Biomolecules: Nucleic Acids and Proteins

Nucleic Acids: DNA and RNA

Carry and transmit detailed instructions for building every human cell and

for every cell of every living organism

Nucleic Acids• Polymer made of monomers – nucleotides

• Contain – Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus

• Store and Transmit all genetic information

• 2 Types:

– Deoxyribonucleic acid - DNA

– Ribonucleic acid – RNA

Nucleic Acid Monomers - nucleotides

A

C

G

T

U

Proteins: Do All The Work

• Large and complex Polymers, made up of long chains of amino acids (monomers)

• Instructions for building Proteins are "written" in DNA

• They have diverse biological roles/ jobs

Protein Jobs• Structure and support: main components of our

tissues – muscle, skin, hair, ligaments, etc.

• Communication & signaling – they can be signals (some hormones are proteins) or the receivers of signals (receptors)

• Defense: All antibodies are proteins

• Regulation: Regulate all processes in the cell

• Catalysis: Enzyme are catalysts, regulation all chemical reactions in cells

Amino Acids – the monomers of Proteins

aminogroup

carboxylic acid group

Carboxyl GroupR group

All amino acids have the same general structure: the only difference between each one is the nature of the R group. So the R group defines an amino acid. It represents a side chain from the central “alpha” carbon atom, and can be anything from a simple hydrogen atom to a more complex ring structure.

Amino Acid – Polar or Not?

There are 20 Amino acids

Building Proteins from Amino Acids

Dehydration synthesis:Carboxyl Group of 1st AminoAcid is linked to the AminoGroup of the 2nd Amino Acid and1 molecule of water is removed. The bond formed is called aPeptide bond/Peptide linkage.

Dipeptide – 2 Amino Acids linked

repeat steps to produce

Polypeptide – many Amino Acids linked

Polypeptides

When more amino acids are added to a dipeptide, a polypeptide chain is formed.A protein consists of one or more polypeptide chains folded into a highly specific 3D shape. Each Protein has a unique 3D Shape which is determined by the order in which the Amino Acids are arranged

Protein StructureThere are up to four levels of structure in a protein: primary - the order, sequence of amino acidssecondary - hydrogen bonds cause simple folding of the chaintertiary – 3D folding - shape of protein quaternary – when 2 or more polypeptide chains interact

Structure of hemoglobin

How is the 3D Shape held together?

hydrophobic interactions:between non-polar sections of the protein.

disulfide bonds: one of the strongest and most important type of bond in proteins. Occur between two cysteine amino acids.

hydrogen bonds:involved in all levels of structure.

How can we destroy the shape of a Protein?

hydrophobic interactions:between non-polar sections of the protein.

disulfide bonds: one of the strongest and most important type of bond in proteins. Occur between two cysteine amino acids.

hydrogen bonds:involved in all levels of structure.