Chapter 2-Chemical Level
Chapter 2: Chemical Level of Body Organization
Page 2: Understanding Matter
Definition of Matter:
Anything that has mass and occupies space.
States of Matter:
Solid, Liquid, Gas.
Composition of Matter:
Composed of atoms of different chemical elements.
Elements:
More than 110 elements exist, each identified by a specific symbol (e.g., O, C, N).
Page 3: Main Chemical Elements in the Body
Major Elements (96% of Body Mass):
Oxygen (O) - 65.0%:
Part of water and organic molecules; generates ATP.
Carbon (C) - 18.5%:
Backbone of organic molecules (carbs, lipids, proteins, nucleic acids).
Hydrogen (H) - 9.5%:
Constituent of water and organic molecules; helps maintain acidity (H+).
Nitrogen (N) - 3.2%:
Component of proteins and nucleic acids.
Lesser Elements (3.6% of Body Mass):
Calcium (Ca) - 1.5%:
Important for bones, blood clotting, and muscle contraction.
Phosphorus (P) - 1.0%:
Component of nucleic acids (DNA/RNA) and ATP.
Other lesser elements included are Potassium (K), Sodium (Na), Magnesium (Mg), Iron (Fe), and others.
yPage 4: Trace Elements
Trace Elements:
Comprise about 0.4% of body mass.
Includes Aluminum (Al), Iodine (I), Zinc (Zn), and other essential elements in micro quantities.
Page 5: Parts of an Atom
Subatomic Particles:
Protons (positively charged), Electrons (negatively charged), Neutrons (uncharged).
Electron- Proton Balance:
Number of electrons equals the number of protons in an atom.
Page 6: Atomic Number and Mass Number
Atomic Number:
Total number of protons in an atom, differentiating elements.
Mass Number:
Sum of protons and neutrons.
Isotopes:
Atoms of the same element differing in neutron number.
Page 7: Electrons and Reactivity
Electron Configuration:
Electrons are arranged in defined energy levels or shells.
First shell holds 2 electrons, second shell holds 8, third shell holds 18.
Valence Shell:
Outermost shell determining an atom's reactivity.
Page 8: Types of Isotopes
Stable Isotopes and Unstable Isotopes:
Unstable isotopes release radiation and are useful in medical imaging.
Page 9: Ions
Definition:
Atoms that have lost or gained electrons, resulting in positive (cations) or negative (anions) charges.
Page 10: Free Radicals
Definition:
Atoms or molecules with unpaired electrons, highly reactive and can damage cellular structures.
Page 11: Free Radicals and Antioxidants
Antioxidants:
Substances that inactivate free radicals.
Includes vitamins A (beta-carotene), C, and E; found in red, blue, or purple fruits and vegetables.
Page 12: Molecules and Molecular Formulas
Molecules:
Formed when atoms combine.
Molecular formula indicates the types and quantities of atoms in a molecule.
Compounds:
Molecules containing different kinds of atoms (e.g., H₂O, NaCl).
Page 13: Chemical Bonds
Definition:
Forces holding atoms together in a molecule.
Types of Bonds:
Ionic Bonds: between ions (cations with anions).
Covalent Bonds: sharing of electrons.
Hydrogen Bonds: interactions between a hydrogen atom and an electronegative atom like oxygen or nitrogen.
Page 14: Ionic Bonds
Characteristics:
Ionic bonds are weak in watery solutions.
Formed from attraction between charged ions (like Na and Cl).
Page 15: Covalent Bonds
Characteristics:
Involve sharing of electron pairs.
Strong bonds, classified into single, double, and triple based on pairs shared.
Page 17: Covalent Bond Types
Polar Covalent Bonds:
Atoms share electrons unequally, resulting in partial charges.
Nonpolar Covalent Bonds:
Atoms share electrons equally.
Page 18: Hydrogen Bonds
Characteristics:
Weak bonds formed between molecules possessing polar covalent bonds (between H and O or N).
Important for structure of proteins and DNA.
Page 20: Chemical Reactions
Definition:
Chemical reactions occur when new bonds are formed or old bonds are broken, often accompanied by energy changes.
Page 21: Energy in Chemical Reactions
Types of Energy:
Potential Energy: Stored energy.
Kinetic Energy: Energy associated with motion.
Chemical Energy: A form of potential energy stored in bonds of molecules.
Page 22: Types of Chemical Reactions
Exergonic:
Reactions that release more energy than they absorb.
Endergonic:
Reactions that absorb more energy than they release.
Page 23: Types of Chemical Reactions
Reactions include:
Synthesis, Decomposition, Exchange, Reversible, Oxidation-Reduction.
Page 24: Enzymes
Definition:
Enzymes are biological catalysts, mainly proteins, that accelerate chemical reactions by lowering activation energy.
Page 27: Inorganic Compounds
Types include:
Water, salts, acids, and bases; water being the most abundant and important.
Page 28: Water Properties
Characteristics:
Polar molecule with unique properties: high cohesion, excellent solvent, temperature regulation, lubrication, and expansion upon freezing.
Page 31: Balance Between Acids and Bases
pH Scale:
Measures acidity; higher H+ concentration indicates a more acidic solution.
Page 34: Buffer Systems
Role:
Helps maintain pH within a normal range; important buffers include bicarbonate.
Page 35: Organic Compounds
Definition:
Molecules with a carbon backbone; include carbohydrates, lipids, proteins, and nucleic acids.
Page 37: Carbohydrates
Composition:
Made of C, H, and O; ratio of H:O is 2:1.
Functions:
Serve as energy sources; structural roles in DNA (ribose).
Page 38: Major Carbohydrate Groups
Types:
Monosaccharides (e.g., glucose), Disaccharides (e.g., sucrose), Polysaccharides (e.g., glycogen, starch).
Page 41: Lipids
Composition:
Made of C, H, O; hydrophobic and transported in lipoproteins.
Types:
Fatty acids, triglycerides, phospholipids, steroids.
Page 46: Proteins
Composition:
Made of C, H, O, N with amino acids as building blocks; 20 different amino acids can form numerous proteins.
Page 50: Functions of Proteins
Categories:
Structural, regulatory, contractile, immunological, transport, catalytic (enzymes).
Page 53: Nucleotides and Nucleic Acids
Components:
Include phosphate group, pentose sugar, nitrogenous bases (e.g., adenine, guanine).
Page 56: Comparison Between DNA and RNA
Differences:
DNA has double-stranded helical structure, while RNA is single-stranded. DNA uses thymine, RNA uses uracil.
Page 57: ATP - Energy Currency
Role in Cells:
ATP is crucial for energy transfer in biochemical reactions; generated from metabolic processes.