The chemistry of life

The chemistry of life

All living organisms are comprised of organic molecules. Organic molecules contain CARBON and HYDROGEN which is not true of inorganic molecules. Carbon is central to life on Earth because it is able to form many bonds. Hence, we are carbon based life forms!

Biological molecules can be broken down into 4 different categories: Nucleic Acids Lipids Carbohydrates Proteins

Carbs are a major energy source for many organisms.

Carbs are polymers of sugars which are made up of Carbon, Hydrogen and Oxygen. The most common sugar we consume is glucose (C6H12O6) but when we consume carbs, they break down into sugars.

Carb functions vary greatly depending on structure and are also important in other ways such as: Forming the structural support for plants and plant cells(cellulose which cannot be digested vs. starches which can). Serving as an energy storage molecule (glycogen).

Lipids are a class of molecules that include fats, waxes and oils.

Lipids are polymers made up of fatty acids and glycerol. Lipids serve many functions the most important of which are: Energy storage molecules. They make up the cell membrane.

The cell membrane is also called the lipid bilayer. Each lipid has a HYDROPHILIC head and a HYDROPHOBIC tail. How would these arrange themselves to form the cell membrane?

This is likely how the first cells formed.

Perhaps the most important molecules of life. There are two types: DNA DeoxyriboNucleic Acid RNA RiboNucleic Acid

Nucleic acids are polymers that are made up of monomers called nucleotides. Each nucleotide is made up of: A Sugar + Phosphate + 1 of 4 Nitrogenous Bases (A, C, T, G or U for RNA) Nucleotides are pretty much identical but differ in their nitrogenous base.

Nucleic acids are vital to life because they contain the information that is necessary to manufacture ALL other biological molecules found in the body ESPECIALLY proteins. Essentially, they control who you are!!! We will learn more about DNA and RNA later in the year.

Proteins are an extraordinarily diverse group of molecules which possess many different functions. Proteins are MORE than just structural parts of your body (muscles and other tissues)!!!

Are polymers made up of amino acids. Generally speaking, our bodies use 20 amino acids to make all the proteins that are required for human life. Of the 20 amino acids, 9 (actually more like 10 during growth, you must take in extra arginine) are ESSENTIAL what does this mean?

Proteins have many other functions in the body such as: Participating in cell signaling. Required for building and repair of body tissues (including muscle) Enzymes, hormones, and many immune molecules are proteins Essential body processes such as water balancing, nutrient transport, and muscle contractions require protein to function. Protein is a source of energy. Protein helps keep skin, hair, and nails healthy. Protein, like most other essential nutrients, is absolutely crucial for overall good health.

Proteins as enzymes/catalysts for chemical reactions in the body = one of the most important roles of proteins. Catalysts speed up the rate of reaction but are unchanged in the reaction. Catalysts work best at specific temps and ph. For ph, think about digestive enzymes Inc. temp usually = inc. rate of reaction Not always true b/c different ideal temps more on that later

The substances that are acted on by enzymes are called the substrate. Reactions can be synthesis reactions OR digestion reactions. Enzyme act on SPECIFIC substrates and SPECIFIC reactions because they work like a lock and key.

The specificity of enzymes (lock and key) demonstrates the importance of protein SHAPE. Proteins must be precisely folded in order for them to function properly. If the folding pattern is changed, the protein cannot function anymore!

A few factors can affect protein shape. Temperatures that are too high can cause proteins to denature. Denaturation = The unfolding of proteins. Renaturation = When proteins re-fold Why are fevers so bad? Mutations in the genetic code can cause an incorrect sequence of amino acids (proteins are made up of a specific sequence of amino acids) which causes the protein to fold incorrectly.