P2 Module 4: Disease+Evolution Flashcards
Pathogen
Microorganism that causes diesease. There are 4 types: bacteria, virus, fungi, protocist
Communicable disease
Disease caused by a pathogen thats transmitted from one host to another
Bacteria special features (3)
-Not membrane bound
-Prokaryotes
-Cell wall made up of peptidoglycan
Bacteria Diseases (3)
-TB: Animals
-Bacterial menginigtis: Humans
-Ring rot: potatoes + tomatos
3 ways bacteria damage host
-Produce toxins which are poisionous and damage host cells (hc)
-Break down cell mem
-Interfere w hc genetic material therefore cells cant divide
Treatment for bacterial disease
Antibiotics
Virus features (2)
-No nucleus
-Non living: have to use host to reproduce
Virus disease (3)
-HIV/AIDS: humans
-Influenza: animals
-TMV: plants
How do viruses damage host?
-Take over cell metabolism
-Viral genetic material gets into hc and is inserted into host DNA.
-When we carry out protein synthesis we make copies of the virus
-Cell burst destroying the cell and spreading to infect other cells
Fungi features (3)
-Eukaryotic
-Cell wall made up of chitin
-Extracellular digestion + release spores
Fungi disease (3)
-Black sigatoka: bananas
-Ringworm: cattle
-Athletes foot: humans
How do fungi disease damage host?
-Digest living cells and destroy them
-Produce toxins which affect host cells and causes disease
Protocist features
-Group of eukaryotic organisms (mem bound)
-Parasitic (use people/animals as their host)
-May need vector
2 protcist disease
-Malaria
-Potato/ tomato late blight
How do protocist damage host?
-Digest and use cells contents to reproduce
Direct transmission
Disease is transmitted directly from one org to another
Examples of direct transmission (3)
Droplet
Sex
Touching infected organism
Indirect transmission
Disease transmitted from one organism to another via an intermediate
Examples of intermediate (4)
Air
Water
Food
Vectors
Animal defences (6)
-Skin
-Mucous membrane
-Blood clotting
-Inflammation
-Wound repair
-Expulsive reflex
2 ways the skin act as a barrier to disease?
-Physical barrier
-Blocks pathogens entering body
-Chemical barrier
-Produces antimicrobial chemicals which clow the growth of microorganisms
How do mucous membranes act as a barrier to disease? (2)
-Protect body openings exposed to environment eg nose and ears
-Secrete mucus that traps pathogens and contains antimicrobial enzymes
How do blood clotting act as a barrier to disease? (2)
-Blood clot= mesh of protein fibres
-They plug wounds to prevent pathigens entering
How do inflammation act as a barrier to disease? (hotness and swelling)
-Swelling, pain, heat and redness
-Swelling: helps isolate any pathogens that entered
-Hot: vasodilation (widening blood vessels), making area hot, brings WBC to area to fight off pathogens
How do expulsive reflexes act as a barrier to disease? (3)
-Coughing + sneezing
-Theyre attempts to expel foreign objects eg pathogens
-Automatic
What are the two types of plant defences?
-Chemical
-Physical
Physical Plant Defences (3)
-Waxy cuticle=physical barrier to path
-Surrounded by cell walls= phy barrier against path that make it past waxy cuticle
-Produce callose, which gets deposited between cell walls it makes it harder for path to enter
Chemical Plant Defences
-produce antimicrobial chemicals which kill/ inhibit growth of pathogen
Immune response (3)
-When path gets past primary defences and enters body immune response happens
-Its the bodys reaction to a foreign antigen
-Involves non specific and specific stages
Diff between non specific and specific
Non= same way for all microorganisms
Specific= antigen specific, involves T and B lymphocytes
Non specific immune response/ phagocyotsis (5)
-Cells at wounds release cytokins (chemicals which attract neutrophils to the area
-Phagocyte recognises path as foreign due to another chemical called opsonins
-Opsonins attach to antigens
-Phagocyte engulf path
-Path is contained in a phagosome
-Lysosome fuses w phagosome
-Phagocyte presents path antigens on surface = APC (antigen presenting cell)
-Triggering specific immune response
Specific immune response pt 1 (T lympocytes) (5)
-Diff T lymp w diff receptors
-Receptors have comp shape to possible antigen that could enter body
-If antigen enters specific T lym bind to them = clonal SELECTION
-Then clonal EXPANSION happens when T lym w receptor thats comp divides by mitosis to produce clones of itself
-Differentiation occurs:
*T killer
*T memory
*T regulatory
*T helper
Differentiation of T lym and their roles (4)
-T killer, kills body cells w virus
-T memory, if infection w same path occurs they go through clonal expansion and differentiate quickly
