Reference appendices, selected answers, a full glossary, and a complete index — designed so this textbook can serve as a permanent library resource long after the course ends
A ratio compares two quantities of the same kind and can be written as a fraction, with a colon, or in words. In biology, ratios appear in genetics (3:1 offspring ratios), ecology (predator-to-prey counts), and physiology (surface-area-to-volume relationships).
A percentage expresses a quantity as a fraction of 100. To convert a ratio to a percentage, divide the part by the whole and multiply by 100. Example: if 45 out of 60 seeds germinate, the germination rate is (45 ÷ 60) × 100 = 75%.
Percentage = (Part ÷ Whole) × 100
Part = (Percentage ÷ 100) × Whole
Ratio A:B means A units for every B units
Very large and very small numbers appear constantly in biology — the number of cells in the human body (~37 trillion = 3.7 × 10¹³), the size of a red blood cell (~8 micrometers = 8 × 10⁻⁶ m), and the mass of a DNA nucleotide (~330 daltons). Scientific notation expresses a number as a value between 1 and 10 multiplied by a power of ten.
| Number | Scientific Notation | Biology Context |
|---|---|---|
| 37,000,000,000,000 | 3.7 × 10¹³ | Approximate number of cells in the human body |
| 0.000001 | 1 × 10⁻⁶ | One micrometer (µm) — typical cell scale |
| 0.0000000001 | 1 × 10⁻¹⁰ | One angstrom — molecular bond length scale |
| 6,500,000,000 | 6.5 × 10⁹ | Approximate number of base pairs in a human genome |
Biology uses metric units throughout. To convert between units, multiply by a conversion factor whose numerator and denominator are equal quantities in different units, so the unwanted unit cancels.
| Unit | Abbreviation | Relationship | Biology Use |
|---|---|---|---|
| Kilometer | km | 1 km = 1,000 m | Ecosystem scale, migration |
| Meter | m | Base unit of length | Organism body size |
| Centimeter | cm | 1 cm = 0.01 m | Tissue and organ size |
| Millimeter | mm | 1 mm = 0.001 m | Small organs, seeds |
| Micrometer | µm | 1 µm = 10⁻⁶ m | Cells, organelles |
| Nanometer | nm | 1 nm = 10⁻⁹ m | Molecules, DNA width |
| Liter | L | Base unit of volume | Blood volume, fluid volumes |
| Milliliter | mL | 1 mL = 0.001 L | Lab volumes |
| Gram | g | Base unit of mass | Organism mass, nutrient amounts |
| Milligram | mg | 1 mg = 0.001 g | Drug dosages, trace minerals |
| Kilogram | kg | 1 kg = 1,000 g | Body mass, biomass |
Graphs in biology show relationships between variables over time, across conditions, or across populations. Before reading a graph: (1) identify the title; (2) read both axis labels and units; (3) note the scale of each axis; (4) identify what each line, bar, or data point represents; (5) then look for patterns, trends, peaks, and comparisons.
| Graph Type | When Used in Biology | What to Look For |
|---|---|---|
| Line graph | Change over time — population growth, enzyme activity vs. temperature | Slope (direction and steepness), peaks, plateaus |
| Bar graph | Comparing discrete categories — species counts, test results | Relative bar heights, differences between groups |
| Scatter plot | Correlation between two variables | Direction and tightness of the trend |
| Pie chart | Proportions of a whole — ecosystem composition | Relative sector sizes; total must equal 100% |
| Histogram | Distribution of continuous data — height, mass, leaf area | Shape (symmetric, skewed), spread, modal class |
Probability in biology is central to genetics. The probability of an event is the number of favorable outcomes divided by the total number of equally likely outcomes. Probabilities range from 0 (impossible) to 1 (certain) and can also be expressed as percentages.
When two events are independent, the probability that both occur equals the product of their individual probabilities. In genetics, the probability that a child inherits a specific allele from the father AND a specific allele from the mother equals P(allele from father) × P(allele from mother).
P(event) = favorable outcomes ÷ total equally likely outcomes
P(A and B) = P(A) × P(B) [if A and B are independent]
P(A or B) = P(A) + P(B) [if A and B are mutually exclusive]
The mean (average) is the sum of all values divided by the number of values. The range is the highest value minus the lowest. In biological data, knowing the mean and range together gives a much better picture than the mean alone — a population average height of 1.7 m means something very different if the range is 0.1 m versus 0.6 m.
