MIcrobiology Exam 3 Eukaryotes Flashcards
The first eukaryotic cell appeared
1.8 billion years ago
Bacteria, Archaea, and eukarya all evolved from
LUCA
Microbial members of domain Eukarya are much
more genetically and ecologically diverse than larger eukaryotes
Eukarya exhibits
morphological and ecological complexity but a limited range of metabolic diversity
Theory of Endosymbiosis
Originated from prokaryotic cells trapped inside other prokaryotic cells
Primary Endosymbioses
acquisition by eukaryotic host cell of respiring bacterium or phototropic cyanobacterium, followed by the evolution of endosymbiont into mitochondria or chloroplasts
Secondary Endosymbiosis
acquisition by a mitochondria containing eukaryotic cell of a red or green algal cell
Mitochondria
Independent division
Circular chromosome with bacterial DNA sequences
Prokaryotic ribosomes
Bacterial membranes and be inhibited by drugs that only affect bacteria
Endosymbiotic Theory Evidence
Similarity between organelles of modern eukaryotic cells and the Structure of bacteria
Endosymbiotic Theory
Well supported
Placed both bacteria and chloroplast on a family tree of bacteria
Mitochondria’s closest relative are rickettsias
(An intracellular bacteria)
Eukaryotic Motility
Cillia
Cilia structure
Similar to flagella in structure, smaller and more numerous
Eukaryotic Flagella
much simpler and thicker than prokaryotic
X10 thicker
The Glycocalyx
Outermost layer
Composed of polysaccharides
Glycocalyx appears as
A network of fibers
A slime layer
A capsule
Cell walls of fungi and most algae
Rigid and provide structural support
Fungal cell wall
Thick inner layer of polysaccharide fibers made out of chitin or cellulose
Algae cell wall
Varied in chemical composition
The cell membrane
bilayer of phospholipids (protein molecules are embedded)
The cell wall contains
Sterols (Provide Stability)
Cytoplasmic membranes of eukaryotes
permeable barriers in transportation
Eukaryotic flagella move the cell by rotating it using the hook in the basal body
False
The Nucleus
Most prominent organelle of eukaryotic cells
The nucleus contains
DNA
The nucleus is separated from
the cell cytoplasm by the nuclear envelope which is perforated with pores
Nucleolus is
where components of ribosomes are made
Rough ER
ER with ribosomes attached
Attached ribosomes make
membrane proteins and secretory protein.
Smooth ER
ER without ribosomes attached
What does the The smooth er do
Detoxifies drugs and poisons, synthesizes lipids (inc. steroids)
Golgi Apparatus
Receives, refines, stores, and distributes chemical products of the cell
Lysosome
A membranous sac of hydrolytic enzymes that can digest (hydrolyze) macromolecules
Lysosomes work best in acidic environments
Autophagy
Lysosomes use enzymes to recycle the cell’s own organelles and macromolecules
Vacuoles
Membrane-bound sacs containing fluids or solid particles to be digested, excreted, or stored
Mitochondria structure
continuous outer membrane with an inner folded membrane
Mitochondria 2.0
Generate energy
Divide Independently
Contains circular strands of DNA and prokaryotic ribosomes
Chloroplasts is found in
Algae and plant cells
Chloroplasts is capable of
converting energy from sunlight to chemical energy through photosynthesis
Chloroplasts produces
oxygen gas as a by product of photosynthesis
Chloroplasts resembles
Mitochondria but larger, containing special pigments
Ribosomes - Protein Factory
Multiple ribosomes are often found arranged in short chains called polyribosomes
Ribosomes Distributed
Freely in the cytoplasm and cytoskeleton
Attached to the rough ER
Appear inside mitochondria and chlorplasts
Size and structure of the ribosomes
Eukaryotic ribosome is 80S, a combination of 60S and 40S subunits
Prokaryotic ribosome is
70S, a combination of 50S and 30S
The Cytoskeleton
is a network of fibers extending throughout the cytoplasm
The cytoskeleton gives
animal cells shape and support
The cytoskeleton controls
intracellular traffic
The cytoskeleton gives cells
some ability to control their movement
In the endosymbiont theory, an engulfed prokaryote that could perform aerobic respiration evolved over generations into
Mitochondria and chloroplasts
Which of the following organelles is responsible for producing most of the ATP in most eukaryotic cell
Mitochondria
Proteins that need to be modified by the golgi bodies arrive from
