Eukaryotes Flashcards
Eukaryotes have
Many subcellular components (organoids) bound by an internal plasma membrane
Primary feature of Eukaryotes is that
Their primary nuclear material (DNA) is bound within a membrane (Nuclear Envelope)
Nuclear Envelope
Membrane that contains DNA
6 Main differences of Eukaryotic cells compared to Prokaryotic cells
- greater size
- nucleus is present with linear chromosomes
- histones are present
- membrane bound organelles in cytoplasm
- flagella complexity
- cell wall structure differs (no capsule present)
Multicellular Eukaryotes include
- plants
- fungi
- animals
Histones
Proteins that bind DNA for regulation
Which Eukaryotes have a cell wall?
- plants
- fungi (composed of chitin)
Epithelial Cell Junctions
Adhesion structures and molecules within external membrane that keep everything in place (animals only)
5 Features of a Eukaryotic Cell
- membrane bound organelles
- nucleus
- protein histone for regulation of DNA organization
- complex genetic expression
- cytoskeleton containing Actin and Tubulin
Eukaryotic Cells contain 5 main types of organelles:
- nucleus
- cytoplasm
- cytoskeleton
- mitochondria and plastids
- chloroplasts (plants)
Structure and Function of the Nucleus (4)
- control centre of cell
- contains DNA (genetic material) in Chromosomes
- synthesises RNA (transcription)
- contains Histones (regulatory proteins that control how cells transcribe DNA)
Nucleus is surrounded by the
Nuclear Envelope/Membrane
Nucleolus
Part of the nucleus that makes ribosomes
What is the Cytoplasm? What are some components found in it?
Gel-like liquid that fills the cell
Components include:
- endomembrane system
- ribosomes
- cytoskeleton
- mitochondria and plasmids
- plasma membrane
- other inclusions
Three functions of the Cytoskeleton + what it contains (2)
- structure/shape
- movement of cell and within cell
- control of cell division
- contains Actin and Tubulin
Actin and Tubulin are found
In the Cytoskeleton of Eukaryotic cells
Functions of Mitochondria
- powerhouse of cell
- generates ATP (energy)
- makes specialized proteins
- cell signalling, control of cell cycle
Mitochondria have their own
DNA that replicates
Chloroplasts
- in plants
- have their own DNA
- convert light energy into chemical energy
- a type of plastid
How do plant cells differ from animal cells? (4)
- cell wall
- plasmodesmata
- chloroplasts
- central vacuole
How do animal cells differ from plant cells?
Animal cells contain
- centrioles
- lysosomes
A Phylogenetic Tree is
A graphic representation of hypothetical origin of species or Taxa (groups of species) over time
Branch Point in Phylogenetic Tree
Shows the last common ancestor of taxa
Branches in Phylogenetic Tree represent
Divergence of species
Three domains of all life forms include
- Bacteria (Prokaryota)
- Archaea (Prokaryota)
- Eukaryotes (Eukaryota)
Serial Endosymbiosis Theory
Explains how Eukaryotes arose:
- cell membrane infolded in a bacterial cell
—> eventually the infolded membrane surround nuclear material (DNA)
—> this advanced cell engulfed other bacterial cells that eventually became organelles
Theory of the origins of flagella, plastids, and mitochondria
Endosymbiotic Origin
3 pieces of Evidence that Endosymbioses is the origin of Eukaryote organelles:
- occurs today
- mitochondria and plastids have their own genomes and similar structures
- genetic sequence of DNA in mitochondria is similar to that of some prokaryotes
6 Similarities between mitochondria and bacteria
- size and morphology
- double membrane like gram-negative bacteria
- similar enzymes and inner membrane transport systems
- reproduction via binary fission
- circular DNA
- own protein synthesis machinery including rRNA and tRNA
Example of current Endosymbioses
Mixotricha paradoxa (termites) —> functions as a symbiotic assemblage of five different species living to form one living cell
Endosymbiont
An organism that lives within another organism
Autotrophy
Ability to be self-sustained by producing foods from inorganic compounds
Example: Algae
Heterotrophy
Food is sourced from organic compounds
Example: animals
Single Celled Eukaryotes (SCE)
Unicellular organisms
Most eukaryotes are
Single celled
Eukaryota can be divided into three kingdoms
- Animals
- Plants
- Fungi
SCE clades/groups are classified based on these 5 features
- molecular sequence
- cell ultrastructure
- locomotory structures
- mitochondria and plastids
- membrane structure
5 super groups of SCE
- Flagellates (diplomondida (giardia) and euglenozoa)
- Alveolata (Apicomplexans (babesia and coccidia) and CIliates)
- Amoebozoans (entamoeba)
- Opisthokonts
- Plant-like Organisms (red and green algae)
Flagellates are also called
Excavata
Flagellate sub groups include
-Diplomondida (ex. Giardia)
-Euglenozoa (ex. Trypanosoma)
Flagellates / Excavata have 3 key features
- anterior flagella (front end)
- flagella (usually 2+ per cell)
- highly modified mitochondria
How do Flagella and Cilia differ?
