Intro To Eukaryotic Organisms Flashcards
1
Q
What are some identifying characteristics of eukaryotes?
A
- Have a membrane surrounding their DNA
- Have a nucleus
- Have internal-membrane bound organelles
- Are larger, 10-100 um in diameter
- Have more complex structure
2
Q
What organisms are eukaryotes?
A
Algae, fungi, Protozoa , animals, plants
3
Q
What are the eukaryotic appendages?
A
Flagella
Cilia
4
Q
What is the difference between the rough and smooth Endoplasmic Reticulum?
A
Rough: associated with ribosomes; makes secretary and membrane proteins
Smooth: makes lipids
5
Q
What are the components of the cytoskeleton?
A
Microtubules
Intermediate filaments
Microfilaments
Centrosome(kinda)
6
Q
What is the function of microtubules?
A
Form the mitotic spindle and maintain cell shape
7
Q
What is the function of the centrosome?
A
Microtubules organizing center
8
Q
What is the function of the intermediate filaments ?
A
Fibrous proteins that hold organelles in place
9
Q
What are the functions of microfilaments?
A
Fibrous proteins; form the cellular cortex
10
Q
What is the function of the Nucleolus?
A
Enclosed region where ribosomes are formed
11
Q
Describe the eukaryotic flagella
A
Long appendages present singly or in bundles that propel the cell with a whip-like motion
12
Q
What is the flagella composed of?
A
Composed of tubulars and microtubules
13
Q
Describe the Cilia of eukaryotes
A
Similar to flagella in structure and function, but cilia are much smaller and more numerous
Cilia move in an undulating manner
14
Q
Cilia are found __________ to the cell
A
Peritrichously
15
Q
Which organism would move faster between those with cilia or those with flagella?
A
The one with cilia
16
Q
Where is chlorophyll found?
A
In chlorophyll containing organelles found in phototrophic eukaryotes- plants, unicellular and multicellular algae and protists
17
Q
How do chloroplasts appear under a light microscope?
A
Relatively large and and readily visible with the light microscope
18
Q
Describe briefly, the structure of chloroplasts
A
Composed of two phospholipid bilayer membranes and contain 70s ribosomes and DNA
19
Q
What are thylakoids?
A
A flattened membrane disc containing all other components needed for photosynthesis
20
Q
When did the first eukaryotic organism evolve?
A
Thought to evolve 1.5 billion years ago
21
Q
What is endosymbiosis?
A
A process where one prokaryote lives inside the cell of another organism to the benefit of both
22
Q
What is the endosymbiosis hypothesis?
A
Mitochondria and chloroplasts are thought to have evolved from bacteria that were engulfed by larger cells
23
Q
What is primary endosymbiosis?
A
Involves the engulfment of a bacterium by another free-living organism
24
Q
What is Secondary endosymbiosis?
A
Occurs when the product of primary symbiosis is engulfed and restrained by another free-living eukaryote.
25
Explain the result of secondary endosymbiosis
Secondary endosymbiosis has occurred several times and has given rise to extremely diverse groups of algae and other eukaryotes
26
How do organisms in the Kingdom: Protista reproduce?
Binary fission
Multiple fission
Sexually by contagion
27
What is binary fission?
Splits into two asexually
28
What is multiple fission?
Producing more than 2 individuals
29
How can protists be classified?
Into 2 major groups:
- plant-like
- animal-like
- fungi-like
In 11 phyla
30
Where are protists usually found ?
In aquatic environment, some are terrestrial while others can be present in a suitable host
31
What sizes are Protista?
Mostly unicellular, microscopic or macroscopic.
32
How do protists acquire nutrients?
These are a heterogenous groups that include, heterotrophic, photoautotrophic or a combination of both forms
33
What are examples oof animal-like protists?
- Sarcodinia
- Ciliophoria
- Zooflagellates
- Leishmaniasis
- Sporozoa
- Malaria
34
Describe Sarcodinia
Free-living animals-like protists that inhabit aquatic and soul environments
They utilize pseudopodia for locomotion, feed by phagocytosis on bacteria, other protists, and organic materials
35
What are entamoebas?
- Parasites of vertebrates and invertebrates
| - Forms cysts that are transmitted from person to person
36
Give examples of entamoebas
E.g. entamoeba histolytica -amoebic dysentery
E.g. Naegleria spp. - primary amoebic meningoencephalitis
37
Describe Ciliophoa
- Complex and unicellular animal-like protists
- utilize cilia for locomotion
- defined shape and 2 nuclei
- some associated with diseases in humans
38
How does Ciliophora reproduce?
