Bio test 4 (lectures 17-19)

Archaea

• prokaryotes without peptidoglycan in their cell walls

• Inhabitants of extreme environments (very hot or acidic)

• Not inhibited by antibiotics

Methanogens

Strict anaerobes, decomposers in sewer systems, produce methane gas

Extreme Halophiles

Thrive in high salt environments. Some are photosynthetic with purple pigment

Extreme Thermophiles

Live in very hot environments. Some can produce sulfuric acid from sulfur.

Domain Bacteria

• Prokaryotes with typical peptidoglycan in their cell walls

• Survive in ordinary environments

• Mostly inhibited by antibiotics

Gram positive bacteria

With thick peptidoglycan (approximately 60-90% of cell walls is peptidoglycan)

Gram negative bacteria

With thin peptidoglycan (10-20%) with thin lipid layer on top. More resistant to antibiotics and drugs.

Cyanobacteria

Photosynthetic blue green bacteria in aquatic environments that can fix atmospheric Nitrogen

Spirochetes

Long spiral bacteria, some are agents of STD’s

Mycoplasmas

• The only bacteria without cell walls

• Hard to grow in artificial medium

• Can cause a mild form of pneumonia

Chlamydia and Rickettsiae

• obligate parasite

• Thought to be virus until scientists found out they are made up of cells

What is the process of transformation

Small pieces of “naked” DNA in the environment are taken up by bacterial cells

Where does transformation occur

Only at a certain stage of growth (I.e., before completion of cell wall)

What parts can get into host cell during transformation

Plasmids and parts of chromosomes from dead cells can get into host cell.

Transduction

Process by which DNA is transferred from a bacteriophage (virus that infects bacteria) to a bacterial cell.

What is conjugation

Bacterial mating

What happens in conjugation

Direct transfer of DNA from one bacterial cell to another via conjugation pilus (F-pilus)

Where does conjugation occur

Usually between two related bacteria but even unrelated bacteria can mate

What is required for conjugation

Contact between donor and recipient cell

Kingdom Protista

Kingdom for extra organisms

Amoeba habitat

Bottom of ponds, contaminated water, some are parasitic

Amoeba shape

Fried egg

How do amoeba move

Extending their pseudopodia (false feet) in one direction and then pouring contents of the cytoplasm in that direction

Euglena

Includes unicellular eukaryotes with no true mitochondria and those with unique flagella

Euglena habitat

Polluted fresh water

Are euglena photosynthetic

When light is present, they are photosynthetic. When light is absent, they become heterotrophic.

Cilates

Largest group of Protozoa that are involved in cleaning the environment

How do ciliates move

Move by cilia (hair-like projections) all over the cells

What do ciliates feed on

Bacteria, fungi, and other pollutants

Dinoflagellates

Named after whirling motion due to two flagella (one extends like a tail, the other lies in a transverse grove like a belt)

Considered a unicellular algae

Example of euglena

Trypanosoma, giardia, trichomonas

Examples of ciliates

Paramecium

Example of dinoflagellates

Gonyaulax

Diatoms

Non-motile, UNICELLULAR ALGAE with glass-like appearance due to silica in the cell wall

Where are diatoms used?

• Used in industry as abrasives for toothpastes, and gloss for paints

• Gives fishy taste to fish

Kingdom fungi

Eukaryotes with cell wall made out of chitin

Heterotrophs

Not capable of photosynthesis and rely on other organisms for food