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A Summary of How Theories Develop in Science: – based on a series of verifiable observations & measurements. leads to a conclusion based on inductive reasoning.

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Presentation on theme: "A Summary of How Theories Develop in Science: – based on a series of verifiable observations & measurements. leads to a conclusion based on inductive reasoning."— Presentation transcript:

1 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. Unit 2: Matter and Energy

2 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.

3 – the basic unit of matter – 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) Electron configuration of oxygen – spaces that electrons have the greatest probability of being found Basic Chemistry

4 The Periodic Table Element –

5 6 C Carbon 12.011 Go to Section: The Element Carbon on the Period Table Atomic number – Atomic mass – Atomic number Atomic mass Why is the atomic mass of carbon not exactly twelve?

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

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

8 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)

9 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)

10 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 Earths surface. When water does freeze, it expands, becomes less dense than liquid water, and floats.

11 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

12 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)

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

14 MethaneAcetylene Butadiene Benzene Isooctane Figure 2-11 Carbon Compounds The Chemistry of Carbon 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

15 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.

16 Carbohydrates 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 Starch Glucose

17 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

18 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

19 Proteins 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

20 General structureAlanineSerine Amino groupCarboxyl group Amino acids - compounds with an amino group (-NH 2 ) 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. Amino Acids

21 Macromolecules

22 Carbon Compounds include that consist of which contain that consist of which contain Concept Map CarbohydratesProteins Glycerol & Fatty Acids Carbon, hydrogen, oxygen Carbon,hydrogen, oxygen, nitrogen, phosphorus Complete the Diagram Word Bank: Carbon,hydrogen,oxygen, nitrogen, sulfurMonosaccharides Nucleotides Nucleic acids LipidsAmino Acids Carbon,hydrogen,oxygen

23 Energy-Absorbing Reaction Energy-Releasing Reaction Products Activation energy Activation energy Reactants Chemical Reactions Example – Photosynthesis (synthesis) Reactants = CO 2 + H 2 O Products = C 6 H 12 O 6 + O 2 Example – Cell Respiration (decomposition) Reactants = C 6 H 12 O 6 + O 2 Products = CO 2 + H 2 O Chemical Reactions - a process that changes one set of chemicals into another Metabolism – the sum of all the bodys chemical reactions CO 2 + H 2 O C 6 H 12 O 6 + O 2 C 6 H 12 O 6 + O 2 CO 2 + H 2 O

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

25 Enzymes Enzyme – complex proteins that lower the activation energy 1.Speed up the chemical reactions in a cell 2.Lower the temperature needed for the reaction to occur 3.Act as catalysts – speed up reactions, but are not used up (can be used over and over)

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

27 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 Soap Sea water Human blood Pure water Milk Normal rainfall Acid rain Tomato juice Lemon juice Stomach acid Neutral Increasingly Basic Increasingly Acidic

28 How Enzymes Work

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