Chapter 4/5 - Immunology and Microbes Flashcards
What is a pathogen?
A disease causing agent
What is innate immunity?
A rapid immune response to a large spectrum of diseases
What is adaptive immunity?
A slow response to more specific diseases
What are the two defences in innate immunity?
Barrier defences and internal defences
What are the two defences in adaptive immunity?
A humoral response and a cell mediated response
What are the barrier defences in innate immunity?
Skin, mucous membranes and secretions
What are the internal defences in innate immunity?
Phagocytic cells,
Natural killer cells
Antimicrobial proteins
Inflammatory response
What is a humoral response?
When antibodies defend against an infection in body fluids
What is a cell-mediated response?
When cytotoxic cells defend against infection in bodily cells
What is lysozyme?
An enzyme that breaks down bacterial cell walls
What are the major immune cells in insects?
Hemocytes
What is phagocytosis?
The ingestion and breaking down of microorganisms
What is the ph of the stomach and skin
Stomach - pH 2
Skin/ Sweat - pH 3-5
What are toll-like receptors? (TLR)
A recognition protein found in mammals that alerts the body of pathogens
What are the two main types of phagocytic cells in the mammalian body?
Macrophages and neutrophils
Describe the function of neutrophils
They circulate the blood and are attracted by the signals of infected tissues - they then ingulf and destroy any infected pathogens
Describe the role of macrophages
Big eaters that engulf and destroy pathogens
Where can you find macrophages?
Either circulating the blood or residing in organs and tissues where they are most likely to encounter pathogens aka the spleen
Where can you find dendritic cells?
Surrounding tissues that have contact with the environment aka skin
Where can we find eosinophils?
Surrounding epithelial tissue
What is the role of eosinophils?
To defend against multicellular pathogens such as parasites by discharging destructive enzymes
What is the role of natural killer cells?
In innate immunity they circulate the body in search of abnormal surface proteins before releasing chemicals that result in cell death
What are interferons?
Proteins that provide an innate defence by releasing chemicals that alert normal cells to prevent viral replication therefore limiting cell to cell spread
What version of interferons can some white blood cells secrete?
A version that enhances phagocytic cell abilities
What are cytokines?
Signalling molecules
What are mast cells?
Immune cells that secrete histamine in order to induce an inflammatory response
What are lymphocytes?
Immune white blood cells
Where do lymphocytes originate?
From stem cells in bone marrow
Where do lymphocytes mature to T cells?
In the thymus
Where do lymphocytes mature to B cells?
Bone marrow
Where do lymphocytes mature to natural killer cells?
In the blood
What is an antigen?
Any substance that initiates an adaptive immune response
What protein allows B and T cells to bind to pathogens?
Antigen receptors
How many antigen receptors reside on the B and T cell surface?
100,000
What is an epitope?
Part of an antigen that binds to an antigen receptors
Describe the structure of a B cell antigen receptors
Y shaped protein consisting of four polypeptide chains= two identical heavy chains and two identical light chains
What links the four chains of B cell antigen receptors
Disulphide bridges
Describe the structure of antigen receptors in T cells
Two chains - one alpha and one beta
What is the name of the display protein that allows T cells to bind to antigens?
Major histocompatibility complex (MHC)
What is self tolerance in immunity?
The way in which B and T cells are able to able to differentiate the normal cells from the antigens
How long is a primary immune response?
10-17 days
How long is a secondary immune response?
2-7 days
Where does the humoral response occure?
In the blood and lymph
What T cell activates the humoral and cell mediated responses?
Helper T cell
What are the three types of antigen presenting cells?
Dendritic cells
Macrophages
B cells
What differentiates a normal body cell from a antigen presenting cell?
Normal cells only have class 1 MHC Antigen presenting cells have class 1 and 2 MHC
What is the CD4 protein?
Found on the surface of helper T cells it allows for helper T cells to bind to antigen presenting cells class 11 MHC
What two things allows for the activation of B cells
A helper T cell
Proteins on the surface of pathogens
How to antibodies prevent infection of cells?