Flagellum: (Latin for whip)
-long, threadlike, on surface of cell
-wave-like and slow beat
Cilium: (Latin for eyelash)
-short, hairlike, on surface of cell
-abundant
-fast and rotating beat
Diplomonadida
- sub group of flagellates
- lack mitochondria (possess “Mitosomes”) and lack plastids
- mostly anaerobic
- mostly symbiotic parasites
Example: Giardia
Mitosomes
Mitochondria-like organelle but not used for ATP generation
Locomotory appendages are called
Flagella
Symbiotic
Live within other organisms
Parasites
Cause harm to the organism they live in
Anaerobic
Adapted to life in low oxygen
Giardia
- part of Diplomonadida (Flagellates)
- intestinal parasite containing resistant cysts that contaminate water supply
Kinetoplastids
- Parasitic flagellates (Euglenozoids)
- has mitochondria with a large circular DNA body
- heterotrophs
- free living
Example: Trypanosoma
Trypanosoma
- Kinetoplastid (Euglenozoid, Flagellate)
- cause Nagana in animals, Sleeping Sickness in humans, Chagas Disease
- can live in circulatory system of vertebrates
Diplomonadida
Sub group of Flagellates
Euglenozoa
Sub group of flagellates
Diplomonadida lack
Mitochondria
Most species of Diplomonadida are
Anaerobic
Giardia is an ____ parasite
Intestinal
Circle of DNA inside kinetoplastid mitochondrion is called
Kinetoplast
Kinetoplastids divide via
Binary fission
Three examples of Kinetoplastids
-African Trypanosomes (sleeping sickness/nagana)
-New World Trypanosome (Chagas Disease)
-Leishmaniasis
Two subgroups of Alveolata Phyla are
-Apicomplexa
-Ciliata
Ciliata and Apicomplexa are subgroups of
Alveolata
Apicomplexans are all ____
Obligatory parasites
Movement of Apicomplexans is done by
Gliding that relies on the flow of their environment
Apicomplexans are named after their
Apical Complex used to invade other cells
Babesia is an example of
Apicomplexans
Babesia is also called
Tick fever
Which Apicomplexan invades the red blood cells of cattle
Babesia
Intracellular parasites live
Within a cell
Organelle similar to chloroplast but lacking chlorophyll is
Apicoplast
Tick Fever can be caused by 3 different pathogens:
-2 species of Babesia
-1 species of prokaryotes
Babesia is a parasite under what subgroup and phylum?
Apicomplexans, Alveolata
Babesia is transmitted to ____ via ____
Cattle; tick
Ciliata is a subgroup of
Alveolata
The freshwater unicellular Alveolates are
Ciliata
Ciliata use ____ for movement and feeding
Cilia
Coccidiosis method of transmission
Oocyst is excreted via faeces to external environment (disease especially important in chickens)
Type of flagellate SCE parasite
African trypanosomiasis (sleeping sickness / Nagana)
Nagana or sleeping sickness is transmitted via
Tsetse fly
A parasite that affects One Health includes
Trypanosomiasis
Nagana affects
Livestock, although the same parasite affects humans
Cilia is similar to flagella but is
Smaller
Balantidium coli mostly originates from ____
Pigs
A vet significant ciliate is
Balantidium coli
A dual nucleus has
-two nuclei
-macro (“desktop”) nucleus
-micro (“iCloud”) nucleus
Conjugation is a form of
Sexual reproduction
Macronucleus
Transcribed nucleus copied from the micronucleus
Micronucleus
Primary nucleus for germ line transmission
Which nucleus is used constantly in Ciliata
Macronucleus
The Macronucleus of ciliates is functional for
About 200 generations
Ciliates reproduce via
Conjugation and cell division
Conjugation of Ciliates
- two cells merge cytoplasm
- Macronucleus is broken down and remade
- micro nuclei make copies of themselves
- cells swap on copy of micronuclei and replicate again
Rumens contain ____ and ____ for ____
Prokaryotes and Ciliates ; Digestion
Algae is divided into
-red algae (rhodophyta)
-green algae (chlorophyta)
Rhodophyta
Red algae
Chlorophyta
Green algae
Red algae is used for
-sushi wraps
-agar (microbiology)
-food stabilizers
-ice cream
Closest relative to green algae are
Land plants
Major autotroph in the marine environment is
Green algae
Chlorophyta are closely related to
Land plants
SCE that are not structured and fluid in shape are
Amoebae
Amoebae move via
pseudopodia (via projections and Cytoplasmic flow through)
Flagellum are usually absent in
Amoebae
Pseudopodium in Latin means
“False foot”
Pseudopodia are used for
Movement and capturing of prey
Amoebae are
Single celled eukaryotes that are fluid like
Amoebae reside in