The rough endoplasmic reticulum
Microscopic Fungi Two groups
Macroscopic fungi (mushrooms, puffballs, gill fungi)
Microscopic fungi (molds, yeasts)
Kingdom Fungi (Eumycota
Large variety and complexity
Existed on Earth for ~650 million years
~100,000 species are known (estimates to be as high as 1.5 million)
Fungal Cells Chemical Traits
Cell Wall -> chitin
Cell membranes -> Sterols (ergosterol)
Two basic morphological types:
Hyphae
Yeasts
Yeasts
Round to oval shape
Asexual reproduction, budding
Hyphae
Long, threadlike cells found in the bodies of filamentous fungi (molds)
Pseudohypha
chain of yeast cells
Some fungal cells are considered
dimorphic
Heterotrophic
Get nutrients from a wide variety of organic substrates
Saprobic
the remnants of dead plants and animals in soil or aquatic habitats
Parasitic
grow on the bodies of current or previously living animals or plants, although very few require a living host
Fungi penetrates
the substrate and secrete enzymes that reduces it to small molecules that can be absorbed by the cells
Fungi are often found in
nutritionally poor or adverse environments, and those with high salt or sugar content
Benefits of Fungi
Decomposing organic matter
Stable associations with plant roots
engineered to produce large quantities of antibiotics, alcohol, organic acids, and vitamins
eaten or used to provide flavoring
Cells of most microscopic fungi grow in
loose associations or colonies
Colonies of yeasts
soft, uniform texture and appearance
Colonies of filamentous fungi are noted for
the striking cottony, hairy, or velvety texture
Reproductive Strategies and Spore Formation
Many can propagate by the outward growth of existing hyphae or by fragmentation
Spores
Primary reproductive mode of fungi
Can be dispersed through the environment by air, water, and living things
Will germinate upon finding a favorable substrate and produce a new fungus colony in a short time
Sporangiospores
formed by successive cleavages within a saclike head
Conidiospores or conidia
free spores not enclosed by a spore-bearing sac
Sexual Spore Formation
Mixing of DNA from two parent fungi creates offspring with combinations
Sexual spores vary from
simple fusion of fertile hyphae of two different strains, or as a complex union of male and female structures
Zygospores
diploid spores formed when hyphae of two opposite strains (called the plus and minus strains) fuse and create a diploid zygote
Penicillium notatum mold
a very common decomposer of citrus fruit, is known for its velvety texture and typical blue-green color.
A number of species are pathogenic to corn and grain:
Reduces crop production
Can cause disease in domestic animals consuming contaminated feed crops
Fungi and Human Disease
Nearly 300 species of fungi can cause human disease
Community-acquired - Fungi and Human Disease
infections caused by environmental pathogens
Hospital-associated- Fungi and Human Disease
infections caused by fungal pathogens in clinical settings
Opportunistic infections-Fungi and Human Disease
caused by low-virulence species infecting already-weakened individuals
Dermatophytes
Unique group of fungi that infect keratinous tissue
Dermatophytes invade
the hair, skin, and nails of a living host
Genua examples of Dermatophytes
Microsporum
Epidermophyton
Trichophyton
Dermatophytes can cause
Ringworm, athlete’s foot, jock itch, fungal nail bed infections
Cryptococcosis
A pulmonary or disseminated infection acquired by inhalation of soil contaminated with the encapsulated yeasts.
Cryptococcosis causative agent
Cryptococcus neoformans
Cryptococcus neoformans
Infection commonly associated with immunosuppressive
EX) Meningitis and meningoencephalitis
Cryptococcus gatti
Infections not associated with immunosuppression
Aspergillosis
An infection caused by Aspergillus species, a common mold
Aspergillus is
ubiquitous in the environment
Aspergillus can be found
in soil, decomposing plant matter, household dust, building materials, plants, food, and water.
Aspergillus fumigatus is
the most prevalent and is largely responsible for invasive aspergillosis with a high mortality rate
Aspergillus flavus
synthesizes a poison called aflatoxin
Aspergillus flavus is lethal to
animals who eat contaminated grain
In humans Aspergillus flavus aflatoxin production can lead to
acute hepatitis, immunosuppression, hepatocellular carcinoma, and neutropenia.
