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.

Carbon skeletons vary in length.

PropaneEthane

Length.

Skeletons may be unbranched or branched.

Butane Isobutane

Branching.

Double bonds.

2-Butene

Skeletons may have double bonds,which can vary in location.

1-Butene

Cyclohexane Benzene

Skeletons may be arranged in rings.Rings.

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

Estradiol

Male lionTestosterone

Female lion

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

Unlinkedmonomer

Short polymer

Unlinkedmonomer

Short polymer

Longer polymer

Dehydrationreaction

Hydrolysis

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

Glucose(an aldose)

Fructose(a ketose)

Structuralformula

Abbreviatedstructure

Simplifiedstructure

2. disaccharide -two monomers (sugars) joined by dehydration reaction

• sucrose (glucose + fructose) = table sugar

• maltose (2 glucose) = grain sugar

• lactose (glucose + galactose) = milk sugar

Glucose Glucose

Maltose

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

Water

Hydrophobictails

Hydrophilicheads

Water

Phospholipid

cholesterol

Carboxylgroup

Amino acid

Aminogroup

Amino acid

Peptidebond

Dipeptide

Dehydrationreaction

Leucine (Leu)

Hydrophobic

Serine (Ser)

Hydrophilic

Aspartic acid (Asp)

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)

Sugar-phosphatebackbone

Nucleotide

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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Basepair

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.

Induced fit – active site changes shape slightly when substrate binds to it.

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

4. Inhibitors – can stop/slow rate

a. competitive – resemble substrate & compete for active site

b. non-competitive – attach to enzyme some place other than active site,

altering shape of active site; substrate cannot fit