Organic MoleculesCarbohydrates, Proteins,

Lipids and Nucleic Acids

NC Essential Standard Bio.4.1

Organic Molecules

• Large compounds or macromolecules that contain carbon• Required by all living things• 4 Organic Molecules:

• Carbohydates, Lipids, Proteins, and Nucleic Acids• All form polymers: chains of subunits

• How do we get these molecules?

Carbohydrates

• Composed of Carbon, Hydrogen and Oxygen• Ratio: 1:2:1 (always 1 C: 2 H: 1 O)

• Collectively called SUGARS• Importance:• Main source of ENERGY for your body!

• Cells convert the carbs you eat into energy the cells can use!

Carbohydrates

• Formation of sugars (into polymers):• Condensation/dehydration reaction• Produces water

• Breakdown of sugars:• Hydrolysis reaction• Requires water

• 3 Classifications of Carbohydrates:• Monosaccharides, Disaccharides, Polysaccharides

Monosaccharides: 1 sugar

• “simple sugars”• Consists of 1 sugar subunit• Ex.: glucose, fructose (fruit), galactose (milk)

• Glucose• the primary energy source for cells• Made by plants during photosynthesis• “blood sugar” in the human body

Disaccharides: 2 sugars

• Sugar made of two monosaccharides• Examples:

• sucrose — common table sugar = glucose + fructose • lactose — major sugar in milk = glucose + galactose

• Serve as energy storage• Form of glucose transfer

in the body

Polysaccharides: Many sugars• Sugar made of more than two

monosaccharides• 3 polysaccharides• Starch – glucose storage in plants; branched

polymers• pasta, grains, rice, potatoes

• Glycogen – glucose storage in animals; highly branched polymers• Provide glucose to blood when needed; energy for

muscles

• Cellulose – found in plant cell walls; organized ‘chain-linked fence’ polymers• Provides structure and support in plants• Fiber!!! – humans can’t digest this; improves bowel

function

Whole Grains vs. Refined Grains• Why are whole grains better

for you than refined grains (processed white flour)• Processing to make white flour

removes many of the nutrients and fiber from the grain

• Leaves behind only the starchy part

• “enriched white flour” – has some nutrients added back synthetically

Carbohydrates in your diet

• Monosaccharides: simple• Glucose, quick energy - enter the bloodstream fast• Candy, honey (fructose), fruits

• Polysaccharides: complex• Polymers, take time to break down and enter bloodstream,

more sustained energy; • fiber (whole grains)!• Starches: Pasta, cereal, breads• Ex. Runner’s diet

Glucose in your body

• Human body requires a steady amount of glucose daily – fuel/energy for the body!• We don’t eat bits of food all day long• Insulin – hormone secreted by the pancreas; removes glucose

from blood and sends it to cells of liver, muscles, and fat so that it can be used or stored (as glycogen)

• Diabetes: improper regulation of blood sugar (glucose); causes high blood sugar• Body does not make enough insulin or does not respond to it

normally

Lipids

•Organic compounds that have much less oxygen than carbohydrates• Referred to as fats and oils• Ex. Beef fat: C57H110O6

• Insoluble in water because they are non-polar• Used by cells for energy storage, insulation (adipose

tissue), protective coating, cell membrane function

Types of Lipids

• 2 Main Types of lipids:• Phospholipids

• Key components in cell membranes• Control movement of materials in and out of cells

• Triglycerides: We consume these!!!• Source of energy; contain more energy than other organic molecules• Can be Saturated or Unsaturated

Triglyceride Structure

Triglycerides• Unsaturated Fats

• Contain double bonds on the fatty acid chains

• Not “saturated” with Hydrogen

• Kinked molecules; not linear

• Example: olive oil, vegetable oil, etc.; usually liquids

• Benefits when used in moderation:• Can reduce cholesterol

and cardiovascular risks

Triglycerides• Saturated Fats• Contain single bonds

between the carbons of the fatty acid chain• “Saturated” with

Hydrogen, as much as it can hold• linear molecules

• Ex. Steak fat, butter fat, usually solid (animal derived)

Triglycerides• Problems with too many

saturated fats:• Don’t really need them in

diet; body makes what it needs• Can increase “bad”

cholesterol• Fat can build up on arteries;

atherosclerosis• Can increase risk of

cardiovascular disease

Proteins• Most abundant organic molecule of the

body!• Composed of C, H, O, N and sometimes S• Amino Acids are the building blocks of

proteins.• 20 amino acids found in nature.• Amino acid polymer order determines the type

of protein.• *DNA code determines polymer order!!!

• Peptide Bond: The covalent bond found between two amino acids to create an amino acid polymer• Protein polymers are called “polypeptide chains”

Proteins

• Importance• Tissue Building!• Keratin: Hair, Fingernails; Exoskeletons• Hemoglobin: Carry O2 in blood• Insulin: lowers blood sugar; helps it get stored as glycogen;

other hormones too• Antibodies: help provide immunity, etc.• ENZYMES

• Proteins that make it easier for a reaction to take place

Proteins - Enzymes

• Enzymes• Make it easier for reactions to occur

• Act as catalysts to speed up a reaction• They lower the activation energy (energy necessary for the rxn. to

occur)• Lock and Key Model

• Makes enzymes only work for specific reaction• Important in controlling reactions of the body

Ex.: amylase, catalase, lactase• “Enzymes are proteins that end in –ase”

Enzyme Structure – Lock and Key

Denaturing Proteins

• Denature: when the shape of the protein gets permanently changed• Enzyme can’t function any longer• Caused by: change in pH or temp

• Cold = usually slows enzymes down• Hot = denatures enzymes• Too acidic or basic = usually denatures enzymes

*Important to maintain homeostasis!

Denaturing Proteins

Nucleic Acids• complex

macromolecules that stores cellular info. in the form of a code.• Made up of smaller

subunits called nucleotides.• Composed of C, H, O, N, P

atoms • Can contain the

information necessary to synthesize proteins.

DNA

• DNA: DeoxyriboNucleic Acid.• A master copy of an organism’s genetic information• Double helix shape• Strands of DNA form genes, which are the components of

chromosomes.

• RNA: RiboNucleic Acid. • Helps in the formation of DNA and many proteins.• Not a double helix – single strand