BI108 Chapter 4 Outline: NucleicAcids and the Origin of Life
4.1—WhatAre the Chemical Structures and Functions of NucleicAcids?
• Nucleotides are the building blocks of nucleic acids
• Base pairing occurs in both DNAand RNA
• DNAcarries information and is expressed through RNA
• The DNAbase sequence reveals evolutionary relationships
• Nucleotides have other important roles
The nucleic acids DNAand RNAare polymers made up of nucleotide monomers. The
sequence of nucleotides in DNAcarries the information that is used by RNAto specify
primary protein structure. The genetic information in DNAis passed from generation to
generation and can be used to understand evolutionary relationships.
4.2—How and Where Did the Small Molecules of Life Originate?
• Experiments disproved the spontaneous generation of life
• Life began in water
• Life may have come from outside Earth
• Prebiotic synthesis experiments model early Earth
Life doesn’t arise through spontaneous generation. It comes from pre-existing life. Water
is an essential ingredient for the emergence of life. Meteorites that have landed on Earth
provide some evidence for an extrat