Tables organize data into rows and columns. To read a biology table: identify what the rows represent, identify what the columns represent, read column headers and units, then find specific values by locating the row and column intersection. Watch for footnotes indicating special conditions.
When examining experimental results: (1) identify the independent variable (what was changed), the dependent variable (what was measured), and the controlled variables (what was held constant); (2) look for a clear pattern in the data; (3) consider whether the result supports or contradicts the hypothesis; (4) identify any sources of error or confounding factors; (5) determine whether the results are general or specific to these conditions.
Never extract a conclusion from data without first checking whether the graph scale, sample size, and control condition have been reported. A result from 5 organisms may not generalize to a population of millions.
| Step | Action | Reason |
|---|---|---|
| 1 | Carry with both hands — one under the base, one on the arm | Prevents dropping; the microscope is precision equipment |
| 2 | Begin with the lowest-power objective lens | Easier to locate specimen; reduces risk of lens-slide contact |
| 3 | Adjust the coarse focus knob while watching from the side | Prevents the objective from crashing into the slide |
| 4 | Use the fine focus knob for final image clarity | Fine adjustment allows sharpening without stage movement risk |
| 5 | Increase magnification only after locating the specimen on low power | Higher power has a smaller field of view; finding first on low saves time |
| 6 | Adjust the diaphragm and light for each objective | Higher magnification generally needs less light; more reduces contrast |
| 7 | Clean lenses only with lens paper, never with tissue or cloth | Other materials scratch optical coatings |
Total magnification = eyepiece magnification × objective magnification
Example: 10× eyepiece × 40× objective = 400× total
| Quantity | Tool | Unit |
|---|---|---|
| Length (macro) | Ruler, meter stick, measuring tape | mm, cm, m |
| Length (micro) | Calibrated ocular micrometer | µm |
| Mass | Triple-beam balance, digital scale | g, mg, kg |
| Volume (liquid) | Graduated cylinder, pipette, burette | mL, L |
| Temperature | Thermometer, temperature probe | °C |
| pH | pH meter, pH indicator strips | pH units (0–14) |
| Time | Stopwatch, timer | s, min, h |
A well-designed biology experiment contains: a clearly stated hypothesis (testable prediction); an independent variable (one factor the investigator changes); a dependent variable (what is measured in response); controlled variables (all other factors held constant); a control group (receives no treatment, as a baseline); an experimental group (receives the treatment); and repeated trials or adequate sample size to account for natural variation.
☐ One independent variable only
☐ Measurable dependent variable defined
☐ Control group identified
☐ Controlled variables listed
☐ Sample size adequate for the type of organism and variation expected
☐ Data recording plan prepared before starting
Convention: the independent variable goes on the x-axis (horizontal); the dependent variable goes on the y-axis (vertical). Always label both axes with the variable name and units. Use an appropriate scale that spreads data across most of the graph area. Give the graph a title that states the relationship being shown, not just the name of the experiment.
| Concept | Key Points | Biology Relevance |
|---|---|---|
| Atoms and molecules | Atoms are the smallest units of elements. Molecules are two or more atoms bonded together. Compounds contain two or more different elements. | All biomolecules are made of atoms; C, H, O, N, P, S are the most common in biology. |
| Water | Polar molecule; forms hydrogen bonds; high specific heat; cohesion; adhesion; excellent solvent; pH neutral (7). | Medium for all cellular reactions; transport in blood and xylem; evaporative cooling; osmosis. |
| pH | Measures hydrogen ion concentration. Scale 0–14. Below 7 = acidic; above 7 = basic; 7 = neutral. Each unit = 10× difference. | Enzyme function, blood pH regulation, stomach acid, ocean acidification. |
| Carbon | Forms 4 covalent bonds; can bond to itself in chains and rings; backbone of organic molecules. | All biomolecules contain carbon; carbon's bonding versatility creates molecular diversity. |
| Carbohydrates | Made of C, H, O in roughly 1:2:1 ratio. Monomers = monosaccharides; polymers = polysaccharides. | Energy source (glucose); structural support (cellulose, chitin); energy storage (starch, glycogen). |
| Lipids | Nonpolar; made mostly of C and H. Include fats, phospholipids, steroids, and waxes. | Cell membranes (phospholipid bilayer); long-term energy storage; hormones (steroids). |
| Proteins | Polymers of amino acids; 20 amino acids; shape determined by sequence and interactions. | Enzymes, antibodies, structural proteins, carrier proteins, hormones, receptors. |
| Nucleic acids | Polymers of nucleotides; each nucleotide has a sugar, phosphate, and nitrogenous base. | DNA stores hereditary information; RNA carries and translates it; ATP is an energy nucleotide. |
| Chemical reactions | Reactants → products; energy released (exergonic) or absorbed (endergonic); balanced by atom conservation. | Metabolism = total of all chemical reactions in a cell; photosynthesis and respiration are key. |
| Enzymes | Protein catalysts; lower activation energy; substrate binds active site; not consumed in reaction; sensitive to pH and temperature. | Every metabolic pathway depends on enzymes; digestion, DNA replication, and cellular respiration all use them. |
Most human enzymes work best near pH 7. Pepsin in the stomach is an exception, working best near pH 2. Changing the pH changes the charge on the enzyme's active site and can denature the enzyme permanently.
