Chapter 5 Flashcards
(72 cards)
1
Q
Parasite
A
needs a host to live, lives st expense of other organisms (host)
2
Q
Parasite role in EE economy
A
- a lot of money spent on curing diseases caused by parasites
- hospitalizations
- treatments
- people who are sick don’t go to work
- lowers food supply
3
Q
Ectoparasite
A
live on host
4
Q
endoparasite
A
live in host
5
Q
obligate parasite
A
part of life cycle must be in living host
6
Q
facultative parasite
A
can be in/on host
7
Q
permanent parasite
A
once in, stay in
8
Q
temporary parasite
A
latch on and leave
9
Q
accidental parasite
A
invade host other than original host
10
Q
hyperparasitism
A
parasites have their own parasites
11
Q
encystment
A
formation of an outer covering that protects from environmental conditions
12
Q
mechanisms to avoid host defenses
A
- encystment
- changing surface antigens quicker than the host can produce antibodies
- by invading host cells
13
Q
biological vector
A
- viral pathogen carried inside body and transmits to host through biting
- ex: mosquito is biological host for Plasmodium falciparum
14
Q
Mechanical vector
A
- house flies carry E coli on their bodies without being infected by it
15
Q
vector
A
an animal that transmits a pathogen from one host to another
16
Q
definite hosts
A
- sexual reproduction life stage occurs in this host
- ex: mosquito for Plasmodium falciparum
17
Q
Intermediate host
A
- asexual reproduction takes place in host
- humans for Plasmodium falciparum
18
Q
reservoir hosts
A
- no reproductive phase takes place in host
- bats, rodents
19
Q
host specificity
A
- range of hosts in which a parasite can mature
20
Q
reproduction of Eukaryotic cells
A
- all have linear chromosomes that must divide during mitosis
- the “ends” of linear chromosomes require special means of replication not required by most bacteria, which feature circular chromosomes instead
- mitosis ensures that each daughter cell receives a full set of daughter chromosomes
21
Q
stages of eukaryotic mitosis
A
- prophase
- metaphase
- anaphase
- telophase
22
Q
asexual reproduction
A
many eukaryotic microbes can proliferate indefinitely by mitosis
23
Q
sexual reproduction
A
- most eukaryotes, single or multicellular, also have this option
- rerquires reassortment of genetic material from different chromosomes
- sexual life cycles alternate between cells that are diploid (2n) and sex cells that are haploid (n)
- two of the haploid sex cells (gametes) join each other by fertilization to regenerate a diploid cell
24
Q
Fungi
A
- chemoheterotrophs
- all are multicellular except yeast
- can be unicellular, filamentous, or fleshy arrangement
- acquire food through absorption
- characteristic feature: sexual and asexual spores
25
unicellular fungi
- do not form hyphae
- ex: Saccharomyces cerevisiae (Baker's Yeast)
26
Multicellular fungi
- does form hyphae
27
hyphae
long, branching, filamentous structure that forms the main vegetative body of most fungi, collectively known as mycelium
28
septate hyphae
- individual cells within the hyphae are separated by cross-walls called "septa"
29
aseptate/coenocytic hyphae
lacks a septa or septum
30
fungal life cycle
- reproduction can be asexual and sexual
31
asexual reproduction in fungi
- hyphae fragmentation
- spores
- conidiospore
- sporangiospore
32
sexual reproduction in fungi
- fusion of nuclei from 2 opposite mating strains of the same fungal species
33
conidiospore
spore not enclosed by sack
- produced at end of conidiopore
34
sporangiospore
- produced within sporangiophore
- has a sack around it
35
single celled yeast
-advantage of being single-celled: rapid growth and dispersal in aqueous environments
- some yeasts are asexual, whereas others alternate between diploid (2n) and haploid(n) forms
- both haploid and diploid forms are single cells
- haploid cells undergo several generations of mitosis and budding (vegetative growth)
- under various stress conditions such as nutrient limitation, haploid cells may develop into gametes and undergo sexual reproduction (mating)
- reproduce asexually by budding off smaller daughter cells
36
medically important fungo
| Zygomycota, Microsporidia, Ascomycota, Basidiomycota
- Zygomycota: saprophytic
- Microsporidia: unicellular fungi, obligate intracellular parasites
- Ascomycota: some are edible, others cause infections
- Basidiomycota" club shaped structures
37
Fungal diseases
- systemic mycosis
- subcutaneous mycosis
- cutaneous mycosis
- superficial mycosis
- opportunistic mycosis
38
Economic effects of fungi
- Saccaromyces cerevisiae: bread, wine, HBV vaccine
- Trichoderma: cellulase
- Taxomyces: taxol
- Entomophaga: biocontrol
- Coniothyrium minitans: kills fungi
- Paecilomyces: kills termites
39
Why are fungi important
- beneficial decomposers
- some fungi secrete to metabolic wastes which are toxic to other microorganisms-- antibiotics
- can be destructive when invading other organisms
40
what to fungi require to invade
- proximity to the host
- ability to penetrate the host
- ability to digest and absorb nutrients from cells
41
protozoa
- nonphotosynthetic
- motile
- chemoheterotroph
- no multicellularity
- unicellular arrangement
- food acquired through absorption, injestion
- characteristic features: motility, some form cysts
42
asexual reproduction of protozoa
- binary fission, bussing, schizogony
43
schizogony
nucleus divides multiple times before the cell divides into many smaller cells
- merozoites: products of schizogony
44
sexual reproduction of protozoa
- conjugation: fusion fo 2 cells, the micronucleus from each cell migrates and eventually fuses
- vegetative form: trophozoite