Antibodies prevent pathogens or viruses from binding to normal cells
What are the five types of immunoglobulin expressed by B cells?
IgA, IgM, IgD, IgE, IgG
What cells produce immunoglobulin?
Plasma cells
What B cell antigen receptors is exclusively membrane bound?
IgD
What is the accessory protein CD8?
It allows for cytotoxic cells to bind with MHC
What is active immunity?
When a pathogen infection of immunisation prompts an immune response
What is passive immunity?
Immunity passed from mother to child
Where would you find antibody class IgA
Soluble in secretions such as tears, saliva, breast milk and mucous
Where would you find antibody class IgG
Crossing the placenta from mother to child
Where would you find the antibody class IgM
First antibody produced in an immune response found on both mature and immature B cells
Where would you find class IgE antibodies?
In tissues as it is important to allergies and. Parasites
Where would you find class IgD antibodies?
On the membrane of mature B cells
What is mutualism?
Both organisms benefit
What is commensalism?
One benefits; the other is unaffected
What is parasitism?
One benefits while the other is harmed
What do obligate aerobes require for cellular respiration?
Oxygen
What are obligate anaerobes poisoned by?
Oxygen
How do prokaryotes metabolise nitrogen?
By converting it to ammonia
What is a virus?
Small nuclei acid genome enclosed in a protein capsid or viral envelope
What do viruses use to replicate?
Enzymes, ribosomes and small molecules
What are phages?
Viruses that effect bacteria
What two ways can phages replicate?
The lyctic cycle and the lysogenic cycle
What is a virulent phage?
A phage that results in the destruction of the host bacterium via lysis
What is lysis?
Rupture or the cell membrane = destruction of the cell
What is a temperate phage?
A phage that can choose between the lytic cycle ie killing the host bacterium of the lysogenic cycle = replicates the host cell
What is a prophage?
A bacteria that has been overtaken by a phage
What phages can undergo the lyctic cycle?
Both temperate and virulent
What does the lyctic cycle result in?
The destruction of the host cell and release of progeny phages
What does the lysogenic cycle result in?
The overtaking of the bacteria host cell
What is an epidemic?
Widespread outbreak of a disease
What is a pandemic?
A global outbreak of a disease
What was the H1N1 virus?
In 2009 a new flu virus was created from pigs, humans and birds causing a pandemic
What was the H5N1?
Bird flu
How do viruses enter plants?
Through damaged cell walls - aka horizontal transmission
What are prions?
Slow acting, indestructible infectious proteins that cause brain disease in mammals
How do prokaryotes reproduce?
Via binary fission
What are fimbrae?
Hair like appendages that attach prokaryotes cells to other cells
What three techniques can result in genetic diversity of prokaryotes?
Transformation, transduction and conjugation
What is transduction?
When foreign dna is introduced into a cell via a virus
What is conjugation?
The temporary union of bacterial cells that results in exchanging of DNA
What are the four modes of nutrition?
- Photoautotrophy
- Chemoautotrophy
- Photoheterotrophy
- Chemoheterotrophy
What are photoautotrophy?
Photoautotrophs are organisms that can make their own energy using light and carbon dioxide via the process of photosynthesis.
What are chemoautotrophies?
an organism, typically a bacterium, which derives energy from the oxidation of inorganic compounds.
What are photoheterotrophs?
they are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source.
What are chemoheterotrophs?
organism which derives its energy from chemicals, and needs to consume other organisms in order to live.
What is gram-positive bacteria?
Positive result in a gram stain test
What colour does gram positive bacteria turn the gram stain?
Violet - due to their thick layer of peptidoglycan
What colour does gram negative bacteria stain?
Pink or red - due to their thick layer of peptidoglycan
What are endospores?
A strong, resistant bacteria
What is bioremediation?
Process used to heal contaminated media
What are endotoxins?
Endotoxins are compounds found in the cell walls of Gram negative bacteria. These compounds help to form a semi-permeable membrane which is designed to protect bacteria from threats.
What are exotoxins?
A toxin secreted by bacteria
