Unit #2 – Biomolecules: The Chemistry of Life

1. Unit #2 – Biomolecules: The Chemistry of Life Learning Focus 1.2 – The Structure & Function of Biomolecules

2. TEKS Objectives • (9)  The student is expected to: • (A)  compare the structures and functions of different types ofbiomolecules such as carbohydrates, lipids, proteins, and nucleic acids • (C) investigate and identify the effects of enzymes on food molecules.

3. Introduction • All life depends on chemistry to function. • During breathing and eating, the body uses oxygen other nutrients in chemical reactions to keep you alive. • In this chapter we will discuss the biological relationship between the elements within our world and the reactions within the body and other living things.

4. Atoms • Everything in the world are made of atoms, including you! • An atom is the smallest particle of an element and the basic unit of matter. • Although atoms are extremely small, they are made of even smaller parts. http://www.zvrk.co.yu/Mskola/fizika/atom/a1.gif

5. Parts of an Atom • Atoms = Building Blocks of Life • The subatomic (smaller) particles that make up atoms are protons, neutrons, & electrons. • The protons and neutrons are always in the center of the atom = the nucleus. • The electrons are always found outside of the nucleus

6. Valence Electrons http://jade.ccccd.edu/mweis/Images/Fireworks%20Drawings/2401%20related%20drawings/drawings%20in%20fireworks/body,%20cell,%20tissue/body_chem/chem_drw_atom_generic.png • The electrons farthest away from the nucleus in the outer shell are called valence electrons. • Valence electrons of elementsreact with each other to form compounds. • Atoms with a few valence electrons like to give up their electrons. • Atoms close to having a full shell go looking for other atoms to “borrow” electrons.

7. Another type of bonding is covalent bonding (see graphic above). When two atoms share the pair of electrons, the two atoms are bound together in a covalent bond. When we draw pictures of molecules we draw a single line between two atoms representing a pair of electrons. Types of Bonds B/W Atoms Images from Blueprint School Support • The valence electrons in the outer shells of all atoms react with one another to form bonds. • A bond is the connection formed between two or more atoms. • In ionic bonding, electrons are completely transferred from one atom to another. • In solution, the reacting atoms form ions (+ and – charged atoms). • The oppositely charged ions are attracted to each other by electrostatic forces (see graphic to the right).

8. Polarity • The oxygen in water takes on two more electrons to become stable (making it slightly negative). • The hydrogen atoms give up their electrons making them slightly positive. • The different charges on the water molecule make it a polar molecule (charged poles). • Think magnets! These ends push apart!

9. Because of the different ends, water molecules tend to stick together. They form hydrogen bonds. There is an attraction between the hydrogen atom of one molecule (+) and the oxygen atom of another (-) which makes a hydrogen bond. This is why drops of water form beads. They are attracted to each other! This is also why some insects are able to walk on the surface of water! Sketch it! Hydrogen Bonds

10. Types of Compounds • Organic compounds contain the element carbon and are found in living things. • Inorganic compounds do not contain carbon and are associated with non-living things. http://www.physicalgeography.net/fundamentals/images/compounds_molecules.jpg

11. Macromolecules & Biomolecules • Everything that is living is composed of molecules with carbon atoms. • Carbon has 4 valence electrons and can, therefore, forms many compounds with many elements. • Living cells are composed of HUGE molecules (macro-molecules) made of thousands of atoms. • The four biomolecules found in living things are carbohydrates, lipids, proteins, and nucleic acids.