| Feature | Prokaryotic | Eukaryotic |
|---|---|---|
| Nucleus | Absent (DNA in nucleoid region) | Present (membrane-bound) |
| Membrane-bound organelles | Absent | Present |
| Size | 1–10 µm | 10–100 µm |
| DNA form | Circular, in cytoplasm | Linear chromosomes in nucleus |
| Ribosomes | Smaller (70S) | Larger (80S) |
| Examples | Bacteria, archaea | Animals, plants, fungi, protists |
| Organelle | Present In | Function |
|---|---|---|
| Cell membrane | All cells | Controls what enters and leaves; maintains cell boundary; site of transport and signaling |
| Cell wall | Plants, fungi, bacteria | Structural support; protection; prevents excessive water uptake |
| Nucleus | Eukaryotes | Contains DNA; controls gene expression; site of transcription |
| Nucleolus | Eukaryotes | Inside nucleus; assembles ribosomal RNA and ribosome components |
| Ribosomes | All cells | Translate mRNA into protein; found free in cytoplasm and attached to rough ER |
| Rough ER | Eukaryotes | Modifies and processes proteins destined for secretion or membrane use |
| Smooth ER | Eukaryotes | Synthesizes lipids; detoxifies substances; stores calcium ions in muscle cells |
| Golgi apparatus | Eukaryotes | Packages, modifies, and ships proteins and lipids to their destinations |
| Mitochondria | Eukaryotes | Cellular respiration; produces most ATP; contains its own DNA |
| Chloroplasts | Plants, algae | Photosynthesis; converts light energy into chemical energy (glucose); contains own DNA |
| Vacuole | Plants (large central); animals (small) | Storage of water, nutrients, waste; maintains turgor pressure in plant cells |
| Lysosomes | Animal cells mainly | Contain digestive enzymes; break down worn-out organelles, pathogens, and cellular debris |
| Cytoskeleton | Eukaryotes | Gives the cell shape; enables movement; includes microfilaments, intermediate filaments, microtubules |
| Centrioles | Animal cells | Organize the spindle during cell division |
| Feature | DNA | RNA |
|---|---|---|
| Sugar | Deoxyribose | Ribose |
| Strands | Double-stranded (double helix) | Single-stranded |
| Bases | A, T, G, C | A, U, G, C (uracil replaces thymine) |
| Location | Nucleus (and mitochondria/chloroplasts) | Nucleus and cytoplasm |
| Function | Long-term storage of hereditary information | Carries, translates, and helps execute genetic instructions |
| Type | Name | Role |
|---|---|---|
| mRNA | Messenger RNA | Carries the genetic code from DNA in the nucleus to ribosomes in the cytoplasm |
| tRNA | Transfer RNA | Brings amino acids to the ribosome; anticodon matches codons on mRNA |
| rRNA | Ribosomal RNA | Structural and catalytic component of ribosomes; makes up most of ribosome mass |
A codon is a triplet of mRNA bases that codes for one amino acid or a stop signal. There are 64 possible codons and 20 amino acids, so most amino acids are coded by more than one codon (the code is redundant but not ambiguous — each codon codes for only one amino acid). AUG is the start codon and also codes for methionine. UAA, UAG, and UGA are stop codons.
