Chapter 2 part 2: Biochemistry

Biochemistry: Essentials for Life Organic compounds Contain carbon Most are covalently bonded Example: C6H12O6 (glucose) Inorganic compounds Lack carbon Tend to be simpler compounds Example: H2O (water)

Important Organic Compounds Carbohydrates- Glucose, cellulose, glycogen, starch Lipids- Phospholipids, steroids, prostaglandins Proteins- Enzymes, insulin, albumin, hemoglobin, collagen Nucleic acids- DNA, RNA

Important Organic Compounds Carbohydrates Contain carbon, hydrogen, and oxygen Include sugars and starches Classified according to size Monosaccharides—simple sugars Disaccharides—two simple sugars joined by dehydration synthesis Polysaccharides—long-branching chains of linked simple sugars

What role do carbohydrates play in the body? 1. They serve as the principal source of body energy. 2. They contribute to cell structure and synthesis of cell products. 3. They form part of the structure of DNA and RNA (deoxyribose and ribose are both sugars). 4. They are converted into proteins and fats. 5. They function in food storage (glycogen storage in the liver and skeletal muscles).

Carbohydrates 6 carbon sugar (hexose) 5 carbon sugar (pentose)

dehydration synthesis and hydrolysis Hydrolysis- the addition of water to break down a molecule into the two parts. Dehydration synthesis is the removing of the hydroxl(-OH) and the hydrogen atoms from two organic substances which merges them into one(covalent bond).

Important Organic Compounds Lipids Contain carbon, hydrogen, and oxygen Carbon and hydrogen outnumber oxygen Insoluble in water Common lipids in the human body Neutral fats (triglycerides) Found in fat deposits Composed of fatty acids and glycerol Source of stored energy

Lipids Figure 2.15a

Lipids Common lipids in the human body (continued) Phospholipids Form cell membranes Steroids Include cholesterol, bile salts, vitamin D, and some hormones

Lipids Figure 2.15b

Lipids Cholesterol The basis for all steroids made in the body Figure 2.15c

Important Organic Compounds Proteins Made of amino acids Contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur

Functions of Proteins and Examples Enzyme- Trypsin, chymotrypsin, sucrase, amylase Transport and storage of molecules- Hemoglobin, myoglobin Motion- Actin, myosin, tubulin (ciliary motion) Structural support- Collagen, elastin Immunity-Antibodies- (immunoglobulins) Neural communication- Endorphins, rhodopsin (pigment for light reception in the eye) Intercellular messenger- Insulin, glucagon, growth hormones

Proteins Amino acid structure Contain an amine group (NH2) Contain an acid group (COOH) Vary only by R groups Proteins are chains of amino acids bound by peptide bonds

Amino acids 20 Amino Acids Glycine (Gly) Serine (Ser) Lysine (Lys) Alanine (Ala) Threonine (Thr) Arginine (Arg) Valine (Val) Asparagine (Asn) Histidine (His) Leucine (Leu) Glutamine (Gln) Aspartic acid (Asp) Isoleucine (Ile) Tyrosine (Tyr) Glutamic acid (Glu) Methionine (Met) Cysteine (Cys) Proline (Pro) Phenylalanine (Phe) Tryptophan (Trp)

Important Organic Compounds Nucleic Acids Provide blueprint of life Nucleotide bases A = Adenine G = Guanine C = Cytosine T = Thymine U = Uracil Make DNA and RNA Figure 2.19a

Purines & Pyrimidines Purines consist of a six-membered and a five-membered nitrogen-containing ring, fused together. Pyridmidines have only a six-membered nitrogen-containing ring.

Nucleic Acids Deoxyribonucleic acid (DNA) Organized by complimentary bases to form double helix Replicates before cell division Provides instructions for every protein in the body Figure 2.19c

Important Organic Compounds Adenosine triphosphate (ATP) Chemical energy used by all cells Energy is released by breaking high energy phosphate bond ATP is replenished by oxidation of food fuels

Adenosine Triphosphate (ATP) Figure 2.20a

Figure 2.21 Membrane protein P P Solute Solute transported (a) Transport work ADP ATP + P Relaxed muscle cell Contracted muscle cell (b) Mechanical work P X P X Y + Y Reactants Product made (c) Chemical work Energy liberated during oxidation of food fuels used to regenerate ATP Figure 2.21