Lesson 4: Domain Bacteria and Domain Archea

Question 1

Domain bacteria

Answer 1

A large and diverse group of organisms that consist of prokaryotic cells
-these are cells that have no nucleus
-the cell walls contain the protein peptidoglycan
-grow everywhere on earth

Question 2

Types of bacteria p1- cell shape

Answer 2

The simplest way to classify bacteria is by cell shape
-> cocci: round (coccus=singular)
-> bacilli: rod (bacillus = singular)
-> spirilla: spiral + shaped (spirillum = singular)

Question 3

Types of bacteria p2- prefix

Answer 3

Bacteria often grow in characteristic patterns or groupings
- the prefix diplo- describes cells arranged in pairs
- the prefix staphlyo- describes cells arranged clusters
- the prefix strepto- describes cells arranged in a chain

Question 4

Bacterial respiration

Answer 4

-obligate aerobes: need a constant O2 supply
-microaerophile: need a very low concentration of oxygen (<21%)
-obligate anaerobes: must live in the absence of O2
-facultative anaerobes: use fermentation of organic molecules for energy like obligate anaerobes though not harmed by oxygen

Question 5

Bacterial energy production- autotrophic

Answer 5

-photographic autotrophs- use light to produce carbohydrates
-chemotrophic autotrophs- use inorganic chemicals such as hydrogen sulfide, nitrate, ammonia, sulfur and iron as energy

Question 6

Bacterial energy production- heterotrophic

Answer 6

-chemotrophic heterotrophs- break down organic molecules for energy
-photosynthetic heterotrophs- …

Question 7

Importance of bacteria

Answer 7

FOOD PRODUCTION: cheese, yogurt, buttermilk, sour cream, and sauerkraut

INDUSTRY: petroleum digestion, waste and poison removal, mining minerals and drug synthesis

HUMAN SYMBIOSIS: intestinal bacteria to digest cellulose or produce vitamins (in humans bacteria produce vitamin K in the large intestine)

Question 8

Bacteria and the environment

Answer 8

Bacteria fill the ecological role of decomposer:
— bacteria that recycle and decompose dead material can be call saprophytes.
— sewage decomposition is accomplished largely by encouraging and controlling bacterial growth. The products are H2O, N2, CO2, and solid leftovers that can be used to fertilize crops
— nitrogen fixation is accomplished in nature only by Cyanobacteria notably rhiziobium in root nodules…

Question 9

Domain archaea

Answer 9

-discovered in 1977 and originally classified as bacteria.
—> classified as their own domain in 1990
-like bacteria, this group of organisms consist of prokaryotic cells
-are biochemically different than bacteria
-live in extreme environments (considered extremophiles):
-> extreme heat (>100 C)
-> acidic and alkaline environments
-> high salinity (high salt concentration)
-> extreme pressure (up to 200 atm)
-produce methane gas and are obligate anaerobes