7.12: Origins Of Life

Question 1

Earth was formed approximately __

Answer 1

4.6 BYA

Question 2

Early earth was not suitable for life until ___ billion years ago.

Answer 2

3.9

Question 3

When was the earliest fossil evidence found?

Answer 3

3. 5 BYA

- Cyanobacteria

Question 4

Early earth contain what kind of molecules?

Answer 4

Inorganic

Question 5

How could inorganic molecules in early earth synthesize organic molecules?

Answer 5

• due to free energy and abundant oxygen

Question 6

Aside from inorganic molecules, how could have organic molecules been transported to earth?

Answer 6

Via meteorites or other celestial events

Question 7

OPARIN and HALDANE hypothesized that early Earth was primarily composed of?

Answer 7

Hydrogen, methane (inorganic) ammonia and water

Question 8

STANLEY MILLER and HAROLD UREY tested OPARIN and HALDANE’s theory in their lab. What did they find?

Answer 8

• they found organic compounds and amino acids formed, aka building blocks of proteins

Question 9

From testing their hypothesis, what did Miller and Urey hypothesize?

Answer 9

• the organic molecules that formed served as the building blocks for macromolecules

Question 10

What is the RNA World Hypothesis? (2)

Answer 10

• proposes that RNA could have been the earliest genetic material
• helps to explain the pre-cellular stage of life

Question 11

How does the endosymbiont theory relate to the topic of the origins of life? (2)

Answer 11

• The endosymbiont theory states that mitochondria and
  chloroplasts may have been engulfed by prokaryotic cells.
• Evidence supports this theory: mitochondria and chloroplasts have their own DNA (circular), double membrane, ribosomes and are capable of surviving on their own.