General Biology II Exam 2 - Prokaryotes Pt. 2: Archaea

archaeaaaaaa

Why are Archaea not just another form of bacteria?

they are both prokaryotes but classified in a separate domain of life because their differences in cell walls, membranes, and genetic machinery are significant enough to place them in separate domains: Bacteria & Archaea

What are all the distinguishing factors between Archaea and Bacteria?

• cell walls - Archaea lack peptidoglycan, which is found in bacterial cell walls; some archaeal cell walls contain proteins, glycoproteins, polysaccharides, or pseudomurein

• cell membranes - archaeal membrane lipids have a different chemical structure from bacterial membrane lipids

• genetics - their DNA replication machinery and some of their genetic proteins are more similar to those of eukaryotes

• ribosomes - Archaea have 70S ribosomes, but their structure and some associated proteins differ from bacterial ribosomes

• chromosomes - some have histones, proteins that help package DNA, similar to those in eukaryotes

• habitats - live in a wide range of environments, including extreme environments, but they are not limited to them

T/F Archaea have peptidoglycan

False

T/F Archaea lack peptidoglycan

True

Archaea DNA replication machinery and some of their genetic proteins are more similar to those of ______?

Eukaryotes

Why are Archaea so prevalent in extreme habitats?

many have specialized cellular structures and metabolic pathways that allow them to survive conditions that other organisms cannot tolerate. however, not all archaea live in extreme environments, many live in ordinary habitats such as oceans, estuaries, and soil

What are the specialized things that allow Archaea to survive in extreme conditions that many other organisms cannot?

special adaptations to their cell membranes and cellular machinery, high environmental tolerance, use of unusual metabolic pathways that allow them to obtain energy in different environments, and the reduced competition from other organisms in these environments

T/F Archaea can survive in extreme conditions and are quite prevalent in these types of areas because of their specialized cellular and internal structures

True

T/F Archaea cannot survive in extreme conditions and are nonexistent in these types of areas because of their fragility to extreme conditions

False

What are the major archaeal lineages?

Cremarchaeota, Euryarchaeota, Thaumarchaeota, and Korarchaeota

Where are Cremarchaeota often found?

hot, acidic, or high-pressure environments

T/F Cremarchaeota are often found in cold, dry, basic environments

False; hot, acidic, high-pressure

T/F Cremarchaeota are often found in hot, acidic, or high-pressure environments

True

T/F Cremarchaeota are abundant in oceans, estuaries, and soils, and many prefer moderate temperatures

False; hot, acidic, high-pressure

Euryarchaeota include __________

methanogens and some salt-loving Archaea

Thaumarchaeota are often found in

oceans, estuaries, and soils, and many prefer moderate temperatures

T/F Thaumarchaeota are abundant in oceans, estuaries, and soils; many prefer moderate temperatures

True

T/F Thaumarchaeota are often found in cold, dry, basic environments

False; oceans, estuaries, soils, moderate temps

T/F Thaumarchaeota are often found in hot, acidic, or high-pressure environments

False; oceans, estuaries, soils, moderate temps