Chapter 2 B i o c h e m i s t r y

Organic vs. Inorganic Compounds Inorganic compounds include all that do not contain carbon, and all that contain simple carbon, but no hydrogen. They are found in living and non-living substances. Organic compounds contain both carbon and hydrogen. Usually they also contain nitrogen and oxygen. They are found in living organisms. H2O and CO 2 vs.

Organic Compounds The Main Points Contains both carbon and hydrogen, and usually nitrogen and oxygen Found only in the bodies or remains of living things Each carbon atom forms four bonds with other atoms (usually double bonds, triple bonds are rare, yet existent) Carbohydrates, lipids, proteins and nucleic acids are four major types of organic compounds

Inorganic Compounds Main Points CO HCI CaCO Any compound that does not contain the element carbon is inorganic Examples of inorganic compounds are carbon dioxide, calcium carbonate, water, salts, phosphates, bases and certain acids such as hydrochloric acid CO 2 HCI CaCO 3

4 Types of Organic Compounds Discussed in This Chapter Four types of organic compounds will be discussed in this chapter- Carbohydrates, Lipids, Proteins and Nucleic Acids.

Carbohydrates Glucose Carbohydrates are compounds of carbon, hydrogen and oxygen in which the ratio of hydrogen to oxygen is 2 to 1. Simple sugars, or monosaccharides, are the simplest carbohydrates. Examples of monosaccharides are glucose, fructose and galactose. Glucose

Dehydration Synthesis Dehydration synthesis is a type of reaction in which two molecules are bonded together by the removal of water. Joining two monosaccharides by dehydration synthesis forms a disaccharide like maltose or sucrose. Many organic compounds are polymers that have long chains of repeating units. A polymer formed by joining many sugar molecules end to end is called a polysaccharide.Starch, glycogen and cellulose are examples of polysaccharides.

Dehydration Synthesis

Dehydration Synthesis

Lipids A lipid is an organic compound, other than a carbohydrate, that consists of carbon, hydrogen, and oxygen. Lipids go by the common names, fats, oils and waxes. Lipids are formed from the combination of fatty acids and glycerol. A fatty acid is an organic acid due to the fact that it contains a carboxyl group. Glycerol is an alcohol, or an organic compound that resembles a base in having one or more OH groups in their molecules. Glycerol has 3 OH groups in its molecule.

Fats and Functions The fats that are solid at room temperature are just referred to as fats. The fats that are liquid at room temperature are referred to as oils. If all the carbon-to-carbon bonds are single bonds, that fat is said to be saturated. If one or more pairs of carbon are joined by a double or even triple bond, they are said to be unsaturated fats. If a fat just has one unsaturated bond, it is known as monounsaturated. If it has more than one it is known as polyunsaturated. Unsaturated fats can be changed to saturated fats through hydrogenation, or adding hydrogen to it.

Saturated and Unsaturated Fatty Acids

Lipids and Functions Waxes are formed by the combination fatty acids and alcohols other than glycerol. Cholesterol is a steroid found in most animal tissues. It plays a role in the buildup of fatty deposits in arteries. Lipids have an extreme importance in many life activities. They are components of cell membranes along with other cell structures. Lipids also provide a great energy supply and serve as cushioning and insulation for the body.

Fatty Acid What is the name of the functional group on the right (-COOH) that makes this an acid? A carboxyl acid group

Dehydration Synthesis of a Fat Glycerol ↑ + 3 Fatty Acids ↓ Yields a Fat 

Amino Acids and Proteins Proteins are compounds that consist of nitrogen, in addition to carbon, hydrogen and oxygen. They serve as enzymes, antibodies, contractile material, hormones, pigments and structural parts in cells and tissues. Proteins also contain one or more chains of amino acids, the structural units of proteins. Glycine and alanine are examples of amino acids. If two amino acids are joined by dehydration synthesis, a peptide bond forms between them. The resulting molecule is a dipeptide. A polypeptide is a chain of amino acids formed by a peptide bond. Alanine

Protein Synthesis (Formation of a Peptide Bond) Click on the above link to see the formation of a peptide bond

Enzymes Enzymes are large, complex proteins. They make it possible for chemical reactions to occur in living cells.They are organic catalysts, because they can affect a reaction without being changed itself. An enzyme acts upon a substrate. The names of the enzymes usually ends with the suffix ase, and the name is often derived from the substrate. For example, maltase is the enzyme that splits one maltose molecules into two glucose ones. Lipase

Enzymes increase the rate of a reaction by decreasing the amount of activation energy needed to start the reaction

The Lock-and-Key Model Somewhere on the surface of an enzyme, there is an active site. The substrate molecules fit the shape of the active site. It then forms a temporary union with the enzyme called the enzyme-substrate complex.The substrate may then break bonds within the substrate molecule and thus separate it into two smaller molecules. This is called the lock-and-key model because the notched surface of a key can open only one lock, just like the shape of the active site of an enzyme fits the shape of only certain substrates.

Method of Enzyme Action Hydrolysis of a disaccharide What process is taking place in the above diagram?

#5 Since sucrose is what the enzyme works on, it is call the __________________. #5 is known as the Enzyme-substrate complex Substrate

Induced Fit vs. Lock and Key The lock and key model is a perfect fit between the substrate and the enzyme. The Induced fit model suggests that when the substrate enters the active site, the enzyme changes its shape to perform work on the substrate.

Characteristics of Enzyme Action Small amounts of an enzyme can affect large quantities of a substrate Enzymes enable cell reactions to proceed at normal temperatures Enzymes work best at certain temperatures Each enzyme works best at a certain pH The rate of an enzyme-controlled reaction depends on the concentrations of enzyme and substrate Some enzymes need substances called coenzymes, or a nonprotein organic substance necessary to the functioning of a particular enzyme, in order to function Some enzymes function inside the cell, others act outside the cell.

Graph showing the affect of temperature on enzyme action.

What does this graph show? The affect of pH on enzyme action What do most enzymes end in? -ase

Review of Carbohydrates

Organic Compounds Carbohydrates Proteins Lipids (Fats & Oils) Nucleic Acids (DNA & RNA)

Carbohydrates 1) Main source of energy for cell activities 2) 2:1 Ratio of Hydrogen to Carbon C6H12O6 3) Examples: Glucose (sugar) & Starch

3 Types of Carbohydrates 1) Monosaccharides 2) Disaccharides 3) Polysaccharides

Monosaccharides Ex: Glucose, fructose Mono = one 1)The most simple of the carbs 2) Are the building blocks of starches Ex: Glucose, fructose

Disaccharides Di = two 1)Two simple sugars combined 2) Known as a "double-sugar" Ex: Maltose= Glucose +Glucose

1)A long chain of monosaccharides Polysaccharides Poly = "many" 1)A long chain of monosaccharides

The End