Chapter 2: Basic Chemistry – Study Notes for ANP College Students

Basic Chemistry

Introduction

Chemistry is fundamental to understanding the structure and function of the human body. This chapter explores the nature of matter and energy, the structure of atoms, chemical bonding, and the properties of important biological molecules.

2.1 Matter and Energy

• Matter: Anything that occupies space and has mass. May exist as one or 3 states: solids(defines shape), liquids (defines volume) , and gases (neither a definite shape or volume).

• Matter may be changed

  • Physically

    • Changes do not alter the basic nature of a substance

    • Examples include changes in the state of matter (solid, liquid, or gas)

  • Chemically

    • Changes alter the chemical composition of a substance

• Energy: The capacity to do work or cause change. Energy does not have mass or occupy space.

  • Kinetic energy: energy is doing work- is always moving

  • Potential energy: energy is inactive or stored- Ex: glucose, gravity

2.2 Major Forms of Energy in the Body:

• Chemical energy: Stored in bonds of chemical substances (e.g., ATP in cells).

• Electrical energy: Movement of charged particles (e.g., nerve impulses).

• Mechanical energy: Directly involved in moving matter (e.g., muscle contraction).

• Radiant energy: Travels in waves (e.g., light energy for vision).

2.3 Elements and Atoms

• Element: A pure substance composed of only one type of atom; cannot be broken down by ordinary chemical means.

To identify elements we need:

• Atomic Number - equal to the number of protons that the atom contains, unique to atoms of a particular element, indirectly tells the number of electrons in an atom

• Atomic mass number - sum of the protons and neutrons contained in an atom’s nucleus

• Atomic weight- approximately equal to the mass number of the element’s most abundant isotope (to be discussed in a moment)

• Major Elements in the Body: Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N).

• Atoms: The smallest unit of an element that retains its properties.

  2.4 Relationship: Elements are made up of atoms; each atom consists of subatomic particles.

2.5 Subatomic Particles

• Protons: Positive charge, mass of 1 atomic mass unit (amu), located in the nucleus.

• Neutrons: No charge, mass of 1 amu, located in the nucleus.

• Electrons: Negative charge, negligible mass, orbit the nucleus in electron shells.

  Particle	Position in atom	Mass (amu)	Charge
  Proton p super plus	Nucleus	1	+1
  Neutron n super 0	Nucleus	1	0
  Electron e super minus	Orbits around the nucleus	1 two thousandth, asterisk	-1

  2.6 Radioisotopes

• Radioisotope: An isotope with an unstable nucleus that emits radiation.

• Radioactivity—process of spontaneous atomic decay

  • Used to tag and trace biological molecules through the body

• Medical Uses: Used in diagnostic imaging (e.g., PET scans) and in treating diseases (e.g., radioactive iodine for thyroid disorders).

2.7 Molecules and Compounds

• Molecule: Two or more atoms chemically bonded together (e.g., O2).

• Compound: A molecule containing atoms of different elements (e.g., H2O).

2.8 Chemical Bonds and 2.9 Reactions

• Chemical reactions involve the making and breaking of chemical bonds through electron interactions.

• Types of Bonds:

  • Ionic bonds: Transfer of electrons from one atom to another (e.g., NaCl).

  • Polar covalent bonds: Unequal sharing of electrons (e.g., H2O).

  • Nonpolar covalent bonds: Equal sharing of electrons (e.g., O2).

  • Hydrogen bonds: Weak attractions between polar molecules; important in water and DNA structure.

  2.10 Types of Chemical Reactions:

  • Synthesis (Combination): Atoms or molecules combine to form a larger molecule. $A + B \rightarrow AB$

  • Decomposition: A molecule is broken down into smaller parts. $AB \rightarrow A + B$

  • Exchange: Bonds are both made and broken. $AB + CD \rightarrow AD + CB$

2.11 Organic and Inorganic Compounds

• Organic compounds: Contain carbon; include carbohydrates, lipids, proteins, and nucleic acids.

• Inorganic compounds: Do not contain carbon (with few exceptions); include water, salts, acids, and bases. Vital properties include: High heat capacity, polarity properties, chemical reactivity, cushioning

2.12 Water and Its Importance

• Water is the most abundant inorganic compound in the body.

• Roles of Water:

  • Solvent for chemical reactions

  • Helps regulate body temperature

  • Acts as a lubricant and cushion

  • Participates in chemical reactions (e.g., hydrolysis, dehydration synthesis)

2.13 & 2.14 Salts, Acids, and Bases

• Salts: Ionic compounds that dissociate in water to form ions (electrolytes). Examples: NaCl or sodium chloride, Ca2+, K+, Cl-. EX: sodium and potassium ins are essential for nerve impulses.

• Acids: Release hydrogen ions (H+) in solution. Example: HCl. Strong acids ionize completely and liberate all their protons. Weak acids ionize incompletely. INCREASES A SOLUTION'S CONCENTRATION OF H+ IONS

• Bases: Accept hydrogen ions or release hydroxide ions (OH-). Example: NaOH.

2.15 pH and Body Fluids

• pH: A measure of hydrogen ion concentration; scale ranges from 0 (acidic) to 14 (basic).

• Blood pH: Normally maintained at about 7.4.

2.16 Dehydration Synthesis and Hydrolysis

• Dehydration synthesis: Joins molecules by removing water.

• Hydrolysis: Breaks molecules apart by adding water.

  2.17 Carbohydrates & Lipids

  • Include sugars and starches

    • Classified according to size and solubility in water

      • Monosaccharides—simple sugars and the structural units of the carbohydrate group

      • Disaccharides—two simple sugars joined by dehydration synthesis

      • Polysaccharides—long-branching chains of linked simple sugars blocks: Monosaccharides (simple sugars)

    Lipids:

  • Building blocks: Fatty acids and glycerol

  • Structure: Mostly C and H, less O

  • Function: Energy storage, insulation, cell membranes

  • Most abundant are the triglycerides, phospholipids and steroids.

• Comparison Table:

Property	Carbohydrates	Lipids
Building Blocks	Monosaccharides	Fatty acids & Glycerol
Structure	Ring-shaped, C:H:O = 1:2:1	Long chains, mostly C & H
Function	Quick energy	Long-term energy, insulation

2.18 Proteins

• Fibrous proteins: Structural, strand-like (e.g., collagen, keratin).

• Globular proteins: Functional, spherical (e.g., enzymes, hormones).

2.19 Enzymes

• Enzyme: A protein that acts as a biological catalyst, speeding up chemical reactions without being consumed.

• Enzymes lower the activation energy required for reactions.

2.20 Nucleic Acids: DNA and RNA

• DNA (Deoxyribonucleic acid):

  • Double helix structure

  • Stores genetic information

• RNA (Ribonucleic acid):

  • Single-stranded

  • Involved in protein synthesis

• Comparison Table:

Property	DNA	RNA
Strands	Double	Single
Sugar	Deoxyribose	Ribose
Bases	A, T, C, G	A, U, C, G
Function	Genetic code	Protein synthesis

2.21 ATP: The Energy Currency

• ATP (Adenosine triphosphate): The primary energy carrier in cells.

• Energy is released when ATP is broken down to ADP (adenosine diphosphate) and a phosphate group.

• Equation: $ATP \rightarrow ADP + P_i + \text{energy}$

Summary

• Chemistry underlies all physiological processes in the body.

• Understanding the structure and function of atoms, molecules, and compounds is essential for studying anatomy and physiology.