Deck 25: The Origin of Life

Question 1

The ____ ion is required for ribozymes to become active and begin self-replication.

A) ferrous iron
B) ferric iron
C) zinc
D) magnesium
E) selenium

Answer 1

D

Question 2

The famous Miller-Urey experiments provided crucial support for the ____ hypothesis.

A) endosymbiosis
B) Oparin-Haldane
C) RNA World
D) Dickerson oxidizing atmosphere
E) hydrothermal vent

Answer 2

B

Question 3

Ribozymes may have originally developed by ____.

A) ATP synthesis
B) the chance assembly of RNA molecules
C) cellular respiration
D) glycolysis
E) electron transfer systems

Answer 3

B

Question 4

Early biological activity may be found in rocks by investigating ____.

A) stromatolites
B) isotope ratios
C) microfossils
D) all of these are correct
E) none of these are correct

Question 5

The first information storage molecule was probably ____.

A) DNA
B) RNA
C) protein
D) carbohydrates
E) lipids

Question 6

The ancestor of the three domains of life was ____.

A) a prokaryotic bacterium
B) an archaean endosymbiont
C) a proto-eukaryote
D) the last universal common ancestor (LUCA)
E) none of these are correct

Question 7

Where did Earth's atmosphere originate?

A) Earth's gravity trapped gases from passing comets.
B) Gases were released from Earth itself as it cooled.
C) Earth's gravity trapped gases from Earth itself.
D) Earth's gravity trapped gases from passing comets, gases were released from the Earth itself as it cooled, and Earth's gravity trapped gases from the Earth itself.
E) Gases were released from Earth itself as it cooled Earth's gravity trapped gases from the Earth itself.

Question 8

Molecules that are able to store and reproduce genetic information are known generally as ____.

A) molecular hard drives
B) molecular replicators
C) DNA
D) RNA
E) ribozymes

Question 9

Modern cells are thought to have arisen from ____.

A) protocells
B) pre-cells
C) gas and dust clouds
D) prokaryotic cells that predated protocells
E) prokaryotic cells that predated pre-cells

Question 10

Why is the distance of Earth from the sun so crucial for life as we know it?

A) The distance provides the optimal temperature for water to occur in a liquid form.
B) The distance allows Earth's orbit to have a year of a reasonable length.
C)   The distance allows for multiple seasons in temperate climates, which was crucial for the emergence of chemicals used to build the first protocells.
D) The distance provides ample opportunity for water to freeze into ice.
E) The distance ensures that ample water is available for all of the organisms on Earth.

Question 11

Organic macromolecules may have formed by ____.

A) addition of water to small organic subunits to facilitates enzymatic synthesis reactions
B) dehydration synthesis reactions that combined smaller subunits into larger molecules
C) increasing availability of inorganic compounds
D) sequestration inside a semi-permeable membrane
E) spontaneous aggregation of the different organic compounds in the atmosphere

Question 12

Aside from the traditional hypothesis that life on Earth developed via organic compounds produced in a reducing atmosphere, which alternative hypotheses is most likely?

A) Life could have arisen from the organic compounds formed around hydrothermal vents far below the ocean floor.
B) Life could have developed on another planet and was then delivered by meteorites.
C) The organic compounds necessary for life were delivered to Earth by meteorites.
D) Life on Earth may have arisen inside land-based volcanoes.
E) The organic compounds necessary for life could only have been produced in an oxidizing atmosphere.

Question 13

What happens when phospholipids are placed in an aqueous solution?

A) They disperse and form polar bonds with other organic molecules present in the solution.
B) They move to the water's surface and form a single-layered membrane between the water and the atmosphere.
C) They repel one another.
D) They spontaneously form bilayers.
E) The hydrophobic tales force the phospholipids to form "beads" at the surface, much like what you see when vegetable oil is added to water

Question 14

Why is the absence of atmospheric oxygen (O₂) so important to the Oparin-Haldane hypothesis?