Reproduce asexually by binary fission and sexually by conjugation
39
Give a general description of zooflagellates
- Lack plastids
- Reduced mitochondria(often anaerobic)
- lack key enzymes
40
List the types of zooflagellates
- Diplomonads
- Parabasalids
- Euglenoids
- Kinetoplastids
41
Describe Diplomonads
- a type of zooflagellate
- 2 nuclei
- Multiple flagella
- E.g. Giardia-intestinal giardiasis
42
Describe Parabasalids
- a type of zooflagellates
- Flagella and undulating membrane
- May have genes from bacteria
- e.g. trichomonas-sexually transmitted
43
Describe Euglenoids
- a type of Zooflagellates
- Characterized by anterior pocket with 1 or 2 flagella
- Autotrophic, mixotrophic or heterotrophic
- e.g. Euglena
44
Describe Kinetoplastids
- a type of zooflagellates
- 1 flagella
- Single large mitochondria associated Kinetoplast
45
Give examples of diseases caused by kinetoplastoids
Trypanosoma-African trypanosomiasis
American trypanosomiasis
Leishmania organism which causes leishmania
46
Describe the structure of sporozoa
- Possess “apical complex” consisting of microtubules and other components that is used to infect host cell
- Have apicoplast(non-photosynthetic plastid)
47
Describe the pathogenicity of Sporozoa
- Parasites of animals and humans and some cause serious disease
- multiple life stages, reproduce asexually and sexually
- vector transmitted, require 2 or more different host
48
Give examples of Sporozoa
Plasmodium, Cryptosporidium and toxoplasma
49
Describe Malaria infection
1. Malaria infection
2. Stages in liver
3. Stages in red blood cells
4. Certain merozoites develop into gametocytes
5. Gametocytes ingested by mosquito
6. Sporizoites form within mosquito
50
What is the causative agent of Malaria?
Plasmodium spp.
51
What transmits Malaria?
Mosquito, Anpheles spp.
52
Describe the life cycle of Plasmodium spp. / malaria
Complex life cycle involving asexual (vertebrate host) and sexual (mosquito) reproduction
53
How does Malaria affect the world?
Associated with high morbidity and mortality worldwide
54
Who does Malaria infect?
Infects vertebrate hosts, including, humans
55
Describe the life cycle of Chlorophyta
Complex life cycle involving sexual and asexual stages
56
Describe the variations of chlorophyta
Microscopic or macroscopic, unicellular or multicellular, motile or non-motile
57
Describe the structure of chlorophyta
- contain beta carotene and xanthophylls in addition to chlorophyll A and B
- cell wall contains cellulose and store food from starch
- similar to plants
58
Where is green algae usually found?
Mostly found in freshwater, some marine or soil, or symboints.
Endolithic algae found in layers near rock surfaces
59
What is Chlorophyta ?
A division of lower plants that comprises the green algae
60
List 2 plant-like protists
- green algae
| - red algae
61
What is Rhodophyta?
A division of lower plants that contains the red algae
62
Describe the structure of Rhodophyta/red algae
- Contain phycoerythrin and phycocyanin in addition to chlorophyll A
- Double cell walls- the outer layers contain the polysaccharides agarose and agaropectin that can be extracted from the cell walls by boiling
63
Where are Rhodophyta usually found?
Most abundant in coastal warm waters in tropical oceans or freshwater
64
Give examples of Rhodophyta
Agar(Gelidium), alginates (var. sources), carrageenan (Chondrus)
65
Describe the rhodophyta life cycle
-eukaryotic, mostly multicellular, reproduce sexually as well as asexually
66
Give examples of fungus-like protists
- water molds “egg fungus”
| - cellular slime methods
67
Describe the structure of water molds “egg fungus”
- Fungus like morphology but not related to fungi
| - cell wall contains cellulose and not chitin
68
How do water molds reproduce?
Reproduce sexually and asexually
69
What is the official name for “egg fungus”?
Water molds
70
Describe water molds “egg fungus” in the environment
Non-photosynthetic and include many saprobes and parasites and appear as white fluffy growths one dead organisms
71
Describe Cellular slime molds
-Individual haploid cells and form diploid only under certain conditions
72
Describe cellular slime molds in the environment
- ingest bacteria by phagocytosis
- cells aggregate to form a multicellular pseudopodium from which arise fruiting body
- some cells become spores
73
What kingdom are fungi in?
