Chapter 4: Archaeal Cell Structure

Question 1

Archaea and Bacteria are both

Answer 1

Prokaryotes

• But they are each distinct taxa (groups)

Question 2

Shape, Arrangement, and Size

Answer 2

• Cocci and rods are the most common Archaeal shapes
• Some cocci cluster and some rods form chain
• There are also curved rods, spiral shapes, and pleomorphic
• Even branched forms

Question 3

Cell Organization

Answer 3

• Archaeal plasma membrane is one of the greatest
differences based on the types of lipids compared to
bacteria
• Cell walls are also diverse and do not contain
peptidoglycan

Question 4

Archaeal Plasma Membrane

• Archaea lipids contain hydrocarbons
from _____ and ____ branched
molecules

• This changes how lipids are
packed together, which impacts
fluidity and permeability
• Important for extremophilic
Archaea

Answer 4

isoprene ; 5C

Question 5

Hydrocarbons are attached to
glycerol by ___ linkages

Answer 5

ether

• These linkages are more
chemically and heat → resistant

Question 6

Archaea have two major
types of lipids:

Answer 6

• Glycerol diether lipids
• Diglycerol tetraether
lipids

Question 7

Membranes with ____ have the typical bilayer membrane

Answer 7

diethers

Question 8

Membranes with ___ form a monolayer with more rigidity

Answer 8

tetraethers

Allows for more stability for extreme → thermophiles

Question 9

Transport for Archaea is very similar to bacteria since they are found most often in _____

Answer 9

nutrient-poor environments

• Most commonly use active transport, primary and
secondary
• Also perform group translocation occurs in some
archaea

Question 10

Archaeal cell wall acts like other cell walls

Answer 10

Maintain shape, stability, strength, and form a barrier

Question 11

Molecules in the cell walls are

Answer 11

very different from those of
bacteria

Question 12

Most common type of Archaean cell wall is an S-layer,
which

Answer 12

consists of many copies of → one protein

Question 13

Some methanogen Archaea have an S-layer that is separated from the
plasma membrane by

Answer 13

pseudomurein

Peptidoglycan-like molecule but
differs with amino acid cross-links
and NAT instead of NAM

Question 14

______ and _____ of Archaea are similar to what
is found in bacteria

Answer 14

Inclusions ; cytoskeleton

• Use genetic analysis to determine what is unique vs
different

Question 15

Archaea and Bacteria both have the ___ ribosome that
consists of the ___ and ____ subunit

Answer 15

70S ; 30S ; 50S

Ribosomal RNA (rRNA) is similar but differ in nucleotide
sequence

Question 16

Archaea have a nucleoid that contains the → chromosome. this chromosome contains….

Answer 16

circular, dsDNA
• But some have multiple chromosomes (polyploid)

Question 17

Many Archaea Have External Structures
Used for

Answer 17

Attachment and Motility

Question 18

Cannulae

Answer 18

hallow, tubelike
structures found on the surface of
thermophilic Archaea

• Function is unknown, but they
might be involved in daughter
cells staying connected in a
network

Question 19

Hami

Answer 19

look like tiny → grappling
hooks
• Most likely function for cells to
attach to surfaces