Biology 2121 Chapter 2

Biochemistry 1. Introduction Biochemistry 2. Macromolecules contain carbon Valance = 4 Bonds with oxygen, hydrogen and nitrogen

Carbohydrates 1. General characteristics Soluble in water (decreases with size) Sizes – small single units to larger compounds 2. Function (s) Energy – 4 kcal/g Cell membrane – cell to cell recognition 3. Structure Monomer – monosaccharide Polymer – polysaccharide

Carbohydrates 1. Monosaccharides C 6 H 12 O 6 - isomers 2. Disaccharides Formed by dehydration Split-up by hydrolysis 3. Polysaccharides Starch, Glycogen

1.Glycogen – STORED IN THE LIVER 2.Starches – plants 3.Cellulose - roughage 1.Glycogen – STORED IN THE LIVER 2.Starches – plants 3.Cellulose - roughage

1. General Characteristics Insoluble in water – soluble in other nonpolar substances (alcohol) Non-polar structure 2. Function(s) Energy – 9 kcal/g Cell membrane, steroids, fat-soluble vitamins 3. Structure Most – fatty acid tail (H-C chain) that is non-polar Lipids

STRUCTURE OF A TRIGLYCERIDE 1.Formation – dehydration synthesis 2.Single bonding between carbons – ‘saturated’ Long FA chains – solid at room temperature 3.CH 2 – fatty acid tails

1. Unsaturated and Polyunsaturated Triglycerides Double bonding between the carbons Chains ‘bend’ or form kinks Plant lipids; olive, corn, safflower oil Chains are shorter than saturated fatty acid triglycerides

PHOSPHOLIPID 1.BILAYER OF A PLASMA MEMBRANE 2.Two FA tails; glycerol; phosphate (polar) 3.Amphipathic – polar and non-polar nature

CHOLESTEROL IS CLASSIFIED AS A STEROL – LIPID. MADE UP OF ‘FUSED’ CARBON RINGS AND SIDE CHAINS OF MOLECULES A ‘PRECURSOR’ TO OTHER STEROIDS – TESTOSTERONE, VITAMIN D Side-chains made each steroid different

Proteins 1. General Characteristics Basic structural component of the body C, H, O and Nitrogen! 2. Function(s ) Cell functions – transport of material across cell membrane; hemoglobin; muscle contractile protein Biological Catalysts - enzymes 3. Structure Monomer: amino acids Peptide bonding via dehydration Polymer: Polypeptide

Formation of a protein 1.Primary Structure As amino acid form straight chains via peptide bonding Occurs during ‘protein synthesis’ - ribosomes of the cell 2.Secondary Structure Twist or bends after primary formation Hydrogen bonds stabilize Between NH and CO 3.Two forms Beta and alpha-helix A polypeptide chain may contain both secondary structures!

Other Structures 1.Secondary structures fold up on themselves. 2.Adjacent amino acids interact or form covalent and hydrogen bond. Forms a 3-D Tertiary structure Enzymes 3.If two or more tertiary structures (polypeptides) interact – quaternary structure Hemoglobin (blood) or myoglobin (muscles)

Proteins – Structural Types

Fiberous – only secondary; insoluble and stable; collagen; keratin Globular – tertiary structure; soluble; enzymes, antibodies

Enzymes 1. What are enzymes? Biological catalysts Specific tertiary structure 2. Substrate and active sites 3. Function(s) Drive chemical reactions in cells! 4. How enzymes work (Lowering of energy activation) Activation Energy (animation)

1.“HOW ENZYMES WORK” – ANIMATION (Chapter 12 – Alternate)“HOW ENZYMES WORK” 2.Biochemical pathways (enzyme mediated)Biochemical pathways 3.Feedback in Biochemical PathwaysFeedback in Biochemical Pathways

Enzyme Denaturation 1.When enzymes (proteins) stop working. 2.Why? Temperature; pH changes Bonds and interactions between amino acids fail – unravels and loses 3D shape Animation 1.DenaturationDenaturation

Activation Energy and Enzymes

Nucleic Acids 1. General Characteristics C, H, O, N and Phosphorus 2. Function(s) DNA – genes – heredity RNA – important in production of proteins 3. Structure Monomer: nucleotide (phosphate - 5 carbon sugar – nitrogen base Polymer: Deoxyribonucleic Acid and Ribonucleic Acid

Nucleotides and DNA 1. Phosphates bonded to 5–C deoxyribose sugar via covalent bonding 2. Sugar bonded to nitrogen base (green and yellow) via covalent bonding 3. Bases bonded via hydrogen bonding (weak; unzips) 4. Base pairing rules: A-T; G-C

Hydrogen bonding between bases Base pairing Sugar-Phosphate backbone Double Helix

ATP – Adenosine Triphosphate 1.Glucose is the fuel that powers the cell. 2.As glucose is oxidized (anabolic), ATP is built up in the process of cellular respiration – mitochondria of the cell 3.Energy is stored in the bonds of ATP 4.Contains ribose sugar (RNA) and adenine base. 5.Three phosphates – two have unstable bonds and negative charges – repel 6.Bonds are broken – energy released – drives cellular work