

Answer 0

Small infectious agents that can replicate only inside the living called of a host. Depend on a host cells machinery to enter, replicate, and assemble new viruses.

Question 1

What is a a) pneumotropic b) lymphotropic c) enterotropic and d) neurotropic infection?

Answer 1

a) One via the lungs: upper and lower respiratory tract epithelial cells
b) lymphatic cells
c) gut epithelial and liver cells
d) neuronal cells

Question 2

What is the term given to a cell in which a virus can enter?

Answer 2

Susceptible cell

Question 3

What do susceptible cells often require?

Answer 3

A specific receptor which can bind a viral attachment protein

Question 4

What are the three types of infections?

Answer 4

Acute, latent or persistent and slow

Question 5

Which (acute, latent or slow) can the immune system contain and clear?

Answer 5

Acute

Question 6

Which (acute, latent or slow) has frequent reactivation?

Answer 6

Latent and slow

Question 7

Which (acute, latent or slow) has the slowest onset of symptoms?

Answer 7

Acute

Question 8

What does HIV stand for?

Answer 8

Human immunodeficiency virus

Question 9

Do a) 10 million, b) 3300 or c) 3.3 million die annually from HIV?

Answer 9

C

Question 10

What does HIV cause?

Answer 10

AIDS- acquired immunodeficiency syndrome

Question 11

What does AIDS target and why?

Answer 11

T helper cells to make them into factories in order to produce thousand of copies of the virus.

Question 12

Why is AIDS so destructive?

Answer 12

Leads to low levels of T helper cells and a loss of cell mediated immunity which highly increases susceptibility to infections

Question 13

How is HIV transmitted?

Answer 13

Unprotected sex, sharing needles, mother to foetus and blood products

Question 14

How many classes of anti-HIV are there today and how to they work?

Answer 14

5 and they target different stages of the viruses life cycle

Question 15

What 5 stages do anti-HIV drugs target?

Answer 15

Entry, integration, transcription, assembly and release/budding.

Question 16

How are anti-HIV drugs takes?

Answer 16

Different classed drugs are combined to act on different points, this is called highly active antiretroviral therapy (HAART)

Question 17

Why is one class of drug not sufficient?

Answer 17

As resistance is common in HIV due to mutations

Question 18

Why are respiratory viruses common?

Answer 18

As the lungs have a very large surface area and come into contact with huge volumes of air every minute.

Question 19

How are respiratory viruses transmitted?

Answer 19

Droplet inhalation, airborne and direct, or exhaled breathe, within close proximity.

Question 20

The deeper you get into the lungs via the respiratory tract the ? Does the infection get?

Answer 20

More severe

Question 21

What does infection cause and how?

Answer 21

General cell destruction, via virus-mediated death and immune mediated death

Question 22

Why is influenza a devil?

Answer 22

Mutates into new strains very easily and frequently

Question 23

What is antigenic shift in viruses?

Answer 23

When 2 virus infect the same cell and a new virus emerges

Question 24

Describe influenzas external morphology?

Answer 24

Polymorphic particles and 3 membrane proteins ( NA, M2 and HA)

Question 25

Describe influenzas interior morphology?

Answer 25

Sheath of matrix beneath membrane and 8 RNA segments encode the viral genes

Question 26

What two steps in influenzas life cycle can be targeted by drugs?

Answer 26

Segment release into the cytoplasm (endoscope release) and general release

Question 27

What drugs are influenza anti viruses?

Answer 27

Neuroamides

Question 28

What two properties do antibiotics have?

Answer 28

To kill (bactericidal) or to inhibit (bacteriostatic)

Question 29

Define the term antibiotics?

Answer 29

A group of drugs that kill or inhibit the growth of pathogens without causing serious damage to the host.

Natural products isolated from bacteria, fungi etc. Semi-synthetic

Question 30

How do bactericidal and bacteriostatic antibiotics work?

Answer 30

Bactericidal disrupt cell wall syntheses and bacteriostatic interfere with DNA/protein synthesis

Question 31

What level of activity do antibiotics have?

Answer 31

Some have very broad and some narrow, a large spectrum

Question 32

How are antibiotics classified?

Answer 32

By mechanism

Question 33

What do sulphonamides or trimethoprim do?

Answer 33

Prevent nucleotide syntheses by inhibiting folate synthesis

Question 34

What do ß-lactams do?

Answer 34

In bacteria and plants they prevent cell wall synthesis

Question 35

What feature do ß-lactam antibiotics have?

Answer 35

A ß-lactam ring

Question 36

What antibiotics inhibit protein syntheses?

Answer 36

Tetracycline (inhibits tRNA binding)
Aminoglycosides (miss read)
Chloroamphenicol (inhibits peptide bond formation)
Pyromycin (causes premature termination)
Enthrythromycin (prevents translocation)

Question 37

What antibiotics inhibit RNA transcription?

Answer 37

Rifamycins

Question 38

How are trimethoprim and sulphonamide given?

Answer 38

Orally. Both absorbed in GI tract

Question 39

What’s the difference between a gram negative and a gram positive bacteria?

Answer 39

Gram negative have an outer membrane which creates a peri plastic space, this is not present in gram positive bacteria

Question 40

What is the structure of peptodoglycan?

Answer 40

N-acetyl glucosamine is linked to N-acetyl muramic acid and chains are cross linked by oligopeptides

Question 41

Is it only ß-lactams that prevent cell wall synthesis?

Answer 41

No

Question 42

How do neuroamides work?

Answer 42

Cleaves salicylic acid from HA ok neighbouring viruses, or cleaves salicylic acid from the previously infected cell