1
Q
how does sickness result (2)?
A
- part of an organism’s body malfunctions (ex: heart attack, diabetes)
- when a pathogen invades an organism’s body and causes infection (virus, bacteria)
2
Q
define pathogen
A
biological agent that produces disease in its host - they are usually microorganisms
3
Q
define infection
A
when a pathogen invades and reproduces within its host, causing it damage
4
Q
define epidemiology
A
study of distribution, cause and risk factors of health-related events (ex: infectious disease) in populations - goal is to control disease and maintain human health
5
Q
what is important for assessing the impact of a disease (4)?
A
mode of infection transmission, how easily new hosts are infected, how well people can fight off disease/recover, environment in which the host lives
6
Q
true or false - diseases are all the same
A
false - disease epidemics vary widely in severity and scale
7
Q
true or false - pathogens are parasites?
A
true
8
Q
define parasite
A
organism that lives in close association with a host and gains advantage from the relationship at the expense of the host
9
Q
define host organism
A
organism on or in which a parasite lives and uses its ressources
10
Q
define microorganism (microbes)
A
organism that is too small to be seen with the naked eye (requires a microscope) - most are benign, but some cause infectious diseases
11
Q
what are 5 kinds of pathogens?
A
fungi, protozoans, helminths, bacteria, virus
12
Q
what are fungi?
A
- eukaryotic organisms: can grow as single celled yeasts or multicellular branched weblike structures (mycelia)
- important sources of food and medicine (ex: mushrooms, penicillin)
- hundreds of species live on/in human body but are harmless
13
Q
examples of fungal pathogens
A
candida albicans - causes yeast infections when population explodes
other: athlete’s foot, fungal pneumonia, ringworm
14
Q
what are viruses?
A
- not really alive: mircroscopic parasites made of tiny packets of DNA and RNA wrapped in a protein coat
- hijack cellular machinery of their hosts
- not cell-based life form
- infect all life forms, including bacteria
15
Q
examples of viruses
A
- influenza A (respiratory infection)
- rhinovirus (common cold)
16
Q
what are bacteria?
A
- single celled prokaryotes without membrane bound nuclei
- between 500 and 1000 species are hosted by humans
- most don’t cause disease, and can even aid health
17
Q
examples of bacteria disease
A
borrelia burgdorferi - lyme disease
escherichia coli - causes deadly food poisoning
18
Q
what are protozoans
A
- single celled eukaryotes with a defined, membrane bound nucleus
- can be free living or parasitic, some parasitic ones cause disease
19
Q
examples of protozoan pathogens?
A
- plasmodium (malaria)
- giardia lamblia (severe diarrhea)
20
Q
what are helminths?
A
- parasitic worms (animals, therefore multicellular and eukaryotic)
- not all cause disease
21
Q
examples of helminth pathogens
A
- schistosoma mansoni: infect digestive track which causes blockages and blood loss
- tichinosis: found in undercooked/raw meat, worm migrates from gut to muscles, including the heart
22
Q
which type of pathogen is described as not being truly “alive”?
A
viruses
23
Q
what type of pathogen causes malaria?
A
protozoan
24
Q
what type of pathogen causes lyme disease?
A
bacteria
25
which microbes live in/on humans without necessarily causing disease?
c. albicans (fungi - yeast infections), e. coli (bacteria - food poisoning)
26
how does bacteria reproduce?
binary fission
27
what is binary fission?
a cell that replicates its DNA and splits in half, with one copy of DNA going to each of the two cells
28
how do bacteria take advantage of their host to grow/replicate?
use nutrients around the host cell to make new bacteria
29
can bacteria reproduce in a dead organism?
yes, it only needs nutrients from its host
30
can a virus reproduce in a dead organism?
no - must invade a functional host cell to produce new virus particles
31
how do viruses reproduce?
they hijack host cell's reproduction machinery and force it to make new virus particles
32
what should you consider when deciding on the way to combat a disease?
consider the pathogen type (bacteria, virus, etc.)
