Download presentation
1
Chapter 02 Chemistry of Life
2
Levels of Chemical Organization and Chemical Bonding
Lesson 2.1 Levels of Chemical Organization and Chemical Bonding Define the term and describe the structure of an atom. Define the terms element, molecule, and compound. Compare and contrast the major types of chemical bonding.
3
Na Elements Matter The substances from which the universe is made
All of the different types of matter Identified by names or chemical symbols Also identified by number Described and organized in the periodic table 11 Sodium Na 22.99
4
What is the symbol and number for carbon?
5
Elements (cont.) Living matter contains 26 of 92 natural elements.
96% of body weight—four elements 4% of body weight—nine elements 0.1% of body weight—13 elements The body’s chemical composition by weight.
6
Levels of Chemical Organization
Atom—smallest unit of matter Nucleus—central core of atom Proton—positively charged particle in nucleus Neutron—uncharged particle in nucleus Atomic number—number of protons in nucleus Atomic mass—number of protons and neutrons combined
7
Atoms Energy levels—orbital regions surrounding atomic nucleus that contain electrons Electron—negatively charged particle Each region has space for a specific number of electrons. The first energy level has room for two electrons. The second energy level has room for eight electrons. An atom is most stable when its energy levels are filled with electrons. Energy level increases the farther away it is from the nucleus
8
Models of the Atom
9
Elements (cont.) Energy Levels (cont.)
Hydrogen Carbon Total number of electrons 1 6 Number of electrons in first energy level 2 Number of electrons in second energy level 4 Energy Levels (cont.) Hydrogen has only one energy level with room for one more electron. Carbon’s first energy level is full. Carbon’s second energy level has room for four more electrons.
10
Isotopes and Radioactivity (cont.)
Examples Isotope Proton Number Neutron Number Atomic Weight Carbon-12 6 12 Carbon-13 7 13 Carbon-14 8 14 Isotopes Forms of an element that have the same atomic number but different atomic weight Different atomic weight because of a different number of neutrons May be stable or unstable (radioactive)
11
Elements, Molecules, and Compounds
Element—a pure substance; made up of only one kind of atom Molecule—a group of atoms chemically bound together in a group Compound—substances whose molecules have more than one kind of atom
12
Name Symbol Function Oxygen O Part of water; needed to metabolize nutrients for energy Carbon C Basis of all organic compounds; component of carbon dioxide, the gaseous byproduct of metabolism Hydrogen H Part of water, participates in energy metabolism; determines the acidity of body fluids Nitrogen N Present in all proteins, ATP (the energy-storing compound), and nucleic acids (DNA and RNA) Calcium Ca Builds bones and teeth; needed for muscle contraction, nerve impulse conduction, and blood clotting Phosphorus P Active ingredient in ATP; builds bones and teeth; component of cell membranes and nucleic acids Potassium K Active in nerve impulse conduction; muscle contraction Sulfur S Part of many proteins Sodium Na Active in water balance, nerve impulse conduction, and muscle contraction Iron Fe Part of hemoglobin, the compound that carries oxygen in red blood cells The elements are listed in decreasing order by weight in the body.
13
Chemical Bonding Chemical bonds form to make atoms more stable.
Atoms react with one another in ways that make their outermost energy level full. Atoms may share electrons or donate or borrow them to become stable.
14
Ionic Bonds Ions form when an atom gains or loses electrons in its outer energy level to become stable Positive ion—has lost electrons; indicated by superscript positive sign(s), as in Na+ or Ca++ Negative ion—has gained electrons; indicated by superscript negative sign(s), as in Cl–
15
Ionic Bonds Ionic bonds form when positive and negative (oppositely charged) ions attract each other Electrolyte—molecule that dissociates (breaks apart) in water to form individual ions; an ionic compound
16
Ionic Bonding
17
Covalent Bonds Covalent bonds form when atoms share their outer energy ions to complete the energy level and thus become stable. Covalent bonds do not ordinarily easily dissociate in water. Covalent bonding is used to form all of the major organic compounds found in the body.
18
Covalent Bonding
19
Hydrogen Bonds Hydrogen bonds do not create new molecules.
Hydrogen bonds weakly bond to neighboring molecules. Hydrogen bonds are present in water, DNA, and proteins. .
20
Hydrogen Bonds
21
Inorganic and Organic Chemistry
Lesson 2.2 Inorganic and Organic Chemistry Distinguish between organic and inorganic chemical compounds. Discuss the chemical characteristics of water. Explain the concept of pH. Discuss the structure and function of the following types of organic molecules: carbohydrate, lipid, protein, and nucleic acid.
22
Inorganic Chemistry Organic molecules contain carbon-carbon covalent bonds and/or carbon-hydrogen covalent bonds; inorganic molecules do not. Organic molecules are generally larger and more complex than inorganic molecules.
23
Water Water is an inorganic compound essential to life.
Water is a solvent (liquid into which solutes are dissolved), forming aqueous solutions in the body.
