Life in the Universe
By: Fredrick and Matt
Requirements for Life
 Three absolute requirements for life to exist
 A suitable temperature range that allows chemical
bonding
 An energy source that allows life to grow, and
reproduce
 A source of liquid water; essential solvent in
biochemical reactions
The Habitable Zone
 This is a zone in a stellar-centered orbit where an
Earth-like planet can maintain liquid water on its
surface and Earth-like life
Planets also need enough gravity to hold to keep
gases from escaping.
Planets need a magnetic field to shield it from solar
winds-which can strip a planet of life sustaining
gases.
Habitable Zone Graph
Hardcore Life
 Extremophiles: are organisms that can tolerate what
are considered to be extreme environments.
Extremophiles
 Video
Making Life
 Miller's ExperimentStanley Miller, a graduate
student in biochemistry, built the apparatus
shown here. He filled it withwater (H2Omethane
(CH4)ammonia (NH3) andhydrogen (H2)but no
oxygen
Making Life Continued
 He hypothesized that this mixture resembled the atmosphere
of the early earth. (Some are not so sure.) The mixture was
kept circulating by continuously boiling and then condensing
the between them. At the end of a week, Miller used paper
chromatography to show that the flask now contained several
amino acids as well as some other organic molecules.In the
years since Miller's work, many variants of his procedure have
been tried. Virtually all the small molecules that are associated
with life have been formed:17 of the 20 amino acids used in
protein synthesis, andall the purines and pyrimidines used in
nucleic acid synthesis.But abiotic synthesis of ribose — and
thus of nucleotides — has been much more difficult.
However, success in synthesizing pyrimidine
ribonucleotides under conditions that might have existed in
the early earth was reported in the 14 May 2009 issue of
Nature.
DNA and Life

DNA, or deoxyribonucleic acid, is the
hereditary material in humans and almost
all other organisms. Nearly every cell in a
person’s body has the same DNA. Most
DNA is located in the cell nucleus (where it
is called nuclear DNA), but a small amount
of DNA can also be found in the
mitochondria (where it is called
mitochondrial DNA or mtDNA).The
information in DNA is stored as a code
made up of four chemical bases: adenine
(A), guanine (G), cytosine (C), and thymine
(T). Human DNA consists of about 3 billion
bases, and more than 99 percent of those
bases are the same in all people. The order,
or sequence, of these bases determines the
information available for building and
maintaining an organism, similar to the
way in which letters of the alphabet appear
in a certain order to form words and
sentences.
DNA and Life

DNA bases pair up with each other, A with
T and C with G, to form units called base
pairs. Each base is also attached to a sugar
molecule and a phosphate molecule.
Together, a base, sugar, and phosphate are
called a nucleotide. Nucleotides are
arranged in two long strands that form a
spiral called a double helix. The structure of
the double helix is somewhat like a ladder,
with the base pairs forming the ladder’s
rungs and the sugar and phosphate
molecules forming the vertical sidepieces of
the ladder. An important property of DNA
is that it can replicate, or make copies of
itself. Each strand of DNA in the double
helix can serve as a pattern for duplicating
the sequence of bases. This is critical when
cells divide because each new cell needs to
have an exact copy of the DNA present in
the old cell.
Video
 Possible life on other planets
All these planets and moons could have life on them.
Wrap Up
 Three absolute requirements for life to exist
 A suitable temperature range that allows chemical bonding
 An energy source that allows life to grow, and reproduce
 A source of liquid water; essential solvent in biochemical reactions
 The habitual zone is a zone in a stellar-centered orbit where an Earthlike planet can maintain liquid water on its surface to sustain Earthlike life.
Works Cited
 Toe, Daniel. "YouTube - Extremophiles - Weird Animals
- We Are The Aliens - BBC Space." YouTube - Broadcast
Yourself. 1 Mar. 2002. Web. 15 Apr. 2011.
<http://www.youtube.com/watch?v=y3GF3PFNx
 Mark, Carl. "Life Beyond Earth - The Habitable Zone."
PBS: Public Broadcasting Service. 20 June 2005. Web. 15 Apr.
2011.
<http://www.pbs.org/lifebeyondearth/alone/habitable.html>.
 Fells, Sunny. "Habitable Zone." Stony Brook Astronomy. 17
Oct. 2007. Web. 15 Apr. 2011.
<http://www.astro.sunysb.edu/fwalter/AST101/habzone.html
>.