The Basics All things are made up of tiny particles called atoms There are only about 100 different types, called elements

The most common elements in biology are: C = carbon H = hydrogen O = oxygen N = nitrogen P = phosphorus

Organic Molecules: The evil Regents Exam writers use the words “organic molecules” when they mean FOOD. Organic means the molecule contains the elements, carbon and hydrogen. If something does NOT contain those 2 elements, we say it is inorganic. The most abundant (common) inorganic compound in your body (& on the planet) is water.

The Big Four Organic Molecules: There are 4 big groups of organic molecules that you must know – carbohydrates Proteins Lipids Nucleic acids (DNA)

1. Carbohydrates: What are they? sugars and starches What is their use in the body? energy What elements do they contain? Carbon, hydrogen, and oxygen The smallest carbos are called simple sugars, or monosaccharides (mono = one saccharide = sugar)

The monosaccharide you need to know is named glucose Glucose’s chemical formula is C6H12O6 Is it organic? Yes How do you know? Has both carbon and hydrogen

The image to the right is a structural diagram of glucose The image to the right is a structural diagram of glucose. It shows how the C, H, & O are arranged in the molecule. Draw a schematic image to show the general shape of a glucose molecule:

If you hook 2 simple sugars (2 monosaccharides) together, you get a disaccharide An example of a disaccharide is table sugar, or sucrose

If you hook MANY simple sugars together, you get a polysaccharide An example of a polysaccharide is starch

Sketch diagrams of a disaccharide and a polysaccharide:

How does the body join molecules together and take them apart? There are 2 simple processes used over and over in the body. Dehydration synthesis: making more complex, larger molecules by removing water. Hydrolysis: breaking up large molecules into smaller molecules with the addition of water.

Dehydration Synthesis C6C C6H12O6 + C6H12O6  C12 H22 O11 + H2O

Hydrolysis C12H22O11 + H2O  C6H12O6 + C6H12O6

Plants use photosynthesis to combine carbon dioxide (CO2) and water (H2O) to make glucose (the monosaccharide you need to know). They capture the energy from the sun and it is stored in the bonds of the glucose.

Plants either use the glucose for energy (by doing cellular respiration) or they can store it in chains (a polysaccharide) called starch (hint: what do we call foods that are made from plants—like spaghetti, bread, or cereal?)

Plants also use their glucose to make their cell wall Plants also use their glucose to make their cell wall. It is composed of “sheets” of glucose chains, called cellulose, making it a very rigid structure! You can probably imagine that with EVERY plant having cellulose around EVERY cell—it’s the most abundant organic compound!

When animals eat plants, the starch is digested (by hydrolysis) into individual glucose molecules (yup, that monosaccharide again!) The animals can either use the glucose for energy (by doing cellular respiration) or they can store it in their liver or muscle cells in long chains called glycogen (sometimes referred to as “animal starch”).

Of course, some animals use polysaccharides for structure, too Of course, some animals use polysaccharides for structure, too! Arthropods (like insects and crustaceans) have exoskeletons made out of chitin. That’s what makes the “crunch” when you step on a beetle or break into your lobster dinner!

Proteins: What types of things are made of protein? Meat (muscle), milk, eggs, beans, lentils, seeds, nuts What is their use in the body? Repair and Growth What elements do they contain? Carbon, hydrogen, oxygen, nitrogen Proteins are long chains of amino acids

There are 20 different things that could go where you see that “R”, so there are only 20 different amino acids. Are there only 20 different proteins? no

Proteins are chains that can be thousands of amino acids long Proteins are chains that can be thousands of amino acids long. The R Group of the amino acids determines what protein it is. Having amino acids in the wrong order, or substituting the wrong one, or skipping one will usually result in a defective protein. Sometimes this is not really a big deal, but sometimes these mistakes can result in diseases like diabetes or Cystic fibrosis

What would you have to remove to do it? What process would your body use to join up all those amino acids into a protein chain? Dehydration Synthesis What would you have to remove to do it? Water

The bond that holds 2 amino acids together is called a peptide bond, so proteins (chains of many amino acids) are sometimes called polypeptide

Actually, a protein is really 1 or more polypeptides bent and twisted into a 3-D shape. The shape of the protein determines its job or function

what type of reaction did you do? If you chemically added water to a long protein chain, what would you end up with? Amino acids what type of reaction did you do? hydrolysis

The primary protein structure is a sequence of a chain of amino acids

The secondary protein structure occurs when the sequence of amino acids are linked by special bonds called hydrogen bonds, causing the chain to curl up (alpha helices) at some locations and form pleats (beta sheets) at other locations.

The tertiary protein structure occurs when certain attractions are present between the segments of the secondary structure, causing the molecule to form folds and kinks.

The quaternary protein structure is a protein consisting of more than one polypeptide (chains of amino acids). It is the functional protein that is the right shape to do a certain job!

Lipids What is an important characteristic of all lipids? Tend to be insoluble in water What are they? fats, waxes and oils What are they used for, in the body? Insulation, long term energy storage, some hormones, cell membranes (phospholipids) What elements do they contain? Carbon, hydrogen, and oxygen

What are the products of the hydrolysis of a lipid? What process do you think is used to connect the fatty acids to the glycerol? Dehydration synthesis What are the products of the hydrolysis of a lipid? Glycerol and three fatty acids

In the image on the right, a triglyceride (a fat molecule) is “flipped” onto its side. See how it kind-of looks like the letter E with the glycerol molecule making up the vertical side of the “E” and the 3 fatty acids making up the horizontal lines of the “E”.

Notice how BIG this molecule is Notice how BIG this molecule is! Look at all of those carbons, all hooked together in chains! Now think back (or look back in your notes) to glucose. In glucose, the energy is stored in its bonds, but it does not have nearly as many as this molecule. Small surprise that we use this molecule for our Energy (fat) reserves (stored)!