Version 2.0, 2012 Apr 11
Astrobiology Exam #2 Study Guide
Exam Date: Friday April 13

Bring a clean, uncrumped ParSCORE Student Enrollment form (the larger 6"x11"pink form), some #2 pencils & an eraser. This is a "closed-book exam". No ipads/smart phones/etc allowed; slide rules and simple calculators are ok. Exam will consist of 50 multiple choice questions.
** Fill out your name and Red ID on the ParSCORE form before the exam starts. Be sure to put your Red ID on both sides of the form. Also, fill in the bubble for "Test Form A" and "Exam #002". Don't bother with the phone number or code.
** Be sure to fill out your ParSCORE form correctly! You will lose points on your exam for errors on the scantron form (1 point per error). Common errors include:
. putting an extra zero in front of your Red ID
. filling in wrong bubble on your Red ID
. Red ID is too faint
. filling in two answers because your writing was sloppy
. not erasing an answer fully

This exam covers all material discusssed and assigned since Exam #1:
+ Lectures
+ Examination of the NEO and SpaceWeather.com webpages.
+ Lecture notes
+ Reading assignments in the Textbook
+ Reading assignments in the Course Reader
+ Reading assignments on Web pages
+ Written homework assignments
++ Wien's Law
The exam will focus on material since the first midterm, but of course certain concepts will carry over (Wien's law, habitable zones, spectroscopy, speed of light, temperature, AU, stellar evolution, Doppler effect, stellar evolution and the origin of elements, etc.).

The follow chapters in the textbook are the most important for this exam:
Ch 4; Ch 5; Ch 6; Ch 7; parts of Ch 10; parts of Ch 11

In the Course Reader, the following are important for this exam:
The Search for Extraterrestrial Life (C. Sagan)
Terrestrial Evolution (by N. Evans)
The Origin of Life on the Earth (L. Orgel)
and some aspects of the Periodic Table and Geologic Time Scale
The class lectures should be your primary source of information.
The on-line notes are very helpful, but are incomplete. The textbook material is very important. Make sure you have done *all* the homework, including the homework that you don't have to turn in: textbook, Class Reader, and the web page reading assignments. Note: Neal Evans' article is particularly important.
Be sure to know:
- "Key Biological Definitions" on page 154
- most of the "Key Geological Definitions" (the ones we discussed in class) on page 117
Here is a list of some material that you will NOT be responsible for knowing for this midterm exam:
- Skip all of the "Movie Madness" sections
- You do not need to know any molecular structures. For example, you will not be asked to know the molecular difference between adenine and guanine. You do need to know what these molecules do though!
- You do not need to know the location of the elements in the periodic table, or their chemical bonding properties, except for carbon.
- You don't need to know the names of specific bacteria species [such as Streptococcus mitis (the bacteria that survived on the Moon) or Helicobacter pylori (the ulcer-causing bacteria that dwells in the stomachs of half of the people on Earth), or Thiomargarita namibiensis ("the sulfur pearl of Namibia"), with the exception of that particular bacteria that can withstand huge doses of radiation....
- Do not confuse specific species with the types of extremophiles; you should know the different types (classes) of extremophiles e.g. thermophilic, halophilic, etc..
- You do not need to know about Darwin's finches (Fig 5.2)
- You will not need to know the values of any physical constants except the speed of light "c" AND Wien's law constant.
- You will not need to know exactly how many meters are in a parsec or how many meters in an AU, or how many meters in a light year. But you need to know the definition of an AU, light year, parsec (the definition, not the actual numbers!), meaning of moon, star, galaxy, isotope, principles of spectroscopy, Doppler effect, themonuclear fusion, Wien's law, etc..
- You don't need to know anything from the following web pages for this exam (but you MOST CERTAINLY WILL for the final exam!):
. . NASA/JPL Mars Exploration Program
. . Mars Exploration Rover Mission (MER)
. . Mars Reconnaissance Orbiter
. . Mars Science Laboratory
. . "Google Mars"
. . NASA+ESA Cassini/Huygens websites.

- You do NOT need to memorize the genetic code! If this information is needed, I will put a copy of the table in the exam itself.
__________________________________________________________________________

Some typical exam questions:
For homework you read Astrobiology Magazine's important news story about the possible discovery of life using arsenic: "Life Built on Arsenic". What vital CHONPS element is the arsenic replacing?
A) carbon
B) hydrogen
C) oxygen
D) nitrogen
E) phosphorus
S) sulfur


For homework you read NASA's Near Earth Object webpage and on that webpage there is a section called "How Many Near-Earth Objects Have Been Discovered So Far?" As of spring 2012, ROUGHLY how many NEOs are known?
A) ~ dozen
B) ~ 80
C) ~ 600
D) ~ 8000
E) ~ 300,000
F) roughly 2.2-2.7 million

On the spaceweather.com website, you can find information about:
A) daily updated image of the sun and sunspot count
B) current aurora
C) predictions of aurora
D) forecasts of space weather
E) the current list of near-miss asteroid encounters
F) all of the above

According to NASA's Near Earth Object website, what is a "PHA"?
A) Possible Habitable Asteroid
B) Probability-High Asteroid
C) Potentially Harmful Apollo
D) Positive Hazard Assessment
E) Potentially Hazardous Asteroid
F) Polarization-Handed Amino

