Lesson 10 (14/10/14)

Date : 14/10/14

Topic : Protists (Algae)

Activities
1. BYON (Bring Your Own Notes)

Notes

Name of microbes

Algae can be separated into seven major divisions.

• Chlorophyta (Green algae) includes single-celled Spyrogyra with filament and flat-leaf mass of cells called thallus (Ulva lactuca).
• Phaeophyta (Brown algae) includes familiar seaweeds found on rocky shores
• Rhodophyta (Red algae) includes those found in warmer seas and several species of economic importaance. 
• Chrysophyta (Golden-brown algae) includes diatoms such as bacillariophyta.
• Xanthophyta (Yellow-green algae)
• Pyrrophyta (Dinoflagellata)
• Euglenophyta

Rhodophyta (red algae) is a group of multicellular aquatiic algae with highly varied organisation of plant body. They have cellulose cell wall or agar and store glucose polymer. They can be found atached to rocky stones. Vegetative reproduction occurs by fragmentation. Asexual reproduction involves formation of different types of spores like monospores, neutral spores, corpospores and tetraspores.  Sexual reproduction occurs by oogamy carried out by antheridia or spermatangia and carpogonia. Life cycle involves alternate generation of haploid gametophytic generation and diploid sporophytic generation. They contain chloropyll a, chlorophyll d, phycocyanin, phycoerythrin,


Phaeophyta (brown algae // seaweed) is a much-advance group of marcoscopic algae found mostly in the sea. They have cellulose cell wall or algin and store carbohydrates. The plant body may be filamentous, hold fast and stemlike stipe, or leaf-like blades. Vegetative reproduction occurs by fragmentation. Asexual reproduction involves formation of motile zoospores and non-motile spores (monospores and tetraspores). Sexual reproduction may be isogamy (fusion of similar gametes), anisiogamy (fusion of dissimilar gametes) or oogamy (a form of anisogamy in which non-motile female gamate is larger than male gamate). It contains fucoxanthin, chlorophyll a, chlorophyll c and xanthophylls.


Chlorophyta is a diverse group of algae and mostly found in fresh water. It has cellulose cell wall and store glucose polymer. It contains chlorophyll a, chlorophyll b, carotenes and xanthophylls. Vegetative reproduction occurs by cell division, fragmentation and stolon formation (creeping horizontal plant stem or runner that can form new plants). Asexual reproduction occurs by fission and formation of zoospores or aplanospores. Sexual reproduction can be isogamous, anisogamous, or oogamous. Types of plant body:

• Unicellular and motile = Chlamydomonas
• Colonial and motile = Volvox
• Colonial and non-motile = Hydrodictyon
• Filamentous = Oedogonium and Cladophora

Chrysophyta contains golden-brown algae, such as diatoms. They contain carotenoids, chlorophyll a and chlorophyll c. Diatoms are algae which have a variety of intricate shapes and contain silicon in their cell walls. Diatoms are unlike other algae under Chrysophyta, they are either nonmobile or glide slowly along surfaces. They store material in oil. They are important in global carbon cycling.



Pyrrophyta or dinoflagellates are unicellular planktons with cellulose cell wall. They have two flagella in perpendicular opposing grooves. They can produce neurotoxins and cause red tides. They contain chlorophyll a and chlorophyll c.


Eugleonophyta or euglenoid algae contain green or colorless flagellates. Some consider euglenoid algae as protozoans because some do not contain chloroplasts and able to feed on organic matter and other organisms.They store food in glucose polymer. They have no cell wall but have pellicle or rigid plasma membrane. No sexual reproduction occurs. They contain chlorophyll a, chlorophyll b, carotene. However, they can spontaneously lose chlorophyll.

Euglena is a typical euglenoid. It has a single large flagellum and several chloroplasts.

Coralline algae are red algae under order Corallinales. It is part of the coral reefs.

Clamydomonas is a typical green alga with two flagella. Each Chlamydomonas cell contains a single, large chloroplast which fills up most of the cell. It also contains an eyespot which is a light-sensitive organelle that helps Chlamydomonas to swim towards light.

Terms in microbiology

Osmotrophy is the uptake of dissolved organic compounds by osmosis for nutrition.

Hydrogenosome is a membrane-enclosed organelle of some anaerobic ciliates, trichomonads and fungi.

Trichomonad is a parasitic protozoan with four to six flagella and an undulating membrane. It infests the urogenital or digestive system.

Syngamy is the fusion of two cells or fusion of their nuclei, in reproduction ; Autogamy is the process of self-fertilization, especially the self pollination of flower.

Thallus is an undifferentiated plant body.

Aplanospores are non-motile spores ; Zoospores are flagellated motile spores.

Antheridia and oogonia are gamates of algae, mosses, ferns, fungi, and other non-flowering plants.

Random facts

• Cytoplasm of protists sometimes divided into outer gelatinous ectoplasm and inner fluid-like endoplasm.
• Pellicle provides support.
• Algae can be unicellular or colonial, microscopic or marcoscopic, can have simple or complex filaments. Habitat of algae can be aquatic habitat, moist soils, dry soils or acidic habitat, Algae may have no cell wall or have cell wall strengthened with calcium carbonate, chitin or silica. The cell wall mostly has modified cellulose fibrils which have added polysaccharides such as pectic, xylan and mannans. Algae can be found as in terrestrial (moist rocks, trees, soil, or as endosymbionts - as in protozoa, worms, corals and fungi), planktonic, benthic (bottom of ocean or lakes) or neustonic (surace layer of water) form.
• Algae can be used to make biofuels (Biodiesel, Bioethanol,  Biobutanol), biomass and produce vegetable oils, supplements and hydrogen.
• Algae can control pollution and is used in wastewater treatment facilities. Algae can capture fertilizers in runoff from farms. When subsequently harvested, the enriched algae can be used as fertilizers. Algae bioreactors are used to reduce CO2 emission
• Alginic acid of phaeophyta can be used for thickening, stabilizing and emusifying purposes. For example, in making ice cream and dental impressions.
• Consequences of algae bloom include disrupting higher links of food web and producing neurotoxin. Neurotoxin produced by algae accumulated in fishes or shellfishes. Example of algae bloom is red tide caused by dinoflagellates, the brevetoxins produced cause respiratory irritation in human. Some algae bloom will consume itself and cause bacterial bloom.
• 

Muddiest point
-

My own exploration

• Coral reefs are mainly constructed by few types of marine organisms, including inverterbrate animals (sponges, octocorals or soft corals, fire corals, etc), "stony" corals and coralline red algae. Both "stony" coral and coralline red algae can extract calcium ions and bicarbonate ions to form calcium carbonate that acts as protective outer skeletons of coral polyps. The reef-building process is slow and can only be built over decades and centuries.
• algae
• Algae description and types
• Algae,rhodophyta,phaeophyta,chlorophyta | Tutorvista.com
• How Are Coral Reefs Formed?
• Algae Control

Reflection on this topic

The topic of protists is quite interesting because there is no distinct characteristics to distinguish each order. The taxonomy and grouping of protists are changing from time to time when new discovery is found. This makes me realize that there is still much discoveries have to be done on microorganisms. We can actually discover them ourselves even though many research has been done before us.

However, it takes me quite some time to understand the topic of algae. For this topic, I plan to make a table to classify the characteristics of each order under algae.