Chapter 2

1. Chapter 2 The chapter that defines all that follow after…

2. Section 1: The Nature of Matter • Atoms: the smallest particle of an element that has the properties of that element • Parts of an atom: • Protons – positively charged, found in core • Neutrons – no charge, found in core • Electrons – negatively charged, found in a cloud around the core

3. Atoms bond together … • Elements • consists of only one kind of atom, • cannot be broken down into a simpler type of matter by either physical or chemical means, and • can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen). NOTE: A molecule consists of two or more atoms of the same element, or different elements, that are chemically bound together. Note that the two nitrogen atoms which comprise a nitrogen molecule move as a unit. • Compounds • consists of atoms of two or more different elements bound together, • can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means), • has properties that are different from its component elements, and • always contains the same ratio of its component atoms. • Ions • Charged (positive/negative) atoms due to loss or gain of an electron • Cations - have more protons than electrons and are positively charged • Anions - have more electrons than protons and are negatively charged

4. Three Types of Bonds Covalent Bonds – (electron sharing) – formed when electrons are shared between two elements – strongest type of bond Ex. H + Cl = HCl Ionic Bonds – (electron donating) – electrons from one atom are donated to another creating an ion (atoms that are positively charged due to the loss of electrons or negatively charged due to addition of electrons) - positive and negative atoms are attracted to each other creating the bond Ex. Na + Cl = Na+Cl- Hydrogen Bonds – (weak electrical attractions) – larger Oxygen molecules pull smaller Hydrogen molecules closer – “almost” share an electron Ex. 2H + O = H2O

5. Section 2: Water and Solutions • Properties of Water • Water is polar – it has a positive and negative side • Solutions – substances dissolved in water (Ex. Salt water) • Polar molecules can dissolve in water creating a solution • Non-polar molecules (like oil) can not dissolve in water and do not create a solution • Water is cohesive – water molecules stick together • Water is adhesive – Water molecules stick to other substances • Water stores heat efficiently (High Specific Heat, High Heat of Vaporization) • Water is less dense as a solid

6. Water is polar … Water is a good solvent. - Water dissolves polar molecules and ions. -hydrophilic: “water-loving” 6

7. Water is polar … Water organizes non-polar molecules. hydrophobic: “water-fearing” - Water causes hydrophobic molecules to aggregate or assume specific shapes. 7

8. Cohesion Cohesion is the property of water that causes it to be attracted to itself. http://www.realeyz.com/photo/macro/photos/leaf_drops.jpg

9. Surface Tension • Surface tension measures the strength of water molecules attracting to one another. • This property allows insects to walk on the surface of water and the creation of waves.

10. Adhesion • Attraction between molecules of different substances • Ex: glass and water • Or a visit to the doc CapillarityWater molecules will “tow” each other along when in a thin glass tube. http://staff.um.edu.mt/rlib1/sm/wpe32.jpg

11. Did you ever wonder: How does water move from roots to leaves when a tree doesn’t have a heart to pump the water? Cohesion-Adhesion Theory (aka Transpiration) -As water evaporates from leaves, it tugs on the water molecules below -Cohesion and adhesion pull water up and replace missing water molecules -Water enters the roots by osmosis www.emc.maricopa.edu/.../BioBookPLANTHORM.html

12. High Specific Heat • Water resists temperature change, both for heating and cooling. • Water can absorb or release large amounts of heat energy with little change in actual temperature.

13. High Heat of Vaporization • In order for water to evaporate, hydrogen bonds must be broken. As water evaporates, it removes a lot of heat with it. • Thus, the heat of vaporization refers to the amount of energy required to convert water from a liquid to a gas.

14. Water is Less Dense as a Solid • Which is ice and which is water?

15. Density of Ice • Most solids are more dense than their liquids • This makes solids sink • Ice is less dense than liquid water • Due to H-Bonds • Important to life because bodies of water freeze top down • Allows life to survive below http://shiftingbaselines.org/blog/images/Iceberg.jpg

16. Acids & Bases pH Scale Measurement of the concentration of hydrogen ions Acid: forms H+ when dissolved in water High concentration of [H+] (or hydronium ion); low conc. of [OH-] Base: reduces H+ when dissolved in water High [OH-] (a.k.a. hydroxide ion); low [H+]

17. Section 3: Chemistry of CellsOrganic Compounds • Organic compounds are those that contain carbon. (with a few exceptions such as carbon dioxide and diamonds) • There are four major types • Carbohydrates • Lipids • Proteins • Nucleic Acids

18. Carbohydrates • Carbohydrates – Made of carbon, hydrogen, and oxygen in the proportion of 1:2:1 • 1 carbon:2 hydrogen:1 oxygen • main source of energy; • provide structure in plants