24
Mixtures Mixtures- consists of two or more substances that are mixed together but not chemically bonded and each ingredient keeps its own properties Type Definition Example Solution Homogeneous mixture formed when one substance (solute) dissolves in another (solvent) Table salt (NaCl) dissolved in water; table sugar (sucrose) dissolved in water Suspension Heterogeneous mixture in which one substance is dispersed in another but is not chemically bonded and will settle out unless constantly mixed Red blood cells in blood plasma; milk of magnesia Colloid Heterogeneous mixture in which the suspended particles remain evenly distributed based on the small size and opposing charges of the particles Blood plasma; cytosol
25
Mixtures (cont.) The Importance of Water
Most abundant compound in body Critical in all physiologic processes Deficiency (dehydration) threatens health Universal solvent Stable liquid at ordinary temperatures Participates in body’s chemical reactions
26
Water Water is involved in chemical reactions: Dehydration synthesis
Hydrolysis Chemical reactions always involve energy transfers, as when energy is used to build ATP molecules Chemical equations show how reactants interact to form products; arrows separate the reactants from the products
27
Water-based Chemistry
28
Acids, Bases, and Salts Acid A substance that releases hydrogen ions
A substance that releases hydroxide ions and accepts hydrogen ions Salt A substance formed by a reaction between an acid and a base HCl H+ + Cl− NaOH Na+ + OH− HCl + NaOH NaCl + H2O
29
Acids, Bases, and Salts Water molecules dissociate to form equal amounts of H+ (hydrogen ion) and OH– (hydroxide ion) Acid—substance that shifts the H+/OH– balance in favor of H+; opposite of base Base—substance that shifts the H+/OH– balance against H+; also known as an alkaline; opposite of acid
30
Acids, Bases, and Salts (cont.)
The pH Scale Measures the relative concentrations of hydrogen and hydroxide ions in a solution. Scale from 0 (most acidic) to 14 (most basic). Each unit represents a 10-fold change. Normal body fluid pH range is between 7.35 and 7.45. Acidosis: Body fluid pH less than 7.35 Alkalosis: Body fluid pH greater than 7.45
31
pH pH—Mathematical expression of relative H+ concentration in an aqueous solution 7 is neutral (neither acid nor base) pH values above 7 are basic; pH values below 7 are acidic
32
pH Neutralization occurs when acids and bases mix and form salts.
Buffers form chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH (proteins, Bicarbonate, or hemoglobin).
33
Organic Chemistry Carbohydrates—sugars and complex carbohydrates
Contain carbon (C), hydrogen (H), and oxygen (O) Monosaccharides—basic unit of carbohydrate molecules (for example, glucose) Disaccharide—double sugar made up of two monosaccharide units (for example, sucrose, lactose) Polysaccharide—complex carbohydrate made up of many monosaccharide units (for example, glycogen; stored by the body)
34
Carbohydrates
35
Lipids—Fats and Oils Triglycerides
Formed by a glycerol unit and joined to three fatty acids Store energy for later use
36
Phospholipids Similar to triglyceride structure, but have phosphorus-containing units—each with a head and two tails The head attracts water (hydrophilic) and the double tail does not (hydrophobic), thus forming stable double layers (bilayers) in water Form membranes of cells
37
Phospholipids
38
Cholesterol Molecules have a steroid structure made up of multiple rings Stabilizes the phospholipid tails in cellular membranes Also converted into steroid hormones by the body
39
Proteins Very large molecules made up of amino acids held together in long, folded chains by peptide bonds Structural proteins Form essential structures of the body Collagen is a fibrous protein that holds many tissues together Keratin forms tough, waterproof fibers in the outer layer of the skin
40
Protein
41
Functional Proteins Participate in chemical processes of the body
Examples include hormones, cell membrane channels and receptors, and enzymes Enzymes—chemical catalysts Help chemical reactions occur Enzyme action sometimes called lock-and-key model
42
Enzyme Action
43
Nucleic Acids Made up of nucleotides A phosphate unit
A sugar (ribose or deoxyribose) A nitrogen base (adenine, thymine or uracil, guanine, cytosine)
44
DNA (Deoxyribonucleic Acid)
Used as the cell’s “master code” for assembling proteins Uses deoxyribose as the sugar and A, T (not U), C, and G as bases Forms a double helix shape
45
DNA
46
RNA (Ribonucleic Acid)
Used as a temporary “working copy” of a gene (portion of the DNA code) Uses ribose as the sugar and A, U (not T), C, and G as bases
47
ATP (Adenosine Triphosphate)
48
Key Terms acid chemistry ion salt amino acid colloid isotope solute
anion compound lipid solution aqueous denaturation molecule solvent atom electrolyte nucleotide steroid base electron neutron substrate buffer element pH suspension carbohydrate enzyme protein catalyst glucose proton cation glycogen radioactive
49
Word Anatomy (cont.) Word Part Meaning Example Chemical Bonds co-
together Covalent bonds form when atoms share electrons. Solutions and Suspensions aqu/e water In an aqueous solution, water is solvent. heter/o- different Heterogeneous solutions are different (not uniform) throughout. hom/o- same Homogeneous mixtures are the same throughout. hydr/o Dehydration is a deficiency of water. phil to like Hydrophilic substances “like” water—they mix with or dissolve it. phobia to fear Hydrophobic substances “fear” water—they repel and do not dissolve it.
50
Word Anatomy (cont.) Word Part Meaning Example Organic Compounds -ase
suffix used in naming enzymes A lipase is an enzyme that acts on lipids. de- remove Denaturation of a protein removes its ability to function (changes its nature). di- twice, double A disaccharide consists of two simple sugars. glyc/o- glucose, sweet Glycogen is a storage form of glucose. It breaks down to release glucose. mon/o- one In a monosaccharide, “mono-” refers to one. poly- many A polysaccharide consists of many simple sugars. sacchar/o sugar A monosaccharide consists of one simple sugar. tri- three Triglycerides have one fatty acid attached to each of three carbon atoms.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.