Biochemistry Chapter 2

Background

• Organic molecules contain both the elements carbon and hydrogen– Glucose C6H12O6

• Inorganic molecules do not contain both carbon and hydrogen– Water H2O

– Carbon Dioxide CO2

Background

• Dehydration Synthesis Reaction– A reaction that builds larger molecules

from smaller molecules

– A water molecule is released during the process

– Small + Small Large + H2O (water)

Background

• Hydrolysis Reaction– A reaction that breaks down larger

molecules into smaller molecules

– A water molecule is used up during the process.

– Large + H2O (water) Small + Small

Background

Dehydration Synthesis Reaction

Small + Small Large + H20

Large + H20 Small + SmallHydrolysis Reaction

Chemistry Review- THE ATOM

• Atom is the basic unit of matter– Remember

• Proton = positive charge• Electron = negative charge• Neutron = neutral charge

• Compound-combo of 2 or more elements

• Molecule- formed when atoms joined together; smallest unit of most compounds

Chemical Bonds

• Ionic bond – 1 or more electrons transferred

• Covalent Bond– electrons shared

• -Van der Walls Forces– weak intermolecular forces– Can develop when molecules are close

together

Water is Essential to Life

• Water Polarity– polar molecule-the charges are

unevenly distributed– like a magnet with poles

• A water molecule is polar because there is an uneven distribution between the O and H atoms– negative near O positive

between H

Polarity allows water moPolarity allows water molecules to attract each otherHydrogen bonds- bonds between H molecules

-weak-allow for special

properties of water

Mixtures: Solution and Suspensions

• Mixture- 2 or more elements or compounds– -physically mixed together but not chemically

combined– -can be separated– ex: salt and pepper, sugar and sand

•  Solutions- mixture of 2 or more substances in which the molecules are evenly distributed– ex: table salt in water– table salt= solute- substance that is dissolved– water= solvent- does dissolving

• Suspension-mixtures with non- dissolved material– ex: -water and sand

Acids, Bases and pH• Remember: ion = charged

particle– pH= “potential of Hydrogen”– indicates the concentration

of H+ ions  pH scale- ranges from 0 – 14 pH 7 = concentration of H+

ions and OH- equal

 Below 7 = acidic = more H+ ionsAbove 7 = basic = more OH- ions• Controlling pH= buffers • buffers= weak acids or bases

– -can react w/strong acids or bases

– prevent sudden changes in pH

Chemistry of Carbon

• I. The Chemistry of CarbonA. Characteristics of Carbon

4 valence electronsallows C to form strong covalent bonds

2. Can form C to C bondsa. Types of bonds

i. single C-Cii. double C=Cii. triple C=C

• 3. Very versatile (can make many different compounds)

Macromolecules

A. Formed by polymerization– 1. Process of joining many monomers

B. Types of Biological macromolecules

1. Carbohydrates2. Lipids3. Nucleic Acids4. Protein

The Macromolecules of Life

1.Carbohydrates2.Lipids (Fats)3.Proteins4.Nucleic Acids

Carbohydrates

• Function: molecules that contain energy and give structure

• Composed of which 3 elements? – Carbon, Hydrogen, and Oxygen

• The ratio of hydrogen to oxygen is 2:1

Carbohydrates

• Basic Building block is a Monosaccharide, which is a simple sugar– Example: C6H12O6 (Glucose)

• Glucose - made during photosynthesis; main source of energy for plants and animals

Carbohydrates

• Diagram of Glucose

Carbohydrates

Fructose - in fruits, sweetest of the simple sugars

Galactose - in milk

Carbohydrates

• Disaccharides are formed when 2 monosaccharides combine in a dehydration synthesis reaction:

– Examples of disaccharides• Lactose = glucose + galactose• Sucrose (table sugar) = glucose + fructose

Carbohydrates

Carbohydrates• Polysaccharides are 3 or more

monosaccharides joined together

• 3 biologically important examples: – Glycogen in animals– Starch in plants– Cellulose in plants

• These molecules have a lot of energy stored in them repeating glucose units

Carbohydrates• Polysaccharide

Lipids (Fats)• Function: these molecules store long-term

energy and make up the cell membrane of cells (phospholipids)

• Lipids are made of which elements? – Carbon, Hydrogen, and Oxygen

• There are many carbon and hydrogen atoms but only a few oxygen atoms

• Do lipids dissolve well in water? – No - they are therefore considered hydrophobic

(water-fearing)

• Some examples of lipids: oils, fats, waxes, steroids, phospholipids

Lipids (Fats)

Lipids

Examples of lipids1. Steriods- act as chemical messengers2. Fatty acids i. Saturated- all single bond ii. unsaturated (olive oil)- one C=C iii. polyunsaturated (cooking oils: corn,

peanut, sesame, canola) – many

C=C

Proteins

• Function: control the rate of reactions, transport materials, form bone and muscle, transport materials. Fight disease, act as enzymes

• Composed of which 4 elements? – Carbon, Hydrogen, Oxygen, Nitrogen and

sulfur

• Basic building block: amino acid (AA)

Proteins

• Basic building block: amino acid (AA)

• Question: How many different amino acids are there? – 20

Proteins

• Dipeptide– 2 amino acids bonded together with a

peptide bond. They are joined by dehydration synthesis reactions

• Polypeptide– long chain of AA bonded together

• Proteins are composed of 2 or more polypeptide chains

Proteins

• Enzymes are biological catalyst made of protein

• What is a catalyst? – A substance that speeds up a chemical reaction

without being altered• How does an enzyme speed up a reaction?

– It lowers the activation energy needed to start the reaction

• Substrate - the molecule(s) that are acted upon by the enzyme

• Active site - the spot on the enzyme where the substrate fits

Proteins - Enzymes

• Lock and Key Model:

Proteins - Enzymes

• Lock and Key Model:

Proteins - Enzymes

• Lock and Key Model:

http://waynesword.palomar.edu/molecu1.htm#lock

Proteins

• How many times can a single enzyme be used?– Thousands

• Enzymes work at specific pH values and temperatures. If the pH or temperature goes too high or too low, the enzyme won’t work properly– ex. Lactase catalyzes (speed up) the breakdown

of lactose into glucose and galactose– ex. Catalase speeds up the breakdown of

hydrogen peroxide

Nucleic Acids• Nucleic Acids are composed of Carbon,

Hydrogen, Oxygen, and Nitrogen, Phosophorous• Nucleic Acids function in living things as the

structure of DNA and RNA– The blueprint of life

• Monomers- Nucleotides – Composed of a 5-Carbon Sugar, Phosphate group,

and Nitrogen Base– Store genetic information– Held together by covalent bonds

• Polymers- Nucleic Acids– A string of nucleotides– DNA or RNA

Nucleic Acids

• There are four nitrogen bases, meaning there are four “types” of nucleotides– Adenine, Thymine, Guanine, Cytosine

• RNA is a single strand nucleic acid• In DNA, two strands of nucleic acid bond

– Double Helix– Adenine always bonds with Thymine– Guanine always bonds with Cytosine

Nucleic Acids

NUCLEOTIDE

RNA

DNA

Biochemistry THE END