-T regulatory, suppress immune system
-T helper, release chemicals called interleukines which stimulate activation of B lym (this is an example of cell signalling)
Specific immune response pt 2 (B lym) (4)
-Interleukins that T helper released will bind to receptor on surface mem of B lym
-Activating correct B lym
-B lym go thru clonal selection and have antibodies on their surface so one B lym will have comp antibody to antigen
-Go through clonal expansion and differentiation:
*B plasma
*B effector
*B memory
Differentiation of B lym and their roles (3)
-B plasma cells: produce antibodies
-B effector: divide to form plasma cell clones
-B memory: if antigen enters body again cells go through clonal expansion and diff quickly to produce plasma cells
Antibodies structure (4)
-Glycoproteins (proteins w carbohydrate group attached)
-Made up of 4 polypeptide chains (2 heavy and 2 light chains)
-Each chain has variable and constant region
-Has hinge region which allows flexibility
Roles of antibodies (3)
-Agglutination
-Neutralising toxins
-Preventing path binding to human cells
Antibody: Agglutination (4)
-Each antibody has 2 binding sites so antibody can bind to two path at same time
-Path clump together
-Phagocyte binds to antibodies and lots of path engulfed at once
Antibody: Neutralising toxins (3)
-Toxins have diff shapes
-Antibodies called antitoxins can bind to toxins produced by path
-Which deactivates them and neutralises them
Antibody: preventing path binding to human cells (2)
-Antibody binds to antigens and block cell surface receptors that path need to bind to host cells
-Therefore path cant attach or infect host cells
Active Immunity + its 2 types
When immune system makes its own antibodies, theres 2 types:
-Natural eg if u have chickenpox as a kid u wont get it
-Artificial eg vaccination
Passive Immunity + its 2 types
When you get given antibodies made by a different organism
-Natural eg baby milk/ placenta
-Artifical eg blood donations
Autoimmune disease
Immune system doesnt recognise self antigens and treat them as foreign antigens and launches an immune response against self tissues
Herd Immunity
If most people are vacccinated disease becomes rare so people who havent been vaccinated are unlikely to catch it
Antibiotics
Chemicals that kill/ inhibit growth of bacteria
-Used to kill bacterial infections
Personalised medicine
-Medicine tailored to individuals DNA, if Drs have ur genetic info they can predict how u will respond to diff drugs
Synthetic biology
Uses technology to design and make artificial proteins, cells and microorganisms
Agammaglobulinemia results in a lack of mature B lymphocytes in a person’s blood.
Suggest and explain one symptom of agammaglobulinemia.
Get infections easily as fewer Ab to cause pathogen destruction + fewer B lymp to provide immunity
Natural Selection
-Individuals within pop show variation in their phenotypes (characteristics) eg by a mutation
-Selection pressures make it difficult to survive eg predation, disease and competition
-Indiv who possess advantageous allele are more likely to survive and have reproductive success (reproduce and pass advantageous allele onto offspring)
-Overtime proportion of pop w advantageous allele increases
-Over generations this leads to evolution as advantageous allele becomes more common
Suggest how the immune system causes damage to the nervous system
-Antigens on neurones
-You produce antibodies against neurones
-Phagocytes attack+breakdown own neurones
Using examples, explain how both genes and environment can cause animals to vary in their
specific immune responses. (6)
Genes
inherit genes that code for immune cells /
antibodies (from parents)
examples: (B/T) lymphocytes, macrophages, etc
different alleles code for different versions of
immune cells/antibodies
ref. to gene segments recombining
alleles code for many different variable regions
reference to MHC alleles
mutation produces new alleles (for antigens /
immune cells )
Environment
exposure to different pathogens determines
immune response
vaccinations produce primary immune responses
examples:MMR, BCG,HPV, (produce) memory
cells etc.
reference to environmental influence on allergies
examples: pollen, hayfever, asthma, etc.
poor diet can weaken immune system examples:
low levels of protein / vitamins, (reducing)
antibodies
reference to epigenetic changes
examples: as a result of diet, stress, chemical
exposure
(auto)immune diseases with an environmental
component / trigger
example: AIDS
Explain why a booster vaccination is needed.
Memory cells reduced in number
