protists (07) ("the left over group") Flashcards
General characterostiscs of protists:
What type (cell type? + the properties?
Where?
Type of reproduction?
- Most diverse kingdom (nothing distinguishable)
-Eurkaryotic; not plants, animals, or fungi
—> Membrane bounded organneles, can be unicellular and very small or can be multicellular and very large
There is no “typically” protist, the only characteristic that all protist share is that they are not animals, plants or fungi.
Vary in movement structures (or if they can move at all)
-Mainly asexual, reproducing using spores, by binary fission. or sexually by conugation.
–> WIthin moist/aquatic surroundings, but also terrestrial environments, such as soil.
Why are protists important? (“The Pros”)
-> Bottom of the good chain, therefore a majour food source.
–> Natural producers, because there are “photosynthetic protists” (such as algae) and they conduct photosynthesis, they are the primary producers in aquatic ecosystems
-they form the base of the food chain, produce oxygfen and organic materials to support other organisms
–> Non-photosynthetic protists are important consumers (Play a critical role in recycling nutrients, decomposing organic material and releasing essential nutrients back into the environment)
—>Dominate the lowest levels of the aquatic food pyramids.
-> Human usage:
–> Nori (sushi)
–> Agar (a medium for growing bacteria)
Why are protists important? (Cons:)
Many protists are parasites, therefore they live in or on other organaismsm and can cause disease.
–> parasite (different from viruses because its a parasite is a LIVING ENTITY, while a virus is a “non-living entity”)
—–> Known for causing malaria (Plasmodium [a single celled protists] that infects a mosquito)
—-> Knwon for causing** Beaver fever** (Scientific name Giadaiasis lambia, a protists contamaintating water)
-> Protists causes “red tide,” an increase in # of algae, toxins that can kill fish and poision people who have eaten affected shellfish.
Protists are thought of what? (why are they the simpliest eukaryotic cells?) +How are protists connected to prokaryotic cells.
Thought of as the first eukaryotes to exisit.
–> their cells have a nuclelus and organelles that are membrane bounded.
–> The internal membranes in eukaryotic cells are made from the folding cell membranes of ancestral prokaroytic cells (therefore the internal membranes in protists are evolved versions of folded cell membranes in of PROKAYROTIC CELLS [unicellular, no membrane bounded organelles])
—-> Why did prokayrotes have folded memebranes? To increase the surface area of a cell, because a larger surface area = more absorbtion.
- Internal organelles most likely devolped wshen the cell membrane of a prokaryote, folded on itself.
Mitochondria and chloroplast, why are they different from organelles? (5)
1) Present-day mitochondria and chloroplasts each have two membranes.
2) inner membranes & outer membranes
—> Inner membranes = similar to the ancestral projaryotes
Outer membranes = matches eukaryotic cells
3) Have their own internal chromosomes (own DNA) (Contains genetic information used by the organelle) These chromosomes are very similar to prokaryotic chromosomes.
4) Reproduce independently within eukaryotic cells by binary fission, just like prokaryotes
What is endosymbiosis?
A relationship in which a single-celled organism lives within the cell(s) of another organism
Simply: when one type of cell lvies within another type of cell.
Chloroplast and mitochonrdria thought to have oringinated by endosymbiosis.
How does mitochrondria and chloroplast connect to endosymbiosis?
Mitochondria and chrolorplasts were once aerobic prokaryotic organismsm, and were engulfed by early anaerobic eukaryotic cells, there being the mirotcondria and the cholorplast were incorparted into the eurkaryotic cells.
Flow chart:
(Animal cell)
–> Ancestral anaerobic eukaruotic cell that has a nucleus and a plasma membrane (anaerobic, therefore does not require oxygen to live),
engulfs a heterotrophic prokaryotic cell (mitocondria), this is SYMBIOTIC because the mitrocondria benefitied from rich food supply by being inside the cell, while the eukaryte benefitted from receiving excess energy
(Plant cell)
–> Ancestral eukaruotic cell that has a nucleus and a plasma membrane (anaerobic, therefore does not require oxygen to live),
—> Engulfs a photosynthetic aerobic prokaryotic cell (chloroplast)
this is a SYMBIOTIC relationship becuase the cholorplast benefited from the CO2 that was produced as a waste product the eukaryotic cell, while the eukaryote benefitted from excess food.
–> Endosymbiotic prokaryoties become permanent residents of their eukaryotic host cells, loosing their ability to live independty.
