Microbes, Man and the Environment

Question 1

Temperature of early earth?

Answer 1

> 100, thus all water was atmospheric.

Question 2

Atmosphere of early earth?

Answer 2

methane, carbon dioxide, ammonia, nitrogen, sulphur dioxide. (reducing conditions, no O2)

Question 3

Evidence that water condensed and formed oceans?

Answer 3

Sedimentary rocks.

Question 4

Timeline from beginning to first fossil evidence of cells.

Answer 4

Earth (4.6 By), sedimentary rocks (3.86 By), filamentous bacteria (3.5 By).

Question 5

Can biologically important molecules be formed abiotically?

Answer 5

Yes, with energy. (Miller and Urey)

Question 6

How are organic macromolecules formed without cells?

Answer 6

Splashing on hot dry surfaces (catalysis)

I.e. Montmorillionite clay (RNA)

Question 7

How do thermophiles gain energy?

Answer 7

FeS + H2S –> FeS2 + H2.

(aka Archaea).

Question 8

How is the phospholipid layer around Archaea different from that of other cells?

Answer 8

Monolayer, phospholipids fused due to hydrophobic side chains.

Question 9

Compare Eukarya, Bacteria and Archaea.

Answer 9

Respectively:
No. Of chromosomes: >1, 1, 1
Chromosomes topology: linear, circular, circular.
Peptidoglycan in cell wall? No, no, yes.
Membrane lipids: ester linked glycerides, ester linked glycerides, ether linked glycerides.
Ribosome size: 80s, 70s, 70s.
A.a initiating protein synthesis: methionine, N-formyl methionine, Methionine