Chemistry of Life Chapter 2 Notes

I. Nature of Matter Chemistry will help you learn about biology because you’re a chemical machine.

A. Atoms All matter consists of atoms. All matter consists of atoms. An atom is the smallest unit of matter that cannot be broken down. An atom is the smallest unit of matter that cannot be broken down.

A. Atoms Page 28, Figure 1. Draw an atom including the electron cloud.

A. Atoms 3 Types of particles make up an atom: Electrons Electrons Negatively charged (-) Protons Protons Positively charged (+) Neutrons Neutrons No charge

A. Atoms Electrons form the electron cloud which has a negative charge Electrons form the electron cloud which has a negative charge Atoms typically have one electron for each proton Atoms typically have one electron for each proton Example: 3 electrons (-), 3 protons (+) = no charge (neutral) = no charge (neutral)

B. Elements ***Look at the periodic table on pages known elements 100 known elements Elements differ in the number of protons they have Elements differ in the number of protons they have Ex. Hydrogen has 1 proton & 1 electron Oxygen has 8 protons & 8 electrons Oxygen has 8 protons & 8 electrons Neutrons are sometimes equal to the number of protons Neutrons are sometimes equal to the number of protons

B. Elements Isotopes- atoms of an element that contain different numbers of neutrons Example-Carbon-12, Carbon-13, Carbon-14 Carbon-12 has 6 protons and 6 neutrons Carbon-13 has 6 protons and 7 neutrons Carbon-14 has 6 protons and 8 neutrons

C. Chemical Bonding - a force that joins atoms of 2 or more different elements Compound-made of the joined atoms of 2 or more different elements. Ex. Na (sodium) + Cl (chloride)  NaCl (table salt) NaCl (table salt)

1. Covalent Bonds Form when 2 or more atoms share electrons to form a molecule. Form when 2 or more atoms share electrons to form a molecule. See page 29, Figure 2. See page 29, Figure 2. Examples of covalent bonds: CO 2, H 2 O Examples of covalent bonds: CO 2, H 2 O

1. Covalent Bonds Electron arrangement: Hydrogen and Helium hold up to 2 electrons in the outer level; all other atoms can hold up to 8 electrons in the outer level Outer level electrons are called “valence electrons”.

2. Hydrogen Bonds in H 2 O The water molecules have a partial positive and negative end. This is called POLAR. The water molecules have a partial positive and negative end. This is called POLAR. Polar molecules have an uneven distribution of charge Polar molecules have an uneven distribution of charge

3. Ionic Bonds Form IONS Form IONS Ions-Atom or molecule that loses or gains an electron; they have an electrical charge because of unequal # of protons and electrons Ions of opposite charge may interact to form an ionic bond Ions of opposite charge may interact to form an ionic bond Example (text pg. 30): Draw an ionic bond in Na Cl Na Cl  NaCl

II.Water and Solutions A. Water in Living Things 70% of the human body is water 70% of the human body is water Cells are filled with water and are surrounded by water. Cells are filled with water and are surrounded by water.

A. Water in Living Things Properties of Water 1. Storage of heat: Water heats slowly and retains heat longer than many other substances. 1. Storage of heat: Water heats slowly and retains heat longer than many other substances. Example: Some organisms release excess heat by sweating (cool off) Feet have more sweat glands than any other part of the body (250,000) and can produce up to a pint of perspiration each day.

A. Water in Living Things Properties of Water 2. Cohesion: attraction between substances of the same kind Cohesion is caused by the hydrogen bonds Cohesion is caused by the hydrogen bonds between water molecules between water molecules Surface Tension: caused by the attraction of water molecules Surface Tension: caused by the attraction of water molecules

A. Water in Living Things Properties of Water 3. Adhesion: attraction between different substances Adhesion powers capillary action in which water molecules move water through a narrow tube such as a stem of a plant Adhesion powers capillary action in which water molecules move water through a narrow tube such as a stem of a plant The attraction of the water to the walls of the tube sucks the water up more strongly than gravity pulls it down. The attraction of the water to the walls of the tube sucks the water up more strongly than gravity pulls it down.

A. Water in Living Things Adhesion Water moves up a plant through a combination of capillary action, cohesion, and other factors

B.Aqueous Solutions What is a solution? A mixture in which one or more substances are evenly distributed in another substance. Importance of solutions in the body Certain substances that dissolve in water can move within and between cells (e.g. sugar) Certain substances that dissolve in water can move within and between cells (e.g. sugar)

1. Polarity of Solutions Ionic compounds and polar molecules dissolve best in water. Nonpolar molecules DO NOT. Ionic compounds and polar molecules dissolve best in water. Nonpolar molecules DO NOT. Cell membranes depend on the interaction of polar and nonpolar molecules. Cell membranes depend on the interaction of polar and nonpolar molecules.

