Unit 2: Matter and Energy A Summary of How Theories Develop in Science: – based on a series of verifiable observations & measurements.  leads to a conclusion based on inductive reasoning -  tests must be... – other people must be able to repeat and verify or reject tests. a theory arises scientific theories enable researchers to make... – that guides research and opens-up new questions. conclusions drawn on evidence can be tested with an experiment or additional observations.

Identify what is wrong with each of the following statements. 1.Everybody knows that gravity exists. There is so much proof for the Law of Gravity that it will not change. 2.Although many scientists believe in evolution, there are still many things that cannot be explained by evolutionary biologists. Therefore, it is just a theory. 3.After completing our lab, we proved that the theory of enzyme activity was right.

– the basic unit of matter Basic Chemistry – the basic unit of matter Electron configuration of oxygen – center of the atom – positively charged particles (+) – particles that carry no charge – negatively charged particles (-), 1/1840 the mass of a proton (equal, but opposite charge) – spaces that electrons have the greatest probability of being found

The Periodic Table Element –

The Element Carbon on the Period Table 6 Atomic number C Why is the atomic mass of carbon not exactly twelve? Carbon 12.011 Atomic mass Atomic number – Atomic mass – Go to Section:

The 6 most common elements that make up living organisms: Elements Found in Biological Organisms The 6 most common elements that make up living organisms: CHONSP or SPONCH The Periodic Table of Elements

Compounds and Chemical Bonds Two Main Types of Chemical Bonds: Ionic Bonds – Covalent Bonds –

Why Ionic Bonds Are Important to Life Break apart easily in water The ions are used to transfer positive or negative charges in cells (i.e. allows information, materials, and short-term energy to be exchanged)

Why Covalent Bonds Are Important to Life Store energy in the bonds (this energy can be used for growth, movement, etc by an organism) Do not break apart in water (the bodies of plants and animals are mostly water – glucose will not release its energy) Form the building blocks of life (proteins, fats, etc. are made of covalent bonds)

2-2 Properties of Water Water is the single most abundant compound in most living things and it possesses many special properties. Water is one of the few compounds that is liquid at the temperatures found over much of the Earth’s surface. When water does freeze, it expands, becomes less dense than liquid water, and floats.

Polarity of Water Water is a polar molecule – Oxygen has more electrons, so it is more negatively charged (i.e. it is electronegative and pulls electrons to it) Hydrogen has fewer electrons, so it is more positive than negatively charged

Hydrogen Bonding in Water – weak bond formed with a positively charged hydrogen atom and other negatively charged atoms Waters polarity and hydrogen bonds give it unusual properties It easily forms a solid (ice), liquid, and gas (vapor). Cohesion – a property dependent upon the strength of attractive forces between molecules of the same substance (water to water) Adhesion – a property dependent upon the strength of attractive forces between molecules of different substances (water to glass)

Why Water Is Necessary to Life Cl- Cl- Na+ Na+ Water Water Water is a solvent – Solute – Water breaks some chemicals apart, allowing atoms to interact and move around, so chemical reactions can take place easily. Go to Section:

The Chemistry of Carbon Figure 2-11 Carbon Compounds Butadiene Methane Acetylene Isooctane Benzene Carbon has 4 valence electrons, allowing it to bond to 4 other atoms Carbon forms strong covalent bonds Carbon bonds easily with other carbon atoms, hydrogen, oxygen, nitrogren, sulfur, and phosphorous = Organic Compounds - Organic compounds interact to perform the basic functions of life

Macromolecules - Macromolecules are built buy joining smaller molecules together. Monomers - small unit that joins together with other small units to form polymers. Polymers - large compound formed from combinations from many monomers.

Carbohydrates Starch Glucose Carbohydrates - compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1. Functions as the energy source for most living things Monosaccharide – simple sugar molecules (glucose, fructose, galactose) Polysaccharide – chains of monosaccharides Glycogen – stored in muscles and the liver of animals Starch – stored in plants Cellulose – found in the stalks of plants, provides strength and rigidity

Lipids Lipids - macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils and waxes. Functions as an energy source and makes up part of the cell membrane and steroid hormones Formed when glycerol binds to fatty acids Insoluble in water Saturated fats – lipids that have the maximum possible number of hydrogen bonds Unsaturated fats – lipids that contain some double bonds

Nucleic Acids Nucleic acids - macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorous. Functions as genetic structure, transmits hereditary information Nucleotide – building blocks of nucleic acids Types of nucleic acids DNA RNA Structure of DNA

Proteins Amino acids Proteins macromolecule that contains carbon, hydrogen, oxygen, and nitrogen Function as enzymes, hormones, builds the structure in bones, muscle and organs Amino acid – the building blocks of proteins

Amino Acids Amino group Carboxyl group General structure Alanine Serine Amino acids - compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end. There are 20 different amino acids that can combine to form proteins. Proteins are made up hundreds of amino acids bonded together and then folded into a particular shape.

Macromolecules

Complete the Diagram Concept Map Carbon Compounds Word Bank: include Carbohydrates Proteins that consist of that consist of that consist of that consist of Glycerol & Fatty Acids which contain which contain which contain which contain Carbon, hydrogen, oxygen Carbon,hydrogen, oxygen, nitrogen, phosphorus Word Bank: Carbon,hydrogen,oxygen, nitrogen, sulfur Monosaccharides Nucleotides Nucleic acids Lipids Amino Acids Carbon,hydrogen,oxygen

Chemical Reactions Chemical Reactions - a process that changes one set of chemicals into another Metabolism – the sum of all the body’s chemical reactions Energy-Absorbing Reaction Energy-Releasing Reaction CO2 + H2O C6H12O6 + O2 C6H12O6 + O2 CO2 + H2O Products Activation energy Activation energy Reactants Reactants Products Example – Photosynthesis (synthesis) Reactants = CO2 + H2O Products = C6H12O6 + O2 Example – Cell Respiration (decomposition) Reactants = C6H12O6 + O2 Products = CO2 + H2O

Energy in Reactions Reaction pathway without enzyme Activation energy without enzyme Reactants Activation energy with enzyme Reaction pathway with enzyme Products Activation energy – the amount of energy needed to start a chemical reaction What is an enzyme?

Enzymes Enzyme – complex proteins that lower the activation energy Speed up the chemical reactions in a cell Lower the temperature needed for the reaction to occur Act as catalysts – speed up reactions, but are not used up (can be used over and over)

Factors that Affect Enzyme Action Temperature Surface Area pH Explain how each of these might affect the function of an enzyme

The pH Scale The pH scale indicates the concentration of H+ ions in solution At pH 7, the concentration of H+ ions and OH- ions is equal Acid – any compound that forms H+ ions in solution Base – any compound that produces OH- ions in solution Buffer – a weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pH Fluids in most cells must be kept between 6.5 and 7.5 or the reactions in cells will be effected Oven cleaner Bleach Ammonia solution Increasingly Basic Soap Sea water Human blood Neutral Pure water Milk Normal rainfall Acid rain Increasingly Acidic Tomato juice Lemon juice Stomach acid

How Enzymes Work