the chemistry of life lab biology – chapter 2 honors biology – chapter 3

The Chemistry of Life

• Lab Biology – Chapter 2

• Honors Biology – Chapter 3

Organic ChemistryOrganic Chemistry

• All living things are mostly composed of 4 elements: H, O, N, C “honk”

• Compounds are broken down into 2 general categories:

• Inorganic Compounds:– Do not contain carbon

• Organic compounds– Contain significant amounts of carbon.– Often found with common "functional

groups"

Carbon: The Carbon: The ““Swiss Army KnifeSwiss Army Knife”” of Chemistry. of Chemistry.  

• Carbon is essential to life for several reasons:– It can form strong stable

(usually non-polar) covalent bonds

– It can form up to 4 chemical bonds

– It can form multiple bonds

Organic Organic CompoundsCompounds

• Organic Compounds often form Polymers

• Long chains of smaller molecules (not atoms) called monomers, bind to form huge Macromolecules

• 4 Types: Carbohydrates, Lipids, Proteins & Nucleic acids

Why do people eat a bowl of pasta before a competition???

CarbohydratesCarbohydrates

• Includes: Sugars, starches, cellulose & glycogen

• Made of Carbon ( C ), Hydrogen ( H ), and Oxygen (O )

• Following ratio of elements CnH2nOn

• Sugars: Provide immediate energy for cells

• Simple sugars include Glucose & Fructose since these are made of only 1 Carbohydrate molecule they are known as Monosaccharides

Glucose: A Monosaccharide

Dehydration Dehydration SynthesisSynthesis

• Monosaccharides can be linked together through the process of Dehydration Synthesis– Water is removed from 2 monocaccharides - resulting in a

covalent bond between the 2 molecules

• Sucrose (table sugar) is made of 2 sugars linked together and these are called Disaccharides

• Require some digestion to be used by cells

HydrolysisHydrolysis

• Dehydration synthesis is a reversible process Called Hydrolysis.

• A water molecule is inserted where the monomers join. Breaking their bonds.

Dehydration Synthesis SimplifiedDehydration Synthesis Simplified

Hydrolysis SimplifiedHydrolysis Simplified

PolysaccharidePolysaccharidess• Starches are many monosaccharides linked

together in a single chain. These are called Polysaccharides.– Plants use Starch for energy storage e.g. Potatoes– Two types of starches

• Amylose - Long strait unbranched chains• Pectins - many linked short Amylose chains

Starch

CelluloseCellulose

• Cellulose is made of long polysaccharide chains• Plants use this for structure (e.g. Wood) - not very digestible• Due to the reverse orientation of the monosaccharide

subunits, digestive enzymes cannot hydrolyze the bonds between them

Cellulose

GlycogenGlycogen

• Glycogen is a moderately branched polysaccharide• Animals use this for short-term energy storage.• Mostly stored in the human liver until converted to

fat

Glycogen

What makes McDonald’s fries taste SOOOO good?

• ?

LipidsLipids• Lipids are

macromolecules including Fats, Waxes and Oils.

• Primary function is energy storage.

• Energy is stored in C-H bonds.

• More efficient in storing energy

• Lipids are made of 2 parts

• Glycerol - an alcohol - Serves as backbone of the molecule

• 3 Fatty acids - Long hydrocarbon chains

Dehydration Synthesis of a Dehydration Synthesis of a LipidLipid

Hydrolysis of a Hydrolysis of a LipidLipid

Types of fatsTypes of fats• Saturated fats have long chains with no double-bonds• Unsaturated fats have double bonds• Polyunsaturated fats have many double bonds

– Each time a double bond is encountered, the molecule "Bends" slightly, resulting in a lower density of the lipid. This makes the molecule more likely to remain liquid at room or body temperatures. And thus, less likely to clog cardiac arteries.

Other Other LipidsLipids

• 4 Other types of biologically important Lipids– Phospholipids - Important for membrane structure– Steroids - eg. Cholesterol & testosterone. Provide

membrane support / serve as hormones– Terpenes - serve as important components of

pigments– Prostaglandins - appear to act like localized

hormones to induce cellular/tissue responses

What do you think is happening to the proteins within these eggs????

ProteinsProteins

• Proteins are made of Amino Acids• There are 20 different amino acids. Each having a

similar general structure - Differ only in their “R” groups

Peptide Peptide BondsBonds• Amino acids form proteins via dehydration synthesis

forming peptide bonds• Two amino acids linked together are called dipeptides• More than 2 linked together are called polypeptides -

polypeptides can be thousands of amino acids long

Dehydration Dehydration synthesissynthesis

of a proteinof a protein

Hydrolysis of a Hydrolysis of a ProteinProtein

Protein StructureProtein Structure

• Protein types include globular proteins which are usually enzymes and Fiberous proteins which usually serve for structure (eg. Hair)

• Proteins Exhibit 4 “levels of structure.

Primary StructurePrimary Structure

• Primary Structure of a protein is it’s sequence of amino acids

• Primary Structure dictates all further levels of protein structure

Secondary StructureSecondary Structure

• The Sequence (primary structure) causes parts of a protein molecule to fold into sheets or bend into helix shapes - this is a protein’s Secondary Structure.

Tertiary StructureTertiary Structure

• The protein then can compact and twist on itself to form a mass called it’s Tertiary Structure

Quaternary Quaternary StructureStructure

• Several Proteins then can can combine and form a protein’s Quaternary Structure

• Various conformations are usually caused by the formation of hydrogen or disulfide bonds.

• PH, changes or heat can disrupt these bonds, permanently denaturing the protein.

Nucleic Nucleic AcidsAcids

• Two types of Nucleic acids

• DNA (Deoxyribonucleic Acid)

• RNA (Ribonucleic acid)• DNA is Formed of in a

"Double Helix" - like a spiral staircase.

NucleotidesNucleotides

• DNA is formed from Nucleotides

• These are made of 3 components– A 5-Carbon Sugar– A Nitrogenous base– A Phosphate group

• Nucleotides form a backbone through linkages from the OH group of the 3rd carbon to a phosphate group of the adjoining nucleotide. These are called Phosphodiester bonds

Types of Types of NucleotidesNucleotides• For DNA There are 4 different Nucleotides categorized as either

Purines (double ring) or Pyramidines (single ringed). These are usually represented by a letter. These Are:

• Adenine (A)• Cytosine (C)• Guanine (G)• Thymine (T)

Base Pairing Base Pairing RulesRules

• Each "Rung" of the DNA "staircase" is formed by the linking of 2 Nucleotides through Hydrogen Bonds.

• These Hydrogen bonds form only between specific Nucleotides. This is known as Base Pairing. The rules are as follows:–  Adenine (A) will ONLY bond to Thymine (T)– Cytosine (C) will ONLY bond to Guanine (G)

Summary of DNA Summary of DNA StructureStructure

RNARNA• AKA ribonucleic acid• RNA differs from DNA in

several important ways.• It is much smaller• It is single-stranded• It does NOT contain

Thymine, but rather a new nucleotide called Uracil which will bind to Adenine.

ATPATP • Short for Adenosine Tri-Phosphate. ATP is

closely related to nucleic acids.• Composed of Ribose, Adenine & a

phosphate group• Phosphate group has ability to

bind/release additional phosphate group allowing it to store or release energy