Science Foundations
Build the essential science knowledge that underpins every nursing concept, from biomolecules to microbiology, chemistry to scientific reasoning.
Biological Systems
Characteristics of life and levels of organization
All living organisms share fundamental characteristics of life. Understanding these properties helps nurses recognize when physiological systems deviate from normal.
Levels of Organization
Chemical → Cellular → Tissue → Organ → Organ System → Organism. Disease can originate at any level and cascade upward.
Structure-Function Relationship
Structure always dictates function. Red blood cells are biconcave to maximize oxygen-carrying surface area. Alveoli are thin-walled for efficient gas exchange.
Why This Matters for Nursing
When a patient presents with multi-organ dysfunction, you're seeing the levels of organization failing in reverse, from organism-level symptoms traced back to cellular injury. Understanding this hierarchy helps you prioritize assessments.
Biomolecules & Metabolism
Proteins, lipids, carbs, nucleic acids, and energy
The four major biomolecules are the building blocks of all cellular structures and functions. Each plays a distinct role in maintaining health.
The Four Biomolecules
Energy Transfer
ATP (adenosine triphosphate) is the universal energy currency. Cells generate ATP primarily through aerobic metabolism (oxygen-dependent). When oxygen is unavailable, anaerobic metabolism produces lactic acid. This is why tissue hypoxia leads to metabolic acidosis.
Biomolecule Function Matching
Match each biomolecule to its primary role
Terms
Definitions
Biomolecules & Metabolism Check
1/3Which biomolecule forms the basic structure of cell membranes?
DNA, Genes & Protein Synthesis
Genetic information flow: from DNA to functional proteins
The central dogma describes how genetic information flows from DNA to functional proteins that run every process in the body.
Transcription
DNA → mRNA
Occurs in the nucleus
Translation
mRNA → Protein
Occurs at ribosomes
Protein Function
Enzymes, receptors, structures
Determines cell behavior
Mutations & Disease
A single nucleotide mutation can alter the protein produced. Sickle cell disease results from one amino acid change in hemoglobin (Glu→Val), causing red blood cells to deform under low oxygen conditions. This is a powerful example of how molecular changes manifest as clinical disease.
Cell Division
Mitosis vs meiosis and clinical relevance
Mitosis
Produces 2 identical diploid (2n) daughter cells. Used for growth, repair, and tissue maintenance. Occurs in somatic cells.
Wound healing depends on mitosis. Cancer is uncontrolled mitosis.
Meiosis
Produces 4 genetically unique haploid (n) cells. Used only for gamete (egg/sperm) production. Includes crossing over for genetic diversity.
Errors in meiosis → chromosomal abnormalities (e.g., Down syndrome = trisomy 21).
Chromosomal Integrity
Maintaining accurate DNA replication during division is essential. Checkpoints in the cell cycle catch errors. When these checkpoints fail (e.g., p53 tumor suppressor mutation), cells can proliferate uncontrollably, which is the basis of cancer development.
Genetics & Cell Division Check
1/3The central dogma of molecular biology describes the flow:
Microbiology Essentials
Pathogens, host interactions, and antimicrobial resistance
Understanding pathogens is essential for infection control, one of the most critical competencies in nursing practice.
Pathogen Categories
Antimicrobial Resistance
Antibiotic resistance occurs when bacteria evolve mechanisms to survive antibiotic exposure. Key nursing actions: complete full antibiotic courses, practice meticulous hand hygiene, use contact precautions for resistant organisms (MRSA, VRE, C. diff), and educate patients on proper antibiotic use.
Immunity
Innate vs adaptive immunity, antibodies, and vaccination
Innate Immunity
Non-specific, immediate defense. Present from birth. Includes skin barriers, mucous membranes, phagocytes (neutrophils, macrophages), inflammation, and fever.
First responders, same response regardless of pathogen.
Adaptive Immunity
Specific, slower but creates memory. B cells produce antibodies; T cells directly attack infected cells. Takes days to activate initially but responds faster upon re-exposure.
Targeted response, memory cells provide lasting protection.
Antibody Logic & Vaccination
Vaccines work by exposing the immune system to a harmless form of a pathogen (inactivated, attenuated, or mRNA-encoded antigen). This triggers adaptive immunity to produce memory B and T cells WITHOUT causing disease. Upon future exposure, the immune system mounts a rapid, targeted response. This is why booster doses enhance the memory response.
