Exam 2 Archaea 10/10 Flashcards

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1
Q

Distinctive properties of Archaea:

A

Archaeons “look” like bacteria.

However, genetic analyses show them to be different.

They live in some of the most inhospitable places (for humans) on Earth.

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2
Q

Distinctive properties of Archaea:

A

Phylogeny

Comparisons of rRNA gene sequences can establish phylogenetic “trees.”

The first portion termed “archaeons” were the methanogens.

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3
Q

Archaea Structure-Bacterial

A

Size is usually 0.5–5 μm in diameter

Similar shapes

Singular, circular chromosome

Lack a membrane-bound nucleus

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4
Q

Archaea Structure-Eukaryal

A

Archaeal DNA is complexed with histones

Homologues of DNA replication enzymes/transcription and translation machinary

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5
Q

Distinct Archaeal Feature

A

Plasma Membrane – Organization and Composition

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6
Q

Archaeal cell structure:

A

Generally 0.5–5 μm in diameter

Can vary greatly (N. equitans = 0.4 μm in diameter, Thermoproteus spp. can be 100 μm long!)

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7
Q

Archaeal cell structure: Shapes can vary

A

Rods, spheres, spirals
Irregular shapes (Sulfolobus spp.)
Rectangular shapes (Thermoproteus spp.)

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8
Q

Archaeal cell structure:

A

The cell envelope
- All archaeons possess a plasma membrane.
- Most archaeons have a cell wall.

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9
Q

Plasma Membrane

A

Can be bilayer OR monolayer
- Contain hydrocarbons derived from isoprene units
- Hydrocarbons attached to glycerol by ether rather than ester linkages

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10
Q

Archaeal cell walls:

A

The cell wall provides physical and osmotic protection

Pseudomurein (N-acetyltalosaminuronic acid)

Some Archaea lack a cell wall

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11
Q

Will lysozyme work against Archaea? Why/why not?

A
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12
Q

Cytoplasm

A

Histones form structures that DNA wraps around.
Histone structure/wrapping is different in Archaea from Eukarya.

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13
Q

Cytoskeleton

A

Cytoskeletal homologues

Ta0583 is an actin homolog in Thermoplasma acidophilum that resembles eukaryal actin.

Cytoskeletal proteins from M. thermoautotrophicum and M. kandleri more closely resemble bacterial cytoskeletal proteins.

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14
Q

Cell Surface

A

S-layer (single layer of many identical armorlike subunits)

Cannulae, hollow glycoprotein tubes that link cells together to form a complex network.

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15
Q

Hami

A

Surface structures

Attachment

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16
Q

Flagella

A

Similar to bacteria in that they rotate to move the cell

Different from bacteria because they are
- thinner (10‒14 nm vs. 20‒24 nm)
- usually composed of two or more different versions of flagellin protein
- likely growing from BASE rather than from TIP

17
Q

Archaeal cell structure:

A

The cell surface
- Some archaeons possess flagella.
-Different from bacteria because they are
likely growing from BASE rather than
from TIP