Disease Flashcards
(42 cards)
What is a disease
Disorder with a specific cause and recognisable signs and symptoms
Define Pathogen
A cellular or non-cellular agent of disease
What is an infection
Invasion and growth of a pathogen within the body of a host
Vector
An animal, usually an insect, that transmits pathogens from host to host
What is an antigen
Compounds which trigger an immune response, including the production of antibodies
Non-self antigens
Any foreign molecule or particle which acts as an antigen in the organism concerned
Self antigens
Any molecule or particle that originates from within the body
Allergens
A type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise by harmless to the body- reactions are allergies
Cellular pathogens
Bacteria, Protists, Fungi, Worms and Arthropods
Non-cellular pathogens
Viruses, viroids, prions
What are prions
Misfolded pieces of protein in the brain cells- lethal and can’t be destroyed
What do prions result in?
Cellular malfunction and brain degeneration
How do Prions infect cells
Come in contact with normal form of protein in a mammal’s brain cell, prions induce normal protein to form abnormal shape, resulting chain reaction continues until prions accumulate to dangerous levels, cellular malfunction and brain degeneration
Similarities and differences in the two types of prions
Primary structures (amino acids) are identical, but the secondary structure is different so the brain can’t identify it as non-self
What are viruses made of?
Consist of a protein coat (capsid) surrounding a nucleic acid (DNA Or RNA), all forms are pathogenic (pathogens)
Viruses
Only attack certain cells in your body as the cell thinks its ingesting something it wants but is really a virus
Enveloped and non-enveloped viruses
Enveloped contains an outer envelope that surrounds the capsid making it harder to be detected by cells. Non- enveloped may stand out to cell.
Life cycle of virus
Attachment, Penetration, Uncoating, replication, assembly, release
Attachment stage
Specific binding site between viral capsid proteins and specific receptors on the host cellular surface
Penetration stage
Virus enters host cell through receptor-mediated endocytosis. Some viruses instead inject their genome into the bacterial cell across cell wall while the viral capsid remains outside
Uncoating stage
Process in which the viral capsid is removed by viral enzymes or host enzymes which results in releasing their viral genomic nucleic acid.
Replication stage
Multiplication of the genome.
Assembly stage
Following the self-assembly of the virus particles, some modification of the proteins often occurs
Release stage
Viruses can be released from the host cell by lysis, a process that kills the cell by bursting its membrane and cell wall if present.
