Biochemistry Macromolecules and Enzymes Unit 02
Organic Compounds Compounds that contain CARBON are called organic.
What is Carbon? Carbon has 4 electrons in outer shell. Carbon can form covalent bonds with as many as 4 other atoms (elements). Usually with C, H, O or N. Example: CH 4 (methane)
Macromolecules Macromolecules are large organic molecules.
Macromolecules, con t. Large organic molecules. Also called POLYMERS. Made up of smaller building blocks called MONOMERS. Examples: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids (DNA and RNA)
How are macromolecules formed?
Answer: Dehydration Synthesis Also called condensation reaction Forms polymers by combining monomers by removing water
How are macromolecules separated or digested?
Answer: Hydrolysis Separates monomers by adding water
Carbohydrates
Carbohydrates Carbohydrates include small sugar molecules to large sugar molecules. Examples: A. monosaccharide B. disaccharide C. polysaccharide
Carbohydrates: Monosaccharides Monosaccharide: one sugar unit 1C: 2H: 1H ratio Examples: Glucose (C 6 H 12 O 6 ) Deoxyribose Ribose Fructose Galactose
Carbohydrates: Disaccharides Disaccharide: two sugar unit Examples: Sucrose (glucose+fructose) Lactose (glucose+galactose) Maltose (glucose+glucose)
Carbohydrates: Polysaccharides Polysaccharide: - many sugar units Examples: - starch (bread, potatoes) glycogen (stored in liver) cellulose (lettuce, corn)
Function of Carbohydrates Carbohydrates Quick source of energy Energy storage Structure (cellulose)
Carbohydrates: Energy Source Energy Source Main source of energy for most organisms Cells utilize glucose for energy Breaking of C-C bonds releases a lot of energy Sugars have 5 C-C bonds per glucose molecule
Carbohydrates: Energy Source Energy Source Plants produce glucose through photosynthesis Animals obtain glucose from plants Human digestive system breaks down carbohydrates to simple sugars Small intestine absorbs simple sugars and blood transports them to cells Cells use glucose to form ATP (Cellular Respiration)
Carbohydrates: Energy Storage Energy Storage Animals Extra glucose is stored as glycogen Liver and muscle cells Plants Stored as starch
Carbohydrates: Structure Structural Unit Cellulose is made up of glucose molecules Makes up cell walls of plants Uses Support plants Important in animal diets by helping digestive tract work smoothly Fun Fact Animals lack the enzyme to digest cellulose Some animals have a symbiotic relationship with a microorganism that can digest cellulose
Lipids
Lipids Lipids Compounds which are not soluble in water. Stores the most energy Examples: Fats/Oils Phospholipids Steroids
Lipids: Fats/Oils Structure of Fat/Oil Composed of 1 glycerol and 3 fatty acids. Fatty acids are insoluble.
Lipids: Fats/Oils Saturated Fats All single bonds Solids Animal Fat Unsaturated Fats 1+ double bond(s) Liquids Fish and Plant Oils
Lipid: Phospholipid Phosphate Head: Polar Hydrophilic (attracted to water) Two Fatty Acid Tails: Nonpolar Hydrophobic (avoids water) Two Layers Outsides: Polar Heads Inside: Nonpolar Tails
Cell Membrane Structure Lipid Bilayer: a double layer of phospholipids that make up the cell membrane
Other lipids Lipids Fatty acids Fats and waxes Steroids Cholesterol Testosterone Phospholipids
Lipids: Functions Functions of lipids Long term energy storage Protection against heat loss (insulation) Protection against water loss Cutin (waxy coating on leaf) prevents water loss Chemical messengers (hormones) Major component of membranes (phospholipids)
Nucleic Acids
Nucleic Acids Nucleic acids are composed of long chains of nucleotides linked by dehydration synthesis.
Nucleic acids Nucleotides include Phosphate group Pentose sugar (5-carbon) Nitrogenous bases Adenine (A) Cytosine (C) Guanine (G) Thymine (T) DNA only Uracil (U) RNA only 31
Nucleic Acids Two types Deoxyribonucleic acid DNA Sugar: Deoxyribose Double helix Ribonucleic acid RNA Sugar: Ribose Single strand
5 DNA - double helix O 3 P P 5 4 5 3 3 O O 1 2 T G A C 1 O 2 3 O 3 5 4 5 P P P 3 O 5 P 33
Function of Nucleic Acids Nucleic Acids Stores and transmit information in the form of a code Passes this information from one generation to the next
Proteins
Proteins Four levels of protein structure: A.Primary Structure B.Secondary Structure C.Tertiary Structure D.Quaternary Structure
Proteins Primary Structure Amino acids (20 different kinds) Bound together by peptide bonds Straight chains
Proteins Secondary Structure 3-dimensional folding arrangement of a primary structure held together by hydrogen bonds. Alpha Helix: Coils Beta Pleated Sheets: Folds
Proteins Tertiary Structure Structures bent and folded into a more complex 3-D arrangement of linked polypeptides Bonds: H-bonds, ionic, disulfide bridges (S-S) Call a subunit
Proteins Quaternary Structure Composed of 2 or more subunits Globular in shape Form in aqueous environments Example: enzymes (hemoglobin)
Proteins: Functions Shape of protein determines its function Functions of Proteins Storage: Transport: Regulatory: Movement: albumin (egg white) hemoglobin hormones muscles Structural:membranes, hair, nails Enzymes: cellular reactions
Proteins: Fun Facts Essential Amino Acids: 8 of the 20 AA must be obtained from diet because humans cannot make them Different organisms need different amino acids Domestic cats must eat taurine, however humans can produce it.
ENZYMES
WHAT IS AN ENZYME? Most enzymes are proteins Act as a catalyst to speed up a chemical reaction by helping molecules react with each other faster
ENZYMES ARE Reusable! Specific for what they catalyze (speed up) End in -ase Named for the reaction they help. For example Sucrase breaks down sucrose Proteases break down proteins Lipases break down lipids DNA polymerase builds DNA
CASE STUDY: LACTOSE INTOLERANCE Lactase breaks down lactose, a common component of dairy products (like milk) People lacking the enzyme lactase are considered lactose intolerant -they can t digest large amounts of milk!!
ENZYMES ARE NOT USED UP! Re-used again for the same reaction with other molecules Very little enzyme is needed to help in many Substrat e Active Site reactions! Product s Enzym
LOCK AND KEY MODEL Remember, enzymes are specific! Lock and Key Model: Shape of enzyme allows substrate to fit Specific enzyme for each specific reaction Chemical Reaction Enzyme + Substrate Enzyme + Product
SO HOW DO ENZYMES WORK? Enzymes work by weakening bonds, which lowers ACTIVATION ENERGY Activation Energy=energy needed for the chemical reaction to occur (energy needed to activate!) By lowering the activation energy, the reaction can occur faster! Reactions can occur without the help but not at the speed our bodies need!
WHAT EFFECTS ENZYME ACTIVITY? Temperature High temperatures can cause enzymes to denature (unfold and lose shape), while low temperatures slow molecules down ph Changes in ph changes protein shape (most human proteins sit at a ph of 6-8) Denaturing=extreme temperature and ph can change enzyme shape, rendering it useless!
WHY ARE ENZYMES IMPORTANT? Every reaction in your body is helped by an enzyme. They are necessary for all biological reactions! Video