Fundamental Concepts in Anatomy & Physiology: Chemistry and Biomolecules

Chemistry Foundations for Anatomy & Physiology

Atomic Structure and Properties

Understanding atomic structure is essential for grasping the chemical basis of physiological processes. Atoms are the basic units of matter, and their properties determine how molecules interact in the body.

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

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

• Atomic Mass Number: The sum of protons and neutrons in the nucleus.

• Isotopes: Atoms of the same element with different numbers of neutrons. Isotopes may be stable or radioactive.

• Electron Location: Electrons orbit the nucleus in energy levels or shells.

Example: Carbon-12 and Carbon-14 are isotopes of carbon, differing in neutron number.

Chemical Bonds and Molecules

Chemical bonds form molecules, which are essential for biological structure and function. The type of bond affects molecular properties.

• Valence Electrons: Electrons in the outermost shell; they participate in chemical bonding.

• Ionic Bonds: Formed when electrons are transferred between atoms, creating charged ions.

• Covalent Bonds: Formed when atoms share electrons.

• Polar Molecules: Molecules with unequal electron sharing, resulting in partial charges (e.g., water).

• Hydrogen Bonds: Weak attractions between polar molecules, important in water and DNA structure.

Example: Water (H2O) is a polar molecule due to unequal sharing of electrons between oxygen and hydrogen.

Organic and Inorganic Compounds

Compounds in the body are classified as organic (containing carbon) or inorganic.

• Organic Compounds: Contain carbon and hydrogen; examples 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.

Biomolecules and Biological Reactions

Macromolecules: Structure and Function

Macromolecules are large, complex molecules essential for life. They include carbohydrates, lipids, proteins, and nucleic acids.

• Carbohydrates: Building blocks are monosaccharides (simple sugars).

• Lipids: Building blocks are fatty acids and glycerol.

• Proteins: Building blocks are amino acids.

• Nucleic Acids: Building blocks are nucleotides.

Example: DNA is a nucleic acid made of nucleotide monomers.

Types of Triglycerides and Fatty Acids

Triglycerides are a type of lipid composed of three fatty acids and glycerol. Fatty acids can be saturated or unsaturated.

• Saturated Fats: No double bonds between carbon atoms; solid at room temperature.

• Unsaturated Fats: One or more double bonds; liquid at room temperature.

Example: Butter contains saturated fats; olive oil contains unsaturated fats.

Enzymes and Biological Reactions

Enzymes are biological catalysts that speed up chemical reactions in the body without being consumed.

• Dehydration Synthesis: Reaction that joins two molecules by removing water.

• Enzymes: Proteins that lower activation energy for reactions.

Example: Amylase is an enzyme that breaks down starch into sugars.

Acids, Bases, and pH

pH Scale and Biological Importance

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.

• Weak Acid/Base: Partially dissociates in water; strong acids/bases dissociate completely.

Equation:

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

Example: Blood has a pH of about 7.4, which is slightly basic.

Genetics and DNA Structure

Nucleic Acids and DNA Base Pairing

Nucleic acids store genetic information. DNA is composed of nucleotides, each containing a sugar, phosphate, and nitrogenous base.

• Nucleotide: Made of a phosphate group, deoxyribose sugar, and a nitrogenous base.

• DNA Base Pairing: Adenine (A) pairs with Thymine (T); Cytosine (C) pairs with Guanine (G).

Example: The sequence ATCG in DNA pairs with TAGC on the complementary strand.

Physiological Applications

Vitamins and Skin

The skin produces certain vitamins essential for health.

• Vitamin D: Synthesized in the skin upon exposure to sunlight.

Example: Vitamin D is important for calcium absorption and bone health.

Proteins in the Skin

Proteins play structural and functional roles in the skin.

• Keratin: A structural protein that provides strength and waterproofing.

Example: Keratin is found in hair, nails, and the outer layer of skin.

Summary Table: Biomolecule Building Blocks

Biomolecule	Building Block	Example
Carbohydrates	Monosaccharides	Glucose
Lipids	Fatty acids & Glycerol	Triglyceride
Proteins	Amino acids	Keratin
Nucleic Acids	Nucleotides	DNA

Additional info: Some details, such as the specific examples and expanded explanations, were inferred from standard Anatomy & Physiology curriculum to ensure completeness and clarity.