19. 3 Types of Carbohydrates Monosaccharide (simple sugars) – the building blocks of carbohydrates Ex. Glucose and Fructose (fruit sugars) Disaccharides (double sugars) – 2 or more monosaccharides put together Ex. Sucrose (table sugar) and Lactose (milk sugar) Polysaccharides (many sugars) – 3 or more monosaccharides put together Ex. Rice, potatoes, beans, corn, pasta, bread

20. Monosaccarides (simple sugars)the building blocks of carbohydrates • EXAMPLES: • Glucose (product of photosynthesis, used in cellular respiration) • Fructose (fruit sugar)

21. Disaccharides (double sugars) 2 or more monosaccharides put together • EXAMPLES • Sucrose (table sugar) • Lactose (milk sugar)

22. Polysaccharides (many sugars) 3 or more monosaccharides put together Examples of polysaccharide groups Starches: plants store energy (extra glucose) in this form (rice, potatoes, beans, corn) Glycogen: animals store energy (extra glucose) in this form in two areas, the muscles and liver, when these are full the remaining energy is stored in fats. Cellulose – used in the structure of the cell wall of plants. Cannot be digested by humans but is essential for digestive health.

23. Lipids • insoluble organic compounds (do not dissolve in water); • made of fatty acids and glycerol in the proportion of 1:3; • 1 glycerol : 3 fatty acids • held together by hydrogen bonds; • store a lot of energy • Contain almost 2x the energy found in carbohydrates (9 calories VS 4 calories) • 4 Types of Lipids • Fats/Oils • Waxes • Phospholipids • Steroids

24. Fats and oils provide long term energy storage and act as insulation to keep animals warm • Fat is solid at room Temp, oils are liquid • Saturated fats – stick butter, lard, that whitish waxy looking stuff that forms on a steak or hamburger in the refrigerator; unhealthy fats, effect heart/liver functions, weight gain, and cholesterol levels • Unsaturated fats – olive oil, fish oil, etc are much better for you and can even raise your level of “good” cholesterol.

25. Waxes & Phospholipids • Waxes – provide protection by repelling water (Ex. Cuticle of plants); naturally occur on fruits and vegetables to prevent dehydration • Phospholipids – make up the cell membrane

26. Steroids • Serve structural and control functions in the body • Examples • Hormones such as Estrogen and Testosterone • Cholesterol that is produced by the body

27. Proteins Large complex molecules made of amino acids (20 amino acids are used to make a variety of protein combinations)How the amino acids are arranged is key to biodiversity. • 6 Major Protein Functions: • Movement – actin and myocin are proteins needed for contraction and relaxation of muscle fibers and therefore muscle movement • Structure – collagen is the most abundant protein in the human body, it gives elasticity and firmness to skin; forms bones, tendons, ligaments, and cartilage. • Defense – antibodies are proteins that help animals fight off invasion by viruses and bacteria • Transport – hemoglobin is the protein in red blood cells that carries oxygen through the bloodstream; a lack of red blood cells is called anemia • Nutrition – casein is a protein in breast milk that stores amino acids for use by newborn mammals; many proteins are used to build muscles and repair injuries • Regulation – enzymes catalyze (speed up) chemical reactions in the cells; we get them from eating raw vegetables (note the verb catalyze is from the non catalyst – a chemical that speeds a chemical reaction without being altered itself) • MSDTNR

28. Nucleic AcidsLarge complex molecules that contain hereditary or genetic information • 2 Types of nucleic acids • DNA (deoxyribonucleic acid) – caries instructions that control the activities of the cell • RNA (ribonucleic acid) – responsible for protein synthesis

29. One more important biological molecule ATP • adenosine triphosphate • energy currency of the cell; contains 2 extra energy storing phosphate groups • cells need a steady supply of ATP to function

30. Section 4: Energy and Chemical Reactions • Energy – the ability to move or change matter; many types including chemical, light, heat, mechanical, and electrical • Energy can be stored or released in a chemical reaction • Chemical reactions are processes in which chemical bonds between atoms are broken and new ones formed producing one or more new substances; • summarized as … reactants → products • Metabolism – all the chemical reactions that occur within an organism • Activation Energy – energy needed to start a reaction (like the first push to get a large object rolling downhill) • Enzymes – act as a catalyst to speed up reactions once started • Enzymes affect specific substances (ex. Amylase affects starch & glucose) and are affected by factors like temperature and pH

31. Steps in the Enzyme Reaction • Coordinating enzyme and substrate are available • Substrate binds to enzyme’s active site • Chemical bonds in substrate break; substrate is converted into its products • Products are released; enzyme is unchanged