1. The Molecules of life Chapter 5

2. 5.1- Carbon is the main ingredient of organic molecules Why are carbon atoms so common in living things? ◦4 electrons in its highest occupied level making it very reactive. Organic molecules  Always contain carbon Inorganic Molecules  Never contain carbon

3. Carbon Skeletons and Functional Groups  Carbon Skeletons – “the backbones of organic molecules.  Functional Groups – a group of atoms within a molecule that interacts in predictable ways with other molecules.

4. Monomers ◦Smaller molecular units, building blocks of polymers Polymers ◦Many monomers linked together into long chains Life’s Large (macromolecules) ◦Carbohydrates ◦Lipids ◦Proteins ◦Nucleic acids

5. Building and Breaking Polymers ◦Dehydration reaction  Each time a monomer is added to a chain, a water molecule is released ◦Hydrolysis reaction  Cells break bonds between monomers by adding water to them (the reverse of dehydration)

6. 5.2 Carbohydrates provide fuel and building material ◦Objectives  Describe the basic structure and function of sugars.  Name three polysaccharides and describe their functions ◦Key terms ◦ Carbohydrate ◦ Monosaccharide ◦ Disaccharide ◦ Polysaccharide ◦ Starch ◦ Glycogen ◦ Cellulose

7. What do athletes mean when they talk about “carbs”? ◦Carbs=Carbohydrates=sugar molecules  Sports drinks- small molecules  Pasta- long molecules (Starch)

8. Sugars – The main fuel supply for cellular work. ◦Carbohydrate – An organic compound made up of sugar molecules  Carbon, Hydrogen, Oxygen  Ratio – 1 C : 2 H : 1 O ◦Monosaccharide – Simple sugars containing just one sugar unit  Examples – glucose, fructose and galactose.

9. Disaccharides – Using the dehydration reaction, cells construct a disaccharide (double sugar) ◦Most common disaccharide-Sucrose  Glucose monomer and a fructose monomer Polysaccharides – Long polymer made up of simple sugars monomers (Complex Carbohydrates) ◦Common Polysaccharides-Starch, glycogen, cellulose

10. 5.3 – Lipids include fats and steroids ◦Objectives  Identify a general characteristic of lipids  Describe the structure and functions of fats  Describe the structure and functions of steriods ◦Key terms  Lipid  Hydrophobic  Saturated fat  Unsaturated fat  Steroid  Cholesterol

11. “Do Now” – Salad Dressing containers usually have a label that says, “Shake well before using” Why? The oil in most dressings doesn’t mix well with the vinegar (mostly water).

12. Characteristics of lipids ◦Lipids are water-avoiding molecules (Hydrophobic – water fearing) Fats ◦Consist of a three-carbon skeleton (glycerol) attached to three fatty acids (long hydrocarbon chains).

13. Saturated fats ◦Contains maximum number of hydrogen atoms ◦All single bonds Unsaturated fats ◦Contains less than the maximum number of hydrogen atoms. ◦One double bond

14. Steroids ◦Lipid where the carbon skeleton forms four fused “rings”  Examples – Estrogen and Testosterone  Function – send chemical signals throughout the body ◦Cholesterol  A steroid that is found in the membrane surrounding your cells  High levels are linked with increase risk for cardiovascular disease (heart and blood vessel)

15. 5.4 – Proteins perform most functions in cells. Do now – Make a list of facts you already know about proteins.  Polymer  Energy  Builds muscles Objectives ◦List functions of proteins ◦Describe the structure of amino acids and proteins ◦Describe factors that influence protein shape

16. The Functions of Proteins ◦A protein is a polymer made from only 20 monomers (amino acids) ◦Responsible for day-to-day functions  Examples of typical protein functions ◦ Form hair and fur ◦ Make up muscles ◦ Defend the body from harmful microorganisms ◦ Send messages from one cell to another ◦ Control chemical reactions in cells

17. Amino Acids ◦Monomer consists of a central carbon atom bonded to 4 partners.  Hydrogen group  Carboxyl group  Amino group  Functional group (side group) or (R-group)  Examples ◦ Leucine ◦ Serine

18. Building a Protein ◦Cells link monomers of proteins (amino acids) together to create polypeptide Chains  Building molecules needs a reaction. Which reaction? ◦ Dehydration reaction ◦Alphabet = 26 letters ◦Creates - ? Words ◦Amino acids = 20 “letters” ◦Creates - ? Polypeptide chains

19. Protein Shape ◦Protein are not linear, but 3D carefully twisted and folded into a particular shape. ◦Will not work properly unless it is in it’s unique shape. ◦Shape is influenced by its environment. ◦Changes in its environment can “unravel” the protein” (denaturation)  Change in temperature  pH

20. 5.5 – Enzymes are proteins that speed up specific reactions in cells. ◦Objectives:  Explain how enzymes affect activation energy.  Describe how an enzyme’s shape is important to its function. ◦Key Terms  Activation energy  Catalyst  Enzyme  Substrate  Active site

21. Enzymes and Activation NRG ◦Where does the NRG from a lit candle come from?  From lighting a match. This is start-up NRG or (activation energy)  Catalyst – compounds that speed up chemical reactions. ◦ By weakening bonds chemical reactions occur faster and/or with less NRG  The main catalysts of chemical reactions in organisms are specialized proteins called enzymes.

22. Enzymes – Provide a way for reactions to occur at the cell’s normal temperature. ◦As to not damage other parts of the cell from excessive heat. How do enzymes work? ◦The enzyme fits with the intended substrate at the active site, like a puzzle piece. *Only the right combination will work.