Biological Molecules

What we are mainly concerned with in our study of chemistry is the molecules that (along with water) make up our bodies and control our functions. The element that is the basis of all these molecules is CARBON.

I. What’s so special about Carbon? A. Structure: 1. Carbon’s atomic number is 6. This means that it has 2 electrons in the first energy level and 4 in the second. 2. So, to become stable, carbon needs to share 4 electrons. a) Carbon really only forms BONDS with other atoms.

3) What this means then is that carbon can bond with 4 other atoms at once. a) This creates a great diversity in the types of atoms carbon can bond with, their size and their shape. b) So, it makes sense that carbon is the base of ALL the different types of molecules that make up ALL living organisms – from the smallest bacterium to the largest blue whale to you and me! 

II. The Macromolecules A. Biological molecules – those that make up organisms – are typically called macromolecules which means LARGE molecules! B. There are 4 main types of macromolecules: 1) CARBOHYDRATES 2) LIPIDS 3) PROTEINS 4) NUCLEIC ACIDS

C) Of these 4, three are types of macromolecules called POLYMERS: large molecules made of many similar or identical subunits that are called MONOMERS. 1. The 3 macromolecules that are also classified as polymers are CARBOHYDRATES, PROTEINS and NUCLEIC ACIDS.

III. Carbohydrates: simple sugars and their polymers A) Molecules are typically made of C, H and O in a 1 : 2 : 1 ratio of atoms. 1.) Example: The formula for the carbohydrate glucose is C6H12O6. B) The building blocks (or MONOMERS) of carbs are called MONOSACCHARIDES or simple sugars

1.) Glucose and fructose (sugar that is found in FRUIT) are examples of simple sugars.

Glucose the basic sugar made by plants in photosynthesis

Fructose occurs naturally in fruits! High fructose corn syrup… a highly processed corn product

2.) Most carbohydrates are made of 2 or more monosaccharides bonded together. 3.) The diagram below shows 2 glucose molecules joining together to form a DISACCHARIDE called maltose. An additional product of this reaction is WATER.

Sucrose = Table sugar Made of glucose & fructose

Lactose is a disaccharide- made of glucose & galactose

C) Many carbohydrates are much bigger molecules made of many monosaccharides. These carbs are called POLYSACCHARIDES or complex carbohydrates. 1.) 4 important examples:

Starch is in A LOT of the plant based food we eat Starch is in A LOT of the plant based food we eat! It has MANY monomers making LONG chains

Cellulose also has many monomers and creates “nets Cellulose also has many monomers and creates “nets.” It makes up plant cell walls!

CHITIN- forms the exoskeleton of invertebrates

2.) Fill in the following table with information regarding some important polysaccharides: Where found in nature Function/Importance Starch PLANTS SUGAR (ENERGY) STORAGE FOR PLANT OR SEEDLING Glycogen ANIMAL LIVER CELLS QUICK RELEASE SUGAR (ENERGY) STORAGE Cellulose PLANT CELL WALL Makes cell walls rigid Chitin INSECT EXOSKELETON Strength

Our bodies use carbohydrates in our foods as a source of quick energy Our bodies use carbohydrates in our foods as a source of quick energy. Simple sugar molecules provide energy to our cells very quickly

IV. Lipids: fats, oils, waxes, cholesterol, steroid hormones. A.) Lipids are not POLYMERS, meaning they are not composed of similar, smaller molecules. 1.) The property that all lipids have in common is that they are not SOLUBLE in water. Or, in other words, they are HYDROPHOBIC. 2.) Lipids are composed of C, H and O atoms like carbs. However, lipids have many more hydrogen atoms relative to oxygen atoms.

B) Many lipids consist of long chains (called HYDROCARBONS) of H and C atoms joined to one smaller molecule. 1.) An example is one of the lipids found in animal fat. In this molecule, a glycerol is joined to a single fatty acid: We use lipids like this (from our food) as an energy source and for energy storage.

Saturated Fat (ie solid at room temperature)

Oils = Unsaturated fats. Has a double bond which make it crooked.

C) Other Important Lipids…Fill in the following table: Type of Lipid Basic Structure Examples Function Steroids CARBON RINGS CHOLESTOROL, ESTROGEN TESTOSTERONE CELL CONTROL THROUGH HORMONE SIGNALING, CELL MEMBRANE COMPOSITION Phospholipids PHOSPHATE HEAD W/ 2 LIPID TAILS Just phospholipids CELL MEMBRANE COMPOSITION

V) Proteins A.) Describe (in detail) the various important functions of proteins in your cells/body. B.) Proteins are made of C, H, O & NITROGEN atoms. 1.) These atoms in turn form the monomers of proteins: AMINO ACIDS. a.) These linked together in a chain form a POLYPEPTIDE CHAIN. b.) When this folds up into a specific shape, it is finally called a PROTEIN. This means it is functional and able to accomplish its task inside a cell.

2). Only 20 different amino acids make up the tens of thousands of proteins that make up living organisms.

The 20 Amino Acids Structural example of 1 Protein

3. ) The amino acids can bond in any order or number 3.) The amino acids can bond in any order or number. Just ONE amino acid difference in a protein can change the entire shape and FUNCTION of the protein.

4.) KEY POINT: The order & number of amino acids determine the final shape AND function of the protein. Any change in amino acid sequence changes the shape and function of the protein. a.) So, what happens if your cells put together a protein wrong (put the amino acids in an incorrect order)? - You get the wrong protein & it will not carry out its function.

VI.) Nucleic Acids – contain C, H, O, N and PHOSPHOROUS. A.) The monomers of nucleic acids are called NUCLEOTIDES. 1.) Each of these can be broken into 3 smaller components: a. NITROGENOUS BASE b. SUGAR c. PHOSPHATE GROUP 2.) Nucleic acids are essentially ONE or TWO strands of nucleotides bonded to one another.

B.) The 2 types of nucleic acids are DEOXYRIBOSE (DNA) and RIBOSE (RNA). 1.) In humans, about 3 BILLION nucleotides make up our DNA molecule and identical copies of this molecule exist in each of our cells. 2.) DNA is our genetic information – the molecule that is transmitted from parent to offspring to determine our traits. How does it do that? What is its function? Well it does that by controlling the construction of PROTEINS which in turn build our cell structures and carry out or facilitate most of cells’ functions!

3.) RNA is an intermediate used in the process of making PROTEINS.