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Is Algae a prokaryote or eukaryote?
- •No nuclear envelopes
- •No membrane-bound organelles, such as plastids, mitochondria, dictyosomes, endoplasmic reticulum
How does algae have feed itself
•Primarily by absorption of food in solution through cell wall
•Some by chemical reactions or by photosynthesis
How does algae reporduce?
vReproduction predominately asexual, by fission.
- •Fission - No mitosis, DNA strand duplicates and is distributed to new cells.
- vNo sexual reproduction
- •Genetic recombination facilitated by pili or by close contact of cells.
Name some distinctions betwen cyanobacteria and traditional bacteria
•Cyanobacteria have chlorophyll a and oxygen is produced from photosynthesis.
- •Cyanobacteria contain phycobilins (blue and red pigments).
- •Cyanobacteria can both fix nitrogen and produce oxygen.
What are some characterists of blue-green bacteria? (Cyanobacteria)
- Can live in extreme heat
- First photosynthic organism
- •Symbiotic with other organisms
- –Amoebae, sea anemones, fungi (producing lichens), cycads
- cycads have amoebae
- -can be found in fresh water as well
Cyanobacteria is the main prinicpal photosynthic organism in plankton.
Describe cyanobacteria form, metabloism and reproduction
- •Often in chains, or colonies held together by gelatinous sheaths
- •Cells blue-green in color in about half of the approximately 1,500 species.
- •Produce nitrogenous food reserve - Cyanophycin
- •Flagella unknown
- •New cells by fission, or by fragmentation of colonies or filaments.
- •In Nostoc and Anabaena, fragmentation often occurs at heterocyst.
- –Heterocyst - Large colorless, nitrogen-fixing cell
- –Also produce akinetes
- oAkinetes - Thick-walled cells that resist adverse conditions
Describe history of cyanobacteria
chloroplasts originated as cyanobacteria or prochlorobacteria living within other cells
•Fossils of cyanobacteria, 3.5 billion years old, found in Australia.
•3 billion years ago, cyanobacteria produced oxygen as by-product of photosynthesis.
•Oxygen accumulated in atmosphere, becoming substantial 1 billion years ago.
•As oxygen accumulated, other photosynthetic organisms appeared and forms of aerobic respiration developed.
•In last half billion years enough ozone for UV shield and for photosynthetic organisms to survive on land.
What are human relevance of cyanobacteria?
Cyanobacteria=plankton, in which other animals eat= food systems!
-algal blooms-poisonus to livestock
What causes Algal blooms?
What toxins do they produce?
High amounts of phorphorous and nitrogen
- Microcystis produces
- the toxin microcystin. Aphanizomenon can produce
- multiple toxins including cylindrospermopsin, saxitoxin andanatoxin.
What is Coleochaete?
Said we probably don't need to know the plant name.
Green algae probably indirect ancestor of land plants.
Shares features with land plants: cells that resemble parenchyma, development of cell plate and phragmoplast during mitosis, a protective covering for zygote, and production of lignin-like compound (helps make it woody=land plants)
What kingdoms are included in Domain Eukarya?
All Eukarytoic cells
•Protista, Plantae, Fungi, Animalia
What kingdom are Algae placed in?
Protista is diverse and heterogeneous
What phylum does Green Algae belong?
What are characteristics of Green Algae?
•Unicellular, filamentous, platelike colonies, netlike tubes, hollow spheres, lettuce-like leaves
- •Greatest variety in freshwater lakes, ponds, and streams
- –Some on tree bark, in animal fur, in snowbanks, in flatworms or sponges, on rocks, in lichen “partnerships.”
- •Have chlorophylls a and b
- •Store food as starch
- •Most have a single nucleus per cell.
- •Most reproduce both sexually and asexually.
What is Chlamydomona?
- Green Algae
- •Common inhabitant of freshwater pools
- •Unicellular (acellular?)Pair of whip-like flagella on one end pull cell through water-(helps this plant move)
- •Two or more vacuoles at base of flagella
- –Regulate water content of cell and remove waste
- •Single, cup-shaped chloroplast with one or two pyrenoids inside
- –Pyrenoids - Proteinaceous structures associated with synthesis of starch
- •Red eyespot near base of flagella
- –Allows alga to swim toward light
How does Chlamydomona reproduce?
Asexual and Sexual Reproduction
Describe Chlamydomona's asexual reproduction.
Haploid is the basal state
- –Nucleus divides by mitosis, and cell contents become two daughter cells within cellulose wall.
- Each develop flagella and swim away.
- No change in chromosome number; all cells remain haploid.
- -budding, spliting
Describe Chlamydomona's sexual reproduction.
Gametes fuse to form a diploid zygote. becomes zygospore, undergoes meiosis internally and split off haploid cells
-Sooo only diploid for a very short amount of time.
What is Ulotrix? and name characteristics
- •Filamentous with holdfast cell at one end
- •Chloroplast - Wide, curved, somewhat flattened, with one to several pyrenoids.
Reproduces asexually and sexually.
Describe asexual reproduction of Ulotrix
- –Cells contents condense, divide by mitosis and become zoospores inside parent cell.
- –Zoospores escape through pore in parent cell wall.
- Resemble Chlamydomonas cells
- Grow into new filaments
Describe sexual reproduction of Ulothrix
•Cell contents condense and divide by mitosis inside parent cell.
- •Each new cell produces flagella.
- •Cells escape from parent cell and become gametes.
What is Sprirogyra? Name Characteristics
- •Filaments of cylindrical cells
- •Chloroplast ribbon-shaped and spirally wrapped around vacuole, with pyrenoids at regular intervals.