A) Oxygen is corrosive and thus would have degraded many of the metallic compounds on Earth's surface, releasing toxic gasses into the new atmosphere.
B) Oxygen is more reduced than hydrogen gas, methane, or ammonia.
C) Oxygen would have supported microorganisms that promote chemical decay.
D) Oxygen is able to reverse reactions by removing electrons and hydrogen from organic molecules, thus destroying the first organic compounds as quickly as they developed.
E) Oxygen would have caused multiple explosions, converting chemical energy into heat energy and rendering that energy unavailable for driving the synthesis of organic molecules.

Question 15

The RNA world proposal suggests that the first information molecules were ____.

A) transfer RNA
B) ribosomes
C) messenger RNA
D) ribozymes
E) unpaired strands of DNA

Question 16

Some scientists believe that RNA was the first information storage molecule because ____.

A) some viruses use RNA as their information storage molecule
B) RNA can be an enzymatic catalyst as well as an information storage molecule
C) amino acids cannot form peptide bonds without ribosomes to catalyze their formation
D) RNA is a less stable molecule than DNA
E) proteins are made of far more amino acid monomers (over 20) than RNA (4)

Question 17

"Prebiotic soup" refers to ____.

A) the interior contents of protocells
B) the cytoplasm of early prokaryotic cells
C) the mix of gases in the atmosphere that gave rise to the first organic molecules
D) the polymerized slime coating ancient clay particles
E) the accumulation of organic molecules that formed in the oceans before there was life on Earth

Question 18

Assuming geological evidence is accurate, life on Earth may have originated ____ billion years ago.

A) 14
B) 4.6
C) 3.5
D) 2.1
E) 1.2

Question 19

What assumption is made by researchers when designing experiments to model how life may have arisen on Earth?

A) The chemical reactions of living things are only possible inside living systems.
B) Living organisms are composed of elements commonly found on Earth, but absent in the rest of the universe.
C) Conditions on Earth have not changed over time.
D) Life arose on Earth from non-living matter.
E) The development of living cells from nonliving matter was very rapid.

Question 20

If RNA was the first information storage molecule, which macromolecule would have been the "next" molecule produced in the progression toward living cells?

A) DNA
B) lipids
C) carbohydrates
D) sugars
E) proteins

Question 21

The evolution of life on Earth was made possible by ____.

A) DNA
B) organelles
C) an environment that favors oxygen photosynthesizers
D) natural selection that favors efficient reproduction of organisms
E) random mutations

Question 22

Who developed the modern endosymbiotic theory?

A) Charles Darwin
B) Lynn Margulis
C) Richard Dickerson
D) Wendy Johnson
E) Stanley Miller

Question 23

The energy source that may have driven the chemical reactions leading to modern Earth's atmosphere was ____.

A) sunlight
B) electrical storms (lightning)
C) photosynthesis
D) radioactive decay
E) heat energy released from Earth's core

Question 24

E ukaryotic evolution relied on ____.

A) horizontal gene transfer from bacteria
B) endosymbiosis of prokaryotic cells
C) an archaean ancestor
D) natural selection
E) all of these are correct

Question 25

The hypothesis that mitochondria and chloroplasts originated from the phagocytic activity of prokaryotes that was not followed by digestion is called the ____.

A) theory of natural selection
B) endosymbiotic hypothesis
C) ribozymes-first hypothesis
D) Oparin-Haldane hypothesis
E) stromatolite hypothesis

Question 26

A characteristic of all modern, living cells is ____.

A) a semi-permeable membrane keeping the internal environment of the cell separate from the external  environment
B) nucleic acids linked in a sequence to form multiple large macromolecule chains
C) a requirement for the nucleic acids to be contained behind a nuclear membrane
D) a mechanism of converting energy from the sun
E) a method of converting protein changes into nucleic acids

Question 27

Why is the protein-first hypothesis not accepted by most scientists?

A) Proteins cannot be catalysts.
B) There is no known mechanism of protein self-replication.
C) Of all of the macromolecules, only DNA can self-replicate.
D) There is no evidence that proteins can store information.
E) Proteins are too complex to have been the first "polymers of life."

Question 28

Archaeans resemble bacteria by the ____, and resemble eukaryotes by the ____.

