section 5, chapter 2
DESCRIPTION
organic molecules: chemistry for anatomy & physiologyTRANSCRIPT
Proteins have many functions:
• Proteins provide structural material.
• They are a source of energy.
Organic Molecules: Proteins
• They are a source of energy.
• Some act as chemical messengers (hormones, neurotransmitters).
• Many proteins are receptors.
• Most enzymes are proteins.
Proteins: enzymes
Enzymes catalyze reactions (increases rate), but are not consumed by the reaction (reusable).
Synthesis reaction involving an enzyme
• An amino group (-NH2)
All amino acids consists of:
Proteins: amino acids
• A Carboxyl Group (-COOH)
• A single Carbon atom
• An “R” group (R = rest of the molecule)
• 1 of 20 possible “R” groups = determines amino acid
Peptide bond (red) joins two amino acids.
4 Levels of Protein Structure
A protein’s shape, or conformation, determines its function. Therefore, it’s important to understand a protein’s shape at 4 levels.
4 Levels of Protein Structure
Red dots indicatehydrogen bonding
4 Levels of Protein Structure
4 Levels of Protein Structure
4 Levels of Protein Structure
Conformation
• Complex 3 dimensional fold of a protein
• Conformation determines a protein’s function
Protein Structure
Denature
• Treatment that alters the shape of a protein to make it nonfunctional
• Heat, pH changes, radiation, certain chemicals may denature proteins
Nucleic Acids
• Includes DNA and RNA
• Genetic information
• Consists of monomers, called nucleotides
Nucleic acids: overview
RNA
• Contains the sugar ribose (ribonucleic acid)
• RNA is a single-stranded nucleic acid.
• Transcribes DNA for protein synthesis
• RNA also may act as an enzyme
DNA
• DNA contains a sugar, called deoxyribose(deoxyribonucleic acid)
• Double-stranded helix
• Encodes genetic information for protein synthesis.
Nucleotides
• Monomers of Nucleic Acids
3 Components of Nucleotides
• 5 Carbon Sugar (S)
• Nitrogenous Base (B)
• Phosphate Group (P)
sugar
phosphate nitrogenous base
RNASugar = ribose
DNASugar = deoxyribose
H bonds
Antiparallel