Describe reproduction of spirogyra.
Asexual- breaks off and creates a new holdfast cell.
- Sexual- By Conjugation
- –Papillae fuse and form conjugation tubes.
- –Protoplasts fuse, forming zygote that develops thick wall.
- –Eventually zygote undergoes meiosis.
What is Oedogonium? Name characteristics
Green algae- with holdfast
•Large netlike chloroplast with pyrenoids at intersections of net
Asexual-fragmentation breaks apart grows new filamentous
Describe Sexual reproduction
- -most of lifecycle is haploid.
- -diploid is mostly just at the zygote, which splits open to produce haploid cells.
- -Oogamete= female cell with egg=
- - Antheridium= produces and releases sperm.
- -Zygote produces 4 zoospores by meiosis that grow into new haploid filaments
What is Chorella? What is Desmid?
Chorella- used for food source, that can be grown in culture. -only asexually
- Desmids= important part of plankton
- -reproduce by conjugation.
What is hydrodicotyon?
Green Algae, hexagonal meshes.
- –Asexual reproduction, as well as isogamous sexual reproduction
- –Isogamous = two flagellated gametes
What is Volvox?
- - Colonial green algae held together in a secretion of gelatinous material, resembling hollow ball
- –Reproduction asexual or sexual
- oSmaller daughter colonies formed inside parent colony
What is Ulva? Explain characteristics.
- (sea lettuce) - Multicellular seaweed with flattened green blades and basal holdfast to anchor blades to rocks
- –Haploid and diploid blades
- oDiploid blades produce spores that develop into haploid blades.
- oHaploid blades bear gametangia that form gametes. Gametes fuse to form zygotes that grow into diploid blades
Exhibit isomorphism - Haploid and diploid blades indistinguishable
What phylum does yellow-green, goldent-brown, diatoms, and brown algae belong?
What is Vaucheria?
- –Oogamous, coenocytic, filamentous species
- oAplanospores formed during asexual reproduction.Sexual reproduction rare
- -Two flagella of motile cells are oriented in opposite directions
Where would you normall find goldent-brown algae?
•Most occur in the plankton of fresh water.
- –Motile cells have two flagella of unequal length inserted at right angles to each other.
- oPhotoreceptor on short flagellum.
What are Diatoms? name characteristics of some.
- •Fresh and salt water, particularly abundant in cold marine habitats
- •Also, dominate algal flora on damp cliffs, tree bark or buildings
- •Look like ornate, glass boxes with lids
- –As much as 95% of wall is silica.
- •Chlorophylls a and c and fucoxanthin
- •Food reserves - Oil, fats or laminarin
Describe Asexual reproduction of Diatoms.
•Asexual reproduction results in half of cells becoming progressively smaller.
•Original cell size restored through sexual reproduction.
What are characteristics of Brown algae?
•Relatively large; none unicellular or colonial
- •Most marine; majority in cold, shallow water
- •Many have a thallus differentiated into a holdfast, a stipe, and blades.
- –Blades may have gas-filled bladders.
- •Chlorophylls a and c, fucoxanthin
- •Food reserve = laminarinAlgin in cell walls
What is sargassum?
How does it reproduce?
Brown algae (Phaeophyceae)
- •Sargassum - Floating brown seaweed
- •Asexual reproduction by fragmentation or autospores.
What is Fucus?
Brown algae, common rockweed
- –Sexual reproduction:
- oReceptacles at tips of branches contain spherical chambers called conceptacles with gametangia inside.
- Oogonium produces 8 eggs.
- Antheridium produces 64 sperm.
- oEggs and sperm released into water.
What phylum is Red algae? Name characteristics of red algae.
•In warmer and deeper waters than brown algaeMost are filamentous with filaments so tightly packed they appear to have flattened blades or branched segments
- •Relatively complex life cycle involving three types of thallus structures
- •Nonmotile reproductive cells
Kelp forests consist of what kind of algae?
what are some cool things about red algae?
•Colors mostly due to phycobilins.
- –Similar to those of cyanobacteria
- oRed algae may have been derived from cyanobacteria.
- •Chlorophylls a, and sometimes d
- •Food reserve - Floridean starch
- •Numbers of species produce agar.
What phylum is the dinoflagellates? Name characteristics.
- vThe Dinoflagellates
- •Red tides - Sudden multiplication of dinoflagellates
- –Some produce neurotoxins that accumulate in shell fish.
- •Cellulose “armor plates” inside cell membrane
- •Two flagella in intersecting grooves
- –One trails behind cell - Acts as rudder
what are some cool things about dinoflaggelates?
•Most have disc-shaped chloroplasts.
- –Contain xanthophyll pigments
- –Chlorophylls a and c
- •About 45% nonphotosynthetic
- •Chromosomes remain condensed and visible throughout life of cell.
- •Starch food reserveMany have tiny projectiles that fire when irritated
What are human ecological relevance to algae?
vProtistan algal phyla at bottom of food chain.
- •Oils are sources of vitamins.
- •Diatomaceous earth
- –Polishes, toothpaste
- –Paint that reflects light
- vOther algae
- –Potential human food source
•Produced by giant kelps and other brown algae
- –Ice cream, salad dressing
- –Latex paint, textiles, ceramics
- –Regulates water behavior
- oControls development of ice crystals
- oRegulates penetration of water
- oStabilizes suspensions
Human importance of algae, continued....
vMinerals and food
- •Iodine from kelp
- •Red algae
- –Food - Dulse, nori
- –Carrageenan - Thickening agent
- •Produced by red alga Gelidium
- –Solidifier of nutrient culture media
- –Retains moistness in bakery products
- –Base for cosmetics