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Home , Fungus, Protist

/Fungi Station Lab Information

1 Protists Information

Background: Perhaps the most strikingly diverse group of on is that of the Protists, Found almost anywhere there is water – from puddles to .

Protists rely on water. Somea re marine (salt water), some are freshwater, some are terrestrial (land dwellers) in moist and some are parasites which live in the tissues of others.

The is made up of a wide variety of eukaryotic cells. All protist cells have nuclei and other characteristics eukaryotic features. Some protists have more than one nucleus and are called “multinucleated”.

Cellular Organization: Protists show a variety in cellular organization: single celled (unicellular), groups of single cells living together in a close and permanent association (colonies or filaments) or many cells = multicellular organization (ex. Seaweed).

Obtaining : There is a variety in how protists get their food. Like , many protists are , meaning they make their own food through and store it as starch. It is estimated that green protist cells chemically capture and process over a billion tons of carbon in the Earth’s and freshwater ponds every . Photosynthetic or “green” protists have a multitude of membrane-enclosed bags () which contain the photosynthetic green called chlorophyll. Many of these organisms’ walls are similar to that of cells and are made of . Others are “”. Like , they eat other organisms or, like fungi, receiving their nourishment from absorbing molecules from their surroundings or digest living things. Some are parasitic and feed off of a living . Some can switch from one mode to another as their environmental conditions change.

These organisms are capable of cell-eating (i.e. ) and cell drinking (i.e. pinocytosis).

Motility: Most protists are motile and have a variety of external cellular extensions. A group of protists, the , have tightly packed rows of specialized short flagella, called cilia, used for moving and feeding. These -ingesting, motile cells are probably the best known protists! Other protists use longer complex whip-like flagella – at longer than their bodies – for locomotion. flagella differ from flagella in both size and structure. Bacteria flagella are much thinner and are not made of tiny . Some move by temporary cytoplasmic extensions, called pseudopods (“false feet”).

Protists also have internal cell with . The , clear gel-like fluid which holds the , moves around carrying the organelles and substances.

Size: Most protist cells, or groups of cells, are microscopic. They cannot be seen with the naked eye but require a to magnify their size so they can be viewed.

Relationships: Many protists engage in symbiotic relationships with another . In this relationship at least one organism benefits: (they both benefit), (one benefits and one is unaffected) and (one benefits and one is harmed). Some protists are parasites, feeding off of a host organism.

Organelles: There are many internal organelles that can be identified in protist cells. Generally there is a large nucleus, containing material, which is clearly visible. Also visible are various or microcavities, that contain fluid or air that is enclosed in a membrane in the cell’s cytoplasm. Careful focusing with the microscope will usually show a number of food vacuoles – colored blobs – that freely circulate in living cells. Often you can observe other “granular inclusions” - and other solid also circulate about in the cytoplasm.

2 (Protozoans) – plus Notebook pg. 16 (label w/functions)

Amoeboid protists move about through extension and retraction of many “false feel,” or pseudopods, over various substrates wherever there is water. The characteristic movement by extension is called “amoeboid movement” and is a common form of locomotion in other cells. Some amebae only form a single pseudopod at one .

The pseudopod is also extended to surround other organisms or food particles and draw them into the body where they are packaged into food vacuoles. This of food-getting is called “phagotrophic” with amoebae usually preferring bacteria as food.

Amoeba proteus has a single nucleus, but it is not uncommon for other amoebae to have many nuclei.

3 (Protozoans) - plus Domain Notebook pg. 17 (label w/functions)

Paramecium’s body surface is uniformly covered with numerous cilia responsible for the organism’s spiraling locomotion.

Paramecium’s cell mouth, or , is situated at the end of the oral groove, which is a ciliated channel. Special groups of cilia create water currents which help funnel bacteria, the paramecia’s usual food. This type of food-getting is called “phagotrophic”, with the cell eating bacteria or other protists.

A food forms around the accumulated food at the base of the oral groove and travels in a cyclic figure- eight direction in the cytoplasm. The contents of the vacuole are subjected to digestive and the products of are diffused into the cytoplasm. Undigested material is released at the posterior end of the body.

