Deck 18: Lifes Origin and Early Evolution

Question 1

What step occurred first in the evolution of life?

A)formation of lipid spheres
B)formation of protein-RNA systems
C)formation of membrane-bound protocells
D)self-assembly of organic monomers
E)formation of ATP

Answer 1

D

Question 2

Earth bacteria are unable to withstand high temperatures and pressure.

Answer 2

True

Question 3

​A protocell is capable of self-replication.

Answer 3

True

Question 4

​The Precambrian began with an Earth that was too hot for life and had no oxygen during the ____ eon.

A)​Archaean
B)​Hadean
C)​Proterozoic
D)​Phanerozoic
E)​Cambrian

Question 5

The prevalence of iron-sulfide cofactors in organisms supports the hypothesis that life arose _____.

A)in outer space
B)on tidal flats
C)near geothermal vents
D)in the upper atmosphere
E)in volcanic springs

Question 6

Astrobiologists study Earth's ____ to find clues about possible extraterrestrial life.​

A)​oceans
B)​mountain tops
C)​average conditions
D)​extreme habitats
E)​hydrothermal vents

Question 7

The earliest species known to reproduce sexually was a(n) ____.

A)archaeabacterium
B)cyanobacterium
C)fungus
D)green alga
E)red alga

Question 8

The first organisms were most probably ____.

A)eukaryotic
B)multicellular
C)protozoans
D)prokaryotic
E)algae

Question 9

Protein synthesis on the primordial Earth may have been catalyzed by ____ before the evolution of enzymes.

A)DNA
B)carbohydrates
C)amino acids
D)RNA
E)lightning

Question 10

What may have been a site for the synthesis of organic molecules on the early Earth with its source of hot water and metal ions from rocks?

A)stratified mica crystals
B)deep sea hydrothermal vents
C)the bottoms of tidal pools
D)dried-out mud flats
E)pockets in lava beds

Question 11

The first major split in evolution separated ____.

A)Archaea from bacteria and eukaryote ancestors
B)Bacteria from Archaea and eukaryote ancestors
C)eukaryote ancestors from Archaea and Bacteria
D)Archaea, Bacteria, and Eukarya lineages from each other
E)Bacteria and Archaea

Question 12

Which organism arose first?

A)archaea
B)animals
C)fungi
D)plants
E)protists

Question 13

​Mitochondria were incorporated into eukaryotes after chloroplasts.

Question 14

Four of the five features below are exclusive to the domain Eukarya. Select the exception.

A)linear chromosomes
B)nucleus
C)mitochondria
D)chloroplasts
E)cell wall

Question 15

Metabolism may have begun when ____ within rocks donated electrons to dissolved carbon monoxide (CO), forming organic compounds.

A)oxygen
B)iron sulfide
C)carbon dioxide
D)hydrogen gas
E)ammonia

Question 16

What compound served to contain interacting organic molecules within a protocell?

A)lipids
B)single amino acids
C)amino acid polymers
D)RNA
E)DNA

Question 17

The first O₂ producing organisms were probably ____.

A)Archaea
B)cyanobacteria
C)green alga
D)red alga
E)plants

Question 18

The first fossilized eukaryotes date to about how many years ago?

A)3.8 billion
B)1.8 billion
C)2.1 billion
D)1 million
E)6,000

Question 19

​Cyanobacteria are ultimately responsible for the ozone layer.

Question 20

Four of the five answers represent likely mechanisms contributing to how life's first building blocks formed. Select the exception.

A)lightning-fueled atmospheric reactions
B)delivery from ancient volcanoes
C)reactions at hydrothermal vents
D)delivery from outer space
E)spontaneous combustion

Question 21

While it is very difficult to find fossils of the earliest cells, there are some probable early cell characteristics. Four of the five answers represent possible traits that the first cells may have had. Select the exception.

A)prokaryotic
B)autotroph
C)aerobic
D)anaerobic
E)heterotroph

Question 22

Chloroplasts ____.

A)evolved from cyanobacteria
B)have been found as symbionts inside mitochondria
C)evolved from photosynthetic eukaryotes
D)have membrane bound nuclei containing DNA
E)are the sites of aerobic respiration

Question 23

Oxygen released by ____ accumulated in early Earth's atmosphere and produced the ozone layer.

A)archaeans
B)aerobic bacteria
C)cyanobacteria
D)early eukaryotes
E)protocells

Question 24

By one hypothesis, clay ____.

A)facilitated assembly of early organic polymers by concentrating monomers through its negative charge
B)was present at hydrothermal vents
C)provided energy for early metabolism
D)has a positive charge and repelled organic monomers
E)helped physically form the plasma membrane of protocells

Question 25

The primitive Earth's atmosphere contained very little to no ____.

A)water vapor
B)free nitrogen
C)free hydrogen
D)free oxygen
E)inert gases

Question 26

Four of the five answers below were organic compounds included in the Miller and Urey experiment designed to study the early synthesis of organic compounds. Select the exception.

A)methane
B)ammonia
C)water
D)oxygen
E)hydrogen

Question 27

Life probably never would have emerged if the ancient atmosphere had been the same as the present one, because ____ interferes with the assembly of simple organic compounds.

A)carbon dioxide
B)hydrogen
C)oxygen
D)nitrogen
E)silica

Question 28

What has been detected in meteorites that have fallen to Earth?

