Mid Semester Exam Study Flashcards
(42 cards)
0
Q
Escherichia?
A
A prokaryote (cell that lacks a membrane bound nucleus)
1
Q
Amoeba?
A
A eukaryote ( a cell that contains a nucleus)
2
Q
Vision?
A
Mature virus comprising all parts
3
Q
Viroid?
A
Infectious circular RNA plant pathogen
4
Q
Prion?
A
Infectious protein
5
Q
Viral nucleic acid
A
- does not contain genes needed for synthesis of new virus
- does not contain genes needed for energy generation
- only RNA or DNA not both (single stranded or double stranded)
6
Q
Viral capsid
A
- protein coat covering virus
- symmetrical
- antigenic properties
- protects nucleic acid from enzymes
- assists in attachment and entry
7
Q
Viral envelope
A
-lipid bilayer made from membrane of host cell
8
Q
A virus lacking an envelope is considered to be?
A
A naked virus
9
Q
Naked viruses are considered more resistant to the environment because?
A
- the envelope is damaged easily
10
Q
Inactivation of a virus outside of a host cell
A
- heat of 60 degrees for 30 minutes
- envelope can be destroyed by detergent
- chemically harder to kill than bacteria
- some can last days at 4 degrees
- some are stable in salt solution
- generally stable at pH 5-9
11
Q
Virus classification
A
- classified by:
- nucleic acid
- DNA virus
- RNA virus
12
Q
A virus genome is either?
A
- DNA or RNA
13
Q
What is a genome?
A
- a virus genome is RNA or DNA never both
- it is encoded in its nucleic acid
- may be single stranded, double stranded, circular or linear, positive sense (mRNA) or negative sense
14
Q
Structure of a virus
A
- nucleic acid genome
- enclosed in protein coat or capsid
- can be further enclosed in envelope
- non- living
- smallest infectious agent
15
Q
3 types of cell cultures for growing a virus?
A
- primary cell culture
- secondary cell culture
- immortal cell culture
16
Q
What is involved in a primary cell culture?
A
- embryonic tissue removed from embryo using sterile techniques
- tissue must then be broken down to individual cells physically (chopped) and chemically (trypsin and/or detergent)
- cells are then placed into an appropriate liquid medium
17
Q
What is involved in a secondary cell culture?
A
- cells are derived by re-trypsination and re-culture in fresh medium of successfully grown primary cells
18
Q
What is involved in an immortal cell culture?
A
- using originate from tumour and are therefore cancer cells, such as CHO, Hela and vero cells
19
Q
Making vaccines- advantages and disadvantages
A
- traditional method for influenza virus vaccine production was to use chicken eggs
- pros: inexpensive, well established
- cons: need millions of eggs, production time is 6 months
20
Q
Characteristics of a Prion
A
- abnormal proteins
- transmitted or inherited
- slow onset (10-30 years)
- no vaccine or treatment available
- causes slow reduced function of brain
- no immunological activity
- in mammalian species
- survives in pastures
- causative agent of spongiform encephalopathies
21
Q
Prions are resistant to what?
A
- chemical disinfectants
- heats (360 degrees, 1 hour)
- DNAse and RNAse
- UV lighting
- ionising radiation
- high temp autoclaving
- burying for 3 years
- formaldehyde fixation
22
Q
Polymerase chain reaction objective?
A
- to amplify unknown DNA, generating millions of copies of a single DNA piece of a DNA sequence
23
Q
What occurs in polymerase chain reaction?
A
- primer binds to unknown DNA
- amplify DNA
- compared with known sequences
24
Steps of polymerase chain reaction
1. Denaturation
- 1 minute at 94 degrees
2. Annealing
- 45 seconds at 54 degrees
3. Extension
- 2 minutes at 72 degrees
25
What is innate immunity?
- NOT SPECIFIC for the pathogen
- combats all pathogens no matter their type (bacteria, viruses, pathogens)
- innate defence
26
What is involved in innate defence?
- surface barriers
- phagocytic cells
- natural killer cells
- inflammation
- anti microbial proteins
- fever
27
What is an antibody?
- protein
- made by B cells
- is a receptor of B cells
- binds to antigens
- product of adaptive immunity
- end product of humeral immunity
28
What are Kinins?
- act on smooth muscle (causes contractions)
- block nervous impulses (causes muscle relaxation)
- causes contractions of vascular endothelial cells (bradykinin)
- releases endothelial cell adhesion molecules
- responsible for pain and itching with inflammation
- inactivated by proteases
29
What are cytokines?
- soluble mediators of the immune system
- chemical drivers of the immune system
- mediate signals between leukocytes (interleukin 1-23)
30
What is acquired immunity?
- the immunity that our body gains over time
- the body generates special chemicals, also known as antibodies that neutralise the harmful toxins produced by the pathogen
- each specific such of pathogen needs a custom chemical to neutralise it
31
What are the major cell types of acquired immunity?
- T lymphocytes
| - B lymphocytes
32
4 branches of acquired immunity?
- specificity
- diversity
- discrimination between self and non- self
- memory
33
Immunological memory
- the ability of lymphocytes to respond faster and more strongly to a re-encounter of the same antigen
34
Variable region of an antibody
- V regions are the variable part of an antibody
| - C regions are the constant part of an antibody
35
The immunoglobulin Ig structure?
- Y-shapes molecule that consists of four polypeptide chains, two identical heavy chains and two identical light chains, connected by disulfide bonds
36
What is the crystallisable region of an antibody?
- also known as the Fc region is the tail region of the antibody that interacts with cell surface receptors called Fc receptors
- this property allows antibodies to activate the immune system
37
What is CD3?
- cluster of differentiation 3
- protein complex and is composed of 4 distinct chains
- these chains associate with T-cell receptors to generate an activation signal in T lymphocytes
38
What are the two types of T cells?
- CD4 T cells and CD8 T cells
- in healthy individuals ratio in circulation is 2CD4: 1CD8
- CD4 binds to cells expressing MHC class 2 molecules
- CD4 cells: dendritic cells, macrophages, B cells and thymus epithelial cells
- CD8 cells bind to cells expressing MHC class 1 molecules ( all nucleated cells)
39
What are the co-receptors on T cells and what do they bind to?
- activation of T cells require co- receptors
- co- receptors are the CD4 and CD8 molecule which are provided by the T cell
- CD4 T cells are helper T cells and bind to MHC class 2 ( exogenous antigens)
- CD8 T cells are cytotoxic and bind to MHC class 1 ( endogenous antigens)
40
What cells have MCH1, 2, CD3, CD4, CD8?
- MHC1: viral replication cells, bacterial cells, parasites, tumours
- MHC2: dendritic cells, macrophages, B cells, thymus epithelial cells
- CD4: T helper cells
- CD8: cytotoxic cells (killer cells)
- CD3: expressed on surface of mature T cells
41
Primary and secondary immune response?
- primary response: first encounter with virus or bacteria. Naive T cells and B cells are activated and form memory cells
- secondary response: re-encounter of the same virus/ bacteria which you now have memory T cells and B cells causing a rapid response
