life’s chemistry

Chapter 3

Life’s Chemistry

Carbon CompoundsOrganic compounds

compounds of living organismsAll contain Carbon atoms

Has 4 available electrons -valence electrons

Allows for great variety of compoundsRingsChainsbranches

Functional Groups A cluster of atoms that influence or control the

molecule they are a part of and who they react with Hydroxyl (OH) – part of all alcohols

(carbohydrates) and lipids Carboxyl (COOH) – part of amino acids which

are part of proteins, also part of lipids Amine (NH2) – part of amino acids which are

part of proteins Phosphates – (PO4) – found in nucleic acids,

and sugars (carbohydrates)

Functional Groups, cont Hydrocarbons – molecules that contain

only C & H Ex. Gasoline Add a functional group – changes the

hydrocarbon FG can be molecules that contain P,

S, N that change function of hydrocarbon

Life depends on FOUR Major Organic MoleculesMolecules that contain carbon in

combination with hydrogen and functional groups

Four major groups:• carbohydrates• lipids• proteins• nucleic acids

Monomer – single unit moleculesPolymers: - monomers bonded together Creates different characteristics Prefix – indicates number of monomers bonded

Mono-1 Di-2 Tri-3 Oligo -5 to 100 Poly – more than 100

POLYMERS EXPAND PROPERTIES OF MONOMERS

Large Carbon Molecule Monomer – small simple

molecules Polymers - repeated

monomers

Building Polymers Relies on Common Chemical Reactions

• Dehydration synthesis – the process of building polymers• Made by loosing a water molecule

• Hydrolysis - the process of breaking down polymers by inserting water• Ex. Digestion

Creating and Breaking polymers Dehydration synthesis: at H on one

monomer and OH on another monomer Hydrolysis – breaks monomers apart

Carbohydrates Organic molecules Made of CHO Source of immediate energy Sugars and starches Found in pasta, breads, rice, wheat,

potatoes, corn, etc. Monosaccharide has 1:2:1 ratio of C:H:O

Differs by how many C they contain (3-7)

Differ by how many atoms are bonded together

Carbohydrates, con’t Glucose is the simplest sugar- that provides energy for cells Most common: glucose, fructose (fruit sugar), galactose

Isomers – same formula but different shape Glucose- blood sugar Fructose – fruit sugar Galactose

Carbohydrates, con’t Disaccharides- smallest complex carb

2 monos bonded together via dehydration

Sucrose (table sugar)= fructose + glucose

Found in sugarcane, sugar beets Lactose (milk sugar) =glucose +

glactose Maltose – 2 glucose bonded

Provides energy in sprouting seeds

Used to make beer

Carbohydrates, con’t Polysaccharide- provide energy storage and structure

Chains of sugars bonded together (aka complex carbohydrate) – up to 1000’s of monomers- usually glucose

.

Carbohydrates, con’tPolysaccharides’ con’t

Cellulose – found in plant cell walls – hard/impossible to digest

Carbohydrates, con’tPolysaccharides’ con’t

Starch – STORED within cell plants – easy to digest Chitin – 2nd most common in nature

Resembles cellulose, but OH functional group replaced with one that has N

Forms exoskeleton of many arthropods (insects, spiders crustaceans) and cell wall of fungi

Starch

Lipids

Lipid – composed of fat and oil Nonpolar organic molecule Composed of CHO – no ratio, some P,

less O than carbs Dissolve organic solvents but not in

water Necessary for vitamin uptake Necessary for growth Store lots of energy (2X/g than carbs)

Lipids, con’t Compose most of cell membranes

(phospholipids) Humans – nerve transmission speeds up due to

lipids around nerves (mylin) Waxes coat leaves, fur and feathers (water

repellent) Human milk – rich in lipids Fat cells become adipose tissue in animals (white

adipose Brown adipose – in hibernating animals –

converts directly to heat

Lipids, con’t

Fatty Acids- most abundant type of LIPID Hydrophobic ends (water hating)- typical of

both ends of a FA Make up phospholipids and Triglycerides (not

waxes and sterols) Simplest lipid in nature Hydrocarbons up to 36 C with acidic funtional

group at one end

Lipids, con’tFatty acid, con’t Can be saturated FA–

all C-C single bonds holds all the H possible Solid at room temp Not healthy- butter or lard