A)organic polymers
B)evidence of cells with a nucleus
C)organic compounds
D)fossilized proto-cells
E)oxygen molecules

Question 29

Experiments like those first performed by Miller and Urey demonstrated that ____.

A)DNA forms readily and reproduces itself
B)amino acids and other organic compounds could form in conditions that mimicked the earth's early atmosphere
C)complete, functioning prokaryotic cells are formed after approximately three months
D)a lipid-protein film will eventually be formed by thermal convection
E)meteorites contained organic compounds

Question 30

Before DNA, ____ likely served as the genetic material.

A)carbohydrate
B)lipid
C)protein
D)RNA
E)free nucleotides

Question 31

​Astrobiologists believe ____ is an essential component for life throughout our universe.

A)​carbon dioxide
B)​liquid water
C)​ozone
D)​gravity
E)​sunlight

Question 32

A rise in oxygen in Earth's air and seas put organisms that engaged in ____ at a selective advantage.

A)aerobic respiration
B)fermentation
C)photosynthesis
D)sexual reproduction
E)anaerobic respiration

Question 33

​The oldest multicellular eukaryote, a(n) ____, can be found in the Proterozoic fossil record.

A)​sponge
B)​cnidarian
C)​annelid
D)​cyanobacteria
E)​red alga

Question 34

Which process or element was present first?

A)aerobic respiration
B)chloroplasts
C)mitochondria
D)fungi
E)photosynthesis

Question 35

What structure may have acted as a boundary for a cell-like environment before protocells formed?

A)clay
B)acidic water from volcanic springs
C)chambers in rocks
D)lipid membrane
E)metal ions from rocks

Question 36

Mitochondria most resemble ____.

A)archaeans
B)aerobic bacteria
C)cyanobacteria
D)early eukaryotes
E)anaerobic bacteria

Question 37

Ribosomes can catalyze formation of peptide bonds. This supports the hypothesis that ____.

A)an RNA world preceded DNA-based genomes
B)RNA can hold more information than DNA
C)the first protists had RNA as their genetic material
D)RNA's only role is that of an enzyme
E)protocells contained DNA

Question 38

The metabolic reactions that occur in all cells require a certain molecule, also believed to be present very early on Earth. What is this molecule?

A)carbon
B)nitrogen
C)water
D)oxygen
E)hydrocarbon

Question 39

In simulations of tidal flat conditions, amino acids form short chains by binding to ____.

A)water molecules
B)clay particles
C)iron sulfide
D)rock chambers
E)hydrothermal vents

Question 40

Stromatolites were formed by ____.

A)animals
B)heterotrophic bacteria
C)photosynthetic bacteria
D)red alga
E)plants

Question 41

Once an endosymbiotic relationship was established between a bacteria and a eukaryotic cell, what effect did it have on their genomes?

A)The bacteria transferred all of its DNA to the eukaryotic nucleus.
B)The endosymbiotic relationship did not affect either cell's genome.
C)The bacteria lost its genome and relied solely on the eukaryotic cell.
D)Both genomes evolved so that eventually the host and the bacteria became incapable of living independently.
E)The eukaryotic genome lost some genes whose function could be supported by the bacteria but the bacterial genome did not change.

Question 42

There are several proposed mechanisms that could have produced organic monomers. What mechanism involves the formation of organic compounds in interstellar clouds?

A)hydrothermal vents
B)lightening fueled-atmospheric reactions
C)organic compounds arriving on Earth via meteorites
D)reactions involving hot water and metal ions from rocks
E)the aggregation of dust and rock bits that orbited the sun to form Earth

Question 43

Four of the five answers listed below are proposed steps leading to the first cells. Select the exception.

A)the concentration of organic subunits in one place
B)the formation of protocells
C)the formation of a cell wall
D)the start of metabolic reactions
E)the development of a genome

Question 44

Discoveries by ____ led other scientists to reconsider the possibility that life most likely arose near hydrothermal vents on the sea floor.

A)Orgel and Crick
B)Ballard
C)Miller and Urey
D)Watson and Crick
E)Starr

Question 45

Eukaryotic nuclei arose through ____.

A)cytoplasmic diffusion
B)formation of a new internal membrane by the eukaryotic cell
C)an endosymbiotic relationship with a bacteria
D)infoldings of the cell's plasma membrane
E)the uptake of the cell's genome by a membrane organelle already present in the cell

Question 46

Four of the five answers below are traits that are signatures of a eukaryotic cell fossil. Select the exception.

A)small cell wall diameter
B)complex patterns
C)large size
D)biomarker such as steroids
E)cell wall with spikes

Question 47

Who demonstrated the possibility of producing organic compounds from gases and water if the mixture is exposed to sparks from an electrode?

A)Miller and Urey
B)Ballard
C)Starr
D)Watson and Crick
E)Orgel and Crick

Question 48

Mitochondria arose from an endosymbiotic relationship between a eukaryotic cell and an aerobic bacterium. Which statement supports this theory?

A)Mitochondria can produce ATP outside of a eukaryotic cell.
B)A mitochondrion can survive indefinitely when removed from a eukaryotic cell.
C)A mitochondrion has its own DNA in the form of a single circular chromosome, like bacteria.
D)Fossilized mitochondria are older than the oldest fossilized eukaryotes.
E)A mitochondrion has only one outer membrane.

Question 49

All species on Earth today are descended from a cell that lived as early as ____ years ago.

A)570 million
B)1.4 billion
C)4 billion
D)more than 5 billion
E)more than 10 billion