Biology 30

1. Biology 30 Unit 1: The Chemical Basis of Life

2. Chemistry Involved in Life Processes Refresher from Chem 20

3. 1. Atoms: • All matter has mass and takes up space • All matter is composed of atoms • Atoms are composed of three particles: • Proton (+) • Neutrons (no charge) • Electrons (-)

4. 1. Atoms: • Nucleus of the atom is made of protons and neutrons • Number of protons and electrons in an atom are the same making the charge neutral • Electrons circle the nucleus at different energy levels to form an energy cloud

5. 2. Elements • An element is a substance composed of only one type of atom • Every atom in the element has the same number of protons • Isotopes occur when atoms of the same element have a different number of neutrons

6. 3. Molecules • Molecule: when atoms join with other atoms of the same or different elements • Stable molecules are created when outermost energy levels are completely filled • Covalent Bonds: the forces involved in the sharing of electrons to fill up an energy level

7. 3. Molecules • Bonds are held together by energy and when broken that energy is released • Weakest chemical bond is hydrogen because it has only one electron

8. 4. Compounds • Compounds: substances composed of different kinds of atoms chemically bonded together • There are two main types of compounds: • Inorganic compounds • Organic compounds

9. 4. Compounds • Inorganic Compounds: • contain no carbon • Only a single carbon atom per molecule • Contain energy that is not useful for organisms

10. 4. Compounds • Organic compounds: • Built with long carbon-to-carbon chains • Large molecules containing stored energy • Energy can be used by organisms • Ex: • CHO’s, • Proteins, • Lipids

11. 5. Chemical Reactions • Chemical Reaction: results from rearranging atoms and molecules of the materials involved • Ex: burning wood adds oxygen to the wood substances

12. 5. Chemical Reactions • Reactions can be written as chemical equations • Reactants: beginning substances • Products: end of reaction • Law of Conservation of Mass: same number of atoms at the beginning and the end of a reaction • Energy is either required or produced when a reaction occurs

13. 6. Ions • Ions: atoms that gained or lost electrons have an imbalance of charged particles • Positive Ions: atoms that donate electrons have an excess of positive charge • Negative Ions: atoms that accept electrons have an excess of negative charge • Ionic bonds form when electrons are transferred

14. 7. Acids and Bases • Water is made of 2 H atoms and 1 O atom • A hydrogen atom breaks away from water molecule: • Positive hydrogen ion • Negative hydroxide ion • Neutral solutions have the same number of hydrogen and hydroxide ions

15. 7. Acids and Bases • Water is made of 2 H atoms and 1 O atom • A hydrogen atom breaks away from water molecule: • Positive hydrogen ion • Negative hydroxide ion • Neutral solutions have the same number of hydrogen and hydroxide ions

16. 7. Acids and Bases • Acids: concentration of hydrogen ions > concentration of hydroxide ions • Have a sour taste... Lemon juice • Basic: concentration of hydroxide ions > concentration of hydrogen ions • Ammonia, soap, oven cleaner • pH scale 1-14 • 1-6 Acids • 7 Neutral • 8-14 Basic

17. Properties of Macromolecules

18. Carbohydrates • These are composed of carbon, hydrogen, and oxygen with the ratio of H:O=2:1 • Monosaccharides (C6H12O6) are called simple sugars because they are made of only one sugar unit. • Glucose is formed by plants during photosynthesis and is the form of energy most easily used by cells. • Monosaccharaide’s link together to form other types of sugars

19. Carbohydrates • Disaccharides (C12H22O11 ) are called double sugars because they are formed when two monosaccharides join together. • Sucrose is made when a glucose and a fructose are joined together. • Whenever monosaccharides link together, a molecule of water is released. This is called a dehydration reaction. • Polysaccharides (C6H12O6)n are called many sugars because they are formed when three or more monosaccharides are linked together. • 4 calories per gram

20. How to Identify Carbohydrates • Only carbon’s, hydrogen’s, and oxygen’s • Twice as many H’s as O’s • Dehydration reaction has H2O as a product • Hydrolysis reaction has H2O as a reactant • The names end in ‘ose’ Lab Tests: • Benedict’s solution changes from blue to a variety of other colors to indicate percentage of sugar • Iodine turns blue black to indicate starch

21. Examples of Charbohydrates • Glucose • Sucrose • Starch • Cellulose • Glycogen • Chitin

22. Diagrams of Charbohydrates

23. Proteins • These are composed of carbon, hydrogen, oxygen, and nitrogen ( and sometimes sulphur) • Built from a combination of twenty subunits called amino acids • The long chains (thousands of subunits) are called polypeptide • Green plants can synthesize all amino acids from simple materials • Animals cannot so they must get them from their diet

24. Proteins • The particular combination of amino acids and the 3D folded shape it forms determines the function of the protein. • Important in living organisms because each type of chemical reaction is controlled by a different type of enzyme, which is formed from proteins • Enzymes are complex proteins that cause a specific chemical change in all parts of the body. • The production of many different enzymes makes thousands of chemical reactions • 4 Calories per gram

25. How to Identify Proteins • Must contain ‘N’ • Sometimes contains ‘S’ • Most labeled molecules end in ‘ine’ Lab Test: • The Bluret Test indicates peptide bonds when color changes from blue to pink purples

26. Examples of Proteins • hair • Nails • Steak (animal flesh) • Milk whey • Silk • Webs • Scabs • Blood cells • Enzymes • hormones

27. Diagrams of Proteins

28. Lipids • These are oily or waxy substances that are composed of carbon, hydrogen, and oxygen but the ratio of H:O is always greater than 2:1 • Fats are made of two types of lipid building blocks: • Glycerole which is a single sugar • Fatty acids which are chains of carbon and hydrogen with an acid grouping on one end • Different fatty acids produce different lipids.

29. Lipids • Lipids can be grouped into: • Fats (animals) • Oils (plants) • Waxes (animals & plants) • Generally fats are used as a concentrated source of stored energy but can also be found in cell membranes and as cushions around body organs.

30. How to Identify Lipids • Only carbon’s, hydrogen’s, oxygen’s but more than double H’s than O’s • Several carbons with double bonds Lab Test: • Sudan IV solution identifies most lipids with a color change from pinks to reds • Translucence test indicates lipids by making untreated paper to transmit light

31. Examples of Lipids • Fats: • Margarine • Butter • Lard • Blubber • Oils: • Canola oil • Flax oil • Vegetable Oil • Waxes: • Bee wax • Ear wax • Cuticle on leaves

32. Diagrams of Lipids

33. Nucleic Acid • Another important group is nucleic acids (DNA, RNA) • They are part of chromosomes and the reading of chromosomes