Transcript Biomolecules
Biomolecules
The Chemical Building Blocks of Life
The Chemistry of Carbon
• Organic molecules contain carbon • Carbon’s four valence electrons allow it to form up to four covalent bonds • Hydrocarbons consist only of C and H – Propane CH 8 • It can easily bond to itself and form long chains – Linear - Cyclic - Branched
Functional Groups
• Chemical properties and reactivity are a result of functional groups • Functional groups maintain chemical properties no matter where they occur • Polar molecules are hydrophilic • Nonpolar molecules are hydrophobic • The degree to which organic molecules interact with water affects their function • Hydroxyl group (-OH) is one of the most common functional groups, it will make a molecule water soluble
Macromolecules – The Sum of the Parts
• Many complex biological activities require large macromolecules • Macromolecules are polymers built by linking together small subunits called
monomers
– Proteins are polymers of amino acids – Nucleic acids are polymers of nucleotides – Starches are polymers of simple sugars
Condensation
It’s not just for the water cycle anymore • Macromolecules are constructed by covalently bonding monomers by condensation reactions where water is removed from the functional groups of the monomers • Dehydration synthesis (water is removed) • A hydroxyl (-OH) from one monomer and a hydrogen (-H) from another are removed • Anabolic reaction
Hydrolysis
• Hydrolysis is the reverse of condensation • Results in the break down of polymers • Hydration reactions add water and break bonds releasing energy
Macromolecules • Perform complex tasks with precision • Basic structure and function of each family similar in all organisms (bacteria – humans)
Families of Biomolecules
• Carbohydrates •Lipids •Proteins •Nucleic Acids
Basic Function
Carbo’s Energy Storage Structure Starch Glycogen Glucose Sucrose Cellulose Lipids Long term storage Insulation Protection Lipid Fats Oils Waxes N. Acids Inheritance Blueprint for metabolism Proteins Catalysts Hormones Structure DNA RNA ATP Proteins Enzymes
Carbohydrates
How Sweet It Is!
• General formula (CH
2 O) n
• Simple sugars or large
molecules made of sugar monomers
• Monosaccharides (monomer)
are covalently linked by condensation reaction to form polysaccharides (polymers)
Sugars
• Monosaccharides – Five carbon: Ribose – Six carbon: glucose and fructose •Disaccharides –Sucrose –Lactose •Polysaccharides –Starch –Cellulose –Glycogen
Polysaccharides
Three Types
• Glycogen – animal storage product that accumulates in the liver - Highly branched Glucose Glycogen glucose bloodstream • Starch – plant energy storage - Helical - Easily digested by animals through hydrolysis
Cellulose
• Polysaccharide found in plant cell walls • For humans cellulose is indigestible and
forms dietary fiber
• Made up entirely of β glucoses – Structure is constrained into straight
microfibrils
• Not an energy source for animals • Chitin – insect exoskeletons
Lipids
• Long-term energy storage • Generally insoluble in water • Structural components of cells (phospholipids) • Cellular messengers (hormones)
More FAT
• Triglycerides are composed of three fatty acids covalently bonded to one glycerol molecule •Fatty acids are composed of CH 2 are hydrophobic units and •Fatty acids can be saturated (all single bonds) or unsaturated (one or more double bonds) •A fat (mostly saturated) is solid at room temp. while an oil (mostly unsaturated) is liquid at room temp.
Phospholipids
• Important structural component of cell memranes • Phosphate group (head) is polar and water soluble (hydrophilic) • Fatty acid tails are hydrophobic •This allows the phospholipids to form bilayers and membranes
Other Lipids
• Steroids – Insoluble in water – Built around a four ringed skeleton • Cholesterol – Component for animal cell membranes – Formation of myelin sheath covering nerves • Hormones – Chemical messengers • Waxes – Many fatty acids linked to a long backbone – Waterproofing in plants, ears, beehives
Proteins
• 50% dry weight of body • Mammal cell contains 10,000 proteins • Control elements (enzymes) – Organic catalysts – Mediators of metabolism – Direct development, maintenance, and growth • Structural elements (cell membrane, muscles, ligaments, hair, fingernails) • Regulate what goes into/out of cells
Building Blocks of Proteins Amino Acids
• Amino acids (monomers) are linked together to form proteins (polymers) – Each unique sequence of amino acids forms a different protein – All living things (even viruses) use the same 20 amino acids • 20 different Amino Acids – Amino end (NH 2 ) – Carboxyl end (COOH) – Hydrogen – R group – variable component
Amino Acids
• Amino Acids are grouped by whether R- group is polar or non polar •Positively charged side chain •Negatively charged side chains •Polar but uncharged side chains •Hydrophobic side chains •Special cases
Protein Assembly
• AA’s are linked together by joining the amino end of one molecule to the carboxyl end of another •Peptide bond forms a chain called a polypeptide •Transcription in nucleus –DNA code –mRNA mRNA •Translation on ribosomes protein
Protein Structure
• • • Primary structure – Specific linear sequence of AA’s in a polypeptide helix, -pleated sheet, or random coil – Changes in primary structure can alter proper functioning of the protein
Nucleic Acids
• Polymers composed of monomer units known as nucleotides • Information storage – DNA (deoxyribonucleic acid) • Protein synthesis – RNA (ribonucleic acid) • Energy transfers – ATP (adenosine tri-phosphate) and NAD (nicotinamide adenine dinucleotide)
Nucleotides
• Nucleotide structure – Phosphate – Nitrogenous base Purines (double-rings) Adenine and Guanine Pyrimidines (single-rings) Cytosine, Thymine, and Uracil – Sugar – either ribose or deoxyribose pentoses in ring form Deoxyribose lacks one oxygen
Functions of Nucleic Acids
• DNA – Physical carrier of genetic information – Restricted to nucleus • RNA – key component of protein synthesis – Messenger RNA (mRNA) – blueprint for construction of a protein – Ribosomal RNA (rRNA) – construction site where the protein is made – Transfer RNA (tRNA) – truck delivering the proper AA to the site of construction