Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All are necessary to life. ~70% water
NOT referring to "Organically Grown" foods
Bottom illustration is of ponderosa pine, showing very strong microfibrils formed from cellulose chains. You can now see why burning a pine log releases so much heat – there are a lot of energy-releasing covalent bonds there!
The Chemistry of Life
The Chemistry of LifeHeartlife 2012-2013 Teacher: Julie Pen Science is Organized Knowledge
Elements of Life• 96% of the human body is made up of: – Oxygen – Carbon – Hydrogen – Nitrogen• Calcium, phosphorus, sulfur, potassium, and other elements in trace amounts
Organic Molecules• Organic Compounds – molecules within living things or arising from previously living organisms – contain Carbon – ALSO contain C-H bonds • nucleic acids • fats (lipids) • sugars (carbohydrates) • proteins (+ enzymes) • many fossil fuels Carbon Atom
Carbon Bonding• With four valence electrons, carbon wants to form four covalent bonds to become stable (octet rule). – many different bonding configurations are possible • straight chains • rings • branched chains – many different molecule sizes • 1 or 2 carbon atoms • hundreds or thousands of carbon atoms in a single molecule
Four Groups of Organic Molecules• Carbohydrates – fuel for cell functions• Lipids – stored energy and membrane structure• Nucleic Acids – genetic information• Proteins – many cell functions
Carbohydrates• Fuel for cell functions• Made up of saccharides (sugars) – Glucose – Sucrose – Dextrose – Maltose – Lactose – Fructose – Amylose – Cellulose, ...and many more
Carbohydrates I Base (CH2O)n or H - C - OH Structure: I Monosaccharides - simple sugars made up of 3 to 6 carbons Disaccharides - 2 monosaccharides covalently linked. Polysaccharides - polymers consisting of chains of monosaccharide or disaccharide units.
MonosaccharidesMonosaccharides are simple sugars made upof 3 to 6 carbons. • The free ends of a straight H C O monosaccharide chain often bond to form a cyclic molecular structure H C OH HO C H H C OH H C OH CH2OH D-glucose
DisaccharidesDisaccharides are two monosaccharides covalentlylinked.• Maltose is made when starch is broken down – it issimply two linked glucoses. 6 CH2OH 6 CH2OH 5 O 5 O H H H H H H 1 4 1 4 OH H OH H OH O OH 3 2 3 2 H OH maltose H OH
Common DisaccharidesOther common disaccharides include:Sucrose(common table sugar) Lactose (milk sugar)
Plant Polysaccharides CH 2OH 6 CH OH CH2OH CH2OH CH 2OHH O H H 5 2 O H H O H H O H H O H Amylose often H OH H 1 H 4 OH H 1 H OH H H OH H H OH H has 300 – 600 O O O O OHOH 3 2 H OH linked glucose H OH H OH H OH H OH amylose moleculesPlants store glucose as amylose or amylopectin, (commonlycalled starch). Amylose is a glucose polymer. • Cellulose (found in plant roots, seed, fruits and tubers) consists of long linear chains of glucose. – Cellulose provides strength and rigidity to plant cell walls and is not digestible by most organisms (dietary fiber).
Animal Polysaccharides CH2OH CH2OH H O O glycogen H H H H H OH H OH H 1 O OH O H OH H OH CH2OH CH2OH 6 CH2 CH2OH CH2OHH O H H O H H 5 O H H O H H O H H H H H H OH H OH H OH H 1 4 OH H OH H 4 O O O O OHOH 2 3 H OH H OH H OH H OH H OH Glycogen is the glucose storage polymer in animals. • The highly branched structure permits rapid release of glucose from glycogen stores, e.g., in muscle during exercise. • The ability to rapidly mobilize glucose is more essential to animals than to plants.
