The Chemistry of Life Chapter 2
Dec 27, 2015
Water makes up approx 70 to 95 percent of most organisms.
When the electrons in a covalent bond are not shared equally they form a polar molecule.
Polar Molecule: unequal distribution of charge, the molecule has a
distinct partial positive end and a partial negative end. Universal Solvent: “like dissolves like”
Water
Properties• High Specific Heat – resists changes in temp.Water retains its state at temperature levels where other liquids would begin to turn into gas or evaporate.
• Cohesion – attraction of water molecules, provides surface tension.
• Adhesion – attraction of water to different substances….meniscus
http://www.youtube.com/watch?v=DAilC0sjvy0&feature=related
Role of Carbon
Carbon has 4 electrons to share and it can share these electrons in three different ways.
4 Covalent bonds it can form
1. Single C - C
2. Double C = C
3. Triple C C
Monomer - singular unit or molecule Polymer - a group of molecules or
units bonded together.
cellulose
FUNCTIONAL GROUPS
Most organic compounds have functional groups of atoms that carry out chemical reactions.
FUNCTIONAL GROUPS -NH2 Amine Proteins
-PO4 Phosphate Nucleic Acids
-COOH Carboxylic Acid Fats -OH Hydroxyl or Lipids &
AlcoholCarbohydrates
ENDINGS
-ose Sugars (Sucrose) -in Proteins (Pepsin) -ase Protein Enzyme (Amylase) -ol Lipid
(Glycerol)
CARBOHYDRATE MONOMERS
Monosaccharides - simplest carbohydrate
Most common arrangement : C6H12O6
Names : Glucose, Fructose, Galactose
CARBOHYDRATE POLYMERS
Disaccharides - 2 monosaccharides covalently bonded
together.
Glucose + Galactose = Lactose (milk sugar) Glucose + Fructose = Sucrose (table sugar) Glucose + Glucose = Maltose (malt sugar)
Polysaccharides - long chains (polymers) Glycogen- made and stored in animals
…highly branched compared to plant starches (store food in the liver as glycogen)
Starch – is made and stored by plants (potatoes)
Cellulose – straight rigid structure that makes up the cell wall in plants (celery, cotton)
Chitin – rigid structure that makes up exoskeleton of insects
CARBOHYDRATE POLYMERS
Processes of Forming and Breaking Bonds
1) Dehydration Synthesis/Condensation - put monomers together by removing water (H2O)
2) Hydrolysis - Add H20 to break covalent bonds
http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html
LIPIDS - C, H, O
Fats, oils, waxes, cholesterol (steroids), phospholipids (C57H110O6)
Nonpolar - insoluble in water, make up cell membrane, energy, used to make hormones, and Elle’s love for *all* her students.
Fat = 3 Fatty acids + glycerol (monomers)
Fatty acid : 1. Chain of C and H atoms 2. Carboxyl group -COOH
Glycerol : 3 Carbon molecule, backbone of a lipid.
(polymer)
LIPIDcarboxyl
Triglyceride http://
users.uma.maine.edu/SusanBaker/triglyceride.html
2 KINDS OF FATS
1. Saturated Fats - single carbon bonds (solids)
2. Unsaturated Fats - double or triple carbon bonds (liquids)
PROTEINS
-N, C, H, O sometime S, and always lovemade up of amino acids
(monomers/basic building blocks of a protein)
1 Carboxyl group
1 amino group (-NH2)
1 side chain (R)
PROTEINS
PEPTIDE BONDS : bonds formed between the amino group of
one amino acid and the carboxyl group of another, with
love.What process allows peptide
bonds to take place?
Dehydration Synthesis
H - N - C - C - OH + H - N - C - C - OH
H O H O
H R H R
Proteins differ in the number and order of amino acids.– Amino acids interact to give a protein its shape.
– Incorrect amino acids change a protein’s structure and function.
hydrogen bond
Hemoglobin
NUCLEIC ACIDSP, N, C, H, OHereditary Material1. DNA - 2 chains
- deoxyribose sugar- phosphate backbone
- nitrogeneous base
2. RNA - 1 chain- ribose sugar- phosphate backbone
- nitrogeneous base
NUCLEIC ACIDS
Nucleotides : monomer of a nucleic acid.
Nucleotides are composed of 3 separate parts
5 Carbon + PO4 + Nitrogen
Base Sugar Phosphate Group
S
P
N
Nucleotide
Nucleotides are made of a sugar, phosphate group, and a nitrogen base.
A phosphate group nitrogen-containing molecule,called a base
deoxyribose (sugar)
• Nucleic acids are polymers of monomers called nucleotides.
NUCLEIC ACIDS
Nitrogen Basesadenine (purine)guanine (purine)cytosine (pyrimidine)thymine (pyrimidine)uracil (pyrimidine)
*Only in DNA
*Only in RNA
ENZYMES
Protein catalysts necessary for most of the chemical rxns that occur in living cells.
Catalysts : a substance that increase the rate of a chemical rxn.
HOW DO YOU RECOGNIZE AN ENZYME?
*Enzymes are usually named after the substrate with an -ase ending.
Substrate : the substance an enzyme acts upon
EXAMPLES : Enzyme that splits maltose into 2 glucose
molecules is maltase Proteins - Protease Lipids - Lipase
HOW DO ENZYMES WORK?
1. The enzyme shape makes it able to do work. Active Site
2. The active site is the place on the enzyme where the rxn occurs.
3. The substance the enzyme act upon is the substrate
* The active site must fit the shape of the substrate
maltose
Enzyme
HOW DO ENZYMES WORK?
4. The substrate and the active site of the enzyme come together briefly to form the enzyme - substrate complex.
*While temporarily together the enzyme may make or break bonds within the substrate.
Enzyme
OH OH
Enzyme* Note enzymes arenot changed by the rxn
HYPOTHESIS FOR HOW AN ENZYME WORKS (2)
1. Lock & Key Hypothesis : Proposes that the substrate fits exactly into
the active site on the enzyme. * Key - Active Site unlocks the lock - substrate
2. Induced Fit Hypothesis : Proposes that the enzyme changes shape
slightly to grasp the substrate at the active site.
* Hand grasping a baseball (molds to shape of object)
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__enzyme_action_and_the_hydrolysis_of_sucrose.html
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html
Diffusion
Diffusion : the net movement of particles from an area of higher concentration to an area of lower concentration.
Key factors in the rate of diffusion: concentration, temperature, and pressure.