Midsem

Question 0

Can viruses survive outside host

Answer 0

No

Question 1

Are viruses the smallest infectious agent or smallest living organism

Answer 1

Smallest infectious agent

Not living

Question 2

What are the two types of RNA and DNA

Answer 2

Single stranded and double stranded

Question 3

Viral nucleic acid

Answer 3

Relies on host

Must be inside to live

Question 4

Why do viruses need living cells to replicate

Answer 4

Lack cellular organelles - ribosomes

To produce viral proteins and replicate the need to hijack host cell

Question 5

What are the three steps for PCR

Answer 5

1. Denaturation for 1 min at 94 degrees
2. Annealing for 45 secs at 54 degrees
3. Extension for 2 mins at 72 degrees

Question 6

What are the three lab methods for culturing viruses

Answer 6

1. In cell culture
2. In embryo acted eggs
3. In laboratory animals

Question 7

how does PCR work

Answer 7

Primers to bind to unknown DNA
Amplifier DNA
Sequenced
Compare sigh known sequence

Question 8

How are viruses detected

Answer 8

Rash ect
History and current signs and symptoms
Immunofluovescence used to determine what virus is

Question 9

Method of inhibition of viruses

Answer 9

1. Filtration
     Filtered out viruses 
     Contamination of filter appears may occur
2. Radiation
     Denature DNA
     Uses cobalt - 60
     Dangerous to use

Question 10

Methods of inactivation of viruses

Answer 10

Chemical:

• detergents
• alcohol
• bleach
• halogens
• acids and alkalises
• formaldehyde
• pendics

Physical

• heat more then 60 degrees for 30 mins
• sterilisation
• autoclaving

Question 11

Characteristics of prion

Answer 11

Causative agents
Can't be transmitted, inherited or idiopathes
Resistance to
- chemical disinfection
-heat
- DNA ase, rna ase, protienase
- uv light
- high temp autoclave
- survive in parasite

Question 12

What is innate immunity

Answer 12

Not specific

Combat all pathogens

Question 13

What is involved in innate immunity

Answer 13

1 surface barriers

- skin
- mucous membrane
- epithelial three parts
    1. Mechanical: mucosal and epidermal epithelium
    2. Chemical: mucous, sebrum, lyzosomes
    3. Microbiological: synthesize and excrete vitamins, prevent colonisation. By pathogens

Question 14

Steps involved in inflammation

Answer 14

1. Presence of dead cells attract phagocytes
2. Presence of dead cells cause cytokine release, lipid mess and mediators of inflammation
3. Causes recruitment of leukocyte

Question 15

What is an antibody

Answer 15

A protein made by B cells which binds to antigens
Specific
Part of humoral immunity

Question 16

What is the variable region on an antibody

Answer 16

Where the antibodies bind

Top part of antibody

Question 17

What is crystallisable fragment of antibody

Answer 17

Same for same species
Interacts with cell surface receptors
Allows antibodies to activate immune system

Question 18

Characteristics of all immunoglobin agents igG, IgM, igA, igD, IgE

Answer 18

IgG- blood, lymph, CSF, perotineal fluid
Equally spread intra/extra vascular
Only ig to pass through placenta
Typical antibody shape

IgM- first produced after immunization of infection
High levels recent infection
First antibody made by fetus

IgA- external secretion (saliva, mucous, tears, b sweat)
Antiviral activity

IgD- low concentrations
Co-expressed with IgM
Autoimmunity

IgE- lowest secum concen
Active against parasites (worms)
Role in hypersensitivey reactions

Question 19

What is acquired immunity

Answer 19

Immunity our body gains over time
Generate antibodies that neutralize toxins
T lymphocytes and B lymphocytes
1. Specificity
2. Diversity
3. Discrimination between self and non self
4. Memory

Question 20

Difference between a primary and secondary response

Answer 20

Antibody response to infection starts with IgM

- look at graph

Question 21

What is immunological memory

Answer 21

Ability of lymphocytes to respond faster and more strongly to a re encounter of same antigen
Vaccination

Question 22

What is CD

Answer 22

Clusters of differentiation antigens
Cell surface molecules
Associated with growth stages
Phenotyping

Question 23

What are the two types of T cells

Answer 23

Helper T cells

Killer T cells

Question 24

What are co-receptors on T cells and what do they bind

Answer 24

Cd4 T cells - t helper cells - release cytokines - binds to MHD class II cd8 T cells - killer T cells - releases cytolytic enzymes - binds to Mhc class I

Question 25

What cells have mhc1, mhc2, cd3, cd4, cd8

Answer 25

Mhc1: viral replication cells, bacterial cells, parasites,tumours and foreign peptides Mhc2: dendritic cells, macrophages,b cells Cd4: t helper cells Cd8: killer T cells Cd3: expressed on surface of mature T cells in association with co-receptor molecule

Question 26

What is the role of a cytokine

Answer 26

Regulation of immune system

Question 27

What are the three types of cytokines

Answer 27

1. Autocrine: releases cytokine to affect its self 2. Paracrine: effect on closer/adjacent other cells 3. Endocrine: chemical that effects another part of body

Question 28

What are the five main categories of cytokines

Answer 28

1. Cytokines regulate adaptive immune response 2. Cytokines that induce differentiation on T cell 3. cytokines that inhibit lineage specific T cell differentiation 4. Cytokines that enhance inflammatory response 5. Cytokines that effect leukocyte movement

Question 29

What is a viral capsid

Answer 29

Protein coat covering virus Antigenic properties Assist in attachment and entry Protect nucleic acid from enzymes

Question 30

What is a virus genome

Answer 30

``` A genome of virus is encoded in its nucleic acid Composed of either RNA or DNA Single or double stranded Linear or circular Positive or negative sense ```

Question 31

What are the three types of cell cultures for growing a virus

Answer 31

1. Primary cell culture: embryonic tissue 2. Secondary cell culture: cells derived from re-trypsin action 3. Immortal cell culture: uses originate from tumor/cancer cells

Question 32

What are the replication stages of DNA and RNA

Answer 32

1. Attachment: virus attaches to cell via protein 2. Penetration 3. Uncoating 4. 5. Early transcription and translation 6. Viral DNA synthesise 7. 8. Late transcription and translation 9. Assembly of viroid 10. Release

Question 33

What is cd3

Answer 33

Cluster of differentiation Protein complex, four distinct chains Associate with T cell receptor and 3 chain to generate activation signal in t lymphocyte