MACROMOLECULESMACROMOLECULESA Brief ReviewA Brief Review

•What are the 4 major macromolecules?•How are they made or broken down?

•What are they made of?•What are they used for?

Macromolecule Basics:Macromolecule Basics:• “MACRO-” = LARGE

• large biological molecules• “building blocks” for life

• 4 macromolecules:• Carbohydrates• Lipids• Proteins• Nucleic acids

• All but lipids are POLYMERS • Polymer - a long molecule consisting of many similar

building blocks (monomers) linked by covalent bonds• Monomer – repeating units of a polymer• ANALOGY = a train

How are How are macromolecules macromolecules made and broken made and broken

down?down?• Synthesis = made

• Dehydration (condensation) reaction – 2 monomers are covalently bonded together through a LOSS of a WATER molecule

• Decomposition = broken down• Hydrolysis (hydration) – covalent

bonds between monomers are broken by the ADDITION of WATER

• Reverse of dehydration!

CARBOHYDRATESCARBOHYDRATES

• AKA: “sugars”, saccharides

• Serve as FUELS, sources of carbon, and structural support

• Composed of “CHO”• Name ends in “-ose”• 2 trademarks of

sugars:• a carbonyl group

(>C=O)• multiple hydroxide

groups (-OH)

GLUCOSE

CARBOHYDRATESCARBOHYDRATES• Carbs can be classified by

the number of monomers that comprise the sugar:• Monosaccharides - “simple

sugars”• Examples: glucose; fructose;

galactose

• Disaccharides – consists of 2 monosaccharides

• glucose + glucose = maltose• glucose + fructose = sucrose

• Polysaccharides (“complex carbs”) – consists of many monosaccharides (usually more than 8)

• examples: starch or glycogen

Reaction??

LIPIDSLIPIDS• LARGE molecules

that are not polymers!• All are

hydrophobic & consist mostly of hydrocarbons.

• Composed mostly of “CHO”• Have less oxygen

atoms than carbs.

?

?

Types of LIPIDS:Types of LIPIDS:• 3 major groups:

• Triglycerides – “fats” & “oils”• FUNCTIONS: long-term energy

storage, protection, & insulation.• Made up of:

• 1 glycerol – an alcohol

AND• 3 fatty acids – long C skeleton (of

hydrocarbons) + a carboxyl group• Saturated vs. unsaturated fats/oils?

• Phospholipids – • Function: major component of cell

membranes!!!!• Structure:

• similar to triglycerides, but only has 2 fatty acid tails

• “TAIL” – nonpolar; hydrophobic• 3rd hydroxyl group is attached to a

phosphate group• “HEAD” – polar; hydrophilic

• Steroids – • Structure: characterized by 4 fused

rings of carbon skeletons• Functions: regulate growth &

development (hormones)

PROTEINSPROTEINS• Account for approx. 50% of

the dry mass of cells!• Composed mostly of “CHON”• Basic structure??

• Proteins consist of one or more polypeptides folded and coiled into specific conformations (shapes).• Polypeptides are polymers

of amino acids.Amino acids polypeptides

protein

basic structure

R = ??

Amine group?

Carboxyl group?

The MANY Functions of Proteins!The MANY Functions of Proteins!

• Structural support (collagen & elastin make connective tissues; keratin makes hair, feathers, & horns)

• Energy storage (ovalbumin-egg whites; casein-milk; plants & seeds)

• Transport of other substances (hemoglobin and red blood cells)

• Signaling within an organism (nerve cell transmission; insulin-regulates blood sugar)

• Movement (actin & myosin-muscle contraction)• Defense against disease (antibodies)• As ENZYMES: regulates metabolism (catalase-breaks

down H2O2)

Nucleic AcidsNucleic Acids• Composed mostly of

“CHONP”• Are composed of

monomers called nucleotides.

• Each nucleotide contains:• A nitrogenous base (N)• A pentose (CHO)• A phosphate group (P)

• 2 types of nucleic acids:• Deoxyribonucleic acid

(DNA)• Ribonucleic acid (RNA)