Does ET Exist? Exam_02
Answers
------------------------------------------------------------------------------------------------------------
Answers:
01 – 10 CEBCC ADECD
11 – 20 AEAEA DCABA
21 – 30 CDEAB ECEBE
31 – 40 BACCE DAABC
41 – 50 DBEAC BCACE
51 – 60 BDBAE BDDBE
------------------------------------------------------------------------------------------------------------
1. In the
Miller-Urey experiment of 1953, the following chemical reaction occurred in
which _______ was produced when an electrical spark was passed through the
gasses thought to represent the Earth’s primitive atmosphere.
(a) DNA (b) sugar (c) an amino acid (d) RNA
(e) Frankenstein.
2. Indirect evidence that life originated on
Earth as early as 3.8 billion years ago is offered by rocks found in Greenland
that _______.
(a)
contain trilobite
fossils
(b)
contain
fossilized DNA
(c)
contain dried up
blood stains
(d)
were obviously
shaped by design rather than by some natural process
(e)
exhibit an
enhancement of the carbon-12 to carbon-13 ratio found in purely inorganic rock
3. RNA is a simpler molecule than DNA and like
DNA contains genetically coded information that cells use to manufacture
proteins. However, certain proteins are
needed to manufacture RNA. So we have a
classic “chicken and egg” paradox --- which came first --- the RNA that
contains the “code” to manufacture proteins --- or --- the proteins that
manufacture RNA? For several reasons
most scientists think that RNA came first.
One of these reasons is ____.
(a)
the RNA molecule
is much less complex than a protein
(b)
certain RNA
molecules can act as enzymes to facilitate chemical reactions. Thus, they might have helped produce a
protein that could assist in their own replication
(c)
RNA is commonly
found in meteorites that have landed on Earth
(d)
RNA is not a
polymer but proteins are
(e)
it was impossible
for proteins to manufacture RNA unless RNA already existed
4. The assembly of polymers like RNA or proteins from monomers probably required _____.
(a)
a grand designer
(b)
a blind
watchmaker
(c)
a template with a
repetitive structure like a clay surface
(d)
sulfuric acid
(e)
the high surface
gravity of a neutron star.
----------------------------------------------------------------------------------------------------------
5. The picture
above shows how two amino acids might stick to the surface of a clay grain and
then link together, giving off a molecule of water, to form a ____.
(a)
rain coat (b) fatty acid (c) polymer (d) Vietnamese clay pot (e) virus
----------------------------------------------------------------------------------------------------------------
6. The seminal process that led to a
self-replicating molecule _______.
(a)
might have
occurred near sub-oceanic volcanic vents concentrated with simple organic
molecules
(b)
must have started
on a comet somewhere deep in outer space
(c)
must have started
only after DNA evolved
(d)
could not
possibly have occurred on any planet anywhere in the galaxy other than Earth
(e)
must have started
inside the first primitive cells
7. The formation of the membrane that surrounded
the first primitive cell might have occurred spontaneously under the right
conditions because ________.
(a)
it's easy to make
drum heads out of animal skins
(b)
the froth in
stagnant ponds is composed of bubbles which are membranes
(c)
snotty mucous
balls form readily in warm, moist places … like noses
(d)
certain polymers,
like phospholipids, naturally form globules in water
(e)
none of the above
8. There are a number of critical steps that led to the emergence of complex life on Earth. We don’t understand the details of many of these steps but we are sure that they occurred. One of these steps was ____.
(a)
polymerization
--- or the assembly of simple organic molecules into long chains
(b)
the emergence of
a self-replicating molecule
(c)
the development
of the cell --- a structure surrounded by a protective membrane that contains
the “machinery” that carries out the chemical processes necessary for life
(d)
the start of
“sexual reproduction” in which an offspring acquires half of its genes from
each parent
(e)
… all of the
above
9. Assembling the organic molecules that make
up life on Earth requires ________.
(a)
a grand designer
(b)
sub-oceanic vents
(c)
a source of
energy to power the necessary chemical reactions
(d)
DNA to serve as a
guide for the assembly process
(e)
an oxygen-rich
atmosphere
10. A high concentration of iridium, rare in the
Earth’s crust, but more common in asteroids, was found in 1979 in the clay
layer that divides the cretaceous and tertiary periods. This discovery was evidence
that ______ was most likely triggered by asteroid impact.