33
how can you target bacteria?
antibiotics - they can:
- block synthesis of cell wall
- interfere with bacterial ribosomes
- inhibit RNA synthethis
- inhibit DNA replication
- increase permeability of cell membrane
34
what is used to combat fungi, protozoans and helmiths?
poisons (chemicals) toxic to the pathogen but not the host - antifugals, antiprotozoals and antihelmintics
35
what is used to combat viruses?
antivirals - disrupt function of viruses (ex: blocking receptors needed to enter host cell, disrupt viral replication) without affecting cellular function of the host
36
define immune system
an organism's immune system helps protect it against invading pathogens
37
what is the innate immune response?
rapid, generic, relies on ability to identify broad classes of pathogens
38
examples of innate immune response?
barriers, internal defenses
39
acquired immune response
slower, specific, relies on ability to learn and remember specific pathogens
40
examples of acquired immune response?
first exposure, subsequent exposure
41
define barriers
physical/chemical barriers that block pathogen from entering the body
42
examples of barriers
skin, stomach acid, digestive enzymes, mucus lining
43
what is internal defense
white blood cells respond to pathogens that breach barriers
44
examples of internal defense
trauma stimulating inflammatory response, white blood cells attack pathogens, pathogens release chemicals that recruit/activate other parts of the immune system (including acquired)
45
what is first exposure?
system learns to identify pathogen - LEARNING
46
examples of first exposure
- immune system learns to identify specific pathogens
- slower response than innate
- special cells are trained to recognizen antigens of invading pathogens
- other cells learn to produce antibodies for specific pathogen
47
what is subsequent exposure
system remembers antigen, stimulating rapid response to infection - REMEMBERS
48
examples of subsequent exposure
- immune system remembers antigens
- stimulates a more rapid response
- specific antibodies are used swiftly
- healthy immune system distinguishes pathogen from host's cells and molecules (doesn't attack itself)
49
define immunity
immunity occurs when an organism is able to protect itself from an invading pathogen
50
true or false - pathogens are infectious agents that cause disease
true
51
true or false - all pathogens are parasidic
true
52
which pathogen uses the cellular machinery of its host to replicate?
viruses
53
what produces immunity to an infection
immune system identifies and remembers specific pathogens it has encountered
54
what is the SIR model?
3 compartments - susceptible, infected, recovered.
every individual in a population begins as susceptible. as they get sick, they move into the infected department. as they recover, they are moved into the recovered compartment. when an epidemic is over, everyone is susceptible or recovered. arrow from S to I is how quickly individuals are infected and arrow from I to R is how quickly they recover. this model can be represented on a graph.
55
three determinants of disease spread
population density (N), transmission rate (beta) and infectious period (L)
56
define population density
how often individuals contact each other
57
define transmission rate
rate of disease transmission between infected and susceptible individuals of population. depends on how often infected/susceptible come into contact, and the probability of a contact resulting in infection
58
define infectious period
average period of time an infectious person can transmit disease to susceptible person
59
what is the name of the line that shows infections over time?
epidemic curve
60
what factors will flatten an epidemic curve?
lower population density, lower transmission rate, short infectious period (fast recovery)
61
formula for infection
beta*S*I
62
formula for recovery
I/L
63
how do you calculate change in I
new infections - new recoveries
64
SIR model assumtions (3)
1- once infected and recovered, individual has permanent immunity
2- everyone has equal chance of contacting everyone in population
3- as soon as individuals are infected, they are immediately infectious
65
equation for basic reproductive number - R0
R0 = SbetaL
66
define birth rate
all newborns enter the population as susceptible, at a rate depending on population size
67
define death rate
individuals in each subpopulation die at a constant rate
68
define the basic reproductive number, R0
average number of infections caused by a sick individual in a susceptible population
69
how do you calculate critical immunization threshold (pc)
pc = (1 - 1/R0)
general biology I
flashcards
Decks in class (20)
# Cards
-
biomolecules97
-
disease spread69
-
lectures 5/6 cell & osmosis120
-
lecture 1 - variance and scientific method25
-
lecture 2 - variance and natural selection13
-
properties of water42
-
mitosis31
-
test 2: lecture 9 - meiosis19
-
intro to genetics15
-
plants lab quiz29
-
test 2: lecture 8 - cell division & dna replication38
-
test 2: lecture 8 - mitosis9
-
test 2: mitosis/meisosis terminology16
-
test 2: non-mendelian genetics38
-
test 2: abiogenesis and natural selection24
-
test 2: evidence for evolution39
-
test 2: speciation41
-
test 2: diversity50
-
digestive organs13
-
cell histology16
