Chapter 2.3: Chemistry of Cells Biochemistry

Organic Compounds Organic molecules are molecules that contain Carbon atoms bonded usually to Hydrogen, Oxygen or other Carbon atoms. The four most important organic compounds found in living things are: - Carbohydrates - Lipids - Proteins - Nucleic Acids

Carbohydrates (The dreaded carb!) Made of Carbon, Hydrogen and Oxygen. For every Carbon atom there is an Oxygen and two Hydrogens. 1 : 2 : 1 Carbohydrates are a huge source of energy. Carbs are made of single sugar molecules called monosaccharides. An example of a monosaccharide is glucose C6H12O6 Notice the ratio!

Carbohydrates cont. Does this look familiar? This is a monosaccharide called glucose. A single sugar molecule can easily be pieced together with another sugar to make a disaccharide. When this is done 1 molecule of water is released.

Forming a disaccharide Notice that when you remove a water molecule the two molecules bond together to form a much larger molecule. What do you think will happen if you throw in a water molecule?

Forming a carbohydrate If you take more than two glucose molecules and bond them together you form a polysaccharide. Each one of the little blue hexagons = a glucose molecule

Examples of Carbohydrates What is the carbohydrate that is stored in plants? Hint: Starch The carbohydrate that is found in animals is called glycogen. These polysacharides store a lot of energy in the form of sugar. Sugar turns into fat. Hence the carb diet When you break down a polysaccharide not only do you lose water you release energy.

Lipids A Lipid is a non-polar organic molecule that is one of the principal structural materials of living cells. A lipid is not soluble in water… Why? Lipids are oily or greasy in texture. Examples of lipids are fats, phospholipids, steroids and wax. Some lipids can be pieced together to form larger molecules.

- Fatty Acid tails (Non-polar tail) Phospholipids Phospholipids, like fat, and cholesterol are made of two distinct parts. - Glycerol (Polar Head) - Fatty Acid tails (Non-polar tail)

Phospholipids Cont. If you take a bunch of phospholipids and put them in water what do you think might happen? Because of the properties of phospholipids, when in the presence of water a group of them will form what is called a phospholipid bi-layer. This is what makes up the cell membrane.

Do you notice any similarity between a fat and a phospholipid? Fat – a lipid in an organism that stores ENERGY. Fat is also made of glycerol and fatty acids. Glycerol is an alcohol Fatty acids are a bunch of Carbons bonded to Hydrogens Do you notice any similarity between a fat and a phospholipid?

Different types of fat There are two different types of fat that store energy in the body. Saturated fat – The Carbons in the fatty acid are all bonded to two Hydrogens, except for the last which is bonded to three. This forms a straight molecule. Unsaturated fat – Some Carbons are only bonded to one Hydrogen, making a double bond and causing a kink in the chain.

Saturated and Unsaturated Fat Which fat is the “bad” fat? Why?

Protein Proteins are made of a chain of amino acids linked together. Great! What’s an amino acid? Amino Acid – The building blocks of a protein. There are 20 different amino acids, each with a different chemical structure. All amino acids are made of Carbon, Hydrogen, Oxygen and Nitrogen. Some of the 20 amino acids are made of sulfur.

Proteins cont. Each amino acid has a similar chemical structure but different functional groups. Another type of functional group is the “R” group. This is what gives us our 20 different amino acids

Proteins cont. Some amino acids are polar Some amino acids are electrically charged. These give proteins a very distinct shape.

Nucleic Acids… an intro Nucleic Acid – a long chain of nucleotides. Once again… Great! What’s a nucleotide? Nucleotide – part of a nucleic acid that has three parts. 1. Sugar 2. Nitrogen base 3. Phosphate group

Nucleotides are put together to make a Nucleic Acid like so…

Nucleic Acid

Nucleic Acids cont. There are two types of nucleic Acids - Deoxyribonucleic Acid (DNA) Double stranded - Ribonucleic Acid (RNA) Single stranded

ATP ATP – Adenosine tri-phosphate (ENERGY) A single nucleotide with two extra phosphates. Main energy resource for cells. Energy from carbs and fat are stored temporarily as ATP. When ATP is broken down it turns into ADP and releases energy.

ATP When one of the phosphate groups are broken off Energy is released

ATP cycle