lecture 10

Question 1

accumulation of organic molecules formed _____
The lack of oxygen allowed ______
And there were no ______

Answer 1

primordial soup
molecules to avoid oxidation
living organisms to metabolize the soup

Question 2

Origin of organic molecules
Deep see vent hypothesis

____ ____ and ____ exit ______ in excess of _____

__________ can be formed in the gradient between hot and cold water

Answer 2

water
metal
hydrogen sulfide 
deep sea thermal vents
300˚C
precursors to organic molecules

Question 3

Stage 2 of four stage process to life is ________

This took place on _________
Not in _________

Answer 3

nucleotides and amino acids became polymerized to form dna, rna and proteins

solid surface or tidal pool
prebiotic soup

Question 4

formation of polypeptide and nucleic acid polymers may occur when and where

Answer 4

when monomers are present and on the surface of clay

Question 5

stage 3 of four stage process to life

Answer 5

polymers became isolated by boundaries(cell walls)

Question 6

polymer boundaries does _____

which resulted in

Answer 6

seperates the environment from the internal polymers, (creates their own micro-climate)
protobiont

Question 7

protobiont

Answer 7

first non living structures that evolved into cells

Question 8

protobiont characteristics (4)

Answer 8

1. membrane separating external environment from internal contents
2. polymers inside that contain information (DNA/RNA)
3. polymers (proteins) also act as enzymes for additional reactions
4. capable of replication (not quite self reproduction)

Question 9

Coacervates are __________

and are a __________

Answer 9

charged polymers which sponataneously associate with each other
scenario for protobiont formations

Question 10

microspheres ___________

And are a _________

Answer 10

water filled vesicle with macromolecular boundary

scenario for protobiont formation

Question 11

liposomes are _____
and are a ______
researchers have shown that clay ______

Answer 11

similar to microspheres but with a lipid outer layer,
(scenario for protobiont formation)
Can catalyze the formation of liposomes that grow and divide

Question 12

starge 4 of four stage process to life

Answer 12

polymers enclosed in membranes evolved cellular properties

- protobionts developed metabolic functions and self replications

Question 13

rna have abilitiy to _____ _____ and ______

So scientists favor it as

Answer 13

store information
have capacity to self replicate
are capable of enzymatic activity

the first macromolecule of protobionts

Question 14

first organisms
They were probably __________ because then they wouldn’t ___________ or have to ___________
And were probabably _________ because the oceans _________

Answer 14

• prokaryotes, single celled microorganisms with anaerobic metabolism
• anaerobic heterotrophs
• require oxygen
• or need to evolve additional metabolic pathways to make organic molecules
• thermophiles
• were continuously heated by impacts of meteorites and volcanoes

Question 15

Anaerobic heterotrophs metabolize ________ via _______
Because ________ were made slowly the anaerobic heterotrophs would have ___________ so then _____ evolved and had an _____

Answer 15

• organic molecules
• fermentation
• organic molecules
• exhausted the supply quickly
• cells that evolved to synthesize own organic organic molecule supply
• advantage

Question 16

Anaerobic autotrophs

Answer 16

chemoautotrophs and photoautotrophs

Question 17

anaerobic chemoautotrophs

Answer 17

obtain carbon from CO2 but obtain energy from the reduction of inorganic chemical bonds

Question 18

anaerobic photoautotrophs

Answer 18

obtain energy from sunlight to fix co2 into carbon compounds

Question 19

following anaerobes

Answer 19

photoautotrophs with oxygenic photosynthesis

Question 20

key innovation made by photoautorophs _______
Which had an advantage because ______
This was termed ________
because _______

Answer 20

use of H20 as the electron donor
water was plentiful
oxygenic photosynthesis
oxygen was a byproduct of this new process

Question 21

Original elements

Answer 21

hydrogen and helium

Question 22

earth an accumulation of

Answer 22

comets and asteroids

Question 23

Original earth was ______
Then it ______
Volcanoes and other vents ______
Which consisted of __________

Answer 23

Too hot for water, and so no life
cooled enough to solidify and oceans formed
formed new atmosphere
CO2, N2, H2S, H20, maybe NH4 and CH4

Question 24

Evidence of oxygen appearing from _____

These layers are called _____

Answer 24

• the presence of rusted iron found in ancient rocks of the time (because oxygen is need for rust)
• banded iron formation

Question 25

First stage of processes to life which formed in the some believe the earth was seeded via

Answer 25

Origin of organic molecules Ancestral atmosphere of the earth (replicate in lab) comets/asteroids with organic molecules

Question 26

Three main hypothesis for primordial soup development

Answer 26

Reducing atmosphere hypothesis Extraterrestrial hypothesis Deep sea vent hypothesis

Question 27

Reducing atmosphere hypothesis ``` Ancestral atmosphere consisted of ______ With O2 absent ______ Under these conditions ______ and _____ experimented to see if they could _______ They found ________ New evidence suggests ____- but was ______ consisting of ______ But still ________ ```

Answer 27

water vapour, H2, methane(CH4), ammonia(NH3) the atmosphere is a reducing environment Miller Urey Produce organic molecules in the laboratory simple organic compounds in their trap The original environment wasn't reducing CO, CO2, N2 and H20 Organic molecules were produced from experiments

Question 28

Extraterrestrial hypothesis Meteorites contain _______ which includes __________ Opponents argue ______

Answer 28

substantial amounts of organic carbon amino acids and nucleic acids Most of this would be destroyed in heating and collision

Question 29

formation of polypeptides and nucleic acid polymers may occur on ______ which is used in ______

Answer 29

surface of clay, | many industrial organic reations

Question 30

Possible scenarios for protobiont formation

Answer 30

Coacervates microspheres liposomes

Question 31

There are limitation to both kinds of ______ | Which include requiring _____

Answer 31

Anaerobic autotrophy | reduced elements or compounds to provide energy(supply could be exhausted again)