Biomolecules Ch - 2The Molecules of Life

Molecules are combinations of atoms What are the 4 elements that make up 96% of living matter? Carbon C Oxygen O Nitrogen N Hydrogen H

Importance of Carbon Carbon has 4 valence electrons carbon can create strong skeletons or backbones

Carbon bonds with Carbon Biomolecules have carbon backbones – They are organic molecules C-skeletons: straight chain, branched chain, ring

Carbon bonds with Hydrogen Hydrocarbons are molecules composed of only hydrogen and carbon Are hydrophobic

Carbon bonds with functional groups Functional groups are groups of atoms that interact in predictable ways Functional groups attach to carbon backbones to create biomolecules

Hydroxyl Group alcohols polar – Hydrophilic – Soluble in water Found in sugars

Carbonyl Ketones (within) and aldehydes (on the end) Polar Found in sugars

Carboxyl Group carboxylic acids Polar Acidic Found in fatty acids and proteins

Amino Group Amines Polar Basic Found in amino acids (proteins)

Phosphate Group Store/transfer energy Polar; water soluble Found in nucleic acids Found in ATP (adenosine triphosphate) = cell energy

Monomers & Polymers Biomolecules are combinations of smaller molecules called monomers Monomers link together to form polymers

Building and breaking polymers dehydration synthesis = monomers combined to make polymers

Building and breaking polymers Hydrolysis = polymers are broken into monomers

4 Biomolecules All polymers are classified into one of 4 biomolecules: – Carbohydrates – Lipids – Proteins – Nucleic Acids

Carbohydrates!

Carbohydrates Ring shape Provide and store energy; building material in plants

Carbohydrates Carbs are hydrophilic – Full of hydroxyls and carbonyls

Monosaccharides 1 ring Example: Glucose (C 6 H 12 O 6 ) energy source

Disaccharides Double Sugars (oxygen bridge) Example: Sucrose immediate energy or stored

Polysaccharides Long polymer of sugar monomers Complex carbs Starch: chain of glucose monomers – used by plants as sugar storage – Animals can break down starch to release glucose and energy

Polysaccharides Glycogen – Used by animals to store extra sugar – Stored in the liver

Polysaccharides Cellulose – Used by plants for building material – Most animals cannot break down cellulose; passes through body as fiber Chitin – Used by fungi for building material

Lipids!

Lipids ALL hydrophobic

Lipids: Phospholipids Phospholipids: form cell membranes

Lipids Fats (triglycerides) 3 C backbone (glycerol) attached to 3 long chains of hydrocarbons (fatty acids) Store energy, cushion organs, insulate

Lipids: Fats Saturated fats – all fatty acids have maximum H atoms – Solid at room T Unsaturated fats – One or more double bond in fatty acid chain, causing in to kink Which do you want to limit in your diet?

Lipids: Steroids C-skeleton of 4 fused rings Steroids are chemical signals – Cholesterol = essential in cell membranes; building block of other steroids

Proteins! When there is something to do, it is a protein that does it.

Proteins Proteins have many important functions. Some are: – Antibodies – Receptors – Enzymes – Neurotransmittors – Energy Storage – Build and Repair muscles and tissue

Amino Acids Proteins are polymers made up of monomers called amino acids Amino Acids consist of one central C bonded to 4 partners: – H-atom – Carboxyl – Amino – An “R-group”

Polypeptides Amino acids link together forming peptide bonds

Protein Structure Polypeptides take shape to from a protein. Each protein has its own unique 3-D shape that determines its function The shape of a protein is determined by how its amino acids interact

Denaturation Proteins can be unraveled and changed by changes in temp, pH, or other changes in environment

Enzymes

Protein: Enzymes An enzyme is a biological catalyst Lower the activation energy of a specific reaction – allow chemical reactions in cells to occur at normal temperatures

Protein: Enzymes Each enzyme has a specific job Used again and again Ability depends on shape

Protein: Enzymes Substrate molecules fit into active site, enzyme molds around substrate – enzyme-substrate complex Enzyme breaks up the substrate