Ch 3 Carbon Compounds

Biology IIDr. D. Mitchell

OAlmost all the molecules a cell makes are composed of carbon atoms bonded to one another and to atoms of other elements.

ONext to water, compounds containing carbon are the most common substances in living organisms.

OCarbon based molecules are called organic compounds.

Carbon’s Unique bonding propertiesO Carbon has 4 valence electrons allowing

them to form covalent bonds with many other elements.

Carbon-based molecules have three general types of structures.

Four main types of carbon-based molecules are found in living things.

1.Carbohydrates

2.Lipids 3.Proteins4.Nucleic Acids

CarbohydratesOconsist of carbon, hydrogen, and oxygen in a

1:2:1ratio Ocan be broken down to provide energy for

cells.OThe most abundant of all biological moleculesOincludes sugars and starches

3 Classes of Carbohydrates

OMonosaccharideODisaccharide

OPolysaccharide

“Saccharide” comes from a Greek word meaning sugar.

MonosaccharidesOOne monomer of sugarOSimplest carbohydrateOExamples:

OGlucose: sometimes known as blood sugar; made during photosynthesis.

OFructose: known as fruit sugar; found in most plants

DisaccharidesO Chain of two sugar monomers that

are covalently bonded.

O Examples: O -Sucrose: naturally found

in many fruits and some vegetables; table sugar

O-Maltose: a malt sugar found in grains.

O-Lactose: a milk sugar.

PolysaccharidesO Chains of many monosaccharides (simple

monomers) O Complex carbohydrates

O Examples:O -Starch: made and stored by plants and are

a source of energy for plants and animals.O Glycogen: sugar-storage equivalent of

starch in animalsO -Cellulose: major building block in plant

cell wall

LipidsO nonpolar molecules that are not

soluble in water.O broken down as a source of energy O greasy or oily to the touchO made mostly from Carbon and

Hydrogen

Types of Lipids

1. Fats and oils- Consist of a molecule of glycerol bonded to molecules of fatty acids.

OFunction: store large amounts of chemical energy in organisms

OAnimal fats are found in foods such as meat and butter

OPlant fats are oils-cooking oils such as olive oil, peanut oil, corn oil, sesame oil, and canola oil.

Triglycerides

O Neutral fats having three fatty acids tails bonded to glycerol.

O Are the most abundant lipids and its richest energy source

Saturated Fatty Acid-contain more than one Carbon-Carbon bond; saturated with hydrogen atoms. O usually solid at room temperature. O Most animal fats (grease, lard, butter) are

saturated fats.

Unsaturated Fatty Acid-contain at least one carbon-carbon double bondO generally liquid at room temperature.O Most plant fats (cooking oils) are unsaturated fats.

O Fats and oils have different types of fatty acids.

– saturated fatty acids– unsaturated fatty acids

2. Phosopholipids - lipids formed by combining a glycerol molecule with two fatty acids and a phosphate group.

O are the major component of cell membranes.

O Have a bilayered structures- a hydrophobic tail (nonpolar) and a hydrophilic head (polar).

3. Waxes- molecule having long-chain fatty acids packed together and linked to long-chain alcohols or to carbon rings

O Have a firm consistencyO Repel waterO Natural waterproof coating of fruits

and some insects

ProteinsO composed of chains of amino acidsO amino acids are molecules that contain

Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulfur.

O Your body makes 12 different amino acids; the others come from the foods that you eat.

O have many functions—serve as structural components, transport aids, enzymes, and cell signals.

Structure of Amino AcidsO consists of a carbon center surrounded

by an amino group (NH2), a carboxyl group (COOH), a hydrogen, and an R group. R stands for "rest" of the compound, which provides an amino acid's unique personal characteristics.

O Amino acids form covalent bonds, called peptide bonds with each other.

O Through peptide bonds, amino acids are linked into chains called polypeptides. A protein is one or more polypeptide.

O Proteins differ in the number and order of amino acids.

Types of Proteins

OEnzymes- promote chemical reactions.

OAntibodies-help defend against infection.

OHemoglobin-the protein in your red blood cells that transports oxygen

Hemoglobin in red blood cells transports oxygen. The structure of hemoglobin depends on hydrogen bonds between specific amino acids. Just one amino acid change causes red blood cells to have the curved shape characteristic of sickle cell anemia. (colored SEM; magnification 3500 X)

Nucleic AcidsO Nucleic acids are polymers of repeating monomers

called nucleotides (sugar, a nitrogen base, and a phosphate group).

O -Function: work together to make proteins.

Types of Nucleic Acids1. DNA - Deoxyribonucleic acid-Function: stores heredity information.-Structure: double stranded-Nucleotide sequence consists of deoxyribose(sugar); 4 nitrogen bases-Adenine, Thymine, Guanine, and Cytosine; and a phosphate group

2. RNA -Ribonucleic acid-Function: plays a role in making proteins.-Structure: single stranded-Nucleotide sequence consists of ribose(sugar); 4 nitrogen bases-Adenine, Uracil, Guanine, and Cytosine; and a phosphate group

Carbon Based Molecule

Monomer Polymer

Carbohydrate

Lipid

Protein

Nucleic Acid

To reinforce the concept of polymers(many) made from repeating monomers(one), complete the following chart:

Review

Check your answersO To reinforce the concept of polymers(many) made from

repeating monomers(one). Complete the following chart:

Monomer- (subunits) Polymer (macro molecules)

Monosaccharide (simple sugars)

polysaccharides starches- cellulose

Amino acids proteins

Nucleotides nucleic acids

Fatty acids lipids(triglycerides)

Draw a mark at the midpoint of a sheet of paper along the side edge. Then fold the top and bottom

edges in to touch the midpoint.

Fold in half from side to side.

Open and cut along the inside fold lines to form four tabs.

Label each tab.