Ophiocordyceps unilateralis infects
Insects
Ophiocordyceps unilateralis is found in
Tropical forest ecosystems
Other members of cordyceps and Ophiocordyceps
also parasitize insects
Histoplasmosis “Ohio Valley Fever” is caused by the fungas
Histoplasma capsulatum
Histoplasmosis “Ohio Valley Fever” affects
The lungs
Histoplasmosis “Ohio Valley Fever” is found
in soils, often associated with bat or bird shit
Candidiasis is typically on the
skin or mucous membranes
Candidiasis is caused by
Yeast - candida
Residential flora
Found on skin, mouth, throat, gut, and vagina
Candida albicans (most common)
Opportunistic pathogen
Thrush, vaginal yeast infection, cutaneous candidiasis
Ergotism
Poisoning produced by eating food affected by ergot
Ergotism symptoms
headache, vomiting, diarrhea, convulsions, hallucinations, and gangrene of the fingers and toes
Ergotism is also known as
Saint Anthony’s Fire, ergotoxicosis, or ergot poisoning
Ergot
a group of fungi in the genus Claviceps
Ergot infects
rye and other cereals
Aflatoxins are produced by
Aspergillus
Which of the following structures would NOT be associated with fungi
chloroplasts
Ergosterol synthesis is often the target of anti-fungal drugs
True
Claviceps can cause several effects in humans and other animals, such as hallucinations and gangrene. It is usually ingested by contaminated
Grain
Which of the following fungi are the cause of ergotism
Claviceps
Algae
A group of photosynthetic organisms
Algae is widespread in
fresh and marine waters
Provide basis of food web in most aquatic habitats
Algae contributes
significantly to oxygen content of the atmosphere through photosynthesis
Algae is
Unicellular, colonial, and filamentous forms
Algaes larger forms can
possess tissues and simple organs
Algae exhibits most organelles including
Chloroplasts
One of the most prevalent groups on Earth
are the single-celled diatoms
Diatoms cell wall contains
silica
Diatoms are high in diversity
useful in forensics in analyses of bodies of water
Forensic Limnology
in order to solve forensic and medical cases
Many animal tissues are inhospitable to algae
algae is rarely infectious
Prototheca
associated with skin and subcutaneous infections in humans and animals
Primary medical threat is due to food poisoning
Caused by marine algae toxins
E.g. Dinoflagellates
Prototheca – an infectious algae
associated with skin and subcutaneous infections in humans and animals
Prototheca lost its
ability to synthesize chlorophyll and adopted a heterotrophic nutrition
Prototheca only
recognized as human and animal pathogens in the 1960s
First human outbreak of Prototheca
2018
Treatment for Prototheca
None
Dinoflagellates
Can cause algae blooms
Paralytic shellfish poisoning
is caused by eating exposed clams or other invertebrates
Ciguatera
a serious intoxication caused by algal toxins that have accumulated in fish (e.g. bass and mackerel)
No antidote and cooking does not destroy the toxin
Diatoms are known for their ____ cell walls
Silica
Algae are typically non-infectious for humans, one exception is
Prototheca
The Protozoa name comes from
greek, first animals
The protozoa
about 12,000 species of single celled creatures
Species in the protozoa are
harmless
A few species of the protozoa are
pathogens
Protozoan Form and Function
Single cells containing all of the major eukaryotic organelles
Ectoplasm- Cytoplasm
clear outer layer involved in locomotion, feeding, and protection
Endoplasm- Cytoplasm
granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles
Heterotrophic
require food in a complex organic form
Predominant habitats are
fresh and marine water, soil, plants, and animals
Trophozoite
motile feeding stage requiring ample food and moisture to stay active
Cyst
Dormant, resting stage when conditions in the environment become unfavorable
Resistant to heat, drying, and chemicals
Can be dispersed by air currents
Important factor in the spread of disease
Reproduction of protozoa
asexual mitotic cell division or multiple fission
Sexual reproduction also occurs in most protozoa:
Ciliates participate in conjugation
Sexual reproduction of protozoa
can be advantageous in evolution
Trichomonas (Trichomonas vaginalis)
Flagellated
Trichomonas (Trichomonas vaginalis) can be
asymptomatic
Trichomonas (Trichomonas vaginalis) treatment
Antibiotics
Trichomonas (Trichomonas vaginalis) in Men
mostly asymptomatic
Irritation inside the penis
Mild discharge
Slight burning after urination or ejaculation
Trichomonas (Trichomonas vaginalis) in women
Greenish-yellow, frothy, “fishy scent” vaginal discharge
Painful urination
Vaginal itching and irritation