Mycetae
74
How many species of fungi are there?
100,000 species
75
How can fungi be categorized?
Microscopic fungi
Macroscopic fungi:
Yeasts
Molds
Some are dimorphic (yeast like and filamentous forms exist)
Usually unicellular or colonial
76
Describe yeasts
- Round or oval shape
- Unique mode of asexual reproduction
- Some form psuedohyphae(false filaments)
77
Describe molds
- Long, threadlike cells
| - Filaments arrangement(hyphae)
78
Give the general mechanism of fungal nutrition
- penetrates the substrates
- secretes enzymes
- breaks down the enzymes into small molecules
- absorbs the molecules
79
Fungal nutrition has large Importance in...
Medical and agricultural
80
Describe possibilities to fungal nutrition
Heterotropic
Acquire nutrients from substrates
Most fungi are saprobes
Can also be parasites
81
What are the functions of hyphae?
- Vegetative hyphae(mycelia)- visible mass of growth on the substrate surface; penetrates the substrate to digest and absorb nutrients
- reproductive(fertile) hyphae- from vegetative hyphae; responsible for the production of spores
82
How do most microscopic fungi grow?
In loose associations or colonies
83
Describe the appearance of microscopic yeast fungi
Soft, uniform texture and appearance
84
Describe the physical appearance of filamentous fungal colonies
Cottony, hairy, or velvety textures
85
What is mycelium?
The woven, intertwining mass of hyphae that makes up the body or colony of a mold
86
What are the organizational features of hyphae?
- Septa- divide the hyphae into segments(most fungi have septate hyphae)
- Nonseptate hyphae- one long, continuous, multinucleate
87
Describe fungal sexual reproduction
- increases genetic variation
- Majority of fungi produce sexual spores at some point
- Sexual reproduction involves fusion of haploid “+” and “-“ mating types
88
Give examples of fungi that asexually reproduce
- sporangiospores
| - conidospores
89
Describe Conidiospores
- Also known as conidia
- Free spores
- Develop either by pinching off the tip of the fertile hypha or by segmentation of a vegetative hypha
90
Describe Sporangiospores
- formed by successive cleavages within the sporangium
- Sporangium attached to the sporangiophore
- released when the sporangium ruptures
91
Nearly all fungi are _______________ and don’t need _________
Free-living
Host
92
How does human infection by pathogenic fungi usually occur?
Usually via accidental contact
93
What types of pathogenic fungi are humans not resistant to?
1. Primary pathogens.
| 2. Opportunistic pathogens
94
What are the benefits of fungi?
- Decomposing organic matter and returning essential minerals to the soil
- Mycorrhize increase the ability of plant roots to absorb water and nutrients.
- Production of antibiotics, alcohol, organic acids, vitamins, food flavorings
95
How do Mycoses/ fungi negatively impact humans?
Not just infections but also allergies, poisoning, agricultural damage
96
What are parasites?
An organism that lives on or in a host organism and gets its food from or at the expense of its host
97
Why do parasites not kill?
Parasites cannot grow and multiply without a host so they don’t kill their host but it can spread diseases and some can be fatal
98
How do parasites differ from predators?
Parasites are much smaller than their host and reproduce at a faster rate
99
What are the 3 classes of parasites that cause disease in humans?
- Protozoa
- helminths
- ectoparasites
100
What type of respiration do protozoan parasites typically use?
Usually facultatively anaerobic
101
How much species of protozoan parasites are there?
Estimated 100,000 species but approx. 25 are important to humans
102
Give a brief description of the anatomy and physiology of protozoan parasites
-unicellular, animal-like microbes, most have some form of motility
- physiologically simple
- Acquire nutrition via pino or phagocytosis or enter via specialized site/structure
103
Describe the life cycles of protozoan parasites
- Most reproduce by simple asexual cell division (binary fission) of the active feeding cell
- Many undergo formation of a cyst
- A few others (e.g., Plasmodium spp. ) have a complex life cycle that includes asexual and sexual phases
104
What is the entamoeba histolytica as a pathogen
Intestinal protozoan parasites
Entamoeba histolytica: uses psuedopodia for locomotion, May invade the colon and cause bloody diarrhea-amoeba dysentery.