To find what amino acid a codon specifies: read the first base (row), then the second base (column), then the third base (sub-row). Example: GUC → Valine (Val)
A Punnett square models the possible genotypes of offspring from a cross. The alleles of one parent are written across the top (one allele per column); the alleles of the other parent are written down the left side (one allele per row). Each box is filled by combining the column allele and the row allele. The result shows the probability of each genotype, not a guarantee for any individual offspring.
| Pattern | Description | Example |
|---|---|---|
| Complete dominance | One allele fully masks the other. Heterozygote looks like dominant homozygote. | Round (RR or Rr) vs. wrinkled (rr) seeds in peas |
| Incomplete dominance | Heterozygote shows a blend of both phenotypes. | Red × white snapdragons → pink offspring |
| Codominance | Both alleles are fully expressed in the heterozygote. | AB blood type — both A and B antigens present |
| Multiple alleles | More than two alleles exist for a gene in the population (though each individual has only two). | ABO blood type (Iᴬ, Iᴮ, i) |
| Polygenic inheritance | A trait is controlled by two or more genes; produces a range of phenotypes. | Human skin color, height |
| Sex-linked | Gene is located on a sex chromosome (usually X). Males (XY) show X-linked traits more often. | Color blindness, hemophilia |
| Symbol | Meaning |
|---|---|
| ○ (open circle) | Unaffected female |
| □ (open square) | Unaffected male |
| ● (filled circle) | Affected female |
| ■ (filled square) | Affected male |
| ○—□ (horizontal line) | Mating/partnership |
| Vertical line dropping to offspring | Parent-offspring relationship |
| Horizontal bracket above siblings | Siblings from the same parents |
| Mutation Type | Description | Effect on Protein |
|---|---|---|
| Point mutation — substitution | One base replaced by another | May be silent (no change), missense (different amino acid), or nonsense (early stop codon) |
| Insertion | One or more bases added | Frameshifts all codons downstream; usually severe effect |
| Deletion | One or more bases removed | Frameshifts all codons downstream; usually severe effect |
| Chromosomal deletion | Large segment of a chromosome lost | Loss of many genes simultaneously |
| Chromosomal duplication | Segment repeated | Extra copies of affected genes |
| Inversion | Segment reversed in chromosome | Genes present but in reverse order; may disrupt gene regulation |
| Translocation | Segment moved to a different chromosome | Disrupts gene pairs; associated with some cancers |
1. Variation: Individuals in a population differ from one another in heritable traits.
2. Heritability: At least some variation is passed from parents to offspring.
3. Overproduction: More offspring are produced than the environment can support.
4. Differential survival and reproduction: Individuals with advantageous traits are more likely to survive and reproduce, passing those traits to more offspring.
| Evidence Type | Description | Example |
|---|---|---|
| Fossil record | Preserved remains and traces of past organisms; shows change over time | Horse evolution series; transitional fish-tetrapod fossils |
| Homologous structures | Similar structures in different species due to common ancestry; may serve different functions | Human arm, whale flipper, bat wing, cat leg — same bones, different uses |
| Analogous structures | Similar function but different structure; due to convergent evolution, not common ancestry | Bird wing and insect wing |
| Vestigial structures | Reduced or non-functional structures inherited from ancestors who used them | Human tailbone (coccyx); whale pelvic bones |
| Embryological evidence | Closely related species share similar embryonic stages | All vertebrate embryos have gill slits and tails early in development |
| Molecular evidence | Similarities in DNA and protein sequences reflect evolutionary relationships | Humans and chimpanzees share ~98% of DNA sequences |
| Biogeography | Geographic distribution of species reflects evolutionary history and continental movement | Marsupials concentrated in Australia; finch diversity in Galápagos |
| Observed evolution | Evolution documented in real time | Antibiotic resistance in bacteria; peppered moth frequency shifts |
| Level | Example (Human) | Example (House Cat) |
|---|---|---|
| Domain | Eukarya | Eukarya |
| Kingdom | Animalia | Animalia |
| Phylum | Chordata | Chordata |
| Class | Mammalia | Mammalia |
| Order | Primates | Carnivora |
| Family | Hominidae | Felidae |
| Genus | Homo | Felis |
| Species | sapiens | catus |
Scientific names are written in italics (or underlined in handwriting). The genus is capitalized; the species is lowercase. Example: Homo sapiens. After first use, the genus may be abbreviated: H. sapiens.