Microbiology & Immunity Check
1/3Why are antibiotics ineffective against viral infections?
Chemistry for Nursing
Atoms, bonds, solutions, pH, and electrolytes
Chemistry concepts directly apply to clinical nursing. Understanding pH, electrolytes, and solution chemistry is essential for safe medication administration and patient assessment.
Atomic Structure & Chemical Bonds
Atoms consist of protons, neutrons, and electrons. Ionic bonds (electron transfer) create electrolytes. Covalent bonds (electron sharing) form organic molecules. Hydrogen bonds give water its unique properties.
Solutions & Concentrations
IV fluids are solutions with precise concentrations. Isotonic solutions (0.9% NaCl) match plasma osmolarity. Hypertonic solutions pull water out of cells. Hypotonic solutions push water into cells.
Acids, Bases & pH
Acids donate H+ ions (lower pH). Bases accept H+ ions (raise pH). Buffer systems (bicarbonate, phosphate, protein) resist pH changes. The bicarbonate buffer system is the most clinically relevant: CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3⁻.
Electrolytes & Ionization
When salts dissolve in water, they dissociate into ions (ionization). NaCl → Na+ + Cl⁻. These ions conduct electricity in body fluids, enabling nerve impulses and muscle contractions. Electrolyte imbalances directly affect cardiac rhythm, muscle function, and neurological status.
Chemistry Concepts Matching
Match each chemistry concept to its clinical relevance
Terms
Definitions
Chemistry Check
1/3A patient receives a hypertonic IV solution. What will happen to their red blood cells?
Math Skills for Science
Scientific notation, ratios, proportions, and unit conversions
Quantitative reasoning is essential in nursing. From calculating medication dosages to interpreting lab values, math skills directly affect patient safety.
Essential Math Concepts
Dimensional Analysis
Always write out your units and cancel them. Example: Order: 500 mg. Available: 250 mg/tablet. Calculation: 500 mg × (1 tablet / 250 mg) = 2 tablets. The 'mg' units cancel, leaving you with tablets.
Math Skills Check
1/2A patient weighs 176 pounds. What is their weight in kilograms? (1 kg = 2.2 lb)
Scientific Literacy
Terminology, evidence-based thinking, and critical reasoning
Nurses must evaluate evidence, think critically, and communicate using precise scientific terminology. These skills form the foundation of evidence-based practice.
Scientific Terminology
Hypothesis: a testable prediction. Theory: well-supported explanation. Variable: factor that changes. Control: baseline for comparison. Peer review: expert evaluation of research.
Critical Thinking in Nursing
Question assumptions. Distinguish correlation from causation. Recognize bias. Evaluate source credibility. Consider alternative explanations. Apply evidence to specific patient contexts.
Evidence-Based Thinking
Not all evidence is equal. A well-designed randomized controlled trial (RCT) provides stronger evidence than an expert opinion. The hierarchy of evidence helps nurses evaluate which findings should most influence clinical practice. Always ask: 'What is the evidence for this intervention?'
Scientific Literacy Check
1/3What is the difference between a hypothesis and a theory?
Cell Structure & Organelles
The functional compartments within every human cell
Every human cell is a miniature factory with specialized compartments called organelles. Understanding organelle function explains why certain toxins, drugs, and diseases affect cells the way they do.
Key Organelles and Their Functions
Organelle Dysfunction & Disease
Lysosomal storage diseases (Tay-Sachs, Gaucher disease) occur when enzyme deficiencies prevent lysosomes from breaking down specific substrates. Mitochondrial dysfunction is implicated in neurodegenerative diseases. Understanding organelle function reveals why these conditions manifest the way they do.
Organelle Function Matching
Match each organelle to its primary role
Terms
Definitions
Cell Structure Check
1/3A patient's liver biopsy shows cells with extensive smooth endoplasmic reticulum. This is most consistent with:
Water & Its Unique Properties
Why water is the foundation of all biological systems
Water comprises approximately 60% of adult body weight and is the universal solvent of biology. Its unique molecular properties make life possible.
Polarity & Hydrogen Bonding
Water is a polar molecule, oxygen pulls electrons more strongly than hydrogen, creating partial charges. This polarity allows hydrogen bonding between water molecules, giving water high cohesion, adhesion, and surface tension.
High Specific Heat
Water resists temperature changes due to extensive hydrogen bonding. This stabilizes body temperature, the body can absorb significant heat before temperature rises. Sweating exploits water's high heat of vaporization for cooling.
