2.3 Carbon Based Molecules

KEY CONCEPTCarbon-based molecules are the foundation of life.

A.Carbon atoms have unique bonding properties.

• Carbon forms covalent bonds with up to four other atoms, including other carbon atoms.

• Carbon-based molecules have three general types of structures.– Straight Chain– Branched Chain– Ring

• Many carbon-based molecules are made of many small subunits bonded together.– Monomers are the individual subunits.– Polymers are made of many monomers.

• Molecules are formed between monomers when a water molecule is lost

• Called condensation reaction or dehydration synthesis

Formation of Macromolecules

Formation of Macromolecules cont.

•Polymers are disassembled (broken up) into monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.

• Hydrolysis means “to break with water”. Bonds between monomers are broken by the addition of water molecules.

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

1. Carbohydrates• Aka sugars • Made of carbon, hydrogen, and oxygen.

- Structure 1:2:1

SucroseC12H22O11

***Dehydration synthesis

• Carbohydrates include sugars and starches.

• 3 types– Monosaccharides

(MONOMERS) are simple sugars.

– Disaccharides are two sugars.

– Polysaccharides many sugars, include starches, cellulose, and glycogen

Glucose, Fructose, and Galactose(Monosaccharides)

•Glucose: Made during photosynthesis Main source of energy for plants

and animals•Fructose:

Found naturally in fruits Is the sweetest of

monosaccharides•Galactose:

Found in milk Is usually in association with

glucose or fructose

Disaccharide

•Disaccharide – two monosaccharide bonded together

• Table sugar (sucrose) = made up of glucose + fructose bonded together

• Milk sugar (lactose) = made up of glucose + galactose bonded together

Polysaccharide•Polysaccharide = more than two monosaccharide bonded together by glycosidic bonds

• Serve as storage material or building material

• Storage (examples: starch, glycogen)

• Structural (examples: cellulose, chitin)

•A complex carbohydrate is a polysaccharide with 12 or more monosaccharide units.

• Pasta and starches are polysaccharides

• Potatoes are a starch

• Carbohydrates can be broken down to provide energy for cells.

• Some carbohydrates are part of cell structure.

Polymer (starch)

Starch is a polymer of glucose monomers that often has a branched structure.

Polymer (cellulose)

Cellulose is a polymer of glucose monomers that has a straight, rigid structure

monomer

• Elements C, H and O• Nonpolar molecules – will not

mix with water – Hydrophobic• Not soluble • Include fats, oils, and

cholesterol– Monomer Glycerol and 3

Fatty Acids – carbon chains bonded to hydrogeno Triglycerides

– Fats and oils contain fatty acids bonded to glycerol.

2. Lipids

• Lipids have several different functions.– Used to store energy for long term– Make up cell membranes– Used to make hormones– Waterproof coverings

• Fats and oils have different types of fatty acids. – Saturated fatty acids

o Carbons single bondedo Come from animals / Clog arteries

– Unsaturated fatty acidso Double bonded carbon atomso Do not come from animals / Don’t clog arteries

At room temperature, the molecules of a saturated fat are packed closely together, forming a solid.

At room temperature, the molecules of an unsaturated fat cannot pack together closely enough to solidify because of the kinks in their fatty acid tails.

• Phospholipids make up all cell membranes.

– Polar phosphate “head”– Nonpolar fatty acid “tails”

Phospholipid

3. Proteins

• Majority of processes in body occur because of proteins– Polymers of amino acid

monomers– Made of Elements C, H, O, N– 20 different amino acids are

used to build proteins in organisms.

– Amino acids made of 3 functional groups- Amine NH2

- R group - Carboxyl - COOH

– Amino acids differ in side groups, or R groups

– Amino acids are linked by peptide bonds

• Proteins differ in the number and order of amino acids.– Amino acids interact to give a protein its shape.– Incorrect amino acids change a protein’s structure and

function.

hydrogen bond

Hemoglobin

What are some functions of proteins?• 4 Types of Proteins & their function in the body:

• Regulatory (ex: Enzymes)• Controls the rate of reactions in your

body

• Transport (ex: Hemoglobin transports O2)• Sending nutrients to different parts of

the body

• Structural (ex: collagen, found in skin and bones)• Forms/ makes up different parts of the

body

• Protective (ex: antibodies protect against disease)• Makes cells that act as fighters for the

body

• Stores and transmits genetic information

• Made of the Elements C, H, N, O, & P

• Two types:• DNA• RNA

• are polymers of monomers called Nucleotides

4. Nucleic Acids

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)

• Nucleotides are made of:– 5 carbon sugar– Phosphate group– Nitrogenous base

• DNA stores genetic information

• RNA builds proteins– Transports DNA info from

nucleus to other cell parts.

DNA

RNA

Monomer + Monomer, etc. = Polymer

Polymer or Macromolecule

Monomer Examples Elements

Carbohydrate Monosaccharides Sugars and Starchs

C, H, O

Lipids Glycerol and Fatty Acids

Fats, Oils and Waxes

C, H, O

Proteins Amino Acids Enzymes C, H, O, N, P

Nucleic Acids Nucleotides DNA and RNA C, H, O, N