A) lack of membrane-bound organelles; presence of a nucleus
B) presence of similar cell wall proteins; presence of similar rRNA sequences
C) ability to perform aerobic respiration; presence of similar cell wall proteins
D) lack of membrane-bound organelles; presence of introns
E) presence of nucleoid region; lack of a nuclear envelope

Question 29

One line of evidence for endosymbiosis is that chloroplasts resemble ____.

A) anaerobic bacteria
B) aerobic bacteria
C) fungi
D) protists
E) cyanobacteria

Question 30

Which feature of Archaea is shared with Bacteria but not with Eukarya?

A) the sequestration of DNA into a nucleus
B) the common occurrence of introns
C) the chemical structure of the cell walls
D) the plasma membrane struct
E) a genome comprised of a single, circular molecule of DNA

Question 31

Natural sources of energy on the early Earth caused ____.

A) spontaneous genetic mutations
B) chemical bonds to break
C) chemical bonds to form
D) chemical bonds to break and form
E) spontaneous genetic mutations and chemical bonds to break and form

Question 32

According to the endosymbiont hypothesis, ____.

A) most of the genes from the endocytosed bacteria moved to the nucleus
B) the host anaerobe became dependent upon the endocytosed bacteria
C) the endocytosized bacteria became dependent on the host cell
D) all endocytosed bacteria were photosynthetic
E) most of the genes from the endocytosed bacteria moved to the nucleus, the host anaerobe became dependent upon the endocytosed bacteria, and the endocytosed bacteria became dependent on the host cell

Question 33

Chloroplasts evolved from endosymbionts but the endomembrane system evolved from __________.

A) mitochondria
B) Archaea
C) the plasma membrane
D) the endoplasmic reticulum
E) stromatolites

Question 34

What is an alternative to RNA as the first polymer of life?

A) single nucleotides
B) non-genetic polymers
C) polymers that do not form a double helix m a double helix
D) other genetic polymers containing different sugars
E) other genetic polymers containing different amino acids

Question 35

Horizontal gene transfer is the movement of a gene from ____.

A) a prokaryotic genome to a eukaryotic genome
B) the chloroplast genome to a eukaryotic genome
C) the mitochondrial genome to a eukaryotic genome
D) a viral genome to the eukaryotic genome
E) all of these are correct

Question 36

Stars provided ____ elements making up cells on Earth.

A) none of the
B) about half of the
C) only the radioactive
D) most of the
E) all of the

Question 37

The Sun provided ____ in order to power the development of life on early Earth.

A) continual energy
B) a temperature range for liquid water to form
C) radiation to power mutations
D) continual energy and a temperature range for liquid water to form
E) continual energy, a temperature range for liquid water to form, and radiation to power mutations

Question 38

According to the Oparin-Haldane hypothesis, ____ was likely absent or near absent in Earth's early atmosphere.

A) O₂(oxygen)
B) H₂(hydrogen)
C) CH₄(methane)
D) H₂O (in vapor form)
E) NH₃(ammonia)

Question 39

According to Oparin and Haldane, the prebiotic soup accumulated because molecules were not ____.

A) broken down by oxygen attack or microbial decay
B) broken down by reduction reactions or fungal decay
C) broken down by oxygen attack or fungal decay
D) broken down by reduction reactions or microbial decay
E) recycled by environmental conditions

Question 40

Evidence for the endosymbiotic theory includes ____.

A) RNA in prokaryotes, mitochondria, and chloroplasts arranged in a single, circular genome
B) endocytosed cells observed to survive in the cytoplasm of the host cell
C) endocytosed organelles observed to survive free in the environment
D) fossils of prokaryotic cells in the process of endocytosing cyanobacteria
E) rRNA sequences that are unique to prokaryotes, mitochondria, and chloroplasts

Question 41

DNA is favored as the storage molecule of genetic information because it ____ than RNA.

A) has more nucleotides
B) has greater chemical stability
C) can assemble into longer coding sequences
D) has more nucleotides and greater chemical stability
E) has greater chemical stability and can assemble into longer coding sequences

Question 42

What is an argument against the theory that RNA was the first polymer of life?

