Test 2 Flashcards
Mars experiences similar seasonal changes to those on earth because
It’s spin axis is tilted at about the same angle to it’s orbital plane as is the earths axis
The search for life in the solar system is essentially the search for
Liquid water
Where on earth have subglacial lakes been searched for life?
The Antarctic
If our sun had been a hotter star, how might the eyes of living organisms on earth have been different?
They would have evolved to see shorter wavelengths
Which NASA mission landed high in the Martian Arctic?
Phoenix
Other than hydrogen and helium, the major components of the atmosphere of Jupiter and Saturn have been found to be
CH4 (methane), NH3 (ammonia) and H20 (water)
Some scientists have suggested that life may have started on Mars first and then been transported to the earth by Martian meteorites. Which if the main theories for the origin of life on earth does this correspond to?
Lithopanspermia
Water exists on Mars. Where and in what state does it NOT exist on this planet m?
As liquid, flowing in river valleys
Humanoid life evolving on a planet similar to the earth, but which was more massive would probably be
Shorter
A chlorine (CI) atom with seven electrons in it’s outer shell (out if a full shell of right) will most likely tract with a metallic element by…
Gaining one electron
Which physical characteristic of methanol is superior even to water?
It exists as a liquid over a wider temperature range
What is the MOST important role that proteins play in living organisms on the earth?
Basic functioning of living organisms
Silicon forms it’s strongest chemical bonds with
Oxygen
Which of the following is probably the LEAST important characteristic of all living things?
Movement
Which of the following types of extremeophile thrives in high temperatures?
Thermophiles
The lakes on Titan are believed to contain mostly
Methane
How many electrons are shared between carbon atoms in a single bond?
6
Modern laboratory experiments, which repeated those of Urey and Miller in exploring the possibility of producing organic molecules (the building blocks of life) from mixtures of gases expected to exist in the atmosphere of early earth, passed electrical discharges through which mixture of gases?
Nitrogen, hydrogen, water vapor, carbon dioxide
The strong intermolecular forces between water molecules which give it it’s characteristic surface tension are due to
It’s strong polarity
Water ice can be found on the surfaces of which terrestrial bodes?
Mars, mercury, the moon
The secondary (2*) structure of a protein is
A sheet or helix
The mechanism of the greenhouse effect, which has resulted in very high temperatures on the surface of venus (and moderate temperatures on earth), can be described as
Solar UV and visible radiation heating the planet surface, the infrared emissions if which are then trapped by CO2 in the atmosphere
Which is the MOST important property of the element carbon that makes it ideal as a fundamental building block if biological molecules?
It readily forms chemical bonds with itself and other elements allowing a wide variety of complex molecules to form
Water molecules are attracted to each other with
Hydrogen bonds
Most of the mass of the human body is made of
Oxygen
Which liquid could most likely replace water as a biological solvent?
Ammonia
According to the current scientific evidence, what is the likelihood that life on earth originated due to the action of some omnipotent being?
Very unlikely but not impossible
Which of the following types of molecules does carbon form?
Chains, molecules with multiple bonds, rings
The Viking labeled-release experiment, which was used to look for life on Mars was based on the idea that
In metabolism, organisms consume nutrients from the soil and produce gases as a byproduct
The theory that seems to account most satisfactorily for the origin of the Moon at the present time is that
A large object collided with earth and ejected the material that formed the moon.
The youngest parts of the surface of mars come from which geological era?
The Amazonian
What is the electromagnetic structure of a lithium (Li) atom with an atomic number, Z of 3?
2 electrons in the n=1 shell and 1 electron on the n=2 shell
What is the major constituent of the atmosphere of Mars?
Co2 (carbon dioxide)
Most of the alternative biological solvents of water are liquids at much lower temperatures. Why is this a disadvantage for life?
Biological reactions would proceed much more slowly
What is the messenger-RNA sequence corresponding to the gene AGCCTG?
UCGGAC
Early on in it’s history, the earth is believed to have had a lot of carbon dioxide in it’s atmosphere. What happened to this carbon dioxide?
It dissolved in the oceans
Which of the following was probably NOT a source of organic molecules, the “building blocks” of life, in the early earth?
Volcanic eruptions
Jupiter’s satellite Europa is believe to be made of…
A large rocky core covered with an “ocean” of ice
The gas that is the major constituent of the atmospheres of venus and mars and a minor constituent of earths atmosphere is
Co2 (carbon dioxide)
On the surface of which planet or moon in out planetary system have experiments been carried out to search for life-forms of evidence of life,
Mars
What is the complimentary sequence corresponding to the DNA fragment GATACA
CTATGT
Why might we think that silicon would be an obvious alternative to carbon as a building block for biological molecules?
It has the same number of outer electrons as carbon and hence should have similar chemistry
Human brigs belong to which domain of life?
Eukaryota
Most of the mass if the human body is made of
Oxygen
The Cretaceous period ended 65 million years ago with the….
Disappearance of the dinosaurs
The atmosphere of mercury…
Is nonexistent
What important role does water play in life on earth?
It acts as a reaction medium
The primary (1*) structure of DNA is
The sequence of nucleic acids
The first self-replicating molecules used by life was probably
RNA
The basic molecular building blocks of carbohydrates are
Saccharides
