Anatomy & Physiology I: Foundational Concepts and Cell Biology – Exam 1 Study Guide

Chapter 1: The Human Body – An Orientation

Levels of Organization and Anatomical Terminology

This section introduces the hierarchical organization of the human body and essential anatomical terminology for describing body structures and positions.

• Levels of Organization: The human body is organized from the chemical level (atoms, molecules) up to the organismal level (the whole body).

• Anatomical Position: The standard reference position for the body, standing upright, facing forward, arms at sides, palms facing forward.

• Directional Terms: Used to describe locations of structures (e.g., anterior/posterior, superior/inferior, medial/lateral, superficial/deep, ipsilateral/contralateral).

• Body Planes: Sagittal (divides body into left/right), frontal (coronal, divides into anterior/posterior), transverse (horizontal, divides into superior/inferior).

• Body Cavities: Dorsal (cranial and vertebral), ventral (thoracic and abdominopelvic), and their subdivisions.

• Serous Membranes: Line body cavities and organs, providing lubrication and protection (e.g., pleura, pericardium, peritoneum).

Example: The heart is located in the thoracic cavity, medial to the lungs, and superior to the diaphragm.

Chapter 2: Chemistry Comes Alive

Basic Chemistry and Chemical Bonds

This section covers the basic principles of chemistry as they apply to the human body, including atomic structure, chemical bonds, and the properties of water.

• Atoms and Elements: Atoms are the smallest units of matter; elements are pure substances made of one type of atom. The most common elements in the human body are carbon, hydrogen, oxygen, and nitrogen.

• Atomic Number and Mass Number: Atomic number is the number of protons; mass number is protons plus neutrons.

• Isotopes: Atoms with the same number of protons but different numbers of neutrons.

• Ions: Atoms that have gained or lost electrons, becoming charged (cations are positive, anions are negative).

• Chemical Bonds: Ionic (transfer of electrons), covalent (sharing electrons), hydrogen bonds (weak attractions between polar molecules).

• Water: The most abundant compound in the body; its polarity allows for hydrogen bonding, making it an excellent solvent.

Example: Sodium (Na) and chlorine (Cl) form an ionic bond to create sodium chloride (NaCl).

Inorganic and Organic Compounds

• Inorganic Compounds: Water, salts, acids, and bases. Acids release H+ ions, bases release OH- ions.

• pH Scale: Measures hydrogen ion concentration; pH 7 is neutral, below 7 is acidic, above 7 is basic.

• Buffers: Substances that minimize changes in pH.

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

Example: Glucose (C6H12O6) is a carbohydrate and an important energy source.

Macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids

• Carbohydrates: Sugars and starches; provide energy. Monosaccharides (glucose), disaccharides (sucrose), polysaccharides (glycogen).

• Lipids: Fats, oils, phospholipids, steroids. Important for energy storage, cell membranes, and hormones.

• Proteins: Made of amino acids; function as enzymes, structural components, and signaling molecules.

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

Example: Enzymes are proteins that catalyze biochemical reactions.

Chapter 3: Cells – The Living Units

Cell Structure and Function

This section explores the structure and function of the cell, the basic unit of life, including the plasma membrane, organelles, and the cell cycle.

• Plasma Membrane: Phospholipid bilayer with embedded proteins; controls entry and exit of substances.

• Membrane Proteins: Integral (span the membrane) and peripheral (attached to surface); functions include transport, signaling, and cell recognition.

• Membrane Transport: Passive (diffusion, osmosis, facilitated diffusion) and active (requires energy, e.g., pumps, endocytosis, exocytosis).

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Tonicity: The effect of solution concentration on cell volume (isotonic, hypertonic, hypotonic).

• Resting Membrane Potential: The electrical charge difference across the plasma membrane, maintained by sodium-potassium pumps.

Example: In neurons, the resting membrane potential is typically around -70 mV.

Organelles and Their Functions

• Nucleus: Contains DNA; controls cell activities. Nuclear envelope surrounds the nucleus; nucleolus is the site of ribosome assembly.

• Ribosomes: Sites of protein synthesis; can be free in cytoplasm or attached to rough endoplasmic reticulum (ER).

• Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; smooth ER synthesizes lipids and detoxifies chemicals.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

• Mitochondria: Powerhouse of the cell; site of ATP (energy) production via cellular respiration.

• Lysosomes: Contain digestive enzymes; break down waste and cellular debris.

• Cytoskeleton: Network of protein filaments (microtubules, microfilaments, intermediate filaments) that provide structural support and facilitate movement.

• Centrioles: Involved in cell division; organize the mitotic spindle.

Example: Muscle cells have many mitochondria to meet high energy demands.

The Cell Cycle and Mitosis

• Cell Cycle: Series of events that cells go through as they grow and divide; includes interphase (G1, S, G2) and mitotic phase (mitosis and cytokinesis).

• Mitosis: Division of the nucleus into two genetically identical daughter nuclei; phases include prophase, metaphase, anaphase, and telophase.

• Cytokinesis: Division of the cytoplasm, resulting in two separate cells.

Example: Skin cells undergo mitosis frequently to replace lost or damaged cells.

Protein Synthesis: Transcription and Translation

• Transcription: The process by which a gene's DNA sequence is copied to mRNA in the nucleus.

• Translation: The process by which mRNA is decoded by ribosomes to produce a specific protein.

• Types of RNA: mRNA (messenger), tRNA (transfer), rRNA (ribosomal).

Example: Hemoglobin is synthesized in red blood cells through transcription and translation of the hemoglobin gene.

Key Table: Comparison of Membrane Transport Mechanisms

Transport Type	Energy Required?	Direction	Example
Simple Diffusion	No	High to Low	Oxygen moving into cells
Facilitated Diffusion	No	High to Low	Glucose transport via carrier proteins
Osmosis	No	High to Low (water)	Water movement across membranes
Active Transport	Yes (ATP)	Low to High	Sodium-potassium pump
Endocytosis/Exocytosis	Yes (ATP)	Varies	Phagocytosis, neurotransmitter release

Key Equations and Concepts

• pH Calculation: $pH = -\log[H^+]$

• Resting Membrane Potential: Determined by the Nernst equation (for a single ion): $E = \frac{RT}{zF} \ln \frac{[\text{ion outside}]}{[\text{ion inside}]}$

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

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard Anatomy & Physiology curricula.