Solvent Properties
Polar and ionic substances dissolve in water (hydrophilic). Nonpolar substances do not (hydrophobic). This governs drug solubility, water-soluble drugs distribute throughout body fluids while fat-soluble drugs accumulate in adipose tissue.
Reactant & Medium
Water participates directly in hydrolysis reactions (breaking bonds by adding water) and dehydration synthesis (forming bonds by removing water). Nearly all metabolic reactions occur in aqueous solution.
Dehydration & Water Balance
Because water is critical for every metabolic process, dehydration impairs cellular function rapidly. Even 2% body water loss affects cognitive function and cardiovascular performance. This is why fluid balance assessment (intake/output, skin turgor, mucous membranes) is a fundamental nursing skill.
Cellular Energy Metabolism
Glycolysis, Krebs cycle, electron transport chain
Cells extract energy from nutrients through a series of metabolic pathways. Understanding these pathways explains why oxygen deprivation is so dangerous and how metabolic diseases affect the body.
The Three Stages of Aerobic Respiration
Oxygen Deprivation & Cell Death
When cells are deprived of oxygen (ischemia), the electron transport chain halts. Cells revert to anaerobic glycolysis, producing only 2 ATP instead of ~36-38 per glucose. Lactic acid accumulates, pH drops, and cellular enzymes denature. Within minutes, irreversible damage occurs in oxygen-dependent tissues like brain and heart. This is the biochemical basis of stroke and myocardial infarction.
Metabolism Summary
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ~36-38 ATP. This single equation connects nutrition (glucose input), respiration (O₂ input, CO₂ output), and cellular energy. Every vital sign you assess reflects this equation in action.
Metabolism & Water Properties Check
1/4Why does water's high specific heat capacity benefit the human body?
Homeostasis & Feedback Loops
How the body maintains internal stability through self-regulation
Homeostasis is the body's ability to maintain stable internal conditions. Every organ system participates in homeostatic regulation through feedback mechanisms.
Negative Feedback
The response OPPOSES the stimulus, returning the variable to its set point. This is the most common feedback mechanism. Example: when blood glucose rises after eating, the pancreas releases insulin, which lowers blood glucose back to normal.
Components: receptor (sensor) → control center (integrator) → effector (response)
Positive Feedback
The response AMPLIFIES the stimulus, driving the variable further from its starting point. Less common but critical in specific situations. Example: during labor, oxytocin causes uterine contractions, which push the baby against the cervix, triggering more oxytocin release.
Always requires an external event to terminate the cycle.
Disease as Homeostatic Failure
Diabetes mellitus is a failure of glucose homeostasis. In Type 1, the receptor/effector (beta cells) is destroyed; in Type 2, cells become resistant to the effector (insulin). Fever represents a temporary resetting of the temperature set point by pyrogens. Understanding feedback loops helps you predict how disruptions at any point in the loop will manifest clinically.
Organic Chemistry Basics
Functional groups, isomers, and biological molecules
Organic chemistry is the study of carbon-containing compounds. Carbon's ability to form four covalent bonds with diverse atoms creates the molecular complexity needed for life. Key functional groups determine how biological molecules interact.
Hydroxyl Group (-OH)
Makes molecules polar and water-soluble. Found in alcohols, sugars, and many drugs. Ethanol (CH₃CH₂OH) is metabolized by alcohol dehydrogenase in the liver.
Carboxyl (-COOH) & Amino (-NH₂) Groups
Amino acids contain both groups. The carboxyl group acts as an acid (donates H+), the amino group acts as a base (accepts H+). Peptide bonds form between these groups during protein synthesis via dehydration reactions.
Phosphate Group (-PO₄)
Found in ATP, DNA, and phospholipids. High-energy phosphate bonds in ATP store and release energy for cellular work. Phosphorylation (adding a phosphate group) activates or deactivates enzymes, a key regulatory mechanism.
Dehydration Synthesis & Hydrolysis
Large biological molecules are built by dehydration synthesis (removing water to form bonds: amino acids → proteins, monosaccharides → polysaccharides) and broken down by hydrolysis (adding water to break bonds). Digestion is fundamentally hydrolysis: enzymes add water molecules to break food into absorbable units.
Advanced Science Concepts Matching
Match each concept to its description
Terms
Definitions
Advanced Science Foundations Check
1/3Blood glucose homeostasis is maintained primarily by: