Deck 15: Life on Other Worlds

Question 1

All know forms of life on Earth use _______ as a medium for chemical reactions.

A) gaseous helium
B) frozen carbon dioxide
C) liquid water
D) frozen water

Answer 1

liquid water

Question 2

An offspring born with altered DNA due to radioactivity, cosmic rays, or errors in reproduction

A) is called a mutant.
B) is called a new species.
C) is more likely to survive than if its DNA were not altered.
D) is no different than if its DNA were unchanged.
E) will never be able to reproduce itself.

Answer 2

is called a mutant.

Question 3

Current searches for extraterrestrial intelligence use radio telescopes at wavelengths

A) which must be shorter than the local wavelengths emitted by Earth s atmosphere
B) which must be longer than the radio wavelength noise naturally emitted by our galaxy
C) Both conditions a and b above must be fulfilled.
D) Wrong! Visual light wavelengths are used because they are blocked by dust between the stars.

Answer 3

Both conditions a and b above must be fulfilled.

Question 4

The number of technological civilizations in our galaxy is limited by

A) the number of stars in our galaxy
B) the fraction of stars with planets
C) the number of planets per star in habitable zone longer than a few billion years
D) the fraction of suitable planet where technical life forms evolve.
E) All of the above.

Question 5

The most likely region of the radio spectrum for communication with other civilizations is the water hole, the part of the spectrum

A) near the radio emission of water.
B) near the radio emission of oxygen molecules.
C) between the radio emission of hydrogen and oxygen.
D) between the radio emissions of hydrogen and OH.
E) near the radio band where water in the Earth s atmosphere strongly absorbs energy.

Question 6

The habitable zone is

A) the region on a planet where conditions are acceptable for life to exist.
B) a region around a star where a planet s temperature would permit the existence of liquid water.
C) very small for a massive star.
D) only found around G and K stars.
E) a region on a young planet where amino acids can begin to form DNA molecules.

Question 7

ALH 84001

A) is a meteorite that shows evidence for life evolving on Mars.
B) is the compound used by Miller to begin his experiment to produce amino acids.
C) is the amino acid produced in the Miller experiment.
D) is the molecule that controls the reproduction of DNA within a cell
E) is the molecule that acts as DNAs messenger that assembles proteins from amino acids.

Question 8

The first complex life appeared on Earth about 0.5 billion years ago during the

A) Jurassic Period.
B) Mississippian Period.
C) Cambrian Period.
D) Precambrian Period.
E) Neolithic Period.

Question 9

Why are massive main sequence stars not likely to have planets that contain life?

A) The life zones around these stars is too small.
B) These stars would sweep away all of the material from which planets could form.
C) These stars are too hot to allow water to exist as a liquid on any planets that might form.
D) These stars are on the main sequence for too short a time to allow life to evolve.
E) These stars are almost always binaries and planetary orbits are unstable around binaries.

Question 10

A cell s DNA molecules are constructed of

A) amino acids.
B) proteins.
C) sugars, phosphates, and bases.
D) all of the above
E) none of the above

Question 11

What limitation(s) make it impossible to travel between stars?
I. Fuel requirements
II. The tremendous distances between stars
III. The finite speed at which objects can travel

A) I
B) II
C) III
D) II III
E) I, II, III

Question 12

____ is the molecule in the cell nucleus that stores the information to make specific proteins out in the cell body.

A) An enzyme
B) DNA
C) RNA
D) ALH84001
E) PAH

Question 13

The best places for life to have formed on Earth are believed to have been

A) near the south pole on the ice.
B) on the continent of Africa in the areas with no water.
C) in liquid water, probably in the oceans or pools of water.

Question 14

DNA molecules contain patterns for the production of

A) proteins.
B) amino acids.
C) phosphates and sugars.
D) four kinds of bases.
E) all of the above

Question 15

Why is it believed that life can not evolve on a planet that orbits a spectral type A, B or O star?

A) These stars produce too much infrared radiation which would destroy carbon-based organisms.
B) These stars have very small life zones.
C) These stars are not capable of producing planets.
D) These stars do not remain on the main sequence long enough for life to evolve.
E) These stars take too long to form.

Question 16

The DNA molecule can be altered

A) by chance mismatching of base pairs.
B) by damage from exposure to radioactivity.
C) if the host cell is intelligent and determines that an alteration would help the cell survive.
D) all of the above
E) a and b above

Question 17

____ is the molecule that carries information from the cell nucleus out into the cell where specific proteins are made from the information.