A cladogram is a branching diagram that shows evolutionary relationships based on shared derived traits. Each branch point (node) represents a common ancestor shared by all organisms on branches stemming from it. Organisms that share a more recent common ancestor are more closely related. Cladograms do not show time or the amount of change — only the branching pattern of ancestry.
| System | Major Organs | Primary Functions | Homeostatic Role |
|---|---|---|---|
| Nervous | Brain, spinal cord, nerves | Rapid electrical signaling; sensory input; motor output; cognition | Coordinates immediate responses to internal and external changes |
| Endocrine | Hypothalamus, pituitary, thyroid, adrenals, pancreas, gonads | Hormone secretion; chemical signaling over longer timescales | Regulates blood sugar, growth, stress response, reproduction, metabolism |
| Circulatory | Heart, arteries, veins, capillaries, blood | Transports oxygen, nutrients, hormones, and wastes throughout the body | Distributes materials to all cells; delivers immune cells; helps regulate temperature |
| Respiratory | Lungs, trachea, bronchi, diaphragm | Gas exchange — oxygen into blood, carbon dioxide out | Maintains blood oxygen and CO₂ levels; assists acid-base balance |
| Immune | Lymph nodes, spleen, thymus, white blood cells | Defends against pathogens; remembers prior infections (adaptive immunity) | Removes pathogens and damaged cells; produces antibodies |
| Digestive | Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas | Breaks down food; absorbs nutrients; eliminates solid waste | Supplies cellular fuel; regulates blood nutrient levels; detoxifies (liver) |
| Excretory | Kidneys, ureters, bladder, urethra; also skin, lungs, liver | Filters blood; removes metabolic wastes; regulates water and ion balance | Maintains blood composition; regulates blood pressure and pH |
| Skeletal | Bones, cartilage, ligaments | Support; protection; movement; mineral storage; blood cell production | Stores calcium for homeostatic release; protects organs |
| Muscular | Skeletal, cardiac, and smooth muscle | Movement; posture; heat generation; pumping blood and food | Generates body heat; enables locomotion and organ function |
| Integumentary | Skin, hair, nails, sweat glands | Barrier against environment; temperature regulation; sensation; vitamin D synthesis | First line of defense; regulates heat loss via sweating and blood vessel dilation |
| Reproductive | Gonads, reproductive ducts, associated structures | Produces gametes; supports fertilization and development | Not directly homeostatic in the individual; maintains the population across generations |
Homeostasis is the maintenance of relatively stable internal conditions in spite of a changing external environment. Most homeostatic systems use negative feedback: when a variable moves away from its set point, a response is triggered that brings it back. Blood glucose regulation and body temperature regulation are classic examples.
Positive feedback amplifies a response rather than reversing it. It is used in processes that need to be completed quickly and completely, then switched off — childbirth contractions and blood clotting are biological examples.
Stimulus → Receptor detects change → Control center processes signal
→ Effector responds → Variable returned toward set point
→ Receptor detects return → Response reduced or stopped
| Level | Definition | Example |
|---|---|---|
| Organism | An individual living thing | A single white-tailed deer |
| Population | All individuals of one species in a given area at a given time | All white-tailed deer in a forest |
| Community | All populations of different species living and interacting in an area | All organisms in the forest — deer, trees, insects, fungi, bacteria |
| Ecosystem | A community plus all the abiotic factors of its environment | The forest community plus its soil, water, light, temperature, and atmosphere |
| Biosphere | All of Earth's ecosystems combined; the global sum of life and its environment | All life on Earth and the systems that support it |
| Trophic Level | Role | Examples |
|---|---|---|
| Producers (Level 1) | Convert light or chemical energy into organic matter via photosynthesis or chemosynthesis | Plants, algae, cyanobacteria |
| Primary consumers (Level 2) | Eat producers; herbivores | Rabbits, caterpillars, zooplankton |
| Secondary consumers (Level 3) | Eat primary consumers | Frogs, small fish, foxes |
| Tertiary consumers (Level 4) | Eat secondary consumers | Hawks, large predatory fish |
| Decomposers | Break down dead organic matter; return nutrients to the soil | Bacteria, fungi |
On average, only about 10% of the energy at one trophic level is available to the next. The other 90% is lost as heat (through metabolism) or in waste. This is why food chains rarely exceed four or five trophic levels, and why there is far more biomass at lower levels than at higher levels.
