Deck 22: The Origin and History of Life

Question 1

The deep-sea vent hypothesis for the formation of prebiotic organic molecules is based on

A) temperature gradients of the hot water coming from the vents and cold ocean water.
B) hot gaseous substances released from the vents.
C) a buildup of radioactive substances around the vents.
D) temperature gradients of the hot water coming from the vents and cold ocean water and hot gaseous . substances released from the vents are correct answers.
E) temperature gradients, proton gradients, and radioactive substances could all lead to the formation of prebiotic organic molecules.

Answer 1

temperature gradients of the hot water coming from the vents and cold ocean water and hot gaseous . substances released from the vents are correct answers.

Question 2

John Bernal suggested that prebiotic synthesis of polymers took place on clay because

A) Clay minerals are known to bind organic molecules.
B) Clay is negatively charged and attracts cations.
C) Some minerals in clay attract organic monomers and catalyze chemical reactions.
D) Clay minerals can attract and bind organic molecules, catalyze chemical reactions and attract cations.
E) Clay is positively charged and can bind organic molecules for polymerization.

Answer 2

Clay minerals can attract and bind organic molecules, catalyze chemical reactions and attract cations.

Question 3

Suppose you wanted to investigate ideas on how polymerization of prebiotic organic molecules may have occurred on the early Earth, which of the following scenarios might best be utilized for this?

A) Mix some RNA nucleotides in water and heat them to boiling temperatures.
B) Mix some amino acids (protein building blocks) in water and add a strong acid or a strong base.
C) Mix some RNA nucleotides in water and repeatedly wet and dry them on clay.
D) Mix some amino acids (protein building blocks) in water and add a bacterium harmless to humans.
E) Mix some amino acids in salt water and cool down to 0C.

Answer 3

Mix some RNA nucleotides in water and repeatedly wet and dry them on clay.

Question 4

A protobiont

A) has a boundary, or membrane.
B) contains polymers inside that store information.
C) has a boundary and contains polymers inside that store information.
D) polymers that have enzymatic functions.
E) has a boundary, contains polymers that store information and other polymers that act as enzymes, and it can replicate itself.

Question 5

When lipids, phosphates, carbohydrates and RNA were placed on clay, a lysosome was formed. Why was the clay an important surface for lysosome formation and how is RNA associated with the lysosome?

A) Clay acts as a catalyst for the formation of a lysosome that can grow and divide; the RNA would be. enclosed inside of the lipid bilayer.
B) Clay would cause anions to stick together, while the cations would be pulled from the carbohydrates. . This chemical reaction would cause the formation of a carbohydrate membrane. RNA would be part of this membrane.
C) The clay surface had nothing to do with the formation of a phospholipid bilayer; water would have . worked just as well. RNA would be a transmembrane catalyst.
D) The positively charged clay surface would react with the negatively charged phospholipids to create . a clay ball that would enclose the RNA molecule.
E) RNA would react chemically with the negatively charged clay surfacE) This would create covalent . bonds; an impenetrable membrane would form. The phospholipids would be caught inside of the membrane.

Question 6

You have just invented a time machine and you want to investigate the past (the dream of every paleontologist!). When is the earliest time in Earth history that you could go back and not have to have an oxygen tank so that you could breathe normally?

A) Cambrian Period
B) Phanerozoic Eon
C) Archaean Eon
D) Quaternary Period
E) Devonian Period

Question 7

Both DNA and RNA can store information, yet DNA is the major information storage molecule in most cells. What are the advantages of using DNA for information storage instead of RNA?

A) DNA strands are less likely to spontaneously break because of the hydrogen bonds between bases.
B) If DNA stored information for the synthesis of RNA, RNA could be freed up for enzymatic functions.
C) Cells with both DNA and RNA would have an advantage over cells with just RNA, because DNA . does not spontaneously break and RNA could carry out enzymatic functions.
D) Reverse transcriptase could occur and DNA could make RNA.
E) DNA could be used to make proteins directly.

Question 8

The age of a fossil can be estimated by analyzing the decay of radioisotopes within the accompanying rock. If you suspected a fossil was 100 million years old, which type of radioisotopes would you use to analyze the accompanying rock?

A) Potassium-40/Argon-40 (half-life = 1.3 billion years; useful dating range =100,000-4.5 billion years)
B) Rubidium-87/Strontium-87 (half-life = 47 billion years; useful dating range = 10 million-4.5 billion years)
C) Uranium-235/Lead-207 (half-life = 710 million years; useful dating range = 10 million-4.5 billion years)
D) Carbon-14/Nitrogen-14 (half-life = 5,730 years; useful dating range = 100-50,000 years)
E) Uranium-238/Lead-238 (half-life 4.5 billion years; useful dating range = 10 million-4.5 billion years)

Question 9

A scientist found an unweathered igneous rock that contained .025 g of potassium-40 and 075 g of argon-40. The half-life of potassium-40 is 1.3 billion years. The rock would be estimated to be

A) 2.6 billion years old.
B) 0.050 billion years old.
C) 1.3 billion years old.
D) 0.001875 billion years old.
E) 1.69 billion years old.

Question 10

Which would be most likely to be fossilized?

A) a small worm with all soft body parts.
B) a thick-shelled oyster that lives under water.
C) a small herb growing at the top of a mountain.
D) an elephant trapped in a tar pit.
E) a thick-shelled oyster that lives under water and an elephant trapped in a tar pit.

