Proteins and Nucleic Acids

Proteins

• Most important substance in the bodies of living things.
• Building blocks for muscle, hair, blood cells, skin, slk, enzymes, insulin, etc.

Amino Acids

• Building blocks of proteins.
• Contain an amine (NH2) group and carboxyl (COOH) group.
• Various side chains (R groups) attach to the carbon adjacent to the N.
• Results in 20 different common amino acids.
• Our bodies can synthesize 12 out of 20.
• The other 8 must come from diet
• Known as essential amino acids

List of Amino Acids

Polypeptide Chains

• Amino acids joined together with peptide bonds.
• Dipeptides: two amino acids joined together
• Aspartame (artificial sweetener)
• Polypeptides: polymers of many amino acids

Polypeptide chain or protein

Proteins

• Polymer of one or more polypeptide chains.
• Some contain several hundred amino acids others several thousand.
• Various structures

Nucleic Acids

DNA Structure

• When cells reproduce, they pass genetic information to one another in long-chain molecules called chromosomes.
• Human body contains 46 chromosomes in the nuclei.
• Segments of chromosomes, called genes, carry the coded information to that directs the production of specific polypeptide chains.
• Nucleotides are the building blocks of nucleic acid.
• Three units:
• 5 carbon sugar (ribose or dioxyribose)
• phosphate group
• ring-shaped nitrogen containing base
• There are five possible nitrogen-congaing bases attached to the sugar:
• Adenine (A)
• Cytosine (C)
• Guanine (G)
• Thymine (T)
• Uracil (U)
• DNA has A, C, G, T
• RNA has A, C, G, U
• DNA is two strains coiled around each other in a double helix
• When cells divide, a DNA strand reproduces by first unraveling with the help of enzymes. 
• Each of the two resulting strands serves as a template, or pattern, for a new complementary chain.
• Complementary bases on the newly forming strand match the now-exposed bases of the old strand.
• When the process of replication is completed, two identical double-stranded DNA molecules result. 

DNA Replication

• One strand goes to each half of the dividing cell.
• DNA and RNA molecules instruct cells on how to make proteins.
• DNA is used as a template to make RNA.
• RNA is made up of nucleotides.
• Trinucleotide groups (3 nucleotides) code for various amino acids.
• As the amino acids join together, they form proteins. 
• The proteins are the chemical manifestation of our physical characteristics. 

This is an example of protein synthesis from RNA

Differences between DNA and RNA

• DNA
• the sugar is deoxyribose
• contains thymine
• double strand
• RNA
• the sugar is ribose
• contains uracil
• single strand