Lab 3

Question 1

what is the brain eating Amoeba

Answer 1

Naegleria fowleri aka the brain-eating amoeba is a free-living, thermophilic microorganism that is found in warm freshwater ecosystems. It consumes bacteria, but after infecting a human it will consume their brain cells. Swimmers can inhale N. fowleri into their nasal cavities leading to brain infection and death within a week or two of symptoms appearing. Symptoms include: nausea, vomiting, headache, fever, hallucinations, and seizure.

Question 2

what are protists

Answer 2

Eukaryotic organisms that cannot be classified as plants, fungi, or animals.

Don’t form a natural phylogenic group.

Many are unicellular, microscopic, and found in aquatic environments. Very diverse.

Question 3

how can protists be divided based on feeding groups

Answer 3

Animal like protists are heterotrophic and consume organic matter. Plant like protists are autotrophic and photosynthesize. Others are mixotrophic and do both. Groups do not reflect phylogeny.

Question 4

what are the 6 common eukaryote subgroups

Answer 4

• Excavata
• Rhizaria
• Chromalveolata
• Archaeplastida
• Amoebozoa
• opisthokonta

Question 5

describe Excavate

Answer 5

Unicellular eukaryotes named fro a ventral feeding groove that gives many organisms an excavated appearance.

Most are heterotrophic and have two or more flagella.

Question 6

describe Euglena

Answer 6

Part of Excavate
Euglena, which has chloroplast and can engulf prey. Roughly oval-shaped, rotate flagellum to move, found in aquatic environments. No cell wall. Have a pellicle (layer of proteins and microtubule fibers) arranged in strips that form a spiral around the cell.

Question 7

what are Rhizarians

Answer 7

Mostly unicellular, heterotrophic organisms with some form of Pseudopodia (temporary, finger-like protrusions of the cytoplasmic body that aid in movement and feeding). Many Rhizarians produce a hard exokeleton. Contains Foraminifera and Radiolarians

Question 8

what are Foraminifera

Answer 8

part of Rhizaria
Foraminifera, aka Forams, produce hard, porous shells or tests. Extend Pseudopodia out of pores in the tests to move and feed. Most are marine and found in very diverse ocean habitats, including marine sediment and fresh water. Some are planktonic and just float

Question 9

What are Radiolarians

Answer 9

part of Rhizaria
Radiolarians form shells and are heterotrophic and planktonic. Commonly form symbiotic relations with algae. Algae produce energy, radiolarians improve access to sunshine and provided waste including CO

Question 10

describe the Chromalveolate supergroup

Answer 10

thought to have evolved from an ancestor which engulfed a red alga cells to obtain chloroplast. No longer thought to be monophyletic but contained diatoms, paramecia, stentor, and dinoflagellates.

Question 11

what are diatoms

Answer 11

part of Chromalveolata
Diatoms are photosynthetic plankton that are enclosed in a silica shell called a frustule. Generate 50% of earths oxygen every year. Can occur as individuals or in colonies. When in colonies their silica cell walls allow them to form geometrically-shaped structures like starts and ribbons, usually bilaterally symmetrical. Extremely abundant in both marine and freshwater. Don’t have flagella, move by secreting a mucus like substance called mucilage, allowing them to attach to a surface or move forward.

Question 12

what are paramecia

Answer 12

Part of Chromalveolata
Paramecia are oval shaped unicellular protists. They have cilia (short little hair like things) for movement and to move food and water into the oral groove, a subcellular structure specialized for absorbing food. Engulfed food is then encapsulated in a food vacuole, which functions in digestion. Paramecia release trichocysts, tiny pointed filaments to anchor the organisms during feeding. Excess water is expelled via a star-shaped contractile vacuole. It has a macronucleus for regulating nonreproductive cell functions and a micronucleus for regulating reproduction.

Question 13

what are stentor

Answer 13

Part of Chromalveolata
Stentor are large, trumpet-shaped organisms that can be up to 2mm when extended. They have a ring of cilia around their “mouth” end to draw in prey and move. Found in freshwater lakes and streams. Usually grouped together in colonies fixed to substrate, but can swim freely whilst contracted into an oval shape. Some algae are ingested but retained in a symbiotic relationship.

