Unit 3: The Chemistry of Life The study of matter & the changes it undergoes Unit 3: The Chemistry of Life Ch. 2 (pg. 30), Ch. 9 (pg. 185-186), Ch. 28 (pg. 586-587)

What is an Element? a substance made of only one type of atom ex. = carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur What is an element? Element = substance that is made of only one type of atom, can’t be broken into simpler substances by ordinary chemical means. Examples: lead, gold, oxygen, carbon, nitrogen, helium, etc. What are elements made of? Elements are made of atoms

What are the 6 Most Abundant Elements in Biological Matter? CHNOPS makes up 99% of mass of all living things

What are Atoms? the smallest part of an element What are atoms? Atoms are the smallest part of an element that has all the element’s chemical & physical properties Examples =oxygen, carbon, nitrogen, hydrogen, silicon, gold Represented by a symbol (as well as name) Take a pile of paper clips (all of the same size and color). Divide the pile into two equal piles. Divide each of the smaller piles into two equal piles. Repeat step 3 until you are down to a pile containing only one paper clip. That one paper clip still does the job of a paper clip (i.e., hold loose papers together). Now, take a pair of scissors and cut that one paper clip in half. Can half of the paper clip do the same job as the single paper clip? If you do the same thing with any element, you will reach an indivisible part that has the same properties of the element, like the single paper clip. This indivisible part is called an atom.

What Makes Up an Atom? Subatomic particle Location charge symbol Proton Nucleus (center of atom) positive p+ Neutron neutral (no charge) n0 Electron Orbit around nucleus (located in energy levels) negative e- 17 p+ 18 n0 Central region called the nucleus Consists of: protons, p+ positive charges neutrons, n0 (neutral/no charge), Most of the mass of an atom (p = 1 amu n = 1 amu, about 0.001 amu heavier than proton) Electrons, e- Negatively charged particles orbit around nucleus, Located in discrete energy levels = shells Often called electron “cloud” (outer most = valence shell) smallest part of atom 0.0005 amu In its neutral state, an atom has an equal number of protons and electrons…so, it has no charge.

Using the Periodic Table of the Elements # of protons 16 also # of electrons bigger of the 2 #s periodic table = tool used to organize info about the elements. Shows atomic number (# protons) and atomic mass (# protons + neutrons). Atomic number: number of protons in nucleus (Because atoms are neutral: # electrons = # protons) Determines the element & its properties Atoms of the same element always have the same atomic number Atomic Mass: total mass of protons and neutrons within an atom’s nucleus (bigger of the 2 numbers) to figure out # of neutrons… atomic mass – atomic number = neutrons protons + neutrons

Electrons & Energy Levels electrons in energy levels (“shells”) around nucleus 1st shell  up to 2 electrons other shells  up to 8 electrons (fill before go to next) 17 p+ 18 n0 Na As the # of electrons in atoms increases, more energy levels are needed to hold them. Each level can hold only a specific number of electrons. 1st  2 2nd  8 3rd  8 For Na (sodium), how many more electrons can the 3rd shell hold? Seven more How many more electrons can the 3rd shell hold?

What Affects the Bonding of Atoms? the # of outer (valence) level electrons If outer level is: not full, atom is unstable will bond with electrons from other atom(s) to fill outer level full, atom is stable won’t bond # of electrons in outermost (valence) shell governs bonding behavior Some atoms already have full valence energy levels (& are stable) do not readily combine with other elements to form compounds If not full, stability can be achieved by forming bonds with other atoms by gaining, losing, or sharing electrons. 3 main bond types: 1. covalent 2. ionic 3. metallic

What causes a Covalent Bond? atoms are held together by shared electrons 2+ atoms share electrons to form a compound. single pair shared = single covalent bond 2 pairs shared = double covalent bond A water molecule is made up of two hydrogen atoms and one oxygen atom. Oxygen is in the 6th column of the periodic table so we know it has 6 electrons in its outermost shell. To be balanced Oxygen needs to gain two electrons or lose six. Hydrogen needs to gain one electron to be balanced. Each hydrogen can form a covalent bond and share its electron.

What causes an Ionic Bond? atoms are held together when they lose or gain electrons Atoms & Bonding Interactive held together when atoms lose or gain electrons charged atom = ion lose  positive gain  negative opposite charges attract forming compounds (salts) Ex. NaCl (table salt) The number of positive or negative charges on an ion is shown as a superscript after the symbol for an atom or group of atoms Hydrogen ions (H+), Hydroxide ions (OH-) Sodium ions (Na+), Chloride ions (Cl-)

What are Molecules/Compounds? combinations of two or more atoms bonded together ex. = O2, H20, C6H12O6, NaCl, HCl What is a molecule? Combination of 2 or more atoms are joined by a covalent bond Examples… oxygen O2, hydrogen H2, water H2O Compounds substance with two or more atoms of different elements combined chemically; Elements combine in a fixed proportion (Can have properties unlike those of the elements from which it is made) Examples water 2 hydrogen and 1 oxygen table salt 1 sodium and 1 chlorine sucrose

