v. organic compounds introduction: organic compounds = carbon organisms=organic why carbon? 1.4...
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V. Organic Compounds
Introduction:
Organic compounds = carbon
organisms=organic
Why carbon?
1. 4 valence e- = 4 covalent bonds
2. can form single, double or triple bonds
3. can bond to other carbon atoms, making long chains, branched molecules or rings.
Structuralformula
Ball-and-stickmodel
Space-fillingmodel
Methane
The four single bonds of carbon point to the cornersof a tetrahedron.
organic compounds unique properties depend on
size & shape of the molecule
groups of atoms (functional groups) attached to it
compounds containing functional groups are hydrophilic (water-loving)
makes them soluble in water
Functional groups (pg. 35 formulas)
1) Hydroxyl group
2) Carbonyl group
3) Carboxyl group
4) Amino group
5) Phosphate group
* Methyl group (non-polar)-
*affects shape & function
VI. Macromolecules
large organic molecules
also called polymers
made of smaller “building blocks” called monomers
Monomers link together to form polymers through dehydration reactions, which remove water
Polymers are broken apart by hydrolysis, the addition of water
A. Carbohydrates – (polysaccharides)
1. monosaccharide (simple sugar) = monomer
• glucose, fructose (fruit), galactose (milk)
• made of C, H, O (1:2:1)
• functional group(s): hydroxyl, carbonyl
• used for energy in cells & as raw materials to manufacture other organic molecules
2. disaccharide -two monomers (sugars) joined by dehydration reaction
• sucrose (glucose + fructose) = table sugar
• maltose (2 glucose) = grain sugar
• lactose (glucose + galactose) = milk sugar
3. Polysaccharides – many monomers (sugars)
• function in cells as a storage molecule or a structural compound
a)Starch- storage molecule in plants made of glucose
b)Glycogen- storage molecule in animals made of glucose
c) Cellulose- polymer of glucose that forms plant cell walls
d)Chitin- used by insects & crustaceans to build an exoskeleton
Starch granules inpotato tuber cells
Glycogengranulesin muscletissue
Cellulose fibrils ina plant cell wall
Cellulosemolecules
Glucosemonomer
GLYCOGEN
CELLULOSE
Hydrogen bonds
STARCH
B. Lipids
• not true polymers
• non-polar, water insoluble (hydrophobic)
• made of C, H, few O
• hydroxyl & methyl groups
• long term energy storage, insulation, cushion/protect organs, prevent water loss, chemical messengers, cell membranes
• contain twice as much energy as a polysaccharide
Fatty acid
Glycerol
1. Fats/Oils (triglycerides)
• made from glycerol and 3 fatty acids (monomers) linked by dehydration reaction
a. unsaturated fats - have fewer than the maximum number of hydrogen atoms (good)
• made of fatty acids that contain double bonds, causing kinks or bends in the carbon chain
• usually liquid at room temp
• plants, fish
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b. saturated fats – have maximum number of hydrogens, no double bonds (bad)
• solid at room temp
• animal fat (lard), butter
2. Phospholipids -important part of cell membrane 3. Steroids -lipids made of fused ring structures
• cholesterol a steroid that plays a significant role in the structure of the cell membrane & sex hormones
4. Waxes – cuticle coating on plants
C. Protein (polypeptide)
• amino acids (20) = monomers
central C atom & 4 other things:
1) amino group
2) carboxyl group
3) another chemical group represented as “R”
4) H
peptide bonds holds amino acids together
• made of C, H, O, N
Carboxylgroup
Aminogroup
1. Functions of Proteins (8) – determined by shape
a. Structural – hair, nails, fibers in tendons
b. Contractile (movement) - found in muscles
c. Signal (regulation) – hormones
d. Storage – egg white (albumin)
e. Transport – hemoglobin carries O2 in blood
f. Defense - antibodies of the immune system
g. Receptors - built into cell membranes
h. Enzymes – control chemical reactions
Four Levels of Protein Structure
Amino acids
Primary structure
Alpha helix
Hydrogenbond
Secondary structure
Pleated sheet
Polypeptide(single subunitof transthyretin)
Tertiary structure
Transthyretin, withfour identicalpolypeptide subunits
Quaternary structure
D. Nucleic Acids (DNA & RNA)
• Nucleotide = monomer
• Made of C, H, O, N, P
3 parts
1) five-carbon sugar (pentose)
ribose in RNA
deoxyribose in DNA
2) phosphate group
3) nitrogenous base (1 of 4)
Phosphategroup
Nitrogenousbase
(adenine)
Sugar
• 4 nitrogenous bases
adenine (A)
thymine (T) (DNA only)
cytosine (C)
guanine (G)
uracil (U) (RNA only)
1. DNA = 2 strands wrapped around each other forming a double helix
• A pairs with T
• C pairs with G
Functions: compose genes, determine the structure of proteins
2. RNA = single strand
Functions: copy & transfer DNA so proteins can be made
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VII. Enzymes
A. Properties
1. large proteins
2. end with –ase
3. very specific to a reaction
4. reusable
B. Function
1. act as biological catalysts (speed up rate of a reaction without being used up)
• lower activation energy needed to start a reaction by weakening chemical bonds
C. Enzyme-Substrate Complex
1. Active site- specific shape on enzyme
2. Substrate- reactant(s) that can attach to active site to react
• lock & key design - shape of active site is so precise that only the intended substrate(s) can attach.
D. Factors Affecting Enzyme Activity (Rate)
1. temperature – too high will denature (unfold) enzyme, too low will slow down rate
2. pH – needs to be around 6-8; other levels can denature enzyme
3. concentration of substrate – if more substrate than enzymes, rate slows down