Chemistry Concepts in Anatomy & Physiology

Definitions of Matter, Mass, Weight, and Energy

Understanding basic chemistry is essential for studying Anatomy & Physiology, as it underpins cellular structure and function.

• Matter: Anything that occupies space and has mass; its amount never changes.

• Mass: The actual quantity of matter in an object; remains constant regardless of location.

• Weight: The force exerted by gravity on an object; varies with gravity.

• Energy: The capacity to do work or put matter into motion.

States and Forms of Energy

Energy exists in two primary states and several forms relevant to biological systems.

• Kinetic Energy: Energy in motion.

• Potential Energy: Stored energy, with the potential to be used.

• Chemical Energy: Stored in chemical bonds; released during chemical reactions.

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

• Electrical Energy: Results from movement of charged particles.

• Mechanical Energy: Directly involved in moving matter.

• Radiant Energy: Travels in waves; includes electromagnetic energy.

Atoms and Subatomic Particles

Atoms are the fundamental units of matter, composed of subatomic particles.

• Atom: Smallest unit of an element.

• Proton: Positively charged, located in the nucleus.

• Neutron: Neutral charge, located in the nucleus.

• Electron: Negatively charged, orbits the nucleus; smallest mass (AMU of zero).

Valence electrons determine an atom's chemical reactivity.

Atomic Structure and Chemical Properties

• Mass Number: Sum of protons and neutrons.

• Atomic Number: Number of protons; determines element identity.

• Atomic Symbol: Shorthand notation for elements.

Chemical Equations: Coefficients and Subscripts

Chemical equations represent reactions, with coefficients and subscripts indicating quantities and composition.

• Coefficients: Indicate the number of molecules involved.

• Subscripts: Indicate the number of atoms of each element in a molecule.

Major Elements in the Human Body

Four elements make up 96% of body weight:

• Carbon

• Oxygen

• Hydrogen

• Nitrogen

Isotopes

Isotopes are atoms of the same element with different numbers of neutrons.

Mixtures vs. Compounds

• Mixture: Physically combined substances (solutions, suspensions, colloids).

• Compound: Chemically bonded elements.

Types of Mixtures

• Solution: Homogeneous, does not settle or scatter light (e.g., salt water).

• Suspension: Heterogeneous, settles over time (e.g., cytosol).

• Colloid: Heterogeneous, may settle (e.g., blood).

• Solvent: Substance doing the dissolving.

• Solute: Substance being dissolved.

Role of Electrons in Bonding

Electron shells and the octet rule govern chemical bonding and stability.

• Valence Shell: Outermost electron shell; stability achieved with 8 electrons (octet rule).

• Hydrogen and Helium: Stable with 2 electrons.

Chemical Bonds

Atoms form bonds to achieve stability.

• Ionic Bond: Transfer of electrons; forms cations (+) and anions (−).

• Covalent Bond: Sharing of electron pairs; can be single, double, or triple bonds.

• Polar Covalent: Unequal sharing of electrons.

• Non-Polar Covalent: Equal sharing of electrons.

• Hydrogen Bond: Weak attraction between molecules (e.g., water).

Types of Chemical Reactions

• Synthesis: Formation of bonds.

• Decomposition: Breaking bonds.

• Exchange: Making and breaking bonds.

• Redox (Oxidation-Reduction): Transfer of electrons between atoms.

Factors Influencing Chemical Reaction Rates

• Temperature: Higher temperature increases rate.

• Concentration: Higher concentration increases rate.

• Particle Size: Smaller particles increase rate.

• Catalysts: Speed up reactions; enzymes are biological catalysts.

Properties of Water

• High Heat Capacity: Absorbs/releases heat without temperature change.

• High Heat of Vaporization: Requires energy to evaporate (sweating).

• Polar Solvent: Dissolves ionic substances.

• Reactivity: Participates in hydrolysis and dehydration synthesis.

• Cushioning: Protects organs.

Ions and Electrolytes

• Electrolytes: Substances that dissociate into ions in solution.

• Ions: Charged particles.

pH Scale and Buffers

The pH scale measures acidity and alkalinity, ranging from 0 (acidic) to 14 (basic).

• Neutralization Reaction: Acid and base react to form water and salt.

• Buffers: Stabilize pH by releasing or absorbing ions.

Organic vs. Inorganic Compounds

• Organic Compounds: Contain carbon (exceptions: CO, CO2).

• Inorganic Compounds: Do not contain carbon.

Monomers and Polymers of Organic Macromolecules

Organic macromolecules are built from monomers.

Stored Carbohydrates

• Animals: Glycogen

• Plants: Starch

Levels of Protein Structure

• Primary: Linear sequence of amino acids.

• Secondary: Alpha helix or beta-pleated sheet.

• Tertiary: Three-dimensional globular shape.

• Quaternary: Multiple polypeptide chains.

Amino Acid Structure

Amino acids are the building blocks of proteins, each containing an amino group, acid group, and an R group.

Lipids: Triglycerides, Phospholipids, and Steroids

• Triglycerides: Solid (fat) if saturated; liquid (oil) if unsaturated.

• Phospholipids: Major component of cell membranes.

• Steroids: Include hormones and cholesterol.

Enzyme Characteristics and Action

Enzymes are biological catalysts that lower activation energy, speeding up reactions.

• Specificity: Enzymes act on specific substrates.

• Activation Energy: Minimum energy required for a reaction.

• Enzyme Action Steps: Substrate binds, products are rearranged, products are released.

DNA vs. RNA

ATP: Cellular Energy Currency

• ATP (Adenosine Triphosphate): Primary energy source for cellular processes.

• AMP, ADP, ATP: Differ by number of phosphate groups (AMP = 1, ADP = 2, ATP = 3).

• Uses: Transport work, mechanical work, chemical work.

Summary Table: Organic Molecules

Key Equations

• General chemical equation:

• ATP hydrolysis:

• pH calculation:

Additional info: Academic context was added to clarify definitions, expand explanations, and provide self-contained study notes for exam preparation.