2. Acids and Bases When hydrogen bonds in H 2 O break, a hydrogen (H+) ion and a hydroxide ion (OH-) forms When hydrogen bonds in H 2 O break, a hydrogen (H+) ion and a hydroxide ion (OH-) forms Draw this: H 2 O  H + + OH - H 2 O  H + + OH -

2. Acids and Bases Water has an equal # of H + and OH - ions Acids-have a high concentration of H + ions Bases-have a lower concentration of H + ions and forms OH - ions pH scale-measures the concentration of H + ions in a solution

2. Acids and Bases See page 33. Draw the pH scale

III. Chemistry of Cells Organic compounds contain carbon atoms that are covalently bonded to other elements. Organic compounds contain carbon atoms that are covalently bonded to other elements. 4 classes of organic compounds found in living things: 4 classes of organic compounds found in living things: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

Carbohydrates -are made up of carbon, hydrogen, and oxygen atoms in 1:2:1 ratio -are a key source of energy -are a key source of energy -are found in most foods, especially fruits, vegetables, and grains -are found in most foods, especially fruits, vegetables, and grains

Monosaccarides Monosaccarides-single sugars Monosaccarides-single sugars Examples: glucose, fructose Examples: glucose, fructose Function: as a major source of energy in cells Function: as a major source of energy in cells

Disaccharides Disaccharides-double sugars (2 monosaccharides) Disaccharides-double sugars (2 monosaccharides) Examples: sucrose (made of glucose and fructose) Examples: sucrose (made of glucose and fructose)

Polysaccharides Polysaccharides-3 or more monosaccharides Polysaccharides-3 or more monosaccharides Examples: starch Examples: starch Function: storehouses of the energy stored in sugar Function: storehouses of the energy stored in sugar Starch-Stored by plants Starch-Stored by plants Glycogen-made and stored by animals Glycogen-made and stored by animals

Lipids Lipids are nonpolar and are NOT soluble in water Lipids are nonpolar and are NOT soluble in water Lipids include: fats, phospholipids, steroids, and waxes Lipids include: fats, phospholipids, steroids, and waxes Fats-Store energy Fats-Store energy Phospholipids-Form cell membranes Phospholipids-Form cell membranes

Lipids ***Look at page 35, figure 9. Examine the difference between saturated and unsaturated fatty acids. * Saturated fats are solid at room temperature * Unsaturated fats are liquid at room temperature

Proteins Large molecules formed by amino acids Large molecules formed by amino acids AMINO ACIDS ARE THE BUILDING BLOCKS OF PROTEIN. AMINO ACIDS ARE THE BUILDING BLOCKS OF PROTEIN. See page 36, figure 10 See page 36, figure 10

Proteins tend to fold into compact shapes

Functions of Proteins Some proteins are enzymes and promote chemical reactions. Some proteins are enzymes and promote chemical reactions. Collagen is a protein found in skin, ligaments, tendons, and bones. Collagen is a protein found in skin, ligaments, tendons, and bones. Antibodies defend against infection. Antibodies defend against infection. Aid in muscle contraction Aid in muscle contraction Hemoglobin is a protein found in blood that carries oxygen from the lungs to body tissues. Hemoglobin is a protein found in blood that carries oxygen from the lungs to body tissues.

Nucleic Acids Found in ALL cells Found in ALL cells It is a long chain of smaller molecules called nucleotides It is a long chain of smaller molecules called nucleotides (A, T, G, and C) (A, T, G, and C) 2 types of Nucleic acids 2 types of Nucleic acids

Nucleic Acids 1. DNA-deoxyribonucleic acid: made of 2 strands; stores hereditary information 2. RNA-ribonucleic acid; made of 1 strand ; manufactures proteins

Nucleic Acids ENERGY MOLECULE IS ATP. ATP is adenosine triphosphate; temporarily stores energy

IV.Energy and Chemical Reactions A. What is energy? A. What is energy? Ability to move or change matter Forms of energy include: Forms of energy include:lightheatchemicalmechanicalelectrical

IV. Energy and Chemical Reactions Page 39, Figure 13

A. What is energy? In chemical reactions energy is stored or released. Reactants  Products NaCl  Na + + Cl - NaCl  Na + + Cl -

B. Activation Energy Activation Energy-energy needed to start a chemical reaction It is a “push” that starts a chemical reaction

C. Enzymes Enzymes-increase the speed of chemical reactions Most enzymes are proteins. Most enzymes are proteins. Decrease the amount of energy needed to start a chemical reaction Decrease the amount of energy needed to start a chemical reaction Page 40, Figure 14

C. Enzymes Allow organisms to maintain homeostasis Allow organisms to maintain homeostasis Example: Carbonic anhydrase allows your body to eliminate CO 2 efficiently Example: Carbonic anhydrase allows your body to eliminate CO 2 efficiently Draw the reaction Draw the reaction CO 2 + H 2 O H 2 CO 3 Carbonic anhydrase

C. Enzymes Enzyme specificity-Enzymes act on only certain substances during a chemical reaction Enzyme specificity-Enzymes act on only certain substances during a chemical reaction These substances are called substrates These substances are called substrates

C. Enzymes Page 41, Figure 15-Label active site, substrate, and enzyme

C. Enzymes What can effect enzyme activity? pH or temperature DATA LAB: Analyzing the Effect of pH on Enzyme Activity ***attached to student notes