| Cycle | Key Reservoirs | Key Processes | Biology Connection |
|---|---|---|---|
| Water cycle | Oceans, ice, groundwater, atmosphere | Evaporation, transpiration, condensation, precipitation, runoff | All life depends on liquid water; plants drive transpiration |
| Carbon cycle | Atmosphere (CO₂), ocean, living biomass, fossil fuels, soil | Photosynthesis, respiration, decomposition, combustion, ocean absorption | Carbon is the backbone of all organic molecules; CO₂ is the atmospheric form |
| Nitrogen cycle | Atmosphere (N₂ gas = 78%), soil, living organisms | Nitrogen fixation, nitrification, assimilation, denitrification | Nitrogen is in amino acids and nucleic acids; most organisms cannot use N₂ directly |
| Interaction | Species A Effect | Species B Effect | Example |
|---|---|---|---|
| Predation | + (benefits) | − (harmed) | Wolf hunting a deer |
| Competition | − (harmed) | − (harmed) | Two plant species competing for light and water |
| Mutualism | + (benefits) | + (benefits) | Bees pollinate flowers; flowers provide nectar to bees |
| Commensalism | + (benefits) | 0 (not affected) | Barnacles on a whale |
| Parasitism | + (benefits) | − (harmed) | Tapeworm in a host's intestine |
Biology has a large vocabulary, but much of it is built from a set of recurring Greek and Latin roots. Learning these roots allows you to decode unfamiliar terms without memorizing each word individually. The table below covers the roots most frequently encountered in high school biology.
| Prefix | Origin | Meaning | Biology Examples |
|---|---|---|---|
a-, an- | Greek | Without, not | anaerobic (without oxygen), asexual, anemia |
aero- | Greek | Air, oxygen | aerobic, aerosol |
anti- | Greek | Against | antibody, antibiotic, antigen |
auto- | Greek | Self | autotroph, autoimmune |
bio- | Greek | Life | biology, biomass, biosphere |
chloro- | Greek | Green | chlorophyll, chloroplast |
chroma- | Greek | Color | chromosome, chromatin |
cyto- | Greek | Cell | cytoplasm, cytoskeleton, cytokine |
di- | Greek | Two | diploid, disaccharide |
endo- | Greek | Within, inside | endocytosis, endoplasmic reticulum |
epi- | Greek | Upon, above | epidermis, epigenetics |
eu- | Greek | True, good | eukaryote, eubacteria |
exo- | Greek | Outside | exocytosis, exoskeleton |
hemo-, haemo- | Greek | Blood | hemoglobin, hemophilia |
hetero- | Greek | Different | heterozygous, heterotroph |
homeo-, homo- | Greek | Same, similar | homeostasis, homologous, homozygous |
hydro- | Greek | Water | hydrophobic, hydrophilic, hydrolysis |
inter- | Latin | Between | interphase, intercellular |
macro- | Greek | Large | macromolecule, macrophage |
micro- | Greek | Small | microorganism, microscope, microbiome |
mono- | Greek | One | monosaccharide, monohybrid |
multi- | Latin | Many | multicellular, multifactorial |
photo- | Greek | Light | photosynthesis, photoreceptor |
poly- | Greek | Many | polysaccharide, polygenic, polymer |
pro- | Greek/Latin | Before, early | prokaryote, prophase |
sym-, syn- | Greek | Together, with | symbiosis, synthesis |
trans- | Latin | Across, through | transcription, translation, transport |
| Root | Origin | Meaning | Biology Examples |
|---|---|---|---|
-cyte, cyto- | Greek | Cell | erythrocyte (red blood cell), leukocyte, oocyte |
-genesis | Greek | Origin, production | oogenesis, spermatogenesis, mitogenesis |
-logy | Greek | Study of | biology, ecology, physiology, microbiology |
-lysis | Greek | Breaking apart | hydrolysis, glycolysis, hemolysis |
-phage, -phagy | Greek | Eating | bacteriophage, phagocyte, autophagy |
