Early Origins of Life

Question 1

Pre-Biotic Soup

Answer 1

Pool of organic molecules suspended in water

Question 2

Abiogenesis

Answer 2

Chemical formation of life

Question 3

Horizontal Gene Transfer

Answer 3

Movement of genetic material between unicellular &/or multicellular organisms other than by the transmission of DNA from parents to offspring

Question 4

What are the properties of life?

Answer 4

1. Homeostasis
2. Structural organization
3. Metabolism
4. Response to environmental stimuli
5. Growth and reproduction
   -Evolved by natural selection
   -Appears to be composed of cells

Question 5

Why was DNA selected for over RNA?

Answer 5

1. DNA is more stable then RNA
2. “Proofreading”
3. Repair structures
4. Lower mutation rates
   -2 & 3 prevent replication errors

Question 6

Why were membranes with phospholipids selected for instead of lipid membranes?

Answer 6

Phospholipid membranes were selected for because the rate of dissociation without phospholipids is greater than with phospholipids
-Dissociation means to come apart and we do not want our cells to come apart

Question 7

Pre-Biotic Hypothesis

Answer 7

Lightning and UV rays provided energy to convert inorganic molecules to organic molecules

Question 8

Evidence for RNA-World

Answer 8

1. Enzymes have RNA co-factors
2. DNA is synthesized from RNA
3. Ribosome catalytic site is composed entirely of RNA
4. Experiments simulation early Earth suggest RNA components existed

Question 9

RNA Features

Answer 9

1. Information storage
2. Replication
3. Enzymatic function