Chapter 2

Organic Chemistry

Organic Chemistry

• Is the study of all compounds that contain bonds between Carbon atoms.

• Carbon compounds are also called organic compounds.

Chemistry of living organisms

• Chemical elements are in living matter– The cell is a chemical factory– Carbon, Hydrogen, Oxygen and Nitrogen

• (C,O,H,N…most abundant in cells)

Chemistry of living organisms

• Small amounts of S, P, Mg, I, Fe, Ca, Na, Cl and K are in cells.– Sulfur, Phosphorus, Magnesium, Iodine, Iron,

Calcium, Sodium, Chlorine and Potassium

Chemical compounds in living matter

• Inorganic– Lack combination of carbon and hydrogen:

• Water• Salts• Inorganic acids and bases

Chemical compounds in living matter

• Organic compounds– Contain carbon and hydrogen

• Carbohydrates• Lipids• Proteins• Nucleic acids

All are called macromolecules or polymers. Polymers are made of smaller subunits called monomers.

Carbohydrates

• Contain C, H, and O

• Mostly starches and sugars

• H and O are present in a 2:1 ratio

• Basic unit is a monosaccharide– Glucose, C6H12O6

Two monosaccharides combine to form a disaccharide in a process called dehydration synthesis

Monosaccharides “simple sugars”

• These molecules consist of open-chain or ring forms of 3 to 8 carbon atoms. The most common type of monosaccharide is the simple sugar "glucose".

Examples of Monosaccharides

Disaccharides• When two monosaccharides are joined together they form a

"disaccharide". This linking of two sugars involves the removal of a molecule of H2O (water) and is therefore called a "dehydration linkage". The reaction is called "dehydration synthesis".

• e.g. Glucose + Glucose = Maltose

Polysaccharide

• 2 or more monosaccharides • The simplest polysaccharide is a long chain (polymer) of

glucose, called "starch".

Polysaccharides

• There are three types of starch:

• (1) Amylose: a non-branching straight chain of glucose - used to store glucose in plants.

• (2) Amylopectin: a branched chain, also used to store glucose in plants.

• (3) Glycogen: another branched chain molecule used to store glucose in animals.

Polysaccharides

• Polysaccharides can also form very important structural components in plants and animals.

• Cellulose: is the principal constituent in plant cell walls.

• Chitin: is an important structural material in the outer coverings of insects, crabs, and lobsters. In chitin the basic subunit is not glucose. These polymers are made very hard when impregnated with calcium carbonate.

Carbohydrate Review

o Monosaccharides or simple sugars include glucose, fructose and ribose

o Disaccharides include maltose and sucrose

o Polysaccharides include starch, cellulose, chitin and glycogen

o Sugar names end in -ose

Carbohydrate Review

• Funtions– Provide chemical energy, either as a polymer

(starch) or released and used as glucose– Components of cell structures such as cell

wall in the case of cellulose– Part of nucleic acid backbone, ribose– Make outer coverings of animals with chitin

Lipids

• Contain C, H and O

• Ratio of hydrogen atoms to oxygen atoms is greater than 2:1

• Ratio is not consistent

• Some lipids are products of dehydration synthesis of 3 molecules of fatty acids and one molecule of glycerol = Triglycerides

Lipids: glycerol + fatty acid

Lipids

• Very hydrophobic: hate water

• Examples: fats and oils, triglycerides and phospholipids

• Functions: stored energy (triglycerides), components of cell structures like the cell membrane (phosopholipids and cholesterol)

Proteins

• Contain C, H, O, N and sometimes sulfur

• Made of structural units called amino acids (there are 20 AAs)

• Two amino acids combine by dehydration synthesis to form a dipeptide. These are joined by a peptide bond.

