Anatomy & Physiology: Chemistry Foundations Study Guide

Anatomy & Physiology Chemistry Study Guide

Atomic Structure and Subatomic Particles

Understanding atomic structure is fundamental to grasping chemical processes in biological systems.

• Subatomic Particles: Atoms are composed of protons (positively charged), neutrons (neutral), and electrons (negatively charged).

• Atomic Number: The atomic number is the number of protons in the nucleus of an atom. It defines the element.

• Atomic Mass: The atomic mass (or mass number) is the sum of protons and neutrons in the nucleus.

• Isotopes: Isotopes are atoms of the same element with different numbers of neutrons, resulting in different atomic masses.

• Standard vs. Nonstandard Isotopes: Standard isotopes are the most common form found in nature; nonstandard isotopes have different neutron counts and may be radioactive.

Example: Carbon-12 and Carbon-14 are isotopes of carbon.

Electrons and Chemical Bonding

Electrons play a crucial role in chemical bonding and molecular interactions.

• Valence Electrons: Electrons in the outermost shell determine chemical reactivity and bonding.

• Polar Molecules: A polar molecule has an uneven distribution of charge due to differences in electronegativity between atoms. Water (H2O) is a classic example.

• Types of Bonds: The three main types of chemical bonds are:

  • Ionic Bonds: Transfer of electrons from one atom to another, creating charged ions.

  • Covalent Bonds: Sharing of electron pairs between atoms.

  • Hydrogen Bonds: Weak attractions between polar molecules, especially involving hydrogen.

Example: Sodium chloride (NaCl) forms via ionic bonding; water molecules interact via hydrogen bonds.

Chemical Reactions and Synthesis

Chemical reactions are essential for metabolism and cellular function.

• Dehydration Synthesis: A reaction where two molecules are joined by removing a water molecule. This is key in forming polymers like proteins and nucleic acids.

• Hydrolysis: The reverse process, where water is added to break bonds.

Example: Formation of a peptide bond between amino acids via dehydration synthesis.

Acids, Bases, and pH

The pH scale measures the concentration of hydrogen ions in a solution, indicating its acidity or alkalinity.

• pH Scale: Ranges from 0 (most acidic) to 14 (most basic); 7 is neutral.

• Acids: Substances with pH less than 7; donate hydrogen ions.

• Bases: Substances with pH greater than 7; accept hydrogen ions.

• Example pH Values: Stomach acid (pH ~2), blood (pH ~7.4), bleach (pH ~13).

Formula:

$\text{pH} = -\log_{10}[\text{H}^+]$

Organic and Inorganic Compounds

Compounds in living organisms are classified as organic or inorganic.

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

• Inorganic Compounds: Do not contain both carbon and hydrogen; examples include water, salts, acids, and bases.

Example: Glucose (C6H12O6) is organic; sodium chloride (NaCl) is inorganic.

Macromolecules: Nucleic Acids, Lipids, and Carbohydrates

Macromolecules are large, complex molecules essential for life.

• Nucleotides: Building blocks of nucleic acids (DNA and RNA). Each nucleotide consists of a sugar, phosphate group, and nitrogenous base.

• Triglycerides: A type of lipid made of one glycerol molecule and three fatty acids.

• Sugars: Simple carbohydrates; monosaccharides (e.g., glucose), disaccharides (e.g., sucrose), polysaccharides (e.g., starch).

Table: Macromolecule Components

Macromolecule	Monomer	Example
Carbohydrate	Monosaccharide	Glucose
Lipid	Fatty acid + Glycerol	Triglyceride
Protein	Amino acid	Hemoglobin
Nucleic Acid	Nucleotide	DNA

DNA Structure and Complementary Base Pairing

DNA stores genetic information using a specific sequence of nucleotides.

• Complementary Bases: In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).

• Double Helix: DNA is structured as a double helix with two strands held together by hydrogen bonds between complementary bases.

Example: The sequence ATCG on one strand pairs with TAGC on the other.

Summary Table: Key Chemistry Concepts

Concept	Definition	Example
Atomic Number	Number of protons	Carbon: 6
Atomic Mass	Protons + Neutrons	Carbon-12: 12
Isotope	Same element, different neutrons	Carbon-14
Dehydration Synthesis	Joins molecules, removes water	Protein formation
pH	Hydrogen ion concentration	Blood: 7.4
Triglyceride	Glycerol + 3 fatty acids	Body fat
Complementary Bases	Specific pairing in DNA	A-T, C-G

Additional info: Some context and definitions were inferred to provide a complete, self-contained study guide suitable for exam preparation in Anatomy & Physiology.