BIOL240 Module 3: Archaea

Who discovered Archaea

Carl Woese and George Fox

What class are most Archaea

Extremophiles

What are Methanogens

Produce methane, only in archaea

What make archaeal membranes more stable

Biphytanyl chains → makes a monolayer plasma membrane

What linkage links glycan chains in Archaea cell walls

β-1,3-glycosidic linkages

What acid is lacked in archaea in cell walls, and what does it contain instead

N-acetylmuramic acid (NAM)

Has N-acetyltalosaminuronic acid (NAT)

What amino acid does Archaea cell walls lack and what d0 they have instead

D-amino acids

Has L-isomers

What are Cannuales

Sugars and proteins tubes that connect to form a network

Flagella in Archaea

Grows from base

rigid rods

two types of flagellin protein

Euryarchaeota

All known methanogens

Crenarchaeota

Extremophiles

Thaumarchaeoto

Oxidize ammonia, most abundant on earth

Nanoarchaeoto

One member - Nanoarchaeum equitans

Korarchaeota

Know very little only in culture

Thermophilic & Hyperthermophiles

Optimal temperatures at:

55C+

80C+

respectively

Acidophiles

Thrive in very acidic environments

barophiles

Thrive in High Pressure environments

How does crenarchaeotes cell membranes be more stable in extreme environments

Modified proteins with more alpha helices

Amino acids that encourage salt bridges and side chain interactions

Thermostable DNA-binding proteins

Helps bind and stabilize DNA

Reverse DNA Gyrase

Increases extent of DNA supercoiling

Halophiles

Salt-loving

How do Halobacterium manipulate its osmolarity

High intercellular potassium concentrations and to prevent DNA denaturing by increase Guanine and Cytosine content

Why are Halobacterium red?

Light-harvesting pigment to supplement ATP requirements

Hypertonic

More solutes and makes cells shrink

Hypotonic

Less solutes and makes cells swell

What environment do methanogens inhabit?

No oxygen - strict anaerobes

• Digestive tracts

• cecum

• rumen

• hydrothermal vents

• wastewater

• termites

Hydrogenoclastic methanogens

Use hydrogen as an energy source

Acetoclastic methanogen

Uses acetate

Methylotrophic methanogens

One-carbon compounds