Chapter 3- Organic Molecules

Transcription

1 Chapter 3- Organic Molecules

2 CHNOPS Six of the most abundant elements of life (make up 95% of the weight of all living things)! What are they used for? Structures, enzymes, energy, hormones, DNA How do we get them? Eating, drinking, and breathing

3 All life is built on carbon (cells are 75% water, 25% carbon compounds, and 3% water) The Almighty Carbon C atoms are versatile 4 stable covalent bonds Must be constantly bonding with CHNOPS for stability Especially important is carbon s ability to bond with other carbons VERY STABLE Hydrocarbons (exclusively carbons and hydrogen) Non-polar Hydrophobic stable

4 Function Groups Carbon chain = skeleton of backbone Diversity of organic molecules comes from the attachment of functional groups Specific combination of bonded atoms that always reacts the same way Polar, forms hydrogen bonds Polar Polar, acidic Polar, basic, forms hydrogen bonds Forms disulfide bonds Phosphate group Polar, acidic

5 Polymers Long molecules built by linking repeating building blocks in chains Building blocks = monomers Covalent bonds B-I-O-L-O-G-Y 4 Major classes of macromolecules: Carbohydrates Lipids Proteins Nucleic acids Four groups of macromolecules can be broken down into polymer and monomer subunits Easier to digest Also easier to take the building blocks to build what you need

6 Biomolecule Synthesis and Degradation Dehydration Reaction Building of biomolecules As subunits are joined together water is released Requires energy Hydrolysis/ Digestion Break down biomolecules with water Opposite of dehydration Must add water to break down molecules Releases energy- we are breaking a bond Requires enzymes

7 Enzymes Molecule that speeds up a reaction by bringing the reactants together H 2 O Remains unchanged by reaction HO H HO enzyme H Think of it as a dating site (dehydration) or a divorce attorney (hydrolysis) for biomolecules HO H

8 Carbohydrates Carbon water - Some form of CH 2 0 Monomer: monosaccharide Simple sugar glucose, ribose Functions: Energy Raw materials Energy storage Structural compounds Examples Glucose- C 6 H 12 O 6 Starch Cellulose glycogen

9 Sugars Most names for sugars end in ose Classified by carbons: 6C= hextose (glucose) 5C= pentose (ribose) 3C =triose (glyceraldehyde) CH 2 OH H HO H OH O H H OH H Glucose OH glyceraldehyde

10 Building sugars Dehydration synthesis monosaccharides disaccharide glucose H 2 O fructose sucrose (table sugar)

11 CARBOHYDRATES Carbon to hydrogen to oxygen ratio of 1:2:1 Monomer= Monosaccharides Single sugar molecule (aka simple sugar) Some form of CH 2 0 Ex. Glucose C 6 H 12 O 6 Disaccharide- 2 monosaccharides Joined in dehydration reaction Ex. Sucrose and lactose Lactose Polysaccharides Large polymers Ex. Starch

12 Polysaccharides Polymers of Sugars Cost little energy to build Easily reversible = easy energy Energy is stored in the C-C bond Harvested in cellular respiration Functions: 1) Energy storage Glycogen- animals (muscles) Starch- plants 2) Structure Cellulose- plants Chitin- arthropods

13 Linear vs. branched polysaccharides slow release starch (plant) energy storage glycogen (animal) fast release

14 Polysaccharide Diversity Molecular structure determines function in starch in cellulose Isomer- identical molecular formulas, but different arrangement of atoms

15 Cellulose Most abundant organic compound on Earth herbivores have evolved a mechanism to digest cellulose most carnivores have not that s why they eat meat to get their energy & nutrients cellulose = indigestible roughage

16 Lipids Lipids are composed of C, H, and O ALL hydrophobic Do not form polymers Big molecules of small units (NOT A CONTINUING CHAIN) Family Types: Fats and Oil Phospholipids Steroids Waxes

