The Chemical Basis of Life Characteristics of Macromolecules Section 6

Organic Chemistry: Studying compounds that contain carbon – life is carbon based Metabolism: how cells acquire, transform, store, and use energy

Polymerization: Large compounds are constructed by joining together smaller compounds. Monomers (smaller cpds) are joined together to form polymers

Carbohydrates – Figures 6.26 & 6.27 Composed of carbon, hydrogen, oxygen - C, H, O

I. Carbohydrates A. Function Main source of energy: stored in the bonds  released when bonds are broken

B. How the body uses them: Absorbed in the digestive tract as glucose enters Breaks down complex carbohydrates If not used  stored or excess can be converted to fat About 50% of the body’s calorie intake should be from carbohydrates

C. Food that supply them Sugars and starches Plant food such as fruits, vegetables, grains Refined: much of the nutritional value and nutrients have been stripped away white flour, white rice, cakes biscuits and snack foods Your body cannot break down cellulose – but referred to as fiber (is important!)

a) Monosaccharides – simple (single) sugars Monomers: glucose, galactose, fructose b) Disaccharides – double sugars Polymers: sucrose (glucose + fructose), lactose (galactose + glucose)

c) Polysaccharides Polymers: starch and cellulose (in plants), & glycogen (in animals) Used for: storing energy

Dehydration Synthesis - “loss of water while putting together” This is how complex carbohydrates are made (these can be stored) The chemical bond is formed between the “- OH” groups in each molecule Draw (on overhead)

A water molecule is added to split apart complex carbohydrates Hydrolysis “water splitting” A water molecule is added to split apart complex carbohydrates Important to the human body because the digestive system must break down the complex carbohydrates Once complex carbohydrates are broken down, they can be used in cellular respiration

II. Lipids Fats, oils or waxes Composed of carbon, oxygen & hydrogen (C, O, H)

1)store energy (hibernation) - insulation 2)form biological membranes A. Function 1)store energy (hibernation) - insulation 2)form biological membranes phospholipid bilayer of cell membranes  Why? helps limit what can enter & exit the cell hydrophobic & hydrophilic parts (Fig 6.28) 3) used as chemical messengers (hormones)

B. How the body uses them 1) Broken down into fatty acids 2) Stored in body tissues Used to store or release energy Fatty acids + glycerol [dehydration synthesis]

Unsaturated lipids: there is 1 or more carbon to carbon double bonds C. Food that supply them Unsaturated lipids: there is 1 or more carbon to carbon double bonds Does NOT contain the max. number of hydrogen atoms possible Draw (on overhead)

Saturated lipids: carbon to carbon single bonds Contains the maximum (saturated) number of hydrogen atoms possible Draw (on overhead)

III. Proteins – Figures 6.29 & 6.30 Composed of nitrogen, carbon, hydrogen, oxygen (N, C, H, O) Monomers: amino acids (there are 20 common amino acids) Peptide bond: joins 2 amino acids [A dehydration synthesis]

A. Function Growth & repair of tissue Transport (hemoglobin transports oxygen) Pump small molecules in and out of cells

B. How the body uses them Digestive enzymes break down into amino acids When needed, proteins can enter the Citric Acid Cycle (cellular respiration)

Eggs, milk, meat, fish, poultry D. Food that supply them Eggs, milk, meat, fish, poultry

IV. Nucleic Acids – Figure 6.31 Store & transmit genetic information Composed of carbon, hydrogen, nitrogen, oxygen & phosphorus (C, H, N, O, P)

Monomers: nucleic acids RNA: ribonucleic acid DNA: deoxyribonucleic acid