Chapt. 17

Question 0

Elements that compose the earth came from…

Answer 0

Stars

Question 1

Before the first cells “evolved,” what conditions had to be met?

Answer 1

1. ) Essential elements: used to compose organic molecules
2. ) Continual source of energy: mainly nuclear fusion reactions within the sun
3. ) Temperature range permitting liquid water: without, metabolic reactions cease

Question 2

Earths core is composed of ______ and _______

Answer 2

Iron and silicates

Question 3

Thin outer crust is made of _________

Answer 3

Silicon dioxide

Question 4

What kind of gradient is on the earths thin outer crust?

Answer 4

Redox gradient (oxidizing at the surface)

Question 5

Hadean eon

Answer 5

First life

Question 6

Stromatolites

Answer 6

Earliest forms of life for which we have clear fossil evidence

Question 7

Limestone

Answer 7

CaCO3

Question 8

Biosignatures

Answer 8

Chemical indicators of life

Question 9

Isotope ratio

Answer 9

If the ratios between certain isotopes of a given element are altered by biological activity

Question 10

Cyanobacterial hopanoids

Answer 10

Steroid-like membrane molecules that are particularly durable

Question 11

Banded iron formations (BIF)

Answer 11

Show alternating O2-rich and anoxic atmospheric conditions

Question 12

Oxidized Fe indicates…..

Answer 12

Rises in O2 from photosynthesis

Question 13

BIFs are evidence of ……

Answer 13

Anaerobic iron phototrophy

Question 14

Earliest metabolism consisted of ……

Answer 14

UV-driven anaerobic redox reactions

Question 15

In metabolism of first cells, what may have driven phototrophy?

Answer 15

Simple light-driven pumps (halo archaea-type)

Question 16

What absorbs light in the center of electromagnetic spectrum?
(Similar to light that reaches the upper ocean layers)

Answer 16

Bacteriorhodopsin

Question 17

Cyanobacteria evolved with ……

Answer 17

Ahloarchaea to Occupy un filled niches

Question 18

____________ show early evolutionary start

Answer 18

Highly divergent methanogenic archaea

Question 19

Three models of early life

Answer 19

Prebiotic soup
Metabolist models
RNA World

Question 20

Prebiotic soup

Answer 20

Some molecules arise abiotic ally from simple reduced chemicals and sparked lightning

Question 21

Metabolism model

Answer 21

Self sustaining abiotic chemical reactions could have formed the basis of cellular respiration

Question 22

RNA world

Answer 22

RNA was used as a genome for virus, uracil is precursor to thymine
Possesses catalytic properties as ribozymes

Question 23

Most commonly used molecular clock

Answer 23

Small subunit rRNA (16 in bacteria, 18 in euks)

Question 24

Maximum parsimony

Answer 24

Best fit phylogenetic tree

Question 25

Reductive evolution

Answer 25

Loss or mutation of DNA encoding un selected traits

Question 26

Who first used SSU rRNA Phylogeny to reveal archaea?

Answer 26

Carl woese

Question 27

Probalistic indicator

Answer 27

Battery of I'd tests all at once