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Life in the universe

Terms in this set (70)

1) The basic unit of life is a cell
2) Cells require energy to function - energy can come from chemical sources (such as food) or
from sunlight
3) Cells contain carbohydrates, proteins, water, fats (lipids), nucleic acids
4) Carbon, Hydrogen, Oxygen and Nitrogen are the most commonly found elements in life,
making up more than 96% of the mass of living matter.
5) Carbon has unique chemical properties that make it essential to life on Earth. It bonds
to four other atoms, and can form double bonds with other carbon atoms. The bonds are
stable over wide ranges in temperatures. Cells gain carbon from carbon dioxide in the earth's
atmosphere or from consuming organic compounds.
6) Proteins are made of amino acids. There are only 20 amino acids found in living creatures
although more than 70 exist. The amino acids found living beings are left handed, unlike
those manufactured artificially which show equal amount of left handed and right handed
molecules (the handedness is akin to the winding of a spiral staircase — it can be clockwise
or anti-clockwise)
7) Water in liquid form is essential to carry out the chemical reactions that take place in cells
because it allows chemicals to dissolve in water, it transports chemicals within and to and from cells and water is one of the chemicals that reacts with other substances in some of the
metabolic reactions (see bottom of pg 175-176).
8) All cells use the molecule ATP (adenosine triphosphate) to generate energy needed for
metabolic reactions. 9) Lipids are essential in building cell membranes.
10) The nucleic acids are deoxyribonucleic acid (DNA) which stores genetic information and
ribonucleic acid (RNA) which uses the information in DNA to enable the cell to function.