Chapter 7 + 8 Flashcards
Disease can be caused by (4)
Genetics
Diet
Environment
Pathogen
Ways disease is spread (7)
Direct contact Indirect contact (e.g. Where they touched) Water Air Food Vectors Travel
Features of a disease (Simpsimp)
Signs
Symptoms
Incubation period
Infective period
Non-infectious disease
Diseases that cannot be transmitted from one individual to another (includes genetic disease)
Infectious disease
Disease that can be transmitted from person to person e.g. Diphtheria
The host of a disease…
May not show signs of disease
Contagious disease
Spread through contact
Autoclaving experiment
Louis Pasteur
Autoclaved with upside down straw took most time
Pathogen
A biological agent (cellular or non cellular) that causes disease in a host/individual
Examples of pathogens (5)
Prions Viruses Bacteria Fungi Worms
Cellular agents
Cellular organisms with a cellular structure
Non-cellular agents
Infective agents that lack a cellular structure
Cellular agent examples
Bacteria, fungi, protists, worms
Non-cellular examples
Virus, viroid, prion
Infection
Invasion and growth of a harmful pathogen within the body of a host
Antigenic virus
A new virus can arise when a host is infected with more than one viral strain at the same time, recombination of these parts may occur between the different strains, resulting I. A viral strain that has not been found before.
Disease
Any change from a state of health that impairs the function of an individual in some way, except that directly resulting from physical injury
Parasite
an organism that lives in or on another organism (host), and feeds and obtains shelter from it, causing harm to the host, usually without killing the host.
Endoparasite
lives inside of host
Ectoparasite
lives outside of host
Things that prevent disease
quarantine, vaccinations/immunisation,
Prions
abnormal and infectious agents, consisting of folded pieces of protein that are responsible for degenerative neurological diseases.
How prions work (3)
convert normal prion proteins into infectious proteins via simple contact (alpha helices-beta), cause cell to burst, released prions
Viruses
particles lacking cellular organisation and consisting of genetic material surrounded by a protein coat; reproduce only in a host cell.
Viruses can’t…
independently reproduce
Viruses don’t…
respire, or produce waste, need to reproduce
Viruses are…
obligate intracellular parasites
In plants viruses cause
stunting, and dwarfism
Viruses are made up of (2)
core of DNA/RNA and protein coat, they are spherical shaped
How viruses enter cell (4)
pierce surface, attach to a receptor site prior to injecting genetic components, or cell may take in virus via endocytosis (e.g. influenza)
How viruses reproduce (6)
attachment/enter, penetration, biosynthesis of viral components, viral parts are assembled together, lysis of host cell (use enzymes)
Obligate intracellular parasites meaning (7)
parasites that can survive only inside cells.
Viroids
small pieces of RNA that cause diseases that cause diseases. Smallest known infective agents, have naked RNA, highly complementary, circular, single stranded RNA, in plants only
Bacteriophages
virus that infects bacteria
Bacteria cell walls are made out of
peptidoglycan
Fungi cell walls are made of
chitin
How bacteria work (5)
attach to wall, DNA injected in, DNA takes over, uses energy in cell, makes new bacteriophages
Host
organism or cell that a specific parasite lives in or on.
Epidemic
large region, short period; spread by travelling
Pandemic
world wide, longer time
Protozoa is…
protist
Three shapes of bacteria
coccus (round), bacillus (rod), spirochaete (spiral),
Capsule
gelatinous layer surrounding the cell wall of some bacteria.
Bacteria can produce toxins
exotoxins which are secreted by bacteria whilst they are alive, and endotoxins are released upon destruction of the bacterium
Virulence
degree to which an organism can cause disease. Capsule increases virulence.
Spore
reproductive structure that is resistant to heat and desiccation in bacteria, fungi and plants
Gram strain
differential stain by which bacteria are classified as Gram positive or Gram negative depending on chemical differences in their cell walls.
Gram positive
violet, penicillin (antibiotic, inhibits cell wall)
Gram negative
pink, drugs
Facultative anaerobe
can live if there is O2 or not
Obligate
can’t live in O2 conditions
Bacteria can cause disease if
there is a host, bacteria can reproduce, can act on tissue,
Vector
in disease, an insect or other animal that carries a pathogenic organism from one host to another.
Gangrene
lack of blood supply, dead tissue
Toxins
substances poisonous to an organism.
Endotoxins
toxins produced by an organism and released only when the organism disintegrates.
