Download Review Sheet – Microbes/Algae

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Marine Biology
Review Sheet – Microbes/Algae
1. List and briefly describe the differences between the 3 domains of microbes.
eubacteria includes the original inhabitants of the sea, dating back several billion years.
Bacteria have cells with simple, prokaryotic organization, a general feature shared with
the domain Archaea. Lack nuclei and other membrane bound organelles (such as mito,
cholor, etc), have single circular chromosome of DNA that contains few genes, most are
surrounded with a nonliving cell wall made of combo of sugars and amino acids that
gives support and protection. Reproduce by binary fission.
Archaea are extremists, small (.1 to 15 microns) and have narrower range of sizes than do
bacteria. They are prokaryotes. Most have cell walls, but lack special sugar-amino acid
compounds of the cell wall. They have different lipids to stabilize the harsh conditions
Eukarya – plants, animals, fungi, algae and single celled animal like protozoans.
Phytoplanton are part of this domain, including diatoms, silicaflagellates, alveolates
(sacs) dinoflagellates (make up HABs), ciliates (protozoans that have cilia to move
around), amoeboid protozoans (radiolarians)
See table at the end of chapter 6 for review of organisms.
2. What role do marine viruses fill in the aquatic environment? Know and
differentiate their 2 life cycles.
Viruses vary from 10 to 400 nanometers in size. Outside of host it is called a
virion…composed of nucleic acid (DNA or RNA) core surrounded by a coat of protein
called a capsid.
Two broad categories of life cycles…lytic -rapid one of infection, replication of nucleic
acid and proteins, assembly of virions, and release by rupture (lysis) of the cell.
Lysogenic cycle – viral nucleic acid is inserted into host genome and may reside ther thru
multiple cell division before becoming lytic.
Ecological role- parasitic, major cause of mortality among plankton, possibly controls
HABs. Important in altering the pelagic food web…population control. Can alter
biogeochemical cycles by controlling bacteria growth. Can facilitate the se
3. Define an extremophile. Give some examples.
Archeons are extremophiles, organisms that live under harsh conditions
Methanogens (anaerobic organisms that live in environments that are rich in organic
matter), hyperthermophiles (high temps), halophiles (salt lovers)
4. Name at least 3categories of extremophiles and describe the environments they
live in.
Methanogens, hyperthremophiles (exceeding 100 degrees c), halophiles (salt
lovers…extremely salty environments)
5. Understand the role chemo-autotrophs, photo-autotrophs, & archeons play in
primary productivity.
Chemo-autotrophs – live in communites and can produce food molecuels from carbon
dioxide and hydrogen sulfide using energy derived from chemical reactions rather than
sunlight.
Photo-autotrophs – produce food via co2 and sunlight
Archeons are prokaryotes that are anaerobic organisms that live in environment rich in
organic matter. Produce methane gas. Tolerate extreme environmental conditions.
6. Describe the role that eukaryotic microbes play in the food chain.
Marine fungi are microscopic decomposers and pathogens. Most are sac fungi that can
degrade the cell walls of terrestrial, maritime and marine plants. Some digest chitin and
other decay resistant moleculres that otherwise would accumulate on seafloor.
Diatoms, silicoflagellates, brown algae are photoautotrophs forming HABs, heterotrophic
decomposers, form deep sea deposits
Alveolates – photoautotroph, some are symbiotic as zooxanthellae, or HAB
Radiolarians – planktonic suspension feeders and benthic grazers, form deep sea deposits
Foraminiferans….same as radiolarians.
7. Differentiate between Fungi, Stramenophiles, Alveolates and Ameboid
Protozoans. Be able to list examples in each group (some of these we looked at
under the microscope in class).
All eukaryotes
Fungi – ascomycotes (yeasts and lichens)…heterotrophs, decomposers
Stramenophiles – photoautotrophs, some forming HABs, hetertrphoic decomposers, form
sea depositis
Alveolates – dinoflagellates, ciliates, photoautotrophs, planktonic and benthic, some
symbiotic, form some HABs
Ameboid protozoans – have organelle called pseudopod that is extension of cell
surface…used for locomotion
i.e
radiolarians – highly diverse class of zooplankton,
formaminiferans- or forams are amoeboid protooans with branched pseudopods that
make elaborate netlike retuclophod used to snare pray or to crawl around over
suraces…consume diatoms and bacteria or form symbiotic relationship with green and
red algea and zooxanthellae (dinoflagellates)
8. List and describe the most common algal blooms. (Focus on type of organism
and ecological impact).
Alveolates (dinoflagellates including ciliates)
9. What are the main differences between red, brown and green algae.
Red algae – chlorophyll a, d and red accessory pigments, cell walls of cellulose,
phycocolloids, mucilate, mineralized calcium carbonate
Usually annual reproduction with 3 multicellular generations, no flagellated stages.
Brown algae – chlorophyll a, c and brown accessory pigments, cell walls of cellulose,
alginates, mucilage
Often perennial reproduction, differentiated sporophyte and gametophyte stages,
produces flagellated spores and sperm.
Green algae – chlorophylls a, b and carotenoids, cell walls of cellulose, sometimes
mineralized with calcium carbonate
Annual reproduction, vegetative growth and sexual reproduction with flagellate spores
and gametes
10. Where would you find mangroves on the globe? What do their root structures
look like? How are they rooted into the earth?
Tropical latitudes with limited wave action, low slope, high rates of sedimentation, soil
that are waterlogged, anoxic and high salts. Roots in sediments…shallow.
11. How do marine flowering plants reproduce?
Sexual reproduction with flowers, seeds, and fruit.
12. How are Kelp structured? How do the air bladders help them survive?