Lecture 1: The origin of life pt 2

Question 1

What are the 4 discrete steps of life on Earth?

Answer 1

1. The abiotic synthesis of complex organic molecules (such as amino acids or nucleotides)
2. The formation of polymers (macromolecules)
3. The formation of protobionts
4. The origin of heriditary information

Question 2

Abiotic

Answer 2

in the absence of life

Question 3

What was the goal of the Miller Urey Experiment?
What did the experiment produce?

Answer 3

To mimic the conditions of Early abiotic Earth
The experiment produced the primordial soup which is the solution of the organic molecules found in the seas of early Earth

Question 4

What was a flaw of the Miller Urey Experiment? Did the experiment still prove something?

Answer 4

Researchers believe there was little CH4 and NH3 in Earth’s early environment.
However it did prove you can create organic molecules abiotically.
Intrestingly, the experiment did not work in the presence of oxygen meaning life could not have originated in areas with lots of O2

All 20 amino acids,DNA,RNA,Lipids,ATP can be made abiotically

Question 5

What are some examples of polymers (in lecture)

Answer 5

DNA consisting of nucleotide chains
Proteins consisting of amino acid chains

Also known as macromolecules

Question 6

What was a problem with the formation of polymers in Early Earth?

Answer 6

Many of the monomers found in the ‘primordial soup’ were so diluted with water that it would be hard for the chemicals to come in contact with one another

Question 7

Why is clay seen as a “gathering ground” for concentrating organic molecules?

Answer 7

Clay contains many compounds with ionic charges that attract these organic molecules
Clay contains iron and zinc which can facilitate polymerization
Clay is believed to have been found near water since it is always found near aqueous environments

Question 8

What are protobionts? What is the importance of the formation of protobionts?

Answer 8

Macromolecules in solution can spontaneously form spheres called protobionts.
Since living organisms consist of cells, macromolecules must be organized in a cell like structure

Question 9

Why are there many different types of protobionts?

Answer 9

They can be made from proteins and or lipids. The most important protobiont is made of lipid bilayers called liposomes. Protobionts can manipulate their environment such as salt concentration in a lipid bilayer.

Lipid bilayers form spontaneously in aqeuous solutions

Question 10

In order to have life, there must be replication of ____-

Answer 10

heriditary material

Question 11

Why do scientists believe that RNA was the original heriditary material?

Answer 11

1. It can be formed in experiments suggesting it was present in the primordial soup
2. It can replicate itself in Zinc (which is in clay)
3. Contains heriditary material
4. It has catalytic properties that can form macromolecules

Question 12

What are the advantages to RNA being its own protobiont

Answer 12

By manipulating its own environment, it can ensure chemical conditions appropriate for replication
The protobiont that replicated the fastest could use the most resources and be successful aka natural selection (survival of the best replicators)