BIO 170 F Exam 2
Comprehensive Questions
with Verified Answers
Graded A+
1. Approximately how many years ago did the earth form?
a Answer:
4.7 by
2. Approximately how many years ago did the first cells (prokaryo
tes)
appear?-
Answer: 3.5 bya
3. Approximately how many years ago did the oxygen oxygeni
c
revolution ( photosynthesis) occur? Answer: 2.7 bya
4. Approximately how many years ago did the first olve
(unicellu-
eukaryotes ev lar)? Answer: 1.8 bya
,5. Approximately how many years ago did the Cambrian explosio
n occur?
Answer:
mya
6. Approximately how many years ago did the first ukaryote
s
multicellular e move to land? Answer: 500 mya
7. What is an organic molecule? Answer: One that has carbon and hydrogen bonded
together
8. What would have been necessary in order to create the first
cell to have evolved (prokaryote), including its essential
components?
(STUDY GUIDE QUESTION Answer: Describe the steps that would have
been necessary for a protocell to develop, and the evidence that
these steps would have occurred.) Answer: First, there would have had to been precursor
chemicals (CO2, H20, H2, etc.) present in a watery environment. Next, those precursor chemicals would
need to react to form small organic molecules (carbs, other lipids, and free floating amino acids). Then,
the organic monomers would join to form polymers. (where would macromolecules go?) Once that had
happened, the formation of RNA/DNA and enzymes would have to occur. Then
,the genetic material would have to encode proteins and the lipids would form spheres. Finally, these
molecules would need to be enclosed by a plasma membrane, and there is a formation of a protocell.
9. What is the evidence for each stage of the origin of life? Answer: Once
there was enough
concentration of these phospholipids in one area, then they would spontaneously form lipid spheres, and,
by chance, that sphere of phospholipids happen to trap some fluid (ocean water), and if that fluid
contained DNA or RNA, proteins, maybe some other organic molecules, that could've been the first cell.
10. What was the first genetic material? Answer: RNA, not DNA
11. At the time the earth was created, there was Answer: Answer: - Lots of
energy available (intense lightning, radioactivity, and UV radiation), or enough energy was
available for chemical reactions to occur.
-Because there was lots of hydrogen atoms and their electrons, there wouldn't have been a need for
as much energy to run chemical reactions, which is known as a reducing atmosphere
12. What is the Miller-Urey experiment? Answer: a chemical experiment that
simulated the conditions
thought at the time to be present on the early Earth, and tested the chemical origin of life under those
conditions.
13. What are the steps of the Miller-Urey experiment?
(STUDY GUIDE Answer: Describe the Miller-Urey experimental setup)
Answer: 1) These 2 scientists created a glass bowl that had ocean water in it, then heated it,
which stimulated the hot oceans at the time.
2) Since oceans were so hot, there was lot of evaporation
3) Evaporation would've went up the tube into their model atmosphere
, 4) Now, in this atmosphere with all of this water vapor, they then added the energy to stimulate lighting
(electric sparks)
5) Molecules and energy being added together were the conditions for inorganic molecules to react with
each other
6) Then there would have to be the cooling of the atmosphere and the condensation of water
7) That water would have been collected from the condensed water
8) Anything heavier than water molecules would have been trapped and collected and the rest of the
water could be cycled back into the model
14. What did the Miller-Urey experiment show?
(STUDY GUIDE Answer: What were the results and conclusion of the
Miller-Urey experi- ment? How do they relate to the hypothesis of how
life might have originated?)-
Answer: After several days, they were able to detect little organic molecules and amino acids at the
bottom of the horizontal tube and so, they determined that small organic molecules could have been
created from inorganic molecules.
15. Other possibilities for the origin of organic molecules? Answer: -
Organic molecules could have formed in areas of volcanic eruptions (strong possibility)
Comprehensive Questions
with Verified Answers
Graded A+
1. Approximately how many years ago did the earth form?
a Answer:
4.7 by
2. Approximately how many years ago did the first cells (prokaryo
tes)
appear?-
Answer: 3.5 bya
3. Approximately how many years ago did the oxygen oxygeni
c
revolution ( photosynthesis) occur? Answer: 2.7 bya
4. Approximately how many years ago did the first olve
(unicellu-
eukaryotes ev lar)? Answer: 1.8 bya
,5. Approximately how many years ago did the Cambrian explosio
n occur?
Answer:
mya
6. Approximately how many years ago did the first ukaryote
s
multicellular e move to land? Answer: 500 mya
7. What is an organic molecule? Answer: One that has carbon and hydrogen bonded
together
8. What would have been necessary in order to create the first
cell to have evolved (prokaryote), including its essential
components?
(STUDY GUIDE QUESTION Answer: Describe the steps that would have
been necessary for a protocell to develop, and the evidence that
these steps would have occurred.) Answer: First, there would have had to been precursor
chemicals (CO2, H20, H2, etc.) present in a watery environment. Next, those precursor chemicals would
need to react to form small organic molecules (carbs, other lipids, and free floating amino acids). Then,
the organic monomers would join to form polymers. (where would macromolecules go?) Once that had
happened, the formation of RNA/DNA and enzymes would have to occur. Then
,the genetic material would have to encode proteins and the lipids would form spheres. Finally, these
molecules would need to be enclosed by a plasma membrane, and there is a formation of a protocell.
9. What is the evidence for each stage of the origin of life? Answer: Once
there was enough
concentration of these phospholipids in one area, then they would spontaneously form lipid spheres, and,
by chance, that sphere of phospholipids happen to trap some fluid (ocean water), and if that fluid
contained DNA or RNA, proteins, maybe some other organic molecules, that could've been the first cell.
10. What was the first genetic material? Answer: RNA, not DNA
11. At the time the earth was created, there was Answer: Answer: - Lots of
energy available (intense lightning, radioactivity, and UV radiation), or enough energy was
available for chemical reactions to occur.
-Because there was lots of hydrogen atoms and their electrons, there wouldn't have been a need for
as much energy to run chemical reactions, which is known as a reducing atmosphere
12. What is the Miller-Urey experiment? Answer: a chemical experiment that
simulated the conditions
thought at the time to be present on the early Earth, and tested the chemical origin of life under those
conditions.
13. What are the steps of the Miller-Urey experiment?
(STUDY GUIDE Answer: Describe the Miller-Urey experimental setup)
Answer: 1) These 2 scientists created a glass bowl that had ocean water in it, then heated it,
which stimulated the hot oceans at the time.
2) Since oceans were so hot, there was lot of evaporation
3) Evaporation would've went up the tube into their model atmosphere
, 4) Now, in this atmosphere with all of this water vapor, they then added the energy to stimulate lighting
(electric sparks)
5) Molecules and energy being added together were the conditions for inorganic molecules to react with
each other
6) Then there would have to be the cooling of the atmosphere and the condensation of water
7) That water would have been collected from the condensed water
8) Anything heavier than water molecules would have been trapped and collected and the rest of the
water could be cycled back into the model
14. What did the Miller-Urey experiment show?
(STUDY GUIDE Answer: What were the results and conclusion of the
Miller-Urey experi- ment? How do they relate to the hypothesis of how
life might have originated?)-
Answer: After several days, they were able to detect little organic molecules and amino acids at the
bottom of the horizontal tube and so, they determined that small organic molecules could have been
created from inorganic molecules.
15. Other possibilities for the origin of organic molecules? Answer: -
Organic molecules could have formed in areas of volcanic eruptions (strong possibility)