Trypanosoma (African Trypanosomiasis) causative agent
(Trypanosoma brucei)
Trypanosoma (African Trypanosomiasis) (Trypanosoma brucei) vector
tsetse fly
Trypanosoma (African Trypanosomiasis) (Trypanosoma brucei) signs and symptoms
Anxiety, Drowsiness during the day, Insomnia at night, Fever, Headache, Mood changes, Sleepiness (may be uncontrollable), Sweating, Swollen lymph nodes, red, painful nodule at site of fly bite, Weakness
Trypanosoma (African Trypanosomiasis) (Trypanosoma brucei) treatment
should be early
Chagas Disease (American Trypanosomiasis) causative agent
Trypanosoma cruzi
Chagas Disease vector
Triatomine bugs, known as ‘kissing bugs’
mainly transmitted by feces of the insect
Chagas Disease acute
maybe asymptomatic or mild like fever, malaise
followed by remission – no symptoms for many years
Chagas Disease chronic
includes digestive problems and heart failure
Chagas disease should be
treated early
Giardia
Most frequently diagnosed intestinal parasitic disease in the United States
Giardia is found in
surfaces or in soil, food, or water that has been contaminated with feces from infected people or animals
Giardia is transmitted by
contaminated sources or fecal-oral route (hands or fomites)
Most common way to get Giardia
swallowing contaminated drinking water or recreational water
Giardia symptoms
Gas; Stomach cramps or pain; upset stomach or nausea; dehydration
Diarrhea (2-5 loose stools a day)
Amoebic dysentery - Amebiasis causative agent
Entamoeba histolytica
Amoebic dysentery - Amebiasis is more common in
tropical areas with poor sanitary condition
Amoebic dysentery - Amebiasis symptoms
Mild diarrhea to severe dysentery
Liver abscesses
commonly asymptomatic
Amoebic dysentery - Amebiasis transmitted by
Oral or anal contact
contaminated food and water
Brain-eating Amoeba causitive agent
Naegleria fowleri
Brain-eating Amoeba found in
Warm fresh water and soil
Brain-eating Amoeba gets in the body through
the nose travels to the brain
Brain-eating Amoeba mortality rate
Nearly always fatal (>97% mortality rate)
(PAM)
Primary amebic meningoencephalitis
Balamuthia mandrillaris
Free living amoeba
Balamuthia mandrillaris is
Very rare but serious infection of the brain and spinal cord
Balamuthia mandrillaris enters the body when
soil containing Balamuthia comes in contact with skin wounds and cuts, or when dust is breathed in or gets in the mouth - then travel to the brain through blood stream
Balamuthia mandrillaris mortality rate
Mortality rate > 95%
Acanthamoeba keratitis
Rare, but severe infection of the eye (cornea)
Acanthamoeba keratitis can result in
permanent visual impairment or blindness
Acanthamoeba keratitis most common in
people who wear contact lenses
Acanthamoeba keratitis is found in
bodies of water, soil, and air
Balantidiasis causitive agent
(Balantidium coli)
Balantidiasis
The only ciliate known to be capable of infecting humans
Balantidiasis cyts are responsible for
for transmission of Balantidiasis
Balantidiasis symptoms
Mostly asymptomatic, but can cause persistent diarrhea, abdominal pain, and sometimes a perforated colon
Balantidiasis symptoms
Mostly asymptomatic, but can cause persistent diarrhea, abdominal pain, and sometimes a perforated colon
Toxoplasmosis causitive agent
Toxoplasma gondii
Toxoplasmosis targets
Pregnant women and individuals who have compromised immune systems should be cautious
Toxoplasmosis transmissions
Mother-to-child (congenital) transmission
Toxoplasmosis symptoms
“Flu” like symptoms swollen lymph glands and muscle ache/pain
Cat litter box disease
contaminated food and water
Crypto
Cryptosporidium
“Crypto” Cryptosporidium
Many species infect animals, some of which infect humans
“Crypto” Cryptosporidium most common is
Respiratory and gastrointestinal illness - most common is watery diarrhea
“Crypto” Cryptosporidium can
Can survive long periods of time outside host
Protected by an outer shell
Tolerant to chlorine disinfection
“Crypto” Cryptosporidium methos of transmission
Water is the most common method of transmission
Drinking and recreational
“Crypto” Cryptosporidium is the
Leading cause of waterborne disease among humans in the United States
“Crypto” Cryptosporidium is the
Leading cause of waterborne disease among humans in the United States
Malaria
Plasmodium
Flagellates that infect the genital tract
Which of the following is the same for both Trypanosoma cruzi and Trypanosoma brucei and the infectious diseases they cause
Importance of early diagnosis and treatment
Which of the following is thought to be one of the agents of frequent cause of non-bacterial diarrhea in North America
Giardia
