Lecture’4:Biologi cal’Molecules’...Overview’ BIOL211’Spring’2012 2 • Macromolecules – Monomers’andpolym ers • The’four’classes’of’biological’molecules’

Lecture 4: Biological Molecules

BIOL 211 Spring 2012 1

Overview


•  Macromolecules – Monomers and polymers

•  The four classes of biological molecules –  Lipids

•  Saturated, unsaturated, trans fats •  Phospholipids •  Steroids

–  Carbohydrates •  Monosaccharides, disaccharides, polysaccharides

–  Proteins •  Amino acids •  Primary, secondary, terGary, quarternary structure

–  Nucleic acids •  NucleoGdes •  DNA and RNA

The four classes of biological molecules

•  All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids

•  These are macromolecules -‐ large molecules composed of thousands of covalently connected atoms

•  Molecular structure dictates func0on All four classes are organic molecules!


“Macro” = “large”

Not all organic molecules are part of one of the four classes of biological molecules!

What do macromolecules look like?


What do they do?


Type of macromolecule Example Func3on

Lipids Fat Cell membranes, energy storage

Carbohydrates Starch, sugar Energy storage, structure

Nucleic acids DNA, RNA Store geneGc material Proteins Trypsin Cell machinery

•  Polymer -‐ a long molecule consisting of many similar building blocks


• Monomer – the building block •  Three of the four classes of life’s organic molecules are polymers –  Carbohydrates –  Proteins –  Nucleic acids

Polymers and monomers (of both nonbiological type)

Monomer

Polymer


Polymers and monomers (of the nonbiological type)

A monomer is a single pa_ern repeated over and over. It can be composed of many

atoms

Nylon monomer


Nylon polymer

Nylon polymer

Kevlar


Polyethylene


Monomer

Polymer

Polymer

Monomer

Class I: Carbohydrates


•  Sugars and the polymers of sugars •  Simplest carbohydrate monomers are monosaccharides

•  More complex carbohydrate polymers are called polysaccharides

•  Purpose: fuel and fuel storage, building material – Sugar – Cellulose

Examples of carbohydrates •  Sugar, starch, cellulose, glucose


Sugars •  Monosaccharides have molecular formulas that are usually multiples of CH2O

•  Glucose (C6H12O6) is the most common monosaccharide

•  Monosaccharides are named by –  The number of carbons in the carbon skeleton •  3, 5, or 6 carbons and where the OHs are

Carbo = carbon, Hydrate = water


Structure of carbohydrates •  Composed of carbon, hydrogen, and oxygen •  Though often drawn as linear skeletons, in aqueous solutions many sugars form rings

15

Monosaccharides •  Some common carbohydrate monomers… –  Fructose

•  Fruit sugar – Glucose

•  Produced by photosynthesis, used as energy storage –  Ribose

•  Important in RNA (ribonucleic acid)

Glucose


High fructose corn syrup


•  Primary sweetener in the U.S. due to corn subsidies and foreign sugar tariffs

•  FDA says GRAS, but sGll health concerns on the rise

•  Normal corn syrup is all glucose –  EnzymaGc processing converts glucose into fructose

•  HFCS is 24% water, the rest sugar –  55% fructose, 45% glucose HFCS used in soda –  Fructose is much sweeter than glucose

Disaccharides •  Two monosaccharides bond together to create a disaccharide

•  Examples of disaccharides: –  Sucrose

•  Table sugar –  Lactose

•  Sugar found in milk

2


Lactose intolerance

•  Inability to digest the sugar in milk •  Caused by a lack of the enzyme lactase, which hydrolyzes lactose into its monosaccharides glucose and galactose

•  Bacteria in your gut can metabolize it through fermentaGon though, which produces hydrogen, carbon dioxide, and methane


Polysaccharides •  Many monosaccharides linked together through glycosidic bonds

•  The structure and function of a polysaccharide are determined by its sugar monomers and how they are connected

•  Two types of polysaccharides: storage and structural

Many


Examples of polysaccharides •  Storage-‐These are oken branched – Starch

Found in plant

– Glycogen found in animals BIOL 211 Spring 2012

21

Structural polysaccharides


•  One structural polysaccharide is cellulose

•  The polysaccharide cellulose is a major component of the tough wall of plant cells


What are the two main types of polysaccharides? What are some examples of

each?


Documents

Lecture’4:Biologi cal’Molecules’...Overview’ BIOL211’Spring’2012 2 • Macromolecules – Monomers’andpolym ers • The’four’classes’of’biological’molecules’