Liquid wastes and excess water are released through two permanently located contractile vacuoles which produce star-shaped tubes in the water-collecting process. Paramecium has a water-permeable body wall. Excess water must be excreted because of the high osmotic gradient between the cell and its outside environment – the cells’ internal salt concentration exceeds that of its surroundings.

Paramecia have two types of nuclei – a micro- and . The single, large macronucleus functions in control of cell activities. The much smaller micronuclei function in the process of .

4 Protozoans (/Parasites) Domain Notebook pg. 18 (use textbook pg. 78 as a reference)

5 and (Plant-like Protists) Domain Notebook pg. 19 (use textbook pg. 74/79 as a reference)

 Need THREE different diatoms

6 - plus Domain Notebook pg. 20 (label) use pg. 80 for reference

Euglena is a photosynthesizer (), it makes own food through chloroplasts in a process called photosynthesis. Euglenoids, along with other green protists, are major recyclers of carbon, the primary component of organic compounds. They store , attained through photosynthesis, in the form of starch.

A very small eyespot is a photoreceptor, located at the anterior end. Euglenoids are positively phototrophic – they actively seek light and use flagella to swim towards it.

Euglena has a large nucleus, usually found in the center of the cell.

7 Spirogyra (plant-like protist) plus Domain Notebook pg. 21 - bottom

Gamophytes, or filamentous green , have symmetrical cells containing complex spiraling band-shape chloroplasts. Spirogyra is an “autotroph” meaning it makes its own food using photosynthesis. Organisms that get their food by eating other organisms who, in turn, consumed autotrophs are called “heterotrophs”. Spirogyra, along with other green protists, are major recyclers of carbon, the primary component of organic compounds. They store energy, attained through photosynthesis, in the form of starch in their cytoplasm.

8 Algae (plant-like protist) Domain Notebook pg. 21 - top () draw and label Domain Notebook pg. 22 - () label with functions

9

The microworld of the open waters, or plankton community, includes a variety of microlife forms that float, drift, or move about feebly – everything from minute protists to large, lumbering copepods and cladocerans.

The plankton is a diverse – a network of feeding relationships. forms, or , feed on protists. Bacertia break down the carcasses of animals, plants, and algae, releasing required by green producer or photosynthesizing forms called . Zooplankton, are “grazers” which feed on the various phytoplankton, protists and bacteria populations.

Under low power (40X) magnification to scan and locate a planktonic form or “plankter” for closer observation.

Look for various adaptations that help plankters compete and survive in this special microhabitat:

 Small size: Small organisms have a greater frictional resistance to sinking per unit weight than larger organisms.  Spines and other things: These structures help increase surface without adding extra weight and are great defense mechanisms against being eaten! Look for: needle, pancake or ribbon shapes in plankters. 10 -like Protists 1 Domain Notebook pg. 23 – slime (label) use pg. 82 of textbook Domain Notebook pg. 23 – downy , water (label) use pg. 83 of text

11 Fungi - plus Domain Notebook pg. 25 - bottom (label ); pg. 27 label ; pg. 28 label

Fungi – , molds, and – are . Because they cannot make their own food, they depend upon organic material for sustenance.

The mold stolonifer appears commonly on as a gray, webby growth spotted with black dots.

This fungus has specialized tube-shaped hyphae called “” that penetrate the growing to obtain nutrients needed to raise the upright stalks that support the bulb-shaped fruiting bodies. When the fruiting body matures, within are and carried by the to new locations where they germinate and develop new mycelia – the network of small hyphae tubes that make up the body of the fungus.

Under certain circumstances other hyphae of “+” and ”-“ types can be produced. These grow together by hormonal attraction and fuse to form a unique structure called a “zygosporangium”. The zygosporangium later germinates to produce a typical asexual fruiting body that will eventually release spores.

12 (Fungus) - plus Domain Notebook pg. 27 - bottom (label asexual 2 reproduction)

Probably the simplest fungi are yeasts. A “yeast” is a common name given to a single-celled fungus. Yeasts reproduce asexually by (i.e. splitting in two) or by – the formation of a small outgrowth or bud from the parent cell.

Yeasts routinely convert to and alcohol. They are used in bread-making, brewing and the production of industrial alcohols.

In , yeasts are distributed. They are especially abundant in substances that contain sugar, such as the surfaces of . They are also found in the soil and in milk.