Origin Of Life

Question 1

What were conditions on the early earth like

Answer 1

Atmosphere composed of CO2 and other greenhouse gasses rather than oxygen.
Temperature is still quite high, but cooling
Liquid water is present

Question 2

What are the molecules of life

Answer 2

DNA (replication)
Proteins (metabolism
Lipids (compartmentalisation)

Question 3

How can RNA be used as a catalyst

Answer 3

Ribozymes
Ribozymes are enzymes composed entirely of RNA
This suggests that RNA could be used in both replication and metabolic processes

Question 4

Where do amphiphilic molecules come from?

Answer 4

The miller-Urey experiment showed that complex molecules can form in conditions that simulated that of the early earth in a primordial soup.

Question 5

How did the first proto cell form

Answer 5

A lipid membrane encapsulated RNA during its random cycles of hydration and dehydration. This created an encapsulated environment that is able to store and replicate information

Question 6

How did the first proto cell evolve into LUCA

Answer 6

-RNA replaced pre RNA since it is more stable and versatile with tertiary structure
-metabolic functions of RNA would be replaced by proteins which provide more structure and variation
-information storage functions of RNA would be replaced by DNA as it’s much more stable and lasts longer

Question 7

What is the evidence for LUCA

Answer 7

All life today uses the central dogma
Has the same chirality for key molecules
Uses the same 20 amino acids
Genetic code is universal

Question 8

Where did life on earth start

Answer 8

Hydrothermal vents or hot springs