Lipids• Formed from fatty acids• Non-polar (hydrophobic) compounds• Functions: – Stored energy & insulation • Triglycerides – Cell membrane structure • Phospholipids – Steroids • cholesterol • testosterone • estrogen • bile acids • Vitamin D ...and many more
Fatty AcidsMost fatty acids, the simplest lipids, are non-polar acidsand thus repel water. • If every carbon atom in a fatty acid chain is joined to another carbon atom by a single bond (and 2 H atoms), it is said to be saturated. saturated • from animals • If a pair of carbon atoms is joined by a double bond, it is said to be unsaturated. unsaturated • vegetable and fish
Stored Energy Lipids• Triglycerides are the main form of lipid used to store energy in the body.• They have a glycerol backbone with three fatty acid tails.• When lipids are metabolized (broken down for use), they produce LOTS of energy
Cell Membrane LipidsCell membrane lipids are amphipathic, having a non-polar amphipathic(hydrophobic) end and a polar (hydrophilic) end. Phospholipids have a phosphate group plus two fatty acid tails. Hydrophobic tails hover together while the polar heads align to form a cell membrane.
Steroids HO Cholesterol• Steroids have a four fused carbon rings and a short branched hydrocarbon tail.• Cholesterol is a steroid found in membranes, and is the precursor for synthesis of hormones (testosterone, estrogen, etc.), bile acids and vitamin D.
Nucleic Acids • Store, carry, and aid in the transmission of genetic information• Only 2 types: – deoxyribonucleic acid (DNA) – ribonucleic acid (RNA)• Made from chains of nucleotides
Nucleotide Structure• Each nucleotide has three parts: – Nitrogen base • Adenine • Cytosine • Guanine • Thymine or Uracil – 5-carbon sugar • Ribose or Deoxyribose – Phosphate group Sugar-Phosphate Backbone
DNADeoxyribonucleic acid – Double-stranded helix – Has the sugar Deoxyribose – Forms chromosomes • carry genetic information – Uses four nucleotide bases • Adenine • Guanine • Cytosine • Thymine
RNARibonucleic acid – single stranded (usually) – Has the sugar Ribose – Transcribes DNA to make proteins – Four nucleotide bases • Adenine • Guanine • Cytosine • Uracil (instead of Thymine)
Proteins• Made from 20 different amino acids• Seven major functions (S3CDET): – Storage: iron, amino acid storage (seeds, milk & egg whites) – Structural proteins: support and shape (collagen in hair/nails, microtubules/microfilaments) – Signaling: membrane receptor proteins & chemical messengers – Contractile: cell movement (cilia/flagella/pseudopodia, muscle) – Defensive: against foreign substance and disease-causing organisms (antibodies) – Enzymes: biological catalysts – Transport: hemoglobin
Amino Acids• Amino acids are the building blocks of proteins.
Protein Structure• Each protein is made from a specific sequences of amino acids joined together by peptide bonds. – There are 1,000s of different proteins!• The sequence of amino acids will determine the physical structure of the protein (how it folds). A single substitution may result in a protein that is not folded properly (sickle-cell anemia) Protein Folding Video
Proteins• Proteins have many different jobs • function is often dictated by shape • shape is determined by the amino acid sequence that affects folding • Examples: hemoglobin, flagella, membrane receptors, hair, antibodies
Summary• Carbohydrates – Easy-access (fast) fuel for cell functions – Formed from simple “sugars” or saccharides – Glucose, Sucrose, Dextrose, Maltose, Lactose, Fructose, Cellulose, Amylose• Lipids – Formed from fatty acids – Mainly non-polar (hydrophobic) compounds – Functions: • Triglycerides - stored energy & insulation • Phospholipid bilayer – cell membranes • Steroids – cholesterol, estrogen, bile acids, Vitamin D, etc.• Nucleic Acids – Store, carry, and aid in the transmission of genetic information – DNA & RNA - made from (chains of) nucleotides – Each nucleotide has three parts: • Phosphate group • Nitrogen • 5-carbon sugar (Ribose or Deoxyribose)• Proteins – Made from amino acids – Seven major functions (S3CDET): • Storage, Structure, Signaling, Contractile, Defensive, Enzymes and Transport
Week 4 LabMicroscope Orientation Proper Use and Care Newsprint wet mount Salt crystals