Basic Chemistry for Anatomy & Physiology: Module 2 Study Notes

Basic Chemistry in Anatomy & Physiology

Chemistry: Foundations and Biological Relevance

Chemistry is the scientific discipline concerned with the atomic composition and structure of substances and the reactions they undergo. It is fundamental for understanding how the body transforms and uses energy, and how cells utilize crucial molecules such as carbohydrates, lipids, proteins, and nucleic acids.

• Chemistry helps us understand molecular interactions, including those that release or absorb energy (e.g., enzyme activity, breakdown of food).

• Biological processes such as metabolism depend on chemical reactions involving carbohydrates, lipids, and proteins.

Matter: Definition and Properties

All living and nonliving things are composed of matter, which occupies space and has mass.

• Mass: Amount of matter in an object.

• Weight: Gravitational force acting on an object's mass.

• Matter exists in solid, liquid, and gaseous states in the human body.

• Physical changes do not alter the basic nature of a substance; chemical changes do.

Energy: Definition and Types

Energy is the capacity to do work or put matter into motion. It has no mass and does not occupy space.

• Energy can be measured only by its effects on matter.

• According to the law of conservation of energy, total energy in the universe is constant: it is neither created nor destroyed.

Types of Energy

• Kinetic energy: Energy of motion, displayed in the movement of particles or objects.

• Potential energy: Stored energy, inactive until released.

Forms of Energy in the Body

• Chemical energy: Stored in chemical bonds; released when bonds are broken (e.g., ATP hydrolysis).

• Electrical energy: Movement of charged particles (e.g., nerve impulses).

• Mechanical energy: Directly involved in moving matter (e.g., muscle contraction).

• Radiant energy: Energy of electromagnetic waves (e.g., sunlight).

Energy Conversion in the Human Body

In cells, chemical energy from food is trapped in ATP (adenosine triphosphate), the body's energy currency.

• ATP is produced from carbohydrates, fats, and proteins during metabolism.

• Energy released from ATP powers cellular processes.

Composition of Matter

Matter is composed of elements, unique substances that cannot be broken down by ordinary chemical means. Examples include oxygen, silver, gold, copper, and iron.

• Elements: Building blocks of matter; each element has unique atoms.

• Atomic symbol: One- or two-letter abbreviation for each element (e.g., C for carbon, O for oxygen).

Atoms: Structure and Subatomic Particles

An atom is the smallest unit of an element, retaining its properties.

• Protons (p+): Positive charge.

• Neutrons (n0): No charge.

• Electrons (e-): Negative charge, equal in strength to protons.

The planetary model of the atom depicts electrons orbiting the nucleus in defined paths (electron cloud).

Atomic Number and Atomic Mass

• Atomic number: Number of protons in the nucleus; determines the element's identity.

• Atomic mass number: Sum of protons and neutrons in the nucleus.

Isotopes and Atomic Weight

• Isotopes: Atoms of the same element with different numbers of neutrons (thus different atomic masses).

• All isotopes of an element have the same number of protons and electrons, so their chemical properties are identical.

Common Elements Making Up the Human Body

The human body is primarily composed of a few major elements, with several others present in smaller amounts.

Element	Atomic Symbol	Percentage of Body Weight	Role in the Body
Oxygen	O	65.0	Major component of water and organic molecules; essential for cellular respiration.
Carbon	C	18.5	Primary element in all organic molecules; backbone of carbohydrates, lipids, proteins, and nucleic acids.
Hydrogen	H	9.5	Component of water and most organic molecules; influences pH.
Nitrogen	N	3.2	Found in proteins and nucleic acids; essential for genetic material and cell structure.
Calcium	Ca	1.5	Important for bones, teeth, muscle contraction, and nerve signaling.
Phosphorus	P	1.0	Component of nucleic acids and ATP; important for energy transfer.
Potassium	K	0.4	Essential for nerve function and muscle contraction.
Sulfur	S	0.3	Component of some proteins.
Sodium	Na	0.2	Important for fluid balance and nerve signaling.
Magnesium	Mg	0.1	Involved in enzyme activity and muscle contraction.
Iodine	I	0.1	Essential for thyroid hormone production.
Iron	Fe	0.1	Component of hemoglobin for oxygen transport.

Key Equations and Concepts

• Atomic Mass Number: $\text{Atomic Mass Number} = \text{Number of Protons} + \text{Number of Neutrons}$

• Law of Conservation of Energy: $\text{Total Energy}_{\text{universe}} = \text{constant}$

• ATP Hydrolysis (energy release): $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$

Organic vs. Inorganic Compounds

Organic compounds contain carbon and are typically found in living organisms (e.g., carbohydrates, lipids, proteins, nucleic acids). Inorganic compounds do not contain carbon as their primary element (e.g., water, salts).

• Organic compounds are the basis of cellular structure and function.

• Inorganic compounds are essential for physiological processes (e.g., water for hydration, salts for nerve function).

Summary Table: Organic vs. Inorganic Compounds

Type	Contains Carbon?	Examples	Role in the Body
Organic	Yes	Carbohydrates, Proteins, Lipids, Nucleic Acids	Structure, energy storage, genetic information
Inorganic	No (usually)	Water, Salts, Acids, Bases	Hydration, pH balance, nerve function

Additional info: These notes provide foundational chemistry concepts essential for understanding physiology, including atomic structure, energy forms, and the chemical basis of life.