Also causes amoebic liver abscess, reproduce asexually
105
What is the Balantidum coli as a pathogen?
Intestinal protozoan parasites
Ciliate protozoan that lives in the colon of pigs, humans and rodents and lead to colonic ulceration, reproduces asexually
106
What is the Giarda lamblia as a pathogen?
Intestinal protozoan parasites
Flagellate protozoan with world-wife distribution, lives in the small intestine and results in malabsorption, reproduces asexually
107
What is Cryptosporidium parvum as a pathogen?
Intestinal protozoal parasites
Non-motile protozoan, more prevelant in the immunicompromised patients, reproduces sexually and asexually
108
Describe Cyclospora cyatenensis as a pathogen
Intestinal protozoal parasites
Non-motile protozoan, parasites the small intestinal mucosa and may cause diarrhea for several weeks, reproduces sexually and asexually
109
Describe Trichomonas vaginalis as a pathogen
Trichomonas vaginalis: flagellate protozoan, sexually transmitted, reproduces asexually
110
Name the intestinal protozoan parasites
- entamoeba histolytica
- Balantidium coli
- Giarda lamblia
- Cryptosporidium parvum
- Cyclospora cyatenesis
- Trichomonas vaginalis
111
Name the extra-intestinal/Blood and tissue Protozoa
- plasmodium spp.
- leishmania spp.
- trypanosoma
- Toxoplasma gondii
112
Describe Plasmodium spp. as a pathogen
Non-motile parasite, causative agent of malaria, transmitted by Anopheles mosquito.
There are 4 species that infect humans: P. falciparum, P. Vivax, P. Ovale and P. malaria
113
Describe Leishmania spp. as a pathogen
Extra-intestinal/blood and tissue protozoan
Flagellate protozoan, transmitted by sand flies, can lead to visceral, cutaneous and mucocutaneous leishmanias
114
Describe Trypanosoma as a pathogen
Trypanosoma: flagellate protozoan cause
In Africa -sleeping sickness (transmitted by the Tsetse Fly)
South America- Chaga’s disease (transmitted by the Reduviid bug)
115
Describe Toxoplasma gondii as a pathogen
Extra-intestinal/blood and tissue Protozoa
Non-motile Protozoa, transmitted by the ingestion of oocytes from cat faeces.
Infection can lead to severe manifestations and is also a cause of neonatal toxoplasmosis
116
Describe the structure of Metazoan parasites
Eukaryotic, multicellular animals that have digestive, circulatory, nervous, excretory and reproductive systems
Has bilateral symmetry, head and tail, and tissue differentiation (endoderm, mesoderm and ectoderm)
117
Where do Metazoan parasites spend their lives?
Spend most of their lives in host
118
What is another name of Metazoan parasite?
Helminths
119
What is are the classifications of helminths?
Nemahelminths(roundworms)
Class- nematoda
Phatylhelminthes(flatworms)
```
Class Trematoda(flukes)
Class Cestoda(tapeworms)
```
120
Give the general features of nematodes(round worms)
1. They have cylindrical bodies and complete digestive tracts
2. Body is covered with a cuticle. The oral opening may have hooks or suckers to attach to mucosal epithelium.
3. There are separate male and female sexes which mate and produce eggs within the human host
4. The worms, larvae or eggs may be diagnostic. Eggs typically have a characteristic shape, cell wall density and cap (“operculum”) on one or both ends
121
Describe Ascaris
Round work and intestinal nematodes
- found world-wide in conditions of poor hygiene
- causes eosinophilia
122
Describe Enterobinus
Pinworm and intestinal nematodes
-prevalent worldwide, found mainly in children
123
Describe Trichuris as a pathogen
Trichuris(whipworm)
- prevalent in warm, humid conditions
- Can cause diarrhea, rectal prolapse and Anaheim’s in heavily-infected people
124
Describe Ancylostoma and Necator as pathogens
Ancylostoma and Necator(hookworms)
A major cause of Anaemia in the tropics
125
Describe strongyloides as a pathogen
- inhabits the small bowel
| - Infection more severe in immunocompromized people(e.g. HIV/AIDS, malnutrition, intercurrent disease)
126
Give examples of tissue nematodes
- toxocara
| - trichinella
127
Give examples of Filarial nematodes
- Onchocerra
| - Wuchereria and Brugia
128
Describe toxicara as a pathogen
- a tissue nematode
- a world wide infection of dogs and cats
- Human infection occurs when embryonated eggs are ingested from dog or cat faeces
129
Describe Trichinella as a pathogen
- a tissue nematode
- Associated with consumption of infected and unfrozen or poorly cooked meat
- Encysted larvae occur in striate muscle and symptoms occur based on location
130
Describe Onchocerra as a pathogen
A filarial nematode
- Transmitted by black fly
- Causes visual impairments, blindness severe itching of the skin in infected individuals
131
Describe Wuchereria and Brugia as a pathogen
Wuchereria and Brugia
- filarial nematodes
- the major causative agent of lymphatic filariasis
132
What are the General features of Trematodes(flukes)?