17 1) Triglycerides (fats and oils) Glycerol (3C alcohol) + fatty acids Fatty acid= long HC tail with carboxyl (COOH) head Long HC chain Polar or non-polar? Hydrophilic or hydrophobic? FUNCTION: Energy storage (2x carbs) Cushion organs Insulation enzyme H 2 O dehydration synthesis

18 Saturated vs unsaturated fats Saturated fatty acid= no double bonds between carbon Long straight chain Most animal fasts Solid at room temperature Unsaturated fatty acids= double bonds with carbon Plant and fish fats Vegetable oils Liquid at room temperature Natural peanut butter

19 2) Phospholipids Constructed like fat but contains a phosphate group instead of a third fatty acid chain Hydrophilic head and hydrophobic tail Tend to form two layers (bilayer) Polar heads associated with other polar heads BIOLOGICAL IMPORTANCE Makes up the majority of the plasma membrane of cells

20 3) Steroids Entirely different structure compared to other lipids Four fused carbon rings Steroid type is based on functional group attached to carbon ring BIOLOGICAL IMPORTANCE Physical stability (cholesterol) Hormones (testosterone) 4) Waxes Long-chain fatty acids bonded with long-chain alcohols Solid are room temperature BIOLOGICAL IMPORTANCE Form protective cuticles Plants use to reduce water loss Ducks use to remain buoyant on water cholesterol

21 Proteins Monomer: Amino acids Amino and acid functional group 20 different amino acids H2O Polymers: a)peptides- 2+ amino acids b)polypeptides- chains (usually <50 amino acids) c) Protein: 1+ polypeptides formed into a shape H H N C H R O C OH

22 Building Proteins Peptide Bond Covalent bond between NH 2 (amine) of one amino acid and the COOH (carboxyl) of another C-N bond Polar Allows for H bonding Polypeptide chains have direction N-terminus = NH 2 end C-terminus = COOH end repeated sequence (N-C-C) is the polypeptide backbone can only grow in one direction

23 Shapes of Proteins Primary Sequence of amino acids Determine by DNA Sickle cell anemia Secondary Coil or folding of protein caused by the position of hydrogen bonds α helix (coil): bond between every fourth amino acid Β pleat (sheet): turns back on itself and forms bonds Tertiary Final 3D shape resulting from coils and pleats Mostly caused by interactions with hydrophobic amino acids and water and hydrogen bonds of amino acids Determines protein s specificity Quaternary Some proteins consist of more than one polypeptide Ex. Hemoglobin has 4 polypeptides attached to each other structure determines function

24 Protein denaturation Unfolding a protein conditions that disrupt H bonds, ionic bonds, disulfide bridges temperature ph salinity alter 2 & 3 structure alter 3-D shape destroys functionality some proteins can return to their functional shape after denaturation, many cannot

25 Protein-Folding Diseases Protein chaperones: proteins in the cell that fold new proteins into their shape A malfunctioning protein chaperone can improperly fold proteins resulting in a non-functional protein Possible diseases related to improper folding: Alzheimer s Disease Fatal brain disease, TSE Mad cow disease

26 Proteins BIOLOGICAL IMPORTANCE: 1) Metabolism: enzymes 2) Support: hair/nail 3) Transport: carrier proteins, hemoglobin 4) Cell communication: insulin 5) Defense: antibodies 6) Regulation: Some hormones epinephrine 7) Motion: contractile proteins in muscles Insulin Hemoglobin

27 Nucleic Acids Monomer: nucleotide Composed of: pentose (5) sugar Ribose in RNA Deoxyribose in DNA phosphate Nitrogen carbon ring The A,T,C,G part

28 Complementary Base Pairs Pyrimidines (single ring) DNA Cytosine and Thymine RNA Cytosine and uracil Purines (double ring) Adenine and Guanine Held together by hydrogen bonds

29 Adenosine Triphosphate (ATP) Nucleotide composed of adenine, ribose, and three phosphates Last two phosphates are unstable and easily broken

30 Nucleic Acids Biological Importance: genetic material stores information genes blueprint for building proteins DNA RNA proteins transfers information blueprint for new cells blueprint for next generation proteins DNA

31