(a)
the Barringer
crater in
(b)
the flattening of
trees in a 30 mile radius near the
(c)
massive deposits
of vaporized dinosaur dung in Vernal,
(d)
the K/T mass
extinction (which included the extinction of dinosaurs)
(e)
the hole in the
ozone layer
11. The ______ that formed on the primitive Earth
were (was) able to protect newly forming organic molecules from breakup by
harmful ultraviolet radiation from the Sun.
(a)
oceans
(b)
clouds
(c)
thick carbon dioxide
dominated atmosphere
(d)
sediment made of
dinosaur remains
(e)
large overlying
land masses that could move around by plate tectonics
12. _____
absorb carbon dioxide.
(a) Cyanobacteria (b) Plants
(c) Blue-green algae (d) Photosynthetic prokaryotes (e) All of these
13. Had it not been for the K/T mass extinction
_______.
(a)
you might not be
taking this exam today
(b)
rodents would
rule the world
(c)
dinosaurs would
have become intelligent enough to build radio telescopes
(d)
the Earth would
be completely covered with oceans and dolphins would be the dominant species
(e)
early Greek
society would have persisted and humans would by now have developed the
technology to build interstellar spaceships and travel to far away solar
systems
14. Organisms that live in the hydrothermal vents
of the deep sea, deep underground in cold basaltic rock, in sea ice, in
(a) parasites (b) eukaryotes (c) protozoa (d) pedophiles (e) extremophiles
15. Photosynthesis probably started ____.
(a)
with
cyanobacteria
(b)
in calcium
carbonate rocks
(c)
with XEROX Corp.
(d)
plants containing
chlorophyll
(e)
on Christmas eve
4000 B.C.E.
16. Suppose we discover an Earth-like planet
orbiting another star whose solar system formed 2 billion years ago, rather
than 4.6 billion years ago when our solar system formed. It is likely that we would find it also inhabited
by many types of land animals, birds, insects, fishes, etc., (assuming we have
the technological capability of finding such life) because _____.
(a)
complex life was
created in the first few minutes of the Big Bang and distributed all around the
universe. It would take root on any Earth-like planet that emerged anywhere
(b)
production of complex life is the ultimate goal
of evolution
(c)
the principle
of mediocrity implies that if complex life exists on Earth then it will
most likely exist on all other Earth-like planets
(d)
the planet would
likely be inhospitable for about 0.5 billion years and the principle of
mediocrity implies that it probably takes longer than 1.5 billion years to
build up complex life from simple life, so it is unlikely.
(e)
there's no reason
to believe that this planet suffered early comet and asteroid bombardment like
ours did and thus life could have developed even more quickly there than it did
here
17. An ET that emerged in a solar system like
ours might go extinct before living beyond the stage of operational intelligence
longer than 1 - 100 million years most likely because _______.
(a)
its Sun might
explode as a supernova
(b)
it might get
wiped out in an attack by hostile aliens
(c)
it might undergo
global catastrophe initiated by impact of a large (>10 km) comet or asteroid
(d)
its Sun might
turn into a white dwarf
(e)
its home planet
might get swallowed up by a black hole
18. _____ could have seeded the primitive Earth
with simple organic molecules that could have helped start the emergence of
life on Earth.
(a)
Comet bombardment
(b)
Intelligent
aliens
(c)
Adam and Eve
(d)
Johnny Appleseed
(e)
Particles in the
solar wind
-------------------------------------------------------------------------------------------------------------------
The sequence of bases ...
CTAGCTTTCATT ... etc. on one strand of DNA codes for the sequence of amino
acids ... leucine, alanine, phenylalanine, ... etc.
19. The genetic code for alanine is _____
(a)
CTA (b) GCT
(c) TTC (d) ATT (e) RATTATTAT
20. The corresponding sequence of bases on the matching DNA
strand is ________
(a)
... GATCGAAAGTAA
...
(b)
... CTAGCTTTCATT
...
(c)
... TTACTTTCGATC
...
(d)
... CUAGCUUUCAUU
...
(e)
... GCTCTAATTTTC
...
-------------------------------------------------------------------------------------------------------------------
21. Which of the following characteristics most
help planetary oceans remain liquid for a long time even when exposed to
sustained, freezing temperatures ____.
(a)
It is a liquid in
the temperature range 195 K to 240 K
(b)
It is cheaper
than ethyl alcohol
(c)
It expands when
it freezes