The general idea: A macromolecule (polymer) is made up of many monomers (building blocks).
Condensation Reaction = monomer + monomer + monomer + etc.........=== joined by covalent bonds to form ===> polymer + water
This lecture topic is not covered in much detail in your textbook in chapter 2.
Why do we need to study chemistry if this is a biology class?? All living organisms, including yourself, are organized from chemical molecules. I remember my freshman biology textbook stating that the human body was made from ~$5 dollars worth of chemicals and lots of water. That is going a little extreme, but let's think about some of the major types of molecules found in living organisms.
CHEMISTRY OF LIVING ORGANISMS
The most common Chemical Elements in Living organisms are abbreviated: C, H, N, O, P, S, Fe, Ca, Mg, Na, Cl, Zn.
Do you know what all those letters mean?
Look at the ingredients of a daily multi-purpose vitamin. All of these chemicals contribute to the structure, function and health of our body tissues.Atoms (the smallest units of a chemical element) are joined together by covalent bonds (strong energy bonds) to form larger molecules. The molecules can be small as in water, oxygen gas, carbon dioxide... or molecules can be huge as in starch, DNA, proteins. Small molecules are made of a few atoms connected by the energy bonds, large molecules have numerous bonds connecting many atoms together. If the covalent bonds in molecules are broken, the released energy can be transferred to another chemical bond, used for cellular work, or lost as heat.
MACROMOLECULES OF LIFE
There are four main classes of the huge molecules
in our body = Carbohydrates, Proteins, Lipids, Nucleic Acids. Although each
class has their own specific function, the macromolecules are created similarly
in a stepwise fashion from small building blocks. Think of a table with
thousands of Lego pieces that is connected together little by little to
create a huge train, bridge, skyscraper, etc.
The general idea: A macromolecule (polymer) is made up of many monomers
(building blocks).
Condensation Reaction = monomer + monomer + monomer + etc.........===
joined by covalent bonds to form ===> polymer + water
Hydrolysis Reaction = polymer + water === can be broken down into ===> monomer + monomer + etc............
A. Carbohydrates (function: energy storage, structure)
monomer = glucose
polymer = glycogen (animals), starch (plants), cellulose (plant cell walls), chitin (insect exoskeleton, shrimp shell)
We eat complex carbohydrates (polymers) such as pasta, breads, potato, and rice. Digestive enzymes in our digestive system breaks down the starch molecules and convert them into monomers (glucose). Glucose is delivered to all the cells of our body to be broken down further to release energy that our cells can use.
Note that although all the complex carbohydrates (polymers) are made of glucose, cellulose monomers are connected by a different chemical bond than glycogen monomers. We only have enzymes that recognize and can break the chemical bond in glycogen but not the bond in cellulose (that is why we eat plants (to get insoluble cellulose fiber passing through our system). This really shows that each type of enzyme in our body is incredibly specific in its action/function.
B. Proteins (many diverse functions: structural, enzymes, antibodies, transport....)
monomer = amino acid; 20 different types
polymer = protein (also called polypeptide )
Each specific type of protein has a specific sequence of amino acids(AA).
The AA sequence determines the specific three-dimensional structure of protein.The protein must have its correct 3-D structure in order to perform its specific function. There are thousands of different types of proteins in our bodies - each with a very specific function. In many cases (the ones we will talk about during this course), one protein which does not function properly ....could cause drastic effects on our overall health.
Examples: lactose-intolerance, alcohol-intolerance, sickle-cell anemia, hemophilia,
C. Lipids (function of triglycerides = energy storage, other lipids have variety of functions). All lipids are alike in that they are hydrophobic = NOT soluble in water.
Triglycerides: Fats and Oils are made of three fatty acids and a glycerol.
Each fatty acid is a long, long chain of many carbons and hydrogens (connected by strong covalent chemical bonds (which provides energy when broken).
Other lipids include cholesterol, steroids, waxes, vitamins A,E,K.
Phospholipids are molecules that have both a hydrophobic and a hydrophillic end.
These are the main molecules that make up the membranes around the entire cell and organelles. Phospholipids will form a bilayer, and thus able to selectively allow certain molecules to pass through but keep other molecules (charged ions, large molecules) out.
D. Nucleic Acids (function of DNA and RNA: genetic information)
monomer = nucleotide
special nucleotide = ATP = energy molecule ("battery") for cells
polymer = deoxyribonucleic acid (DNA), ribonucleic acid (RNA)
We will discuss the structure and function of nucleic acids in detail in the second half of the course. But basically, many genetic diseases are due to a defect in the function of one protein (which was caused by a defect in the DNA).
*See Reading 2.1 on page 20-21 of textbook for examples of genetic defects in these basic molecules. Note that the four classes of macromolecules are needed in the body in large amounts. Vitamins and minerals are micornutrients, needed in very small quantities in our body.
REQUIRED:
RECOMMENDED:
Unfortunately, our textbook does not have a good simplified explanation of the basic chemistry and cells topic. So if you need more reading on this topic, get a General Biology textbook or visit these on-line biology textbook links (which has more in-depth coverage than I expect from you):