The Protista Kingdom Ajla Basic Joshua Edoimioya Chapter 28

The Protists Protist are a group of organisms put into the kingdom Protista – Also known as the most diverse group of them all. ALL protists are EUKARYOTIC (all cells have a nucleus) Tend to live in moist environments Can be heterotrophic or autotrophic Mostly unicellular – Can be multi-cellular, such as algae

Endosymbiosis Endosymbiosis: When a unicellular organism will live inside a host and engulf the cells within the host organism Results in endosymbionts, which then lead into organelles. Led to more diversity within Protists Due to the addition of different organelles being created within them.

Endosymbiosis Example Can be used to explain how eukaryotes received their organelles For example, their mitochondria: – Engulfed alpha preobacteria (endosymbiont) – Evolved into mitochondria Also seen in heterotrophic eukaryotes – Engulfed a photosynthetic cyan bacterium – evolved into plastids – Eventually led to the creation of red algae and green algae

Diplomonads Have two equal-sized nuclei Contain multiple flagella Eukaryotic flagella – Extension of the cytoplasm – Consist of bundles of microtubules that cover the plasma membrane An example of a diplomonad is Giardia intestinalis, an intestinal parasite

Parabasalids Lack plastids Their mitochondria lacks : – DNA – an electron transport chain An example is Trychonympha Live in the guts of animals, such as termites – Contains endosymbiotic bacteria that helps termites break down wood

Euglenozoans Is divided into two groups Kinetoplastids and Euglenids Kinetoplastids: Have one large mitochondrion and a kinetoplast which stores extra-nuclear DNA Live in symbiosis with host organisms Most of them are pathogenic Euglenoids: – Store surplus carhbohydrates from photosynthesis – All contain flagella

Alveolates Separated into three groups: Dinoflagellates – a group of flagellates – Mutualistic relationship with coral polyps, the animal that creates coral reefs Apicomplexans – A group of parasites found in animals and humans – Explains parasites spreading through tiny host, called sporozoites Ciliates: – Move and feed by means of cilia

Stramenopiles Include several groups of heterotrophs Name means “straw” “hair” Refers to the flagellum with covered in what seems to be hair-like Can be divided into four groups: – Oomycetes – Diatoms – Golden Algae – Brown Algae

Oomycetes – Includes water mold, white rusts, and downy mildews – Cell wall made of cellulose Diatoms – Unicellular algae that have a unique glass-like wall – Reproduce asexually by mitosis Golden Algae – Named from their color – Components of freshwater and marine plankton Brown Algae – Largest and most complex algae – All are multicellular – Color is caused from carotenoids in their plastids

Cercozoans Contains organisms that are referred to as amoebas Move by means of pseudopodia – Pseudopodia : extensions from the cell surface that also determine the direction it moves in Extensions are known as pseudopods

Radiolarians Mostly marine protists Also move using pseudopodia These pseudopodia are known axopodia Radiate from the central body

Red Algae 6,000 species are reddish Due to the accessory pigment, phycoerythrin Phycoerythin masks the green of chlorophyll Multicellular and are also referred to as seaweeds Depend on currents to receive games for fertilization

Green Algae Named for their grass-green chloroplasts Similar ultra-structure and pigment composition of plants Closely related to land plants

Structure of Euglena

Structure of Paramecium

Alternations of Generations in Algae Applies only to life cycles where both haploid and diploid stages are multicellular EX: Laminaria – diploid cells are called sporophytes because it reproduces cells called zoospores – Zoospores develop into haploid male and female gametophytes which give rise to new sporophyte

Harmful and Beneficial Impacts of Humans It is helpful in that it is photosynthetic and produces oxygen and food for organisms that consume algae. Some algae are eaten directly by people such as the seaweed used in some sushi rolls. A few algae produce odor and toxins that can cause harm to humans. Brown Alga ( Laminaria) is used in soups – Pudding – Ice cream – Salad dressing

Life Cycle of Plasmodium

How Humans Get Infected

Algae and Land Plants Charophyceans – closest algal relatives of land plants Four key traits that strongly suggest a relationship – Rose-shaped complexes for cellulose synthesis Synthesize the cellulose microfibrils of the cell wall – Peroxisome enzymes Enzymes that help minimize the loss of organic products as a result of photorespiration – Structure of flagellated sperm Similar sperm structures between the land plant and algal – Formation of a phragmoplast Alignment of cytoskeletal elements and Golgi-derived vesicles across the middle of middle of a diving cell

Algae Growth Algae live and thrive off of nutrients Causes them to grow at uncontrollable rates Can live off on several things found in large bodies of water: – Pollen Spread from wind and floats on top of water – Rain Adds nutrients to water – Rotten foliage (fallen leaves) When they decay, they become food – Sun Causes increase in decay process

Sources html html Holtzclaw, Fred W., Theresa Knapp. Holtzclaw, Neil A. Campbell, and Jane B. Reece. AP* Biology: To Accompany Biology, Campbell, Reece, 7e AP* Edition. San Francisco: Pearson Benjamin Cummings, Print m.gif