Proteins• Amino acid + amino acid = protein chain or

polypeptide

• Form through synthesis and break down through hydrolysis (addition of H2O)

• Proteins can be made of one or more polypeptides

• Proteins differ in number, kinds and order of amino acids

• Examples: insulin, hemoglobin and enzymes

Proteins

• Functions: – Control the rates of reactions– Regulate cell processes– Help form bone and muscles– Carry substances into and out of cells– Help fight disease

Enzymes

• Are proteins

• Act as catalysts: speed things up

• Enzymes increase the rate of reactions by decreasing the activation energy of reactions

• Structure: large complex proteins made of one or more polypeptide chains

• Names end in -ase

Enzymes

• Protein nature: either pure proteins or proteins associated with non-protein parts called coenzymes (vitamins)

• Active sites: enzymes are larger than their target molecules and they fold to create pockets where reacting molecules fit in

Animation of enzyme active site

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

Enzyme

• Functions to affect the rate of the reactions. Makes it go faster

• Substrate is the beginning reactant in the reaction

Enzymes

• Facts:– Substrate binds to enzyme at active site– Enzymes act on substrates to reduce energy

needed to make product– Substrate is changed– Enzyme separates from products and can form

an association with another substrate– Enzyme, as a catalyst is not used up in the

reaction– Increases reaction rate

Enzymes

• Lock and Key model: enzyme is compared to key since only one key will open a lock and enzymes are specific to one type of substrate

Enzymes

• Factors that influences them:– Temperature: increases temperate… goes

faster• Optimum temp is when it is the most effective• High temps denature (break down) the protein

Enzymes

• Also influenced by pH– pH 3 best for stomach– pH 8 best for intestines– pH 7 best for cells and blood

Enzymes

• Amount of enzyme present also effects the rate of the enzyme action

Nucleic Acids

• Contain H, O, N, C and phosphorus

• Are the monomers that make up nucleic acids

• Each consists of a 5-C sugar, a phosphate group and a nitrogenous base.

• Function: store and transmit hereditary information– Two kinds: DNA and RNA

Nucleic Acids

• Sugars vary between DNA and RNA

• DNA has deoxyribose

• RNA has ribose

Nucleic Acids

• Nitrogen bases vary between the two

• DNA has guanine, cytosine, adenosine, and thymine

• RNA replaces thymine with uracil but the others are the same

Nucleic Acids

• DNA’s nitrogenous bases always pair the same.

• A-T and C-G

• RNA’s nitrogenous bases always pair the same

• A-U and C-g

Quiz

1. Which group of organic molecules is the build block of enzymes?

A. carbohydrates

B. proteins

C. lipids

D. nucleic acids

2. Which of the following carbohydrates is a polysaccharide?

A. glucose

B. fructose

C. starch

D. sucrose

3. Which of the following macromolecules is NOT connected properly with its subunit?

A. simple sugars – carbohydrate

B. amino acids – protein

C. fatty acids and glycerol – lipids

D. glucose – nucleic acids

4. What element is found in all organic compounds?

A. nitrogen

B. carbon

C. iron

D. oxygen

5. The formation of a larger molecule from two smaller molecules with the removal of water is called?

A. hydrolysis

B. dehydration synthesis

C. metabolism

D. ion formation

6. DNA and RNA are two types of

A. carbohydrates

B. lipids

C. polysaccharides

D. nucleic acids

7. What is the function of enzymes?

A. they provide energy for chemical reactions

B. they decrease the amount of activation energy needed to begin a chemical reaction

C. they transport food in the blood

D. they are chemically destroyed as they break apart molecules in the cell

8. Which of the following factors affect the rate of enzyme action?

A. pH

B. temperature

C. amount of enzyme present

D. all of these

9. which of the following is a type of enzyme?

A. protease

B. lipase

C. amylase

D. all of the above

10. which material does the enzyme lactase act upon?

A. lipids

B. proteins

C. lactose

D. amino acids

11. What is the name of the material that is acted upon by enzymes?

A. coenzyme

B. inhibitor

C. substrate

D. fribrin

12. All enzymes are composed of

A. lipid molecules

B. sugar molecules

C. protein molecules

D. fatty acids

Answers

1. b 8. d

2. c 9. d

3. d 10. c

4. b 11. c

5. b 12. c

6. d

7. b