Fundamental Chemistry Concepts for Anatomy & Physiology

Chemistry in Healthcare and Anatomy & Physiology

Importance of Chemistry for Healthcare Students

Chemistry provides the foundational understanding of matter and energy, which is essential for comprehending physiological processes in the human body. Knowledge of chemical principles helps healthcare students understand cellular functions, drug interactions, and metabolic pathways.

• Matter: Anything that occupies space and has mass.

• Mass: The amount of matter in an object.

• States of Matter: Solid, liquid, and gas.

• Energy: The ability to do work; crucial for biological processes.

Forms and Properties of Energy

Types of Energy

Energy exists in various forms and is constantly converted within biological systems.

• Kinetic Energy: Energy in action (e.g., muscle contraction).

• Potential Energy: Stored energy (e.g., energy in chemical bonds).

• Chemical Energy: Energy stored in chemical bonds, such as in food molecules.

• Electrical Energy: Movement of charged particles; essential for nerve impulses.

• Mechanical Energy: Energy involved in movement (e.g., walking, cycling).

• Radiant Energy: Energy that travels in waves, such as ultraviolet (UV) radiation.

Energy Conversion: Energy can be transformed from one form to another, which is fundamental in physiological processes.

Elements and Atomic Structure

Elements and Atoms

All matter is composed of elements, which are pure substances that cannot be broken down further. The human body is primarily made of carbon, oxygen, hydrogen, and nitrogen.

• Atomic Symbol: One or two-letter abbreviation for each element.

• Atoms: The smallest units of elements, consisting of subatomic particles.

Subatomic Particles

• Protons: Mass = 1, Charge = +1

• Neutrons: Mass = 1, Charge = 0

• Electrons: Mass ≈ 0, Charge = -1

• Orbitals: Regions around the nucleus where electrons are likely to be found.

Atomic Numbers and Isotopes

• Atomic Number: Number of protons in the nucleus.

• Mass Number: Sum of protons and neutrons.

• Isotopes: Atoms of the same element with different numbers of neutrons; some are radioactive and undergo decay.

Molecules, Compounds, and Mixtures

Molecules and Compounds

Molecules are formed when two or more atoms are held together by chemical bonds. If the atoms are of the same element, it is a molecule of that element; if different, it is a compound.

Mixtures

• Solutions: Homogeneous mixtures; composition is uniform throughout (e.g., air, seawater).

• Solvent: The substance present in greater amount.

• Solute: The substance present in lesser amount.

• Colloids: Mixtures with particles that can have different compositions (e.g., Jello, cytosol).

• Suspensions: Heterogeneous mixtures with large solutes that can settle out (e.g., blood).

Concentration of Solutions

• Percent (%): Used for concentration (e.g., blood glucose).

• Milligrams per deciliter (mg/dL): Common clinical measurement.

• Molarity (M): Number of moles of solute per liter of solution.

Avogadro's Number: $6.02 \times 10^{23}$ particles per mole.

Chemical Bonds and Reactions

Types of Chemical Bonds

Chemical bonds are energy relationships between electrons of reacting atoms, holding atoms together in molecules.

• Ionic Bonds: Formed when electrons are transferred from one atom to another, creating ions (cations and anions).

• Covalent Bonds: Formed when atoms share electron pairs; can be single, double, or triple bonds.

• Non-polar Molecules: Electron pairs are shared equally.

• Polar Molecules: Electron pairs are shared unequally, creating partial charges.

Octet Rule: Atoms are most stable when their outer electron shell (valence shell) is full (2 electrons for the first shell, 8 for others).

Chemical Reactions

• Reactants: Substances that interact in a reaction.

• Products: Substances formed as a result.

• Anabolic Reactions: Synthesis reactions ($A + B \rightarrow C$).

• Catabolic Reactions: Decomposition reactions ($A \rightarrow B + C$).

• Exergonic Reactions: Release energy.

• Endergonic Reactions: Absorb energy.

Factors Influencing Chemical Reactions

• Temperature

• Concentration

• Particle Size

• Catalysts (enzymes)

Biochemistry: Organic and Inorganic Compounds

Organic Compounds

Organic compounds contain carbon and are typically bonded to hydrogen, oxygen, nitrogen, or phosphorus. They are essential for life and include carbohydrates, lipids, proteins, and nucleic acids.