1. Trematodes have a dead-end digestive system, nutrients are taken and expelled from the same opening
2. Trematodes and cestodes are both classified into the phylum, Platyhelminth/flatworms
133
Describe the life cycle of Trematodes
Trematode life cycle involves more than one host, a mollusk and a vertebrate
134
Give examples of Trematodes(flukes)
- Fasciolopsis (intestinal fluke)
- Fasciola (liver fluke)
- Paragonimus(lung fluke) and Clonorchus(Chinese liver fluke)
135
Describe Fasciolopsis as a pathogen
- Fasciolopsis (intestinal fluke)
- A common parasite of human and pigs
- One of the largest Trematodes to infect man lives in the upper intestine
- Chronic infection leads to inflammation, ulceration and hemmorhage of the small intestine
136
Describe fasciola as a pathogen
- A parasite of sheep, humans become infected when ingest metacercariae that have encysted on watercress
- The adult trematode lives in the intra-hepatic bile ducts of the liver. “Fascioliasis” can lead to severe anaemia in humans
137
Describe Paragonimus (lung fluke) and Clonorchis(Chinese liver fluke)
- a wide spread in the Far East and South East Asia
| - The parasite is acquired by ingestion of infective metacercariae in raw or pickled crustaceans
138
Give details of the anatomy of Cestodes/tapeworms
Tapeworms have flat segments called proglottids develop sequentially from a head called the scolex
The worm has no digestive tract but absorbs nutrients directly into the proglottis and scoleces
139
Give the function of the scolex
The scolex of the cestodes(tapeworms) contains suckers and/or hooks used to attach to the intestinal epithelium
140
What are the usual hosts of Cestodes(tapeworms)?
Humans are usually the definitive hosts. When they are the immediate hosts more serious disease occurs
141
Describe the sexual reproduction of cestodes(tapeworms)
Tapeworms are hermaphroditic, each proglottid producing sperm and egg, and engaging in self-fertillization , releasing fertilized eggs.
Proglottids May break off sequentially from the elongating tapeworm bodies as well
142
Give examples of intestinal tapeworms
Taenia(beef tapeworm)
Taenia(pork tapeworm)
143
Describe the pathogenicity of Taenia(beef tapeworm)
Occurrence worldwide
- acquired via ingestion of contaminated, uncooked beef
- a common infection but causes minimal symptoms
144
Describe the pathogenicity of Taenia(pork tapeworm)
- occurrence worldwide
- Acquired by ingestion of contaminated, uncooked pork that contains cystercerci
- less common, but causes cysticercosis-a systemic disease where cysticerci encyst in muscles and in the brain and may lead to epilepsy
145
Give an example of systemic tapeworms
Eichinococcus(dog and rodent tapeworms)
146
Describe the pathogenicity of Systemic tapeworms
- hyadatid disease occurs when the larval stages of these organisms are ingested
- The larvae May develop in the human host and cause space-occupying lesions in several organs e.g. brain, liver
147
Patient has space-occupying lesions on liver,brain and other organs, what is at play?
Echinococcys-systemic tapeworm
148
A woman obtains a pathogen from a black fly and becomes visually impaired and has severe itching, what is the pathogen?
Onchocerra-filarial nematode
149
A patient is immunocompromised, what pathogens are they at risk of receiving?
Strongyloides- intestinal nematodes of the small bowel
Cryptosporidium parvum- intestinal protozoan
150
A patient has been exposed to both the TseTse fly and reduviid bug, what diseases and pathogen are they at risk of?
Tryponasoma
Africa-sleeping suckness(tsetse fly)
South America -Chaga disease(reduviid bug)
151
What is a fungus?
A heterotrophic eukaryotic organism whose cell wall is made of chitin