- some cells produce cysts: encystment
45
Giardia duodonales
- Phylum: metamonada
- order: diplomonadida
- diarrheal illness
- spread through cysts from feces that contaminate water supplies
- flagella
- no mitochondria
46
Euglenozoa
- move by flagella
47
Trypanosomatida
- trypanosomes consist of an elongated cell with a single flagellum
- they have unique organelle called the kinetoplast, which consists of a specialized mitochondrion that provides energy for the flagellum
- sleeping sickness, Chagas disease, and Leishmaniasis
- slender and stumpy forms (slender divide in blood stread of mammals, stumpy form only in fly, develops and grows in salivary gland--> transferred to humans
48
Trypanosoma species
- sleeping sickness (T. brucei): colonizes blood and brainafter being transmitted via tse tse fly bite
- Chagas disease(T. cruzi): transmitted by "kissing bugs" and affect heart tissue/tissue of digestive system
- spread by insect bites
49
Amebozoa
- voracious predators, consuming other protists and bacteria, and can reach several mm in size
- infective stage trophozoites-- move by pseudopods (actin microfilaments produce pseudopods-> protoplasm flows into this-> moves organism)
50
E histolytica
transmitted by cysts in feces
51
Naegleria fowleri
- "brain eating" amoeba
- it can cross blood-brain barrier and feed on brain
- causes PAM (Primary Amoebic Meningoencephalitis)
- found in spinal fluid
52
Apicomplexa
- major group of parasites of humans and other animals
- apical complex is specialized structure that facilitates entry of the parasite into a host cell
- apical complex= concentration of organelles, vacuoles, microtubules that allow parasite to enter host cells
- possess an elaborate cortex composed of alveoli, pores, and microtubules
- underwent extensive reductive evolution, losing their flagella and cilia
53
Babesia microti
- babeosis
- transmitted by tick
- causes recurring fever that can be fatal
- common transfusion-transmitted pathogen
54
helminths
- worms
- microscopic eggs/larvae
- chemoheterotroph
- all are multicellular
- arranged in tissues and organs
- acquire food through ingestion and absorption
55
helminth characteristics
- bilaterally symmetrical
- have head and tail end and its tissues are differentiated into 3 distinct tissue layers (triploblastic): ectoderm, mesoderm, endoderm
56
nematodes
- roundworms
- cylindrical with a digestive tube that ends in anus
57
trematodes
- flukes
- oval-shaped flatworms with a digestive tube that ends in cecum (no outlet)
58
Cestodes
- tapeworms
- parasitic flatworms
- absorb nutrients through their skin
59
Enterobiasis vermicularus
- pinworms
- only infect humans
- eggs and larvae are microscopic
60
Ascaris lumbricoids
- largest intestinal parasites in humans
- can also infect lungs
- only fertilized eggs are infective
61
flukes
- infect many kinds of animals, but most require a mollusk as their primary host
- flatworms (Platyhelminths) with internalized mouth, pharynx, and digestive tube, but the tube ends in one or more pouches called caeca
- expels its waste back out its mouth
- 2 suckers: one near mouth and one on ventral side of body
62
tissue flukes
- attach to the bile ducts, lungs, or other tissues
- lung: Paragonimus westermani
liver: Fasciola heptica
63
blood flukes
- found in blood in some stages of their life cycle
- various species of the genus Schistoma
64
Schistosoma
- found in freshwater snails
- burrow through skin into blood, migrate to lungs, then liver and other organs
65
cestodes
- tapeworms are transmitted through larvae embedded in uncooked meat
- different species are found in pork (Taenia solium), beef (Taenia saginata), and fish (Diphyllobothrium latum)
66
scolex
head with suckers that attach to the intestine wall, and a long chain of hermaphroditic proglottids which contain reproductive organs of both sexes
67
Taenia saginata
- beef tapeworm
- cow is intermediate host
- enter humans through ingestion of undercooked, contaminated meats
- adult worm develops in intestines
68
Arthropods
- invertebrates
- includes insects, arachnids
- a lot are free living, some parasitic
69
Arachnid parasites
- 8 legged mites and ticks
- mites cause mange (in animals) and scabies (in animals or humans)
- scabies in humans is caused most often by Sarcoptes scabiei
- Mites attach to skin by suckers and burrow under the skin using special mouthparts and cutting surfaces on the forelegs
- as they burrow, they lay eggs that hatch into larvae
- larvae come out of skin to attach to a hair follicle, where they feed and molt until they reach the adult stage
70
ticks
- resemble mites in the 8 legged form, but are larger and usually do not burrow completely into the skin
- ectoparasites that suck blood for nutrients to produce eggs, then gall off to disperse their progeny
- the deer tick (Ixodes scapularus) is famous for carrying the spirochete of Lyme disease (Borrelia burgdorferi)
71
insect parasites
- sucking lice are wingless ectoparasites that suck blood and then produce eggs
- tend to be highly specific to one host species, and different species have a preference for different body sites: head lice, body lice, pubic lice
- difficult to eliminate because the eggs are attached firmly and are not killed by normal shampoos
72
bedbugs
- they detect the host mainly from the exhaled carbon dioxide
- they suck the host's blood and depart to lay eggs unnoticed
- bedbugs were nearly eradicated in the US in the mid 20th century by the use of DDT and other pesticides
- today, bedbugs resist the older pesticides and are killed by newer chemicals with toxic side effects