Soil, fresh water, and marine environments
Two types of opportunistic parasitic amoebae are
-Acanthamoeba
-Naegleria
Free-living ____ can enter the brain/eye of host usually through freshwater contact
Amoebae
E.histolytica is under the phyla
Amoebae
E.histolytica can be found in ____ but rarely causes disease
Dogs
Slime moulds were thought to be ____ but are actually _____
Fungi; Amoebae
_____ have elements of both unicellular and multicellular life
Slime Moulds
Opisthokonts Latin meaning
Opistho: “behind”
Konts: “flagellum”
Opisthokonts have a
Single posterior flagellum
Unicellular species with a single flagellum are
Opisthokonts
Important group related to animals are
Choanoflagellates
“Choano” means
Collar
Choanoflagelltas use ____ for feeding
Flagella to produce a water current
Multicellular group within the Opisthokonts are
Animals
Metazoa arose from ____, specifically _____
Opisthokonts; Choanoflagellates
Fungi arose from
Opisthokonts
Babesia infects the
Red blood cells of cattle
Parasite that forms assemblages in RBCs and feast on cell until it ruptures
Babesia (tick fever)
A very efficient Apicomplexan parasite is
Babesia
Babesia is part of the subgroup ____ and phyla ____
Apicomplexa; Alveolata
Which parasite has resistant cysts
Giardia
Abiotic Components are
Interactions with the physical and chemical environment
Biotic Components are
Interactions with other organisms
Intraspecific Interactions are
Interactions between individuals of the SAME species
Interactions between individual of different species is called
Interspecific Interactions
Three main types of Interspecific Interactions include
- competition
- predation
- symbiosis
Symbioses in Latin means:
Sym: “together”
Bioses: “life”
Associations where organisms live together is called
Symbioses
Three primary sorts of symbiotic relationships include
-commensalism
-mutualism
-parasitism
When two organisms benefit from their relationship
Mutualism
When one species benefits and one is neither harmed nor benefits is
Commensalism
B.hepatica (adult stomach flukes in cattle) are an example of
Commensalism
Ciliates digesting cellulose in the ruminant stomach is an example of
Mutualism
One species benefits and one species is harmed
Parasitism
A parasite that lives within a host is called an
Endoparasite
A parasite that lives on the external surface of the host is called an
Ectoparasite
Nagana (sleeping sickness) is a parasite that affects
Animals and humans
Malaria
- Apicomplexan
- Intracellular parasite that invades RBCs
Which parasite can hide from the immune system
Malaria
Haemolysis is
The breakdown of red blood cells
Apicomplexan disease affecting the lining of livestock GI tract
Coccidiosis
Important parasite of intensive livestock production (especially chickens)
Coccidiosis
Kangaroos are especially sensitive to
Coccidiosis
Coccidiosis is a disease associated with
Stress and overcrowding
Asexual reproduction of Coccidiosis occurs in
The intestinal mucosa
Sexual reproduction of Coccidiosis occurs in ____ and travels to _____ via _____
Intestinal mucosa (GI tract); external environment; faeces
Which 3 parasitic SCE have a similar life cycle?
- entamoeba
- B. coli
- giardia
2 stages of entamoeba
- trophozoite —> active feeding stage, metabolically active, intestinal
- cyst —> dormant stage, rounded, forms a cell wall. Is outside the host
Life cycle of entamoeba
- ingestion of cyst contaminated food or water
- excystation (division)
- trophozoite migrate to large intestine
- invades intestinal mucosa and causes invasive infection
- the non invasive cysts exit host through stool
Transovarial Transmission
- the passing of a pathogen from a parent to its offspring through the ovaries (egg)
- offspring capable of transmitting the infection
Example of transovarial transmission
Babesia tick
Life cycle of babesia
2 hosts (tick and mammal)
- Tick feeds on blood, pumping in saliva
- transovarial transmission (eggs of infected female tick become infected with parasites and are infected at birth)
- fertilised in midgut
- sporogony produces sporozoites
- sporozoites mature to trophozoites
Life cycle of Balantidium coli
- Ingested via cycts in contaminated food or water
- excystation occurs in small intestine –> trophozoites invade large intestine and some the colon wall
- encystation occurs to produce infective cysts
- mature cysts passed in faeces