In his Scientific American article, Carl Sagan discusses an important biomarker signature of life, detected by the Galileo spacecraft. Which of the following is a indicator of life?
A) the presence of water vapor in the atmosphere
B) the presence of molecular oxygen in the atmosphere
C) the presence of tholins in the atmosphere
D) the presence of carbon dioxide in the atmosphere
E) the presence of nitrogen in the atmosphere

A web site reports the discovery of "a 4.378119104 billion year-old fossil of a bacterium." You are highly skeptical. Why?
A) This is older than the Earth.
B) Dating of rocks is nowhere near that precise.
C) Rocks that old are practically non-existent on Earth due to crust recycling by plate tectonics (subduction).
D) choices B) and C)
E) choices A), B), and C)

How many different types of nitrogenous bases (or nucleotides) are used in DNA? How many of these bases are in a single codon (the fundamental unit of the genetic code)?
A) 2; 2
B) 4; 2
C) 4; 3
D) 20; 3
E) 20; 4

Amino acids are the chemical building blocks (monomers) of what type of molecule?
A) cellulose, starch, and/or glycogen
B) nucleotides
C) DNA and RNA
D) proteins
E) ATP

Which of the following is true about the isotope carbon-13?
A) It has 13 protons in its nucleus.
B) It is radioactive and has a half-life of about 5730 years.
C) It is formed by collisions between cosmic rays and gases in the Earth's atmosphere.
D) It has 13 neutrons in its nucleus.
E) It can be used to help deduce when life started on Earth.

According to spaceweather.com, space weather includes all of the following EXCEPT:
A) the solar wind speed and density
B) X-ray solar flares
C) sunspot number
D) current aurora
E) interplanetary magnetic field and coronal holes
G) ALL of the above are actually part of space weather

According to NASA's Near Earth Object, what is the difference between a comet and an asteroid?

Some "be-sure-to-know-these" hints:
- What is "CHONPS"?
- Why does "organic" mean?
- Why is liquid water thought to be necessary for life?
- What does it mean when we say "all terrestrial life is carbon-based"?
- What does "temperature" really measure?
- What are monomers and polymers?
- Why are amino acids important?
- What is a ribosome?
- What is "endosymbiosis"?
- What is a chloroplast? What is a mitochondrion?
- Why we think all life on Earth had a common ancestor?
- What are the key things essential for life (as we know it)?
- What are extremophiles?
- What makes a hypothesis a scientific hypothesis and not just an idea?
- Approximately what is age of the Earth? How do we know?
- What are three largest divisions (domains) of terrestrial life?
- What is a "NEO"? How many are there?
- What is the habitable zone? In what cases is it irrelevant?
- What are asteroids?
- What are meteorites?
- What is a "potentially hazardous asteroid"?
- What do the letters "UFO" stand for?
- How does the habitable zone change with time? With the star's spectral type?
- What is the difference between infrared, ultraviolet, radio and X-rays?
- What is the difference in meaning between the words "galaxy", "solar system", and "universe"?
- Who is Carl Woese?
- Why won't deep-sea water boil if its temperature is 400 degrees C?
- What does it mean to say, "It has been, and always will be, the Age of the Bacteria"?
- What are the 3 major pieces of evidence for ancient life on Earth?
- What is DNA?
- How does RNA differ from DNA?
- What is the "RNA World" hypothesis?
- What are proteins used for, and how are they made?
- What is a codon?
- What is a gene?
- What is evolution and what is natural selection?
- What is molecular "handedness"?
- What are the functions of proteins?
- What is subduction?
- What is a "black smoker"?
- What is "plate tectonics"?
- What is the K-T boundary? What was the K-T event?
- What did the father and son Alvarez team discover?
- Who was Alfred Wegener?
- What is a stromatolite?
- What is the C-12 / C-13 isotopic signature of life?
- What is a "domain"?
- What is an extremophile?
- What does the word "archaea" signify?
- What is a procaryote? What is a eucaryote?
- What is a sedimentary rock?
- What is a thermophile? A halophile?
- What is a spore?
- What is the "Tree of Life"?
- What is a mutation?
- What is a "lithautotrophe"?
- What chirality are biological amino acids?
- What is the difference between DNA and RNA?
- What is ATP?
- What is endosymbiosis?
- What does Natural Selection mean?

More questions to help you prepare:
What do ribosomes do, and why is this so important?
What is the Principle of Occam's Razor?
What do we mean by "space weather"?
What is an enzyme?
What role do supernovae play in the origin, evolution and development of life?
If someone says, "But it's only a theory...", why does that make no sense in a strict scientific way?
What can you use spectroscopy for?
What does "terraforming" mean?
What is the Kuiper Belt?
What are the key ingredients necessary for life as we know it?
What are the complementary DNA bases for the DNA codon ATG?
What are the complementary RNA bases for the DNA codon ATG?
What are lichens, and why are they important for astrobiology?
Why is it important that life seems to have started relatively quickly after the Earth formed?
What evidence gives us clues about when life started on Earth?
What is the "LUCA", and what is its significance?
What is the Miller-Urey experiment?
Why are the spectacular results of the Miller-Urey experiment not as important as they once were thought to be?
What is the Cambrian Explosion?
What does NASA's astrobiolgy motto "follow the water" mean?
And a few more:
- What is the difference between infrared, ultraviolet, radio and X-rays?
- What is the difference in meaning between the words "galaxy", "solar system", and "universe"?
- What is the greenhouse effect?
- Is there any greenhouse effect on Earth?
- What causes the greenhouse effect on Venus?

Good Luck on the exam!