12. Macromolecules are Huge! • One molecule of water (above). • One example of a macromolecule (lipid) to the right. • No Yellow? No Notes! http://www.matchrockets.com/images/h2omol.jpg http://www.chem.arizona.edu/faculty/mcgr/triazo.GIF

13. Carbohydrates • Carbohydrates are made up of carbon, hydrogen and oxygen atoms • ratio - 1C : 2 H:1 O. • Ex C6H12O6 • Carbohydrates are used as a source of energy for living things. http://www.faqs.org/nutrition/images/nwaz_01_img0048.jpg http://newsletter.wsu.edu/eplay/user_pics/375x250_veggies.jpg

14. CFU #1 - Is it a Carbohydrate? • Complete the CFU #1 portion of your daily worksheet. • Tell if each chemical formula represents a carbohydrate or not

15. Simple carbohydrates are often called sugars (glucose, fructose (from fruits) and galactose (from milk)). Simple sugarsaremonosaccharides (one + sugar). Large molecules of carbsare called polysaccharides (many + simple sugars). Strings of monosaccharides make up a polysaccharide. Animals convert carbs and store the energy in the form of glycogen found in cells (often muscle cells). Plants store their carb energy in the form of starch and use cellulose for structure (think tough and fibrous like celery!). Carbohydrates Cont. http://biology.clc.uc.edu/graphics/bio104/glucose1.jpg

16. CFU #2 – Glycogen or Starch? • On your daily worksheet fill in the blanks below the picture with the type of carbohydrate you would most likely find in the object

17. CFU # 3 Nutrition Labels • Review the nutritional label. Answer the following questions on your daily worksheet • How many grams of carbohydrates are found in this food? • What types of carbohydrates are listed? • Why do you think our bodies need carbohydrates? http://www.nestle.ca/NR/rdonlyres/EF764B3A-5216-46BA-95DC-B573C44EF266/0/BistroPestoGrChkn_NFT.gif

18. Lipids • Lipids (commonly known as fats, oils, and waxes) are a large macromolecule made from carbon, oxygen, and hydrogen atoms. • Hydrogen to oxygen ratio is (much greater than) >>>2:1. • Lipids are generally do not mix in water (hydrophobic). • They can be used tostore energy. • They are foundin cell membranes and help our skin keep from drying out. • Lipids are made up of glycerol and chains of fatty acids http://www.indiana.edu/~origins/images/lipid.gif

19. Types of Fats • Lipids can be saturated with only single bonds between atoms; solid at room temperature, and not healthy (butter, lard, manteca). • Unsaturated fats are considered the healthiestand are liquid at room temperature (olive oil, peanut oil, etc.) • Lipids can be monounsaturated (with one double bond between two atoms). • Polyunsaturated fats have more than one double bond. http://www.wholefoodsmarket.com/products/oil/images/oils300w.jpg

20. http://www.cramscience.ca/images/uploaded/uploadedLarge/1ff8e0a92c3974adacb557e5afa82bca.jpghttp://www.cramscience.ca/images/uploaded/uploadedLarge/1ff8e0a92c3974adacb557e5afa82bca.jpg

21. CFU # 4 • Answer the questions under the CFU #4 section of your daily worksheet

22. Proteins • Protein is our last macromolecule and contains the elements carbon, hydrogen, oxygen, and nitrogen. • They are made up of strings of amino acids. • There are more than 20 different amino acids found in nature. • Some proteins help to control cell processesand they are used to form muscles and bones. • They also help to fight disease and are used to transport substances.

24. An enzymeis a proteinthat acts as a biological catalyst. Enzymes work in cells. Catalysts speed up chemical reactions. The enzyme attaches to the substrate that it works with (the reactants). Now that the enzyme is connected to the substrates, the substrates will react and produce products. This is called the lock and key model because -specific enzymes will only work on specific substrates. Enzymes & The Lock & Key Model http://stezlab1.unl.edu/reu1999/dputn226/ChemHelp/RET_Web_Pages/Enzymes/lock_key1.gif

25. Nucleic Acids • Nucleic acids are macromolecules containing hydrogen,oxygen, carbon, nitrogen, and phosphorus. • Nucleic acids make up our DNA and RNA! • Their function is to storegenetic information; the DNA in your cells is responsible for giving you your unique characteristics and traits. • DNA’s unique shape is called a double helix. http://www.scq.ubc.ca/wp-content/dna.gif

26. In Conclusion • To review… • In this unit we reviewed the structure of atoms. • We investigated four macromolecules needed for life • Carbohydrates • Lipids • Proteins • Nucleic acids • We learned that enzymes help to speed up reactions in body cells.