A) An enzyme
B) DNA
C) RNA
D) ALH84001
E) PAH

Question 18

Presuming that it takes several billion years of complex live to evolve in a stable environment, the stars most likely to currently have inhabited planets are

A) G to K main sequence stars.
B) B to A main sequence stars.
C) G to K giants.
D) white dwarf stars
E) neutron stars.

Question 19

The Miller experiment created

A) life.
B) artificial proteins.
C) DNA.
D) simple molds.
E) amino acids.

Question 20

DNA is important to a cell because

A) DNA is the cell membrane that allows nutrients to enter the cell and waste to leave.
B) DNA contains the information necessary to make all of the molecules required by the organism.
C) DNA contains the information necessary for the cell to reproduce itself.
D) all of the above
E) b and c above

Question 21

The Miller experiment created synthetic DNA.

Question 22

The Viking landers searched for life on ____________________.

Question 23

The DNA molecules contain six different bases.

Question 24

When considering the number of technologically advanced civilizations in our Galaxy, it is useful to consider

A) the average life span of an alien.
B) the average life span of the civilization.
C) the distance to the civilization s planet.
D) the type of advanced communication they use.

Question 25

DNA molecules cannot be altered by chance errors in reproduction.

Question 26

The portion of the electromagnetic spectrum between the 21 cm line of neutral hydrogen and the 18 cm line of OH is known as the ____________________.

Question 27

A single human cell encloses about 1.5 meters of DNA containing 4.5 billion base pairs. How far apart are these base pairs in the DNA?

A) 3.3*10^-10nm
B) 3.3*10¹⁰nm
C) 3*10⁹ nm
D) 300 nm
E) 0.34 nm

Question 28

The oldest easily identifiable fossils appear in sedimentary rocks that formed 3.4 billion years ago during the ____________________ period.

Question 29

The most important quantity necessary for life to form appears to be the existence of ____________________ on the surface of the planet.

Question 30

____ shows that the building blocks of life form naturally under a wide range of circumstances.

A) The Miller experiment
B) The Chicxulub event
C) The earliest fossils
D) The Drake equation
E) Stromatolites

Question 31

The oldest fossils on Earth

A) show that life began in Africa.
B) show that life began in lush regions between large rivers.
C) show that life began in the oceans.
D) are at least 5 billion years old.
E) at most 5 million years old.

Question 32

The ____________________ is a region around a star where liquid water can exist.

Question 33

Chemical evolution concentrated the various smaller molecules into the more stable forms.

Question 34

____ is a segment of a chromosome that controls a specific function.

A) DNA
B) RNA
C) An enzyme
D) A gene
E) An amino acid

Question 35

All life on Earth is based on carbon chemistry.

Question 36

The Miller experiment succeeded in creating ____________________.

Question 37

Deoxyribonucleic acid is better known as

A) vitamin D.
B) reproductive enzymes.
C) RNA
D) DNA
E) vitamin B12

Question 38

What is important about the habitable zone around a star that makes astronomers believe life could exist there?

A) The level of UV radiation from the star is minimal there.
B) Only in the life zone can complex organic molecules be found.
C) Planets in the life zone will always have oxygen atmospheres.
D) In the life zone water can exist as a liquid.

Question 39

DNA is coiled into a tight spiral and makes up the ____ that are the genetic material in a cell.

A) genes
B) amino acids
C) enzymes
D) nucleus
E) chromosomes

Question 40

The oldest fossils on Earth are more than 3 billion years old.

Question 41

Describe three things that limit travel between stars.

Question 42

What did Butler mean when he said, The chicken is the egg s way of making another egg ?

Question 43

What is ALH84001 and why is it significant to discussions of the evolution of life?

Question 44

What kind of information is stored in the DNA molecules?

Question 45

What is the significance of the Miller experiment?

Question 46

Why must the information in a species DNA be changeable?

Question 47

How can we select stars whose planets are likely homes for life?

Question 48

How does the likelihood of the survival of technological societies restrict the number of civilizations with which we might communicate?

Question 49

What are the three properties of living things that the chapter identifies?

Question 50

What part of the radio spectrum is thought most likely to be successful for communication with other civilizations? Why?

Question 51

What is the difference between chemical evolution and biological evolution?

Question 52

The Viking spacecraft searched for life on Mars by looking for the effects of life on the upper atmosphere.

Question 53

If life is to develop on a planet, the planet must lie well inside the inner edge of its star s habitable zone.

Question 54

The wavelengths that are most likely for communication with other civilizations are those in the water hole.

Question 55

Even if societies on stars in distant galaxies survive at a technological level for only 10 years, that is long enough to establish two-way communication with them.