Question 11

The first known fossils of living cells were preserved in rocks that are 3.5 billion years old, but scientists postulated that the first cells arose many millions of years prior to this time. These first cells were most likely ...

A) aerobic, photosynthetic, eukaryotic.
B) aerobic, photosynthetic, prokaryotic.
C) anaerobic, heterotrophic, prokaryotic.
D) anaerobic, heterotrophic, eukaryotic.
E) anaerobic, chemotrophic, eukaryotic.

Question 12

To explain the origin of the nuclear genome, which of the following hypotheses are most widely accepted?

A) Endosymbiotic relationship.
B) Symbiotic relationship.
C) Mitochondrial relationship.
D) Both the endosymbiotic and symbiotic relationships.
E) Endosymbiotic, symbiotic and mitochondrial relationships.

Question 13

The major difference between the endosymbiotic relationship theory and the symbiotic relationship theory is

A) In the endosymbiotic relationship theory the archaeon engulfs the smaller bacterium while in the . symbiotic relationship theory the Archaeon and Baterium unite, joining their plasma membranes.
B)In the endosymbiotic relationship theory the archaeon and bacterium unite, joining their plasma . membranes while in the symbiotic relationship theory the archaeon engulfs the smaller bacterium.
C)In the endosymbiotic relationship theory the origin of both mitochondria and chloroplast are . explained but the origin of the nucleus is not explained, while the symbiotic relationship theory explains the origin of mitochondria, chloroplast and the nucleus.
D) In the symbiotic relationship theory the origin of both mitochondria and chloroplast are explained but . the origin of the nucleus is not explained, while the endosymbiotic relationship theory explains the origin of mitochondria, chloroplast and the nucleus.
E) Both theories have an explanation for the mitochondria and chloroplast, but the symbiotic theory fails to explain the origin of the nucleus.

Question 14

Which of the following are thought to have occurred because of the increase of oxygen (O₂) in the atmosphere during and after the Silurian Period?

A) Conquest of land by arthropods.
B) Conquest of land by arthropods and vertebrates.
C) Increases in animal body sizes and conquest of land by plants.
D) Conquest of land by arthropods and vertebrates, and plants.
E) Conquest of land by arthropods and vertebrates and an increase in animal body sizes.

Question 15

Because hardly any oxygen (O₂) was in the early Earth's atmosphere, the single-celled microorganisms probably used which of the following to produce energy to drive metabolic processes?

A) Aerobic cellular respiration.
B) Anaerobic cellular respiration.
C) Sulfuric acid respiration.
D) Both aerobic and anaerobic cellular respiration.
E) Sulfuric acid, aerobic and anaerobic respiration.

Question 16

In 1909, Charles Walcott discovered fossils in the Burgess Shale of the Canadian Rockies. The area was formed by an underwater mudslide that provided an oxygen free environment, so decomposition was minimal. Why were these fossils so unique?

A) They were from the Cambrian period.
B) There were both vertebrate and invertebrate (soft bodied) animals fossilized.
C) Only invertebrate (soft bodied) animals were found and no vertebrate animals or plants.
D) Before this discovery, it was thought that mudslides could not occur underwater.
E) The first bird fossil, Archaeopteryx, was discovered in this area.

Question 17

At the end of the Permian period a large mass extinction occurred; 90-95% of the marine and terrestrial species were eliminated. Which of the following are thought to be the possible cause(s) of this mass extinction?

A) Glaciation.
B) Meteorites colliding with the Earth.
C) Volcanic eruptions.
D) Competition between marine and terrestrial animals.
E) Glaciation or volcanic eruptions.

Question 18

In eukaryotes, genes involved in transcription and translation are derived from

A) ancient bacteria.
B) primitive RNA.
C) archeal ancestors.
D) clay templates.
E) primitive RNA and clay interactions.

Question 19

The origin of the mitochondrion and chloroplast by endosymbiosis, hypothesizes that these organelles originated by

A) the fusion of two archean cells to form the eukaryote with the eukaryotic mitochondrion and chloroplast inside.
B) the absorption of RNA from prokaryotic cells.
C) prokaryotic cells being engulfed and becoming internal symbionts within an early eukaryotic cell.
D) only the absorption of DNA from dead prokaryotic cells used as food.
E) prokaryotic cells being engulfed and becoming external symbionts within an early bacteria cell.

Question 20

The Carboniferous Period is known for

A) Rich coal deposits found in rocks of this age.
B) The first examples of gymnosperms on land.
C) The first angiosperms developed.
D) The carboniferous explosion of marine invertebrates; sea urchins, arthropods, and crustaceans.
E) The appearance of reptiles and large mammals.

Question 21

The event called the Cambrian Explosion resulted in an abrupt increase in

A) geological activity.
B) diversity of major animal groups.
C) algal diversity.
D) the number of days in the year.
E) the amount of fish, of a single species, in the seas.

Question 22

Which of the following would likely fossilize under normal environmental conditions?

A) An elephant that died near a waterhole that dried up.
B) A bird that died and fell into the forest litter.
C) A slug that died in leaf litter.
D) A soft shelled crab that dies in an estuary.
E) Both a bird and slug that die and fall in leaf litter.