A) Only limited replication of proteins is possible.
B) The transfer of information from RNA to DNA under early conditions is difficult.
C) The early nucleotides could not form a polymer.
D) RNA cannot transfer genetic information to xeno-nucleic acids.
E) The synthesis of RNA nucleotides under early conditions is difficult.

Question 43

Volcanic activity on early Earth was responsible for the release of ____.

A) gases for the early atmosphere
B) oxygen for photosynthesis
C) water vapor necessary to form the first oceans
D) gases for the early atmosphere and oxygen for photosynthesis
E) gases for the early atmosphere and water vapor necessary to form the first oceans

Question 44

One criticism of the Miller-Urey experiment among scientists is it ____.

A) was based on an oxidizing environment
B) was likely contaminated with modern atmosphere
C) added too much energy
D) was based on a reducing environment
E) did not add the proper starting components

Question 45

One function provided by cell membranes is ____.

A) the free passage of materials into and out of the cell
B) the exclusion of nucleic acids
C) structural integrity
D) protection from parasitic genetic information
E) to counteract size restrictions

Question 46

What is a criticism of the hydrothermal vent origin of life theory?

A) Hydrothermal vents are too hot and would have destroyed the organic molecules even as they formed.
B) Hydrothermal vents are too salty and would have destroyed the organic molecules even as they formed.
C) Hydrothermal vents are unstable in general and would have dissipated the organic molecules.
D) Hydrothermal vents lack sufficient oxygen for the evolution of aerobic organisms.
E) Hydrothermal vents contain too many dissolved mineral ions.

Question 47

The ____ provides evidence that RNA molecules generated the first proteins.

A) redundancy of the genetic code
B) ability of rRNA to catalyze the formation of peptide bonds between amino acids
C) polymerase activity of some ribozymes
D) cleavage of mRNA molecules by rRNA
E) physical structure of polypeptides

Question 48

The continuously sparking electrodes in the apparatus used in the Miller-Urey experiment simulated ____.

A) solar energy
B) lightning strikes
C) volcanic eruptions
D) radioactivity
E) hydrothermal vents

Question 49

Evolutionarily, Archaea likely arose ____ Bacteria.

A) as a direct result of
B) concurrently
C)   before
D) after
E) distinct from

Question 50

The final step in the development of eukaryotic cells was likely ____.

A) duplication of function in the endosymbiont and host cell
B) transfer of genes and function from the endosymbiont to the host cell
C) circularization of DNA
D) formation of membrane-bound organelles
E) ingestion of photosynthetic bacteria

Question 51

The earliest photosynthesizers likely used ____ as electron donors.

A) chloride gas
B) hydrogen peroxide
C) hydrogen sulfide
D) magnesium sulfide
E) ammonia

Question 52

Cells with ____ are able to harvest the greatest amount of energy from electrons.

A) double membranes
B) photosystems
C) cytochromes
D) chloroplasts
E) nuclei

Question 53

Experimental studies have produced ribozymes that ____.

A) reverse transcribe DNA from an RNA template
B) polymerize new RNA from an RNA template
C) cleave cellular membranes
D) produce completely new RNA strands
E) polymerize new proteins from an RNA template

Question 54

Fatty acids and ribozymes are incompatible as early molecules of life because ____.

A) they have different pH requirements
B) they most likely developed millions of years apart
C) fatty acid vesicles are impermeable to ribozymes bound to ferrous oxide
D) magnesium is required for ribozyme function but causes fatty acids to precipitate
E) magnesium is required for fatty acids to form vesicles but causes ribozymes to precipitate

Question 55

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A)   mitochondria, plastids, and bacteria have cell walls of the same composition
B) mitochondria and plastids are similar in size to bacteria
C) mitochondria and plastids are similar in structure to archaea
D) plastids can live free of a eukaryotic cell
E) mitochondria and cyanobacteria process energy similarly

Question 56

Around 150 living genera of animals provide direct support of the endosymbiont theory by ____.