Unsaturated FA some C=C double bonds Causes FA to kink and spread tails More H could be added Liquid at room temp Plants are more unsaturated – olive oil

More healthy fat

Lipids, types con’t Triglycerides 3 fatty acids attached to glycerol (dehydration

synthesis) Saturated : butter and animal fat, solid at room temp

Saturated with hydrogen – no double bonds Unsaturated: plant seeds, soft and liquid at room

temp DOUBLE bonds – mono unsaturated = 1 double

bond Phospholipids

Found in cell membranes (lipid bi-layer) 2 fatty acids attached to glycerol attached to a

phosphate Has one FA replaced by a phosphate group

Phosphate is VERY negative –hydrophilic Other end is hydrophobic

Lipids, types con’t Sterols – make up hormones

and Cholersterol 4 fused carbon rings Slight changes yield

Hormones Vitamins Cholesterol

»Produced in liver»Keeps cell membranes

fluid»Can be modified into

Sex hormones – testosterone and estrogen

Lipids, types con’t Waxes protect cells

Long FA attached + alcohol (OH functional group

Waterproof plants, water repellent, waterproof fur, feathers, leaves, fruits, some stems.

ProteinsHighly Diverse Molecules

Organic compoundMade of CHON + S or P

Protein, con’t Amino acid composed of

Amine (NH2) Carboxyl group R group (unique to each amino

acid) H atom Central C atom

Proteins are polypeptides 20 naturally occurring amino acids Makes infinite variety of proteins

Proteins, con’t Monomer is called an amino acid- makes a poly peptide

chain Polymer is amino acids bonded to each other

Peptide bonds created by dehydration synthesis – carboxyl group of one aa and nitrogen group of another aa

Dipeptide, tri, oligo and poly etc

Proteins have a 3-dimensional shape (conformation):

• primary (1o) structure - amino acid sequence of polypeptide chain

• secondary (2o) structure - coiling & folding produced by hydrogen bonds

• tertiary (3o) structure - shape created by interactions between R groups

• quarternary (4o) structure - shape created by interactions between two or more polypeptides

A change to the shape of a protein causes denaturation.

Levels of Protein Structure Primary chain Secondary – H bonds between parts of

peptide backbone Coils, sheets, loops, combination of all

3 Motifs, common patterns from

secondary fold Alpha helices Beta-pleated sheets

Tertiary- interactions between R groups with each other or water

Disulfide bond Abundant in keratin (forms hair,

scales, beaks, wool, and hooves Causes the permanent wave in hair

curls Quaternary

More than one poly peptide Held together by H or ionic bonds

hemoglobin

Proteins, con’t

FunctionsMovement – muscle compounds are protein

Structure – forms connective fibers

Proteins, con’tFunctions, con’t

Transport – hemoglobin transports oxygen Storage – casein in milk stores amino acids

for babies

Proteins, con’tFunctions, con’t

Regulation – some hormones – insulin

Proteins, con’t Functions, con’t

Defense – antibodies are proteins

Proteins, con’t

Functions, con’t Biochemical control – enzymes (life’s catalysts)

»Proteins that speed up reactions»Substrate – what the enzyme is acting upon- substance

being changed»Active site – where the enzyme binds and where change

takes place

Protein, con’t

Denaturation – caused by loss of homeostasis Destroys structure

Soap breaks ionic hydrophbic interactions

Salting does the same Heat also

Nucleic Acids-Carriers of the Genetic Blue Print VERY large molecules Two kinds

DNA – deoxyribonucleic acid Contain hereditary

information Double helix

RNA- ribonucleic acid Transfers DNA

information to make proteins

Some act as enzymes

Single strand

Nucleic Acid, con’t Complex molecule containing nucleotides

Sugars DNA – deoxy-ribose sugar (5 carbon) RNA – ribose sugar (5 carbon)

Phosphates Nitrogen bases

DNA Adenine Thymine Cytosine Guanine

RNA Cytosine Guanine Adenine Urasil

DNA Contain information that will

be copied to RNA Information leads to protein

production by cell 3 bases in a row will code for

a specific amino acid Aa adding up to a protein is

part of the genetic code Gene

Codes for an entire protein 2 strands of DNA are said to

be “complimentary”

RNA Single strand Makes use of DNA

information without damaging DNA

Some RNA acts as enzymes

ATP is an RNA nucleotide Carries energy for all

biological functions Urisil (U) (only in

RNA)