Exotoxin
toxin secreted into the surrounding medium by a micro-organism as it grows.
Chemotherapy
use of chemicals in the treatment of disease.
Classifying viruses (3)
kind of host cell, type nucleic acid (RNA or DNA), different structures that make up the protein coat (shape, symmetry, number of coats.)
Bacteria
essential for life, can tolerate extreme conditions
In order to reproduce bacteria needs
adequate nutrients and water, and an appropriate temperature and pH.
Bacterial infections more in animals that in plants due to…
alkalinity
Carrier
a person who shows no sign of an infectious disease but is host to the causative agent and can transmit it to other people.
2 main types of immune responses
specific and non-specific
Other names for specific and non-specific respectively
innate, adaptive
First line of defence (10)
intact skin, fatty acids on skin (acidic), sebum, mucus in respiratory tract, cilia, acid in stomach, natural flora, lysozome in tears and saliva, lactoperoxidase, spermine
Sebum
oily fluid secreted by sebaceous glands in the skin and hair
Lysozome
enzyme that catalyses the lysis of bacteria
Lactoperoxidase and spermine are…
toxic
Intact skin
acts as a barrier to microbe entry, secretes fatty acids and sweat to inhibit microbial growth, low pH
Natural secretions
contain bactericidal agents, e.g. tears and saliva
Mucous membranes
located in respiratory tract/nasal passage/digestive tract, cells secrete mucous which traps microbes
Natural flora
inhibits growth of pathogens, when altered leads to opportunity infection, e.g. bacteria in gut
First line plants
galls, waxy cuticle and epidermis, chemicals
Galls
little cavities that form around invading pathogens (walls off the infections through thickened cell layer)
Chemicals example
(pathogenic organisms) e.g. phenolic compounds
What is in the second line (PENCCII)
phagocytes, enzymes, natural killer cells, complement proteins, inflammation, interferon, cytokines,
Phagocytes
white bloods cells that engulf and destroy microbes and foreign matter. Made in bone marrow.
Types of phagocytes
neutrophil, monocyte (most common),
Neutrophils
white blood cell that phagocytoses pathogenic organisms
Macrophages
white blood cell that phacgocytoses pathogenic organisms,
Monocyte
immature (undifferentiated) form of macrophage
Dendritic cell
leukocyte that phagocytoses organisms
Eosinophils
white blood cell that kills eukaryotic pathogens by secreting destructive enzymes
Basophils
white blood cell that is involved with the allergic response
Lymphocytes
cells that are associated with the lymphatic system
Two types of lymphocytes
B cells, T cells?
B cells
lymphocytes that are produced in the bone marrow
T cell
produced in the bone marrow except they migrate to the thymus to mature
Lymphatic system
fluid from tissues drays into lymph vessels, lymph in lymph vessels pass through masses of tissue called lymph nodes, lymph in lymph nodes contain lymphocytes which are involved in the immune response
Antigens
proteins that identify cells and that can potentially be recognised by an immune system leading to an immune response
First and second line are
non-specific
First line of defence is
physical and chemical barriers to entry
Second line is
non-specific immune response when pathogens enter the body
When a monocyte leaves the blood stream….
becomes macrophage
Natural killer cells
kill virus infected body cells. Other white blood cells can attach to and destroy parasites. Cytotoxins or endotoxins.
How NK cells destroy kill virus infected cells/parasites
contain receptors to self antigens, any cell missing self receptor is killed through perforation of the cell membrane
What is pus
dead white blood cells
Complement proteins
assist the phagocytes to engulf foreign matter by attaching to it. Made in liver.
Functions of complement proteins
make pathogens easier to phagocytose, perforate cell wall and membrane of bacteria
How many complement proteins in body
20?