Question 14

what are Dinoflagellates

Answer 14

Part of Chromalveolata
Dinoflagellates are red and brown unicellular organisms. There are about 2,000 marine dinoflagellate species, and there are also some freshwater species. Second most abundant marine photosynthetic organisms after diatoms. roughly half are photosynthetic and other are heterotrophic. Many have tough shell of overlapping cellulose plates. Have two flagella, one transverse and one longitudinal, both come into contact with the cingulum, a groove between the cellulose plates. The transverse flagellum is wide, flat, and wrapped around the cell in the cingulum, beats to left to propel forward and provide spin. The longitudinal flagellum beats posteriorly to steer.

Question 15

what is Archaeoplastida

Answer 15

a supergroup that Includes land plants, red algae, green algae, and some other protists. All posses chloroplasts and several are multicellular. Includes Spirogyra, Volvox, red seaweed, and brown seaweed.

Question 16

what is Spirogyra

Answer 16

Spirogyra is a green alga (chlorophyte) that grows in freshwater as a filamentous organisms in tread-like colonies. Unicellular but looks multicelluler. can form thick mats

Question 17

what is Volvox

Answer 17

Volvox is another chlorophyte that lives in freshwater, forms spherical colonies of individual cells interconnected by very fine strands of cytoplasm. the sphere of cells can rotate and swim by coordinating the beating of flagella. Reproduce asexually and sexually. Daughter colonies form in both cases and grow inside the hollow sphere of the colony. To form a new colony, the clump of cells must turn itself inside out to orient their flagella properly, called colony inversion.

Question 18

What are Rhodophytes

Answer 18

part of Archaeplastida
Red algae (Rhodophyta) are predominantly multicellular algae found in marine environments. Lack flagella and cilia, and have photosynthetic accessory pigments called Phycobiliproteins that make them red. Allows them to grow at greater depth than green algae since blue and purple wavelengths can be absorbed by red algae, and they penetrate deeper than green light.

Question 19

what are brown algae

Answer 19

Brown Algae, or Phaeophyta, are multicellular algae found in colder marine environments. Most contain a photosynthetic accessory pigment called fucoxanthis, makes them brown-green.

Question 20

how do some algae mimic plants

Answer 20

Some algae, including red and brown, grow into macroscopic, plant-like structures in their marine environments. The blades and stipes of seaweed resemble the leaves and stems of terrestrial palnts. They also have a holdfast that anchors the organisms to a substrate. Brown seaweed also have a float or air bladder that allows the blades to float at the surface. Not true plants since they lack roots, stems, leaves, a vascular system, internal conducting systems for fluids and nutrients.

Question 21

What are the Amoebozoans

Answer 21

Contains a number of amoeboid protists, have ability to change shape often due to presence of pseudopodia. includes Amoeba a unicellular organisms that uses pseudopodia for locomotion and feeding.

Question 22

what are Opisthokonta

Answer 22

Contains organisms that are propelled by a singular posterior flagellum surrounded by a collar of microvilli, nonmobile finger-like projections that aid in food digestion.

Includes Choanoflagellates which are found as both individuals and colonies. Most closely related to animals. Choanocyte cells of sponges resemble choanoflagellates

Question 23

what is Köhler illumination

Answer 23

Sets up the microscope for optimal contrast and resolution

Involves adjusting the light intensity, light path, and the condenser.

Question 24

how do you set up Köhler illumination

Answer 24

1. Close field iris diaphragm until a small circle can be viewed
2. Centre the circle of light using the condenser centering screws
3. Adjust the conderser knob until the edges are sharp
4. open the field Iris diaphragm until the circle of light just disappears from FOV

Question 25

what is the scale bar formula

Answer 25

Draw size/Actual size=drawnscalebar/represented scale bar

Question 26

describe Prokaryotes

Answer 26

Genome consists of one bacterial chromosome of DNA with no end

Bacteria can be rod shaped bacilli, spheres cocci, or spirals spirochetes. Some form filaments or cluster

Question 27

what are Hetrocysts

Answer 27

Some Cyanobacteria like Anabaena have cells in the filaments that are darker and larger called heterocyst which do nitrogen fixation.

