Lecture 15

Question 1

What is the panspermia theory?

Answer 1

Life on earth arose from extraterrestrial sources - meteorites

Question 2

What are the two meteorites that the panspermia theory is based on?

Answer 2

• Antartica meteorite
  which contained water, carbon dioxide & magnate
• Murchison Meteorite
  which contained building blocks: nucleotides, amino acids lipids and sugar

Question 3

What is the chemical theory?

Answer 3

Life arose by chemical processes on earth
- all the components necessary for life were present on earth, provided they were exposed to the right environmental conditions

Question 4

What is the first step of the chemical evolution theory?

Answer 4

• Abiotic synthesis of molecules

e. g amino acids, nucleotides

Question 5

What is the second step of the chemical evolution theory?

Answer 5

• Abiotic formation of macromolecules

Joining together to form nucleic acids & protiens

Question 6

What is the third step of the chemical evolution theory?

Answer 6

-Membrane formation

enclosing of these molecules in membranes

Question 7

What is the fourth step of the chemical evolution theory?

Answer 7

• Self replication

origin of self replication molecules that allow inheritance

Question 8

What is the endosymbiosis theory?

Answer 8

That mitochondria and plastids were originally small prokaryotic cells that were absorbed by ancestral eukaryotes

Question 9

What evidence supports the endosymbiosis theory?

Answer 9

• Mitochondria & chloroplasts contain their own genome/DNA
• Semi-autonomous can produce some but not all of their proteins
• self replicate like prokaryotes

Question 10

Explain the Primordial soup hypothesis:

Answer 10

• Early oceans contained plenty of solutions
  -Lightning could have powered the formation of amino acids and amines
  provided that the earth’s atmosphere was reducing