General characeristics?
Very hard to distinguish because theres nothing disguishable, therefore other kingdoms must be consulted first before putting an organismsm into this grouup?
- Only characteristic they all share is that they are not animals, plants, or fungi
- They all Vary greatly
-> they are all Uni and multicellular
-> Different cell features, ways of moving, ways of getting nutrients and energy, methods of reproducing
-> Can be all poller opposites.
What are the “pros” of protists?
-> Play a key role as producers OR consumers (they help keep things in balence)
-Ie: Swaweed (green algae, brown alage, red alage, etc) has gas filled bladders that help them float to the top for more sunlight.
–> Primary producers in aqatic environments.
—> Climate change affects protists in many different ways
-> Increased acidity from more rainfall [due to warmer temperatures] interfere with a protists ability to produce outer protective shells, which reduces ability to stay alive, therefore damage/threatens major aquatic food webs that rely on photosyntetic protists as primary producers.
–> Warmer temperatures may also allow other protists to survive better, therefre increasing population size, which can interfere with the natural food web in unpredictable ways.
-> some protists live as symbiotic organisms in the bodies of other animals.
–> ie: the animal “coral” depends on protists as a food source.
What are the life cycles or protists?
Single cell protists:
Asexual Reproduction: Binary Fission (cells divide into two genetically identical daughter cells, very similar to mitosis)
Sexual Reproduction: Conjugation (cells allign and exchange genetic material)
Multicellular protists
–> Sexual reprodction involving the formaltion of sex cells (meiosis)
-> Egg and sperm cells (both haploids) —> Fuses to form a diploid zygote.
Alternation of Generations
–> At one point the cells reproduced asexually and in the same life cycle they produce sexually.
–> Alterations of generations (Spores)
a life cycle in which diploid individuals produce spores that create haploid individuals; the haploid individuals reproduce sexually, producing diploid individuals and completing the cycle
Steps of binary fission?
Replication of DNA:
The single, circular chromosome of the bacterium replicates itself.
The two copies of the chromosome move to opposite ends of the cell.
2. Cell Growth:
The cell elongates and increases in size.
New cell membrane and cell wall material are synthesized.
3. Cytokinesis:
A septum (partition) forms in the middle of the cell, dividing the cytoplasm.
The cell wall grows inward, completing the separation of the two daughter cells.
Formation of Two Daughter Cells: (Seperation)
The cell splits into two identical daughter cells, each with a complete copy of the original DNA.
Steps of conjugation/ How does conjugation work?
Two cells joining together to exchange genetic info! method of horizontal gene transfer
How?
1. Donor cell + recipipant cell attach to each other with pillius (Hair like structure for attachement, similar to villi and cillia)
–> Donor cell has a plasmid (Moveable, circular piece of DNA, a part from the nucleoid)
2. Cells make contacts with each other
3. DNA (plasmids) is cut at a specific point and is transfered to the recpiant cell through the pilius
—> Both the donor and recipant has the strand of DNA, as they both replicate.
4. Then the cells seperate, eaching carrying the plasmid DNA
How does alterations of generations work?
1: a diploid **sporophyte ** (an organisms that can produce spores) produces a single-cell haploid spore (a reproductive structure, that is capable of growing into a new indivdual).
- these spores attach to a surface and begom dovodomg amd growing into multicellupar haploid hametophytes (a haploid orhanismsm that produces haploid sex cells)
3) The gametophytes produce uce haploid sperm and eggs, and when the egg is fertilizes by the sperm, it becomes a diploid zygote, that grows into a sporoophyte which redoes the whole cycle.
There are 3 types of protisits: Plant-like protists:
ie: algae
- Usually multicellular
- Aquatic and contain chlorophyll
Carry out photosynthesis - autotrophic
-Some have flagella (signiifying that this animal is immediately not a platnt)
-Made in our food amd can be ediable
Size range from a single cell (ex. diatoms) to 60 m in length (ex. green algae)
3 groups of protists: Animal like protists
ie: Protozoa
Many are parasitic
ex. plasmodium causes malaria;
ex. flagellates Trypanosoma (a type of protists) causes African Sleeping Sickness
- Trypanosoma are in the salivary glands of tsetse flies (biting flies) → flies bite human and pass it on → trypanosoma reproduce in human blood and spinal fluid → person becomes dizzy, falls into a coma, and dies
- Heteroptrophic, feeding on other organismsm or lacking cell wapps.
- Motile.