Question 28

describe Prokaryote Phylogeny

Answer 28

Domain Archaea

Euryarchaeotes

Crenachaeotes

Nanoarchaeotes

Korarchaeotes

Domain Bacteria

Proteobacteria

Chlamydia

Spirochetes

Cyanobacteria

Gram-Positive bacteria

Question 29

describe gram staining

Answer 29

Gram positive. 2 layers, plasma membrane + Peptidoglycan layer (purple)

Gram negative: 3 layers, plasma membrane + Peptidoglycan layer + outer membrane (red)

Negative are sensitive to antibiotics like tetracycline, positive can be killed by antibiotics like streptomycin.

Testing involves satining with crystal violet and Iodine, then rinsing and couterstaining with safranin

Question 30

describe Archaeans

Answer 30

• diverse group
• occupy extreme enviroments
• Ex Halobacterium spp from salt ponds

Cell walls don’t contain peptidoglycan, have unique lipid composition in cell membrane, similar RNA polymerase and ribosomal protein to Eukaryotes. Probably more similar to early Eukaryotes.

Question 31

what are the 3 major extant groups of Archaeans

Answer 31

3 major extant groups:

1. Halophiles (salt lovers)
2. Methanogens (reduce CO2 to CH4)
3. Thermophiles (live in hot springs)

Question 32

what subgroups are in SAR

Answer 32

3 major subgroups

• Stramenopila
• Alveolata
• Rhizaria

Question 33

what is within Stramenopila

Answer 33

Stramenopila

includes Bacillariophyta AKA diatoms

unicellular algae with glass like silica cell walls

100,000 species

cell wall have two valves called frustules

Also Phaeophyta the brown algae: most complex protists, similar to plants

Question 34

desire Alveolata

Answer 34

Alveolata: Some photosynthetic, some parasitic, some heterotrophic protists. Have small, internal, membrane bounded cavities under the plasma membrane.

Dinoflagellates: important phytoplankton, many are mixotrophic, half are heterotrophic. Cause red tide due to carotenoid pigments produced from reproduction. Neurotoxin also produced

Question 35

what is the Unikonta supergroup

Answer 35

• protists, fungi, animals
• 2 major subgroups
  
  • Opistholonta
  • Amoebozoa

Question 36

what does Amoebozoa contain

Answer 36

Amoebozoans

Contains amoebas and slime molds

Mycetozoa (slime molds)

resemble fungi, but have cellulose cell walls, centrioles, and produce flagellated cells at some point

Question 37

describe red algae

Answer 37

Rhodophyta (red algae)

some of oldest multicellular life

1.2-1.6 billlion years old

various colours. Acessory pigments like phycobilins and carotenoids give colours.

No flagellated stage

Question 38

describe green algae

Answer 38

Chlorophyta (green algae)

unicellular and multicellular

similar to land plants as they:

• have cell plates in cell division
• starch used for storach
• have chlorophy a, b, and carotenoids
• cellulose in the cell wall

Question 39

describe volvex and how they reproduce

Answer 39

A colony of Volvox sp. consists of 500 to 50,000 cells. held together by a gelatinous matrix and are connected by thin strands of protoplasm. produced by either asexual or sexual reproduction may be contained in the parent colony. In sexual reproduction, several cells in the colony differentiate into motile sperm and a few others become non-motile eggs. Sperm swim to the eggs, and fuse with them to form zygotes. Zygotes develop into daughter colonies inside the parent colony and are released when it dies. Because the male and female gametes can be distinguished from one another, Volvox is described as being oogamous. The cells that produce sperm are called antheridia, and those that produce eggs are called oogonia. Because of this differentiation of cell types and division of labor, the colony has some of the properties of a truly multicellular organism.