Mrs. Williams Biology Honors Semester One

Section 1: Atoms, Ions, and Molecules  Atoms are the smallest unit of an element  Three particles  Protons (+ charge)  Electrons (- charge)  Neutrons (no charge)  Nucleus contains protons and neutrons

Elements  Elements are pure substances consisting of only one type of atom  Cannot be broken down further!  Listed in the periodic table  Atoms of each element differ by the # of protons

Isotopes  Isotopes are atoms of an element with different number of neutrons  Atomic # is the same; mass # is different  Most have same chemical properties

Radioactive Isotopes  Radioactive isotopes have unstable nuclei that break down at a constant rate over time  Uses for radioactive isotopes  Dating of rocks and fossils  Treating cancer  Killing bacteria on food  Trace movements of substances within the body

Ions and Bonding  Ions are formed when an atom gains or loses an electron  Ionic bonds vs. covalent bonds  Read on pages 38 & 39 about ionic and covalent bonding to yourself  Compare and contrast the two bonding types with your table partner

Bonding IonicCovalent  Forms through the electrical force between oppositely charged ions  Ex: NaCl  Sodium (Na+), a positively- charged ion is attracted to chlorine (Cl-), a negatively- charged ion.  Forms when atoms share a pair of electrons  Generally very strong bonds  Depending on the # of electrons, two atoms may form several covalent bonds  Ex: CO 2 - Fig. 2.4

Chemical Compounds  A chemical compound is a substance of two or more elements in definite proportions  Different chemical properties than the original elements  Compound composition given in chemical formula  For example: NaCl and H 2 O

Chemical Reactions  Chemical reactions are the breaking and forming of chemical bonds  Reactants- original elements or compounds  Products- ending elements or compounds

Section 2: Properties of Water  Water – H 2 O  Polar molecule  Has a region with a slight positive charge and a region with a slight negative charge (page 40 - fig. 2.5)  Hydrogen bond  An attraction between a slightly positive hydrogen atom and a slightly negative atom (often O or N)

Properties Related to Hydrogen Bonds – page 41  1. High Specific Heat  Water resists changes in temp; very important in cells!  2.Cohesion  The attraction among molecules of a substance  Caused by hydrogen bonds  Produces surface tension  3. Adhesion  Attraction among molecules of different substances

Water is a Solvent! Page 42  Solution  Mixture of substances that is the same throughout (a homogenous mixture)  Has two parts  Solvent – the substance that is present in the greater amount and that dissolves another substance  Solute – a substance that dissolves in a solvent

Acids and Bases  Some compounds break up into ions (an atom that has gained or lost electrons) when they dissolve in water  Acids release a proton (H + ) when they dissolve in water  Bases remove H + ions from a solution  A solution’s acidity is measured by the pH scale (page 43, figure 2.9)

Dissociation of Water

pH Scale  Scale measuring amount of H + (really H 3 O + )  Ranges from 0-14  Below 7- acids  Higher H +  Above 7- bases  Higher OH -  7- Neutral  Equal numbers of both

Origin Statement – August 7 th  In your notebook, answer the following WITHOUT USING NOTES: 1. Describe an atom. List all parts and their charges. 2. How do we determine atomic number? 3. What is an isotope? 4. Describe the 3 properties of hydrogen bonding. 5. Acids have a pH between ? and ? Bases have a pH between ? and ?

Section 3: Carbon-based molecules  Carbon-based compounds  A monomer is a basic repeating building block  A polymer is many monomers connected together  Draw a visual representation of a monomer and polymer!

Dehydration Synthesis  Building larger molecules from smaller ones (requires energy)  Monomer → Polymer

Hydrolysis  Break down large molecules into smaller ones (releases energy)  Polymer → Monomer

Carbon Compounds  Condensation/Synthesis Monomer Polymer Hydrolysis

Carbohydrates  Made of C, H, and O in a 1:2:1 ratio  Monomers  Monosaccharide  Examples: glucose, fructose, galactose  Dimers  Disaccharides  Examples: sucrose and lactose  Polymers  Polysaccharides  Examples: starch, glycogen, chitin, and cellulose

Carbohydrates

Carbohydrates (Starch)

Carbohydrates (Glycogen)

Carbohydrates (Chitin and Cellulose) Chitin Cellulose

Uses for Carbohydrates  Provide energy for body functions  Used to build nucleic acids  Other structural functions

Tests for Carbohydrates  Benedict’s Test for Simple sugars  Iodine Test for Complex Sugars

Lipids (Fats & Oils)  Made of C, H, and O (phospholipids have P)  Triglyceride  1 Glycerol, 3 Fatty Acid Chains  Examples: Fats found in adipose tissue  Phospholipid  1 Glycerol, 2 Fatty Acid Chains  Example: Molecules found in cell membrane  Steroid  4 Carbon ring structure  Example: cholesterol, testosterone, estrogen, and other hormones

Lipids

Cholestero l Progesterone Testosterone

Uses for Lipids  Energy source  Padding and insulation  Structural  Hormones  Water-proofing

Tests for Lipids  Sudan IV Test  Sudan IV turns red in the presence of lipids  Newspaper Test  Lipids leave a translucent spot on newspaper/brown paper bags (think fast food bags)

Protein  Made of C, H, O, S, and N  Monomer  Amino acids (20 found in the body; 12 made by you…the others come from foods you eat)  Polymer  Polypeptide  Amino acids are held together by a peptide bond

Amino Acid Structure H C R COOH H3N+H3N+

Amino Acid Structure

Polypeptide H3N+H3N+ R COOH H C H3N+H3N+ R H C H3N+H3N+ R H C H3N+H3N+ R H C

Uses for Proteins  Structural – form bones and muscles  Enzymes - speed up rates of reactions  Transport – Help bring substances into or out of cells  Antibodies – Helps fight diseases/immunity

Test for Proteins Biuret Test – purple or pink indicates protein

Energy of Reactions  Reaction Types  Energy Releasing  Reaction is spontaneous (not fast, necessarily)  Activation energy – energy need to get the reaction started  At the end of the reaction, energy is released into the environment  Energy Absorbing  Rxn is not spontaneous  Activation energy- energy needed to get the rxn started  At end of the rxn, energy is absorbed from environment

Energy Reaction Diagrams

Enzymes - IntroIntro  Catalyst for the reaction (speeds it up)  Substrate (reactant) enters the active site of the enzyme to form an enzyme-substrate complex  After the rxn, the product leaves  The enzyme remains unchanged

Enzymes

Action of Enzymes  Speeds up the reaction by lowering activation energy

Enzyme Reaction Rates  Rates can be affected by:  Temperature  pH  Amount of enzyme

Nucleic Acids  Made of C, H, O, N and P  Monomer- Nucleotide  DNA  Sugar - Deoxyribose  Nitrogen Bases – A, T, G, C  RNA  Sugar- Ribose  Nitrogen Bases- A, U, G, C Phosphate Sugar Nitrogen Base

DNA Nucleotide = Phosphate = Deoxyribose Purines Pyrimidines = Adenine = Guanine = Thymine = Cytosine

A = T G = C AT G C

Nucleic Acids

RNA Nucleotide = Phosphate = Ribose Purines = Adenine = Guanine Pyrimidines = Uracil = Cytosine

RNA Structure Single-stranded

Uses for Nucleic Acids  They work together to make proteins by storing genetic information

ATP Structure Adenine Adenosine Ribose High Energy Bonds Phosphates

ADP Structure