A) hosting Archaea in their cells
B) having bacterial ribosomes in their cells
C) using the cell membrane to protect against bacterial invaders
D) ejecting cyanobacterial invaders
E) hosting eukaryotic algae or cyanobacteria in their cells

Question 57

The leading candidate for the molecular replicator during the origin of cells is ____.

A) pyranose
B) xeno-nucleic acids
C) protein
D) RNA
E) DNA

Question 58

The most basic essence of life is ____.

A) reproduction of a keystone species
B) reproduction of genetic information
C) reproduction of cells
D) photosynthesis
E) redox reactions

Question 59

Evidence for the possible evolution of information storage from RNA to DNA is the fact that ____.

A) they use the same nucleotides
B) some modern viruses synthesize DNA from an RNA template
C) bacteria use RNA as a genetic information storage molecule
D) RNA is a simpler molecule than DNA
E) RNA and DNA will form complementary pairs

Question 60

Which feature of Archaea is shared with Eukarya but not with Bacteria?

A) the sequestration of DNA into a nucleus
B) the common occurrence of introns
C) the chemical structure of the cell walls
D) the plasma membrane structure
E) a genome comprised of a single, circular molecule of DNA

Question 61

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A) 0.5
B) 1
C) 1.7
D) 2
E) 3.7

Question 63

Most scientists believe that prokaryotes evolved from eukaryotes .

Question 64

Life today derives nearly all its energy from ____.

A) glucose molecules
B) the sun
C) hydrothermal vents
D) geochemical activity
E) radioactive decay

Question 65

The earliest evidence of biochemical reactions by living cells dates to about ____ billion years ago.

A) 0.5
B) 1
C) 1.5
D) 2
E) 3.7

Question 66

Which line of evidence supports the protein-first hypothesis?

A) Amino acids existed on prebiotic Earth and in meteorites.
B) Proteins display more chemical diversity than nucleic acids.
C) Proteins display more structural diversity than nucleic acids.
D) Protein function can be reproduced in a population.
E) Nucleic acids are too simple to have been the first "polymers of life."

Question 67

Scientists agree that life originated on Earth .

Question 68

Stromatolites are fossils of ancient, photosynthetic cyanobacteria .

Question 69

Protocells likely grew within microscopic compartments in porous alkaline vent chimneys, where ____.

A) protocells could use the energy provided by H⁺gradients
B) the vents offered physical protection
C) protocells could use readily available ammonia sources
D) the vents funneled geothermal warmth
E) the vents were the right size

Question 70

The first truly living cells must have been prokaryotic in structure .

Question 71

Many of the eukaryotic genes for information processing came from ____.

A) an archaeal ancestor
B) horizontal gene transfer from a chloroplast
C) horizontal gene transfer from a mitochondrion
D) horizontal gene transfer from a prokaryote
E) horizontal gene transfer from a bacterium

Question 72

The RNA molecules of an RNA world on early Earth may have been composed of bases other than A, U, G, and C because ____.

A) DNA does not use all four bases
B) these nucleotides will not form a double helix
C) these nucleotides cannot be created in a Miller-Urey like experiment
D) G is somewhat unstable in water
E) C is somewhat unstable in water

Question 73

The nonequilibrium created by ____ represents a renewing source of energy.

A) temperature gradients
B) acidic ocean vents
C) alkaline ocean vents
D) radioactive decay
E) protocell formation

Question 74

Phylogenetic systems based on morphology cannot reveal the relationships between different kingdoms .

Question 75

Carl Woese and George Fox derived the three-domain system based on ____.

A) comparing shared morphological characters
B) determining the activities of molecular replicators
C) comparing sequences of ribosomal RNA (rRNA) genes
D) analyzing membrane lipid composition
E) searching for introns in the genomes

Question 76

If life evolved in hydrothermal vents, is it likely the first cells were in the Domain Archaea?

Question 77

Early life most likely evolved where ____ was plentiful.

A) lightning
B) solar energy
C) hydrothermal vents
D) geochemical activity
E) radioactive decay

Question 78

Archaea genomes contain introns .

Question 79

Proteins may have been the first information-storage molecules because they can self-replicate as well as catalyze reactions .

Question 80

Mitochondria probably developed before the atmosphere was oxygen rich .