Fundamental Chemistry Concepts for Anatomy & Physiology

2.1 Atoms and Elements

Introduction

Atoms and elements are the foundational building blocks of matter, essential for understanding the chemical basis of physiological processes in the human body.

• Charge, Mass, and Location: Atoms consist of protons (positive charge, found in the nucleus), neutrons (neutral charge, found in the nucleus), and electrons (negative charge, found in orbitals around the nucleus). The mass of an atom is primarily due to protons and neutrons.

• Comparing Atoms and Elements: An element is a pure substance consisting of only one type of atom. Atoms of different elements have unique numbers of protons.

• Major Elements in the Human Body: Key elements include carbon (C), hydrogen (H), oxygen (O), nitrogen (N), calcium (Ca), and phosphorus (P).

• Atomic Structure Terms:

  • Atomic number: Number of protons in the nucleus.

  • Mass number: Sum of protons and neutrons.

  • Isotope: Atoms of the same element with different numbers of neutrons.

  • Radioisotope: Isotope with an unstable nucleus that emits radiation.

• Isotope Production: Isotopes are produced naturally or artificially by altering the number of neutrons in an atom.

2.2 Matter Combined: Mixtures and Chemical Bonds

Introduction

Matter can exist as mixtures or as compounds formed by chemical bonds. Understanding these forms is crucial for grasping physiological chemistry.

• Types of Mixtures:

  • Solutions: Homogeneous mixtures where solute is dissolved in solvent.

  • Colloids: Heterogeneous mixtures with larger particles that do not settle.

  • Suspensions: Heterogeneous mixtures with large particles that settle out over time.

• Electron Number and Chemical Bonds: The number of electrons in an atom’s valence shell determines its chemical reactivity and bonding capacity.

• Molecules, Compounds, and Ions:

  • Molecule: Two or more atoms bonded together.

  • Compound: Molecule containing atoms of different elements.

  • Ion: Atom or molecule with a net electric charge due to loss or gain of electrons.

• Covalent and Ionic Bonds:

  • Ionic bond: Transfer of electrons from one atom to another, forming charged ions.

  • Covalent bond: Sharing of electrons between atoms.

  • Polar covalent bond: Unequal sharing of electrons, resulting in partial charges.

  • Nonpolar covalent bond: Equal sharing of electrons.

• Hydrogen Bonds and Surface Tension: Hydrogen bonds form between polar molecules, such as water, and contribute to properties like surface tension.

2.3 Chemical Reactions

Introduction

Chemical reactions are processes that change substances into different ones, fundamental to metabolism and physiology.

• What Happens During a Chemical Reaction: Atoms are rearranged, bonds are broken and formed, resulting in new substances.

• Energy in Chemical Reactions:

  • Endergonic reactions: Absorb energy.

  • Exergonic reactions: Release energy.

• Types of Chemical Reactions:

  • Synthesis: Building larger molecules from smaller ones.

  • Decomposition: Breaking down molecules into smaller components.

  • Exchange: Rearranging parts between molecules.

• Factors Influencing Reaction Rates: Temperature, concentration, particle size, and catalysts (including enzymes).

• Enzymes: Biological catalysts that speed up chemical reactions without being consumed.

2.4 Inorganic Compounds: Water, Acids, Bases, and Salts

Introduction

Inorganic compounds are essential for physiological processes, with water being the most abundant and important.

• Physiological Importance of Water: Water acts as a solvent, regulates temperature, and participates in chemical reactions.

• Hydrophilic vs. Hydrophobic Molecules: Hydrophilic molecules interact with water; hydrophobic molecules do not.

• Acids and Bases:

  • Acids: Release hydrogen ions ($H^+$) in solution.

  • Bases: Accept hydrogen ions or release hydroxide ions ($OH^-$).

• pH Scale: Measures hydrogen ion concentration; pH < 7 is acidic, pH = 7 is neutral, pH > 7 is basic. Formula: $pH = -\log_{10}[H^+]$

• Buffers: Compounds that stabilize pH by absorbing or releasing $H^+$ ions.

2.5 Organic Compounds: Carbohydrates, Lipids, Proteins, and Nucleotides

Introduction

Organic compounds are carbon-based molecules vital for structure and function in living organisms.

• Monomers and Polymers: Monomers are small building blocks; polymers are large molecules made by joining monomers. Dehydration synthesis forms polymers; hydrolysis breaks them down.

• Molecular Structures:

  • Carbohydrates: Composed of monosaccharides (e.g., glucose).

  • Lipids: Include fats, oils, and steroids; made of fatty acids and glycerol.

  • Proteins: Made of amino acids; structure determines function.

  • Nucleic acids: DNA and RNA; made of nucleotides.

• Examples and Functions:

  • Carbohydrates: Energy source (e.g., glucose).

  • Lipids: Energy storage, cell membranes.

  • Proteins: Enzymes, structural components.

  • Nucleic acids: Genetic information storage and transfer.

• Protein Structure:

  • Primary: Sequence of amino acids.

  • Secondary: Alpha helices and beta sheets.

  • Tertiary: 3D folding of polypeptide.

  • Quaternary: Multiple polypeptides joined.

  Protein shape is crucial for its function.

• ATP Hydrolysis: ATP (adenosine triphosphate) is the cell’s energy currency. Hydrolysis of ATP releases energy: Formula: $ATP + H_2O \rightarrow ADP + P_i + \text{energy}$ ATP hydrolysis powers cellular processes.

Additional info:

This study guide expands on the syllabus learning objectives with academic context, definitions, and examples to support exam preparation.