When body is infected… what happens (antibody)
antibody-antigen complex occurs, which activates complement protein
Role of complement protein
stick to invading microbes to make them more readily identified by phagocyte, stimulate phagocytes to become more active, attract phagocytes to site of infection, destroy membranes of microbes
Interferon
acts on uninfected cells to make them resistant to viral infection, cause production of antiviral proteins, useful if virus doesn’t have to travel far
Cytokines
protein molecules that act as messengers between cells, produced by all cells in immune response, particularly T cells
Inflammation
occurs when arterioles in the area around a cut dilate to increase permeability, resulting in an increased blood supply to the area, blood carries phagocytes to area, phagocytes move to surrounding tissue, release histamine to attract more phagocytes, creates clots, and pus
How inflammation occurs
macrophages and dendritic cells have receptors on their cells that can bind to molecules found only in damaged cells or pathogens and when these receptors bind, the macrophages and dendritic cells secrete cytokines which causes the nearby blood vessels to dilate and become ‘sticky’ and permeable, hence more blood passes through this area and fluid leaks into this area leading to redness and swelling. Neutrophils and monocytes adhere to blood vessels and migrate to the extracellular space, they use their receptors to detect the pathogenic agents, they phagocytose these agents and destroy them by fusing vesicles with lysosomes
Inflammation controlled by
plasma enzyme systems and serotonin
Basophils used in
inflammation, allergic response
Third line of defence includes
lymphocytes - T cells, B cells, plasma cells, clonal selection, ….. response, cellular response
?????
Where B cells are made
bone marrow
T cells made
created in bone marrow, mature in thymus
Difference between specific and not
specific remembers specific type of antigen
MHC stands for
Major Histocompatibility Complex
Class 1 markers
all body cells except red blood cells
Class 2 markers
only on T and B cells as well as some macrophages
Antigen
a material that triggers an immune response.
Types of B cells
memory B cells
Types of T cells
T helper cells, Cytotoxic T cells, suppressor T cells, memory T cells,
‘Self antigens’
the antigens of B and T cells that identify non self and trigger T/B to act
Plasma cells
help us reproduce a large number of antibodies quickly, but often overproduces so we have spare which undergo apoptosis
Clonal selection
antigen selects what B cell will lead to death, selected B cells reproduce (clone), and this continues, most of these will differentiate into plasma cells (creates delay)
T cells do not
make antibodies, they have a specific shape to match antigen
Helper T cell
(flag) displays parts of dead foreign material on self
Cytotoxic T cells
(identify and kill) kills viral infected cells, identify its antigen and class marker, punch holes in infected cell (contents ooze out),
Antibiotics
naturally occurring substances that inhibit the growth of, or destroy, bacteria and other micro-organisms
Narrow-spectrum
characterises an antibiotic that is effective against a few pathogens only
Broad-spectrum
characterises an antibiotic that is effective against many different pathogens
Sensitivity test
find out drug to use for bacterial infections
2 types of vectors
injecting, carrying
Suppressor T cells work by
directly killing immune cells, inhibiting secretions, secreting proteins that alter immune cell functions - stop when it is “defeated” to not waste resources
Mast cells
nflammatory response - a cell filled with basophil granules, found in numbers in connective tissue and releasing histamine and other substances during inflammatory and allergic reactions.
Five types of antibodies (immunoglobulin)
IgM, IgG, IgD, IgA, IgE
IgM
antibody that is secreted first by plasma cells in an immune response. It is composed of five antibody molecules joined together.
IgG
antibody that is secreted some time after IgM in the initial immune response, and is the only antibody secreted in a secondary immune response (second or subsequent infection by the same antigen). This is composed of single antibody molecules
IgD
this is the antibody receptor found on B cells
IgA
this is found in the respiratory tract and gastrointestinal tract, and neutralise infectious agents that commonly attempt to invade through these mechanisms. This is composed of two antibody molecules joined together end on end.
IgE
this is involved in the allergic response.
On antibody, there is a … portion
Fc portion that can bind to neutrophils and macrophages
Fc portion
antibody can neutralise toxin, antigen-antibody complexes can be formed (agglutination), phagocytes attached to antibody can engulf an antibody-antigen complex making it better to engulf for phagocytes (jam on toast), activate complement proteins which perforate pathogenic agents,
Specific immune response has memory which is…
the capacity to recognise antigens that have previously entered the body
Hypersensitivity
allergic response and autoimmune disease
Allergic response
IgE antibody, bind via Fc of mast cell, histamine
Histamine causes
pain, itchiness, swelling, can be anaphylactic shock
Autoimmune diseases examples
e.g. type 1 diabetes, rheumatoid arthritis, multiple sclerosis
Induced immunity
artificial
Natural immunity
natural
Passive immunity
given antibodies
Active
produce on own
B cells
(have antibodies, identifies, produce, secrete) have immunoglobulin (antibodies) on surface, identify antigens, recognise only one type of antigen, identifies antigen, produces antibody and secretes it
An antibody is what kind of macromolecule
Protein
How do fibrons work in clotting
They act as nets that trap platelets (and also red blood cells)