Biological Chemistry: Inorganic Molecules simple structure H20, 02, NH3, CO2 inorganic even though it contains carbon an exception to the rule Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

Biological Chemistry: Organic Molecules contain: carbon & usually hydrogen many atoms Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

Biological Chemistry: Monomers & Polymers monomer = small molecule polymer = large molecule made of repeated monomers Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

4 major types of organic biological molecules amino acid polypeptide (protein) nucleotide nucleic acid (DNA & RNA) monosaccharide polysaccharide fatty acids & glycerol Lipid carbohydrates lipids (fats) proteins nucleic acids Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

Examples of Carbohydrates sugar cellulose starch major source of energy (& energy storage) in the body Monomer = Monosaccharides All have the same empirical formula CH2O. C6H12O6  glucose Polymer = Sugars, Starches, Cellulose Contain C,H,O in a ratio of 1:2:1 Ratio of H:O is 2:1 just like H2O Ex. C6H12O6

Functions of Carbohydrates energy source, energy storage, support (plant cell walls) cellulose major source of energy (& energy storage) in the body Monomer = Monosaccharides All have the same empirical formula CH2O. C6H12O6  glucose Polymer = Sugars, Starches, Cellulose Contain C,H,O in a ratio of 1:2:1 Ratio of H:O is 2:1 just like H2O Ex. C6H12O6

Examples of Lipids oil fat Building blocks (not monomers) = fatty acids & glycerol Long-term energy storage, cell membrane, hormones, insulation, nerve transmission

Functions of Lipids long-term energy storage, cell membrane, hormones, insulation, nerve transmission Building blocks (not monomers) = fatty acids & glycerol Long-term energy storage, cell membrane, hormones, insulation, nerve transmission

Examples of Proteins Meat,/ fish/ eggs/ nuts/ beans muscle hormone Amino Acids = Building blocks of (polypeptides & then) proteins Contain: have a central carbon atom an Amino group  NH2 an Acid group  -COOH A variable group  R (one of 20 different atoms or group of atoms) There are 20 different types of amino acids found in the natural world. proteins make up muscle, enzymes, hormones, meats/fish/eggs/nuts/beans Enzymes make reactions happen

Functions of Proteins structure, enzymes, transport materials in & out of cells, hormones, muscle hormone muscle Amino Acids = Building blocks of (polypeptides & then) proteins Contain: have a central carbon atom an Amino group  NH2 an Acid group  -COOH A variable group  R (one of 20 different atoms or group of atoms) There are 20 different types of amino acids found in the natural world. proteins make up muscle, enzymes, hormones, meats/fish/eggs/nuts/beans Enzymes make reactions happen

Examples of Nucleic Acids (entire structure) Examples of Nucleic Acids Monomers = nucleotides made of sugar-phosphate backbone & 1 of 4 nitrogenous bases (In DNA… Adenine, Thymine, Cytosine, Guanine & in RNA… Uracil instead of Thymine) Polymers = nucleic acids (DNA & RNA) DNA = Deoxyribonucleic Acid Stores info for putting amino acids together to make proteins The basis of genes & heredity RNA = Ribonucleic Acid Helps to build proteins Why do living things need DNA? so they can pass on genetic code & continue the species

Functions of Nucleic Acids DNA genetic “blueprint” RNA helps to build (synthesize) proteins Monomers = nucleotides made of sugar-phosphate backbone & 1 of 4 nitrogenous bases (In DNA… Adenine, Thymine, Cytosine, Guanine & in RNA… Uracil instead of Thymine) Polymers = nucleic acids (DNA & RNA) DNA = Deoxyribonucleic Acid Stores info for putting amino acids together to make proteins The basis of genes & heredity RNA = Ribonucleic Acid Helps to build proteins Why do living things need DNA? so they can pass on genetic code & continue the species

Organic Biological Macromolecules Elements Contained Monomer (building blocks) Polymer Function Carbohydrates (sugars, starches, cellulose) C, H, O monosaccharide (simple sugars such as glucose) polysaccharide (such as starch & cellulose) Energy source, energy storage, plant cell walls Lipids (fats, oils, & waxes) Fatty acids & Glycerol (2 types of simple molecules… NOT monomers.) Not applicable Long-term energy storage, cell membrane, hormones, insulation, nerve transmission Protein (muscle, enzymes, hormones, meats/fish/eggs/ nuts/beans) C, H, O, N, S Amino acids (20 different A.A.) Polypeptides Structure, enzymes, transport materials in & out of cells, hormones, muscle Nucleic Acids (DNA & RNA) C, H, O, N, P Nucleotides (sugar-phosphate backbone & nitrogenous bases) Polynucleotide (Nucleic Acids) Carries genetic code (“blueprint for organism”) & directs protein synthesis A monomer is a molecule that is able to bond in long chains. Polymer means many monomers. Sometimes polymers are also known as macromolecules or large-sized molecules. Usually, polymers are organic (but not necessarily). Enzymes make reactions happen