Inorganic Compounds

All other chemicals, including water, salts, acids, and bases.

Water

• Composes 60-80% of living cells.

• Absorbs and releases heat, aiding in temperature regulation (homeostasis).

• Universal solvent; important for chemical reactions.

• Provides cushioning (e.g., cerebrospinal fluid).

Salts

• Important for nerve conduction and muscle contraction.

• Dissociate into ions in water, enabling electrical activity.

Acids and Bases

• Acids: Release hydrogen ions ($H^+$), taste sour, react with metals (e.g., vinegar).

• Bases: Accept hydrogen ions, taste bitter, feel slippery (e.g., bicarbonate).

pH Scale

• Ranges from 0 (most acidic, more $H^+$) to 14 (most basic, less $H^+$).

• 7 is neutral.

• Neutralization: Acid + Base → Salt + Water.

• Body maintains pH between 7.35-7.45 (regulated by kidneys and lungs).

• Bicarbonate Buffer System: Maintains blood pH.

Macromolecules: Carbohydrates, Lipids, Proteins, and Nucleic Acids

Carbohydrates

Carbohydrates are organic molecules containing carbon, hydrogen, and oxygen in a 2:1 ratio. They serve as a primary energy source.

• Monosaccharides: Single sugar units (e.g., glucose, galactose, fructose, ribose, deoxyribose).

• Disaccharides: Two linked monosaccharides (e.g., sucrose, lactose, maltose).

• Polysaccharides: Chains of simple sugars (e.g., starch in plants, glycogen in animals).

Functions:

• Cellular fuel

• Genetic material components

• Cell surface identification

Lipids

Lipids are insoluble organic compounds containing carbon, hydrogen, and oxygen. They are important for energy storage, cell membranes, and signaling.

• Triglycerides: Made of fatty acids and glycerol; store energy and found beneath the skin.

• Saturated Fatty Acids: Single bonds; solid at room temperature.

• Unsaturated Fatty Acids: Double bonds; liquid at room temperature (oils).

• Phospholipids: Modified triglycerides with two fatty acids and a phosphate group; form cell membranes with hydrophilic and hydrophobic ends.

• Steroids: Four interlocking rings; important for cell membranes, vitamin D synthesis, steroid hormones, and bile salts.

Proteins

Proteins make up 10-30% of cell mass and perform many vital functions. They are polymers of amino acids joined by peptide bonds.

• Roles: Enzymes, hemoglobin, muscle structure.

• Structure: Determines function; can be fibrous (structural) or globular (functional).

• Denaturation: Loss of function due to high temperature or pH changes.

Enzymes

• Globular proteins that act as catalysts, speeding up chemical reactions.

Nucleic Acids: DNA and RNA

Nucleic acids are polymers of nucleotides containing carbon, oxygen, hydrogen, nitrogen, and phosphorus.

• DNA: Located in the nucleus; stores genetic information and replicates before cell division.

• RNA: Located outside the nucleus; carries out instructions from DNA.

• Both: Composed of nucleotides.

ATP: Cellular Energy Currency

When glucose is broken down, energy is stored in ATP (adenosine triphosphate), which can be hydrolyzed to release energy for cellular processes.

• ATP Hydrolysis: $ATP + H_2O \rightarrow ADP + P_i + \text{energy}$

Summary Table: Types of Chemical Bonds

Bond Type	Mechanism	Example	Polarity
Ionic	Electron transfer	NaCl (sodium chloride)	Polar
Covalent (Non-polar)	Equal electron sharing	O2 (oxygen gas)	Non-polar
Covalent (Polar)	Unequal electron sharing	H2O (water)	Polar

Summary Table: Major Macromolecules

Macromolecule	Monomer	Main Function	Example
Carbohydrate	Monosaccharide	Energy source	Glucose
Lipid	Fatty acid + Glycerol	Energy storage, membranes	Triglyceride
Protein	Amino acid	Structure, enzymes	Hemoglobin
Nucleic Acid	Nucleotide	Genetic information	DNA, RNA

Additional info: Some explanations and examples have been expanded for clarity and completeness. Figures and tables referenced in the original notes have been described or recreated in text and HTML table format.