Biology: Evolution and Diversity of Microbial Life

Are fungi prokaryotic or eukaryotic? Are most fungi unicellular or multicellular? Do the cells have cell walls? If so, what is contained in the cell wall?

Eukaryotic, multicellular. Have cell walls that contain chitin like arthropod exoskeletons instead of cellulose like plants.

How do amoeboids move?

Move by pseudopods

Chemotrophs

gain energy from oxidizing inorganic or organic chemicals

What are methanogens? Where do they live? What do methanogens produce?

methane generators; anaerobic fermenters that produce large amounts of methane gas; found in stagnant water and in intestinal tracts of many animals.

Bacillus (plural = bacilli)

rod-shaped

Chlamydomonas

Unicellular green algae. Two whip-like flagella.

How do flagellates move?

Unicellular; move by one or more flagella. Most are free living in fresh water, ocean, soil; some are parasites and cause human disease.

Do most bacterial cells have cell walls? What chemical is contained in most bacterial cell walls?

Yes, peptidoglycan.

Spirogyra

(1) Long chains of cells attached end to end. (2) Distinctive spiral chloroplasts - hence the name. Filamentous green algae.

Give several economic uses of red algae.

(1) Source of agar, a gelatin-like material used to make: (a) Capsules for vitamins and drugs. (b) Dental impression material. (c) Culture medium in microbiology laboratories (d) Electrophoresis gel to separate proteins and nucleotides. (e) In food preparation: baked goods, jellies, and desserts. (f) Additive in cosmetics. (g) Thickener in ice cream (2) Source of carrageenan used in cosmetics, chocolate manufacture, creamy foods, beer, toothpaste, shampoo, fire fighting foam, paint stabilizer and shoe polish - nice variety. (3) Food: some are eaten. Porphyra is a leafy red alga popularly used as a sushi wrap

acidophiles

(acid loving) live in acid environments down to pH 1.

thermophiles

(heat loving) live in boiling hot springs and hydrothermal ocean vents

What are decomposers?

(organisms that feed on wastes and dead organic matter)

halophiles

(salt loving) live in salt concentrations up to 30%

What are the three major sub-groups of protists? Describe each as being plant-like, animal-like, or fungus-like.

1. Protozoa: protists having generally animal-like characteristics. Heterotrophic by ingestion. 2. Algae: protists having generally plant-like characteristics. Photosynthetic autotrophs. 3. Fungus-like protists: protists having generally fungus-like characteristics. Mostly heterotrophic by absorption.

When did multicellular life appear?

1.2 billion years ago.

About ___ of euglenoids have chloroplasts and are ___________ (autotrophs or heterotrophs?). In the absence of sunlight they may become ________________________ (autotrophic or heterotrophic?)

1/3. Autotrophs. Heterotrophs.

When did the first eukaryotic cells appear?

2.1 billion years ago.

About ___ of euglenoids live as _____________ (autotrophs or heterotrophs?) that ingest or absorb food.

2/3. heterotrophs.

When did mammals first appear?

221 million years ago.

When did Cyanobacteria show up? Importance?

3.7 billion years ago. They're photosynthetic.

The Earth is estimated to be how old?

4.6 billion years old.

When did animals appear?

570 million years ago.

When did humans first appear?

6 million years ago.

When did dinosaurs become extinct? At the end of what time period?

65 million years ago. Cretaceous Period.

What is the chemical composition of the Earth today?

78% nitrogen 21% oxygen 1% carbon dioxide, water and other gases.

Thylakoids

A flattened membrane sac containing chlorophyll inside the chloroplast, used to convert light energy to chemical energy.

Why is classification of euglenoids a problem?

A problem to classify because some have both plant-like and animal-like characteristics: photosynthesize like plants and swim actively like an animal

What does Trypanosoma brucei cause? How is it transmitted? What is a vector?

African sleeping sickness; transmitted by bite of tsetse fly. Tsetse fly is a Vector, an organism that transmits the disease organism.

What is the habitat of the brown algae?

All marine water.

Apicomplexans

Also called sporozoans because they produce spores at some point in their life cycle. All are disease causing parasites. Nonmotile (non-moving) - no cilia, no flagella, no pseudopodia.

Autotroph

An organism that makes its own food

Heterotroph

An organism that obtains organic food molecules by eating other organisms or substances derived from them.

Are Cyanobacteria autotrophs or heterotrophs? Do Cyanobacteria carry out photosynthesis? Do their cells contain chlorophyll? Do their cells contain chloroplasts?

Autotrophs. Yes. Yes, and yes.

Are most bacteria harmful?

Bacteria and Archaea are essential to life: while many people think of these organisms first as disease causing "germs" most of them are not harmful and many are actually helpful.

What is the habitat of the red algae? Are the red algae unicellular or multicellular? Are they smaller or larger than the brown algae?

Because of their special pigments, they are able to live more than 200 meters in depth and still photosynthesize successfully. multicellular.Some are microscopic, others up to a meter in length.

Earliest life forms are how old?

Between 4.2 and 3.7 billion years old.

How are many species of dinoflagellates bounded (covered) or protected? Describe their flagella. What kind of movement does the cell exhibit?

Bounded by protective cellulose plates. Most with 2 flagella (1) One free and one in transverse groove (2) Causes it to spin like a top

What is the largest and most complex of the Protista? Are brown algae unicellular or multicellular? How big can the brown algae get?

Brown Algae. Multicellular. Up to 300 ft long.

What was the cause of the 1840's Irish potato famine?

Caused by water molds that destroyed the entire country's potato crop, the main food crop, resulting in more than a million people dying of starvation and millions more emigrating away from Ireland.

What does Plasmodium vivax cause? How is it transmitted? What symptoms occur when the parasite invades red blood cells?

Causes one type of malaria. Transmitted by infected female Anopheles mosquito (vector). Chills and fevers as red blood cells burst releasing toxins and parasites to infect more blood cells.

What does Trypanosoma cruzi cause? What is its vector?

Chagas disease. Transmitted by a vector commonly called the "kissing bug" because it likes to bite its victims on their lips while they sleep.

How are protozoans classified?

Classified into 4 groups according to means of locomotion and physical characteristics. Flagella, cilia, pseudopodia, or no means of movement.

Volvox

Colonial green algae. Hollow sphere of flagellated green algae. Thousands of flagellated cells each resembling Chlamydomonas.

What is contained in the cell walls of coralline algae? How do they affect the growth of a coral reef?

Coralline algae have cell walls containing calcium carbonate and add to the growth of coral reefs.

How common are the diatoms? Describe their cell walls? What is contained in the cell wall? What is their significance with regard to being a food source and an oxygen producer?

Diatoms are the most numerous eukaryotic unicellular algae in oceans and are important primary producers in the oceanic food chain. Also common in fresh water. (1) Box-like construction: Cell wall has two halves that fit together like box and lid. (2) Cell wall contains silica (glass-like) and does not decompose when cells die. (1) Important food source. (2) Major producers of earth's oxygen.

What domain contains the Cyanobacteria? What is the common name for the cyanobacteria?

Domain Bacteria. blue-green algae.

Into what domain are the fungi classified? Into what kingdom are the fungi classified?

Domain Eukarya: Kingdom Fungi

How do the ciliates get their food? How do they get rid of wastes?

Food moves down a gullet, food vacuoles form, digestion by lysosomal enzymes, absorption of digested nutrients into the cytoplasm.

Phototroph

Get energy from the sunlight

What are Foraminifera? What type of shell (test) do they have? Where do they live? What is their relationship to the White Cliffs of Dover and Egyptian pyramids?

Have a calcium carbonate shell (or test). Mostly marine. Great abundance. Over millions of years have produced deposits that have formed white, chalky limestone rock. White Cliffs of Dover, England and some of the Egyptian pyramids are composed of foraminiferan limestone.

What is found in the cell walls of the green algae? What type of chlorophyll do they contain? How do they store their reserve food? Is this similar to or different from plants?

Have a cell wall of cellulose. Have both chlorophylls a and b. Store reserve food as starch.

Are fungi autotrophic or heterotrophic? Do fungi have chlorophyll? Do they have chloroplasts? If heterotrophic, is it by ingestion or absorption?

Heterotrophic by absorption: release digestive enzymes into the surrounding environment then absorb the digested nutrients.

Facultative anaerobes

In the presence of oxygen they use aerobic respiration. When oxygen is absent, they use anaerobic fermentation. Example: E. coli, an intestinal bacterium and Salmonella: a common cause of food poisoning.

Why was the formation of the Ozone layer important?

It blocked UV rays.

What is the endosymbiont theory of the origin of mitochondria and chloroplasts?

It has been proposed the chloroplasts and mitochondria of eukaryotic cells originated as photosynthetic and aerobic bacteria (respectively) that were engulfed by another prokaryote.

What are the largest of the brown algae? What are some uses of the brown algae?

Kelps: the largest and most highly developed protists. Some up to 300 feet long. Harvested by man for food, fertilizer, and as a source of algin. (1) Provide food and habitat for marine organisms. (2) Human food. (3) Fertilizer. (4) Algin is used as an emulsifier (smoothing agent) in ice cream, cream cheese, cosmetics, and more.

What are the habitats of the green algae?

Live in freshwater, ocean, and even on land (terrestrial).

Are algae major producers of food for oceanic and fresh water communities? What is phytoplankton?

Major producers of food for oceanic and fresh water communities as phytoplankton, suspended photosynthesizing organisms, usually microscopic, in oceans and fresh water. Also found in soil, on rocks and on trees.

What does the cell wall of water molds contain that is different from the cell walls of fungi?

Most have a filamentous body similar to fungi but differing because the cell walls contain cellulose where fungal cell walls contain chitin.

Was the Earths atmosphere like it is today?

No, it was primitive and toxic. It had an absence of oxygen.

Obligate anaerobes

O2 is toxic, organisms cannot live in the presence of oxygen

Define pathogenic. Do most bacteria or only a few species of bacteria make people sick?

Pathogenic=disease causing. only a small percentage of bacteria make you sick.

Are algae autotrophs or heterotrophs? Do algae carry out photosynthesis? Do their cells contain chlorophyll? Do their cells contain chloroplasts?

Photosynthetic autotrophs. All contain chlorophyll in chloroplasts. Significant oxygen producers through photosynthesis.

Domain Bacteria

Prokaryotic, single celled organisms, asexual reproduction

Domain Archaea

Prokaryotic, single celled organisms, asexual reproduction.

Do Cyanobacteria have prokaryotic or eukaryotic cells?

Prokaryotic.

Describe a symbiosis that dinoflagellates may have with corals. How may this affect coral growth?

Reef forming corals often contain large numbers of symbiotic dinoflagellates providing nutrients to the corals that help them grow much faster than they would without this relationship.

Obligate aerobes

Require O2 for generating ATP in respiration

What type of alga is Fucus? What is the common name for Fucus?

Rockweed (Fucus): small, shallow-water.

Pilli

Short appendages functioning in attachment to surfaces.

Are any archaea known to cause human disease?

So far, no archaeans have been linked to human disease.

What is a capsule or slime layer?

Some prokaryotes, Outside the cell wall. Adds protection, aids attachment, gives resistance from drying out.

What is a symbiosis? Describe mutualistic, commensal and parasitic symbioses.

Symbiosis: organisms of two different species living together. (1) mutualistic: both members benefit (2) commensal: one member benefits; the other is neither helped nor harmed. (3) parasitic: one member benefits; the other is harmed

Humans have bacteria living on their skin and inside their bodies. Give two examples where this is beneficial to humans.

Their very presence does not leave room for harmful bacteria to grow. Some of the intestinal bacteria "pay their rent" by producing vitamins we need.

What advantage does their special pigments provide?

These brown pigments are very efficient light absorbers and allow the alga to live in deeper water where there is less light for photosynthesis.

What transmits Toxoplasma? What particular danger does it pose to humans?

Transmitted in cat feces may harm the developing fetus. Pregnant women are advised to avoid cat feces.

What is the habitat of most protozoans? What is zooplankton?

Usually live in water but species are also found in moist soil or inside other organisms. Protozoans are an important part of the zooplankton, microscopic suspended organisms in the oceans or fresh water, that feed on other organisms.

What causes a "red tide?" What can be the results of the red tide toxins?

When waters are warm and nutrients high, certain dinoflagellate species may produce a bloom (rapid reproduction and growth in numbers) called a "red tide." (1) Toxins cause wide-spread fish kills (2) Toxins can paralyze humans who eat shellfish that have fed on the dinoflagellates

What is a plasmodium?

a multinucleated cytoplasmic mass, up to 10 inches in size, that moves like an amoeba. In unfavorable conditions, the plasmodium stops moving, forms fruiting bodies and produces spores much like fungi.

What reproductive structure do water molds produce that is not found in true fungi?

a swimming spore

Name three characteristics we use to group algae.

a. Color pigments. b. The chemistry of the cell wall. c. The way they store reserve food. d. DNA studies

Give at least four examples where humans use prokaryotes for beneficial purposes.

a. Food: production of vinegar, sauerkraut, sourdough bread, yogurt, etc b. Chemicals: production of ethanol and acetone c. Medicines: transgenic bacteria have had human genes inserted to make insulin, blood-clotting factors and more. d. Waste treatment: bacteria and archaea are used in septic tanks and sewage treatment plants to break down organic wastes. Other bacteria are used to detoxify pollutants and clean up oil spills.

Plasmids

accessory segments of DNA, usually in small rings out in the cytoplasm of prokaryotic cells Easily exchanged between cells

What does Entamoeba histolytica cause?

amoebic dysentery.

Radiolarians have what kind of shell (test)?

are found as part of the marine plankton and have intricate and beautiful silica (glass) containing tests.

Are protists unicellular and/or multicellular?

both

What type of cells do organisms in Domain Eukarya have? What are the four eukaryotic kingdoms?

cells with the genetic material (DNA) contained within a membrane bound structure called the nucleus, and contain various organelles with specific functions. Kingdoms Protista, Fungi, Plantae, and Animalia.

What is nitrogen fixation? Why are nitrogen fixing bacteria important?

changing atmospheric N2 to ammonia, NH3 . Only a few bacteria and archaea can use N2 directly but all organisms need nitrogen, so the nitrogen fixers are literally essential to life on Earth.

How do the ciliates move? Know that Paramecium and Stentor are ciliates.

cilia.

Endospore

dormant, thick walled structure that can survive harsh climate such as boiling water, drying, ultraviolet radiation and disinfectants. Can cause Botulism, which is deadly food poisoning and Anthrax, which is a soil bacterium that can be inhaled and deadly. Very dangerous.

Based on biochemistry, are archaea more like bacteria or eukarya?

eukarya.

The first Archaeans were discovered in what types of environment?

extreme environments

Can euglenoids have an eyespot? If so, what is its function?

eyespot or stigma shades a photoreceptor aiding a sense of direction when detecting light.

What is the role of contractile vacuoles?

for ridding cell of excess water.

Is Amoeba proteus free-living or a parasite?

free living.

What is the habitat of the euglenoids?

fresh water.

What does Giardia lamblia cause?

giardiasis, a severe diarrhea.

Staphylococcus

grape-like clusters of spherical cells

Are protozoans usually heterotrophic or autotrophic? Are most protozoans motile? Are protozoans unicellular or multicellular?

heterotrophic. usually motile. unicellular.

Are Cyanobacteria an important part of the food chain? Do some species produce deadly toxins?

important both in the food chain and for oxygen production, but some also produce toxins that can kill fish and other animals in the water and animals that drink the water.

What does Cryptosporidium cause? Why is this organism significant regarding water treatment plants?

in animal and bird feces and in surface waters, this organism can pass through water treatment plant filters and is not killed by chlorine treatment. Causes gastroenteritis with watery diarrhea.

What is the significance of dinoflagellates as a food source?

like diatoms, are extremely numerous in the ocean and are important primary producers providing a food source for small animals in the ocean.

Where does Trichonympha collaris live? What relationship do they have with their host?

lives in gut of termites, mutualistic. Trichonympha cannot eat the wood but it can digest the cellulose and share the nutrients.

Streptococcus

long chains of spherical cells

How do the amoeboids feed?

phagocytosis.

Are cells of archaea prokaryotic or eukaryotic?

prokaryotic.

Do any archaea live in moderate environments?

scientists find that many archaeans live in moderate environments such as soil or open ocean.

Coccus (plural = cocci):

spherical shaped

Spirillum (plural = spirilla)

spiral- or corkscrew-shaped

What is diatomaceous earth? What is it used for?

the silicaceous remains (skeletons) of dead diatoms accumulated into thick layers on the ocean floor from prehistoric times. This is mined and used as filtering agents, sound-proofing materials, and scouring materials, and for many other purposes.

How do some bacteria move?

through flagella.

What helps to keep the shallow water brown algae from drying out when the tide is out?

water-retaining material (algin) that keeps them from drying out when shallow water species are exposed during low tide.

Are any protozoans parasitic?

yes.

Do slime molds form spores? Compare plasmodial and cellular slime molds. What causes cellular slime molds to aggregate?

yes. only aggregate when food runs out. The aggregate slug-like structure then reproduces by forming fruiting bodies that produce spores that survive until favorable conditions return.

Do prokaryotic cells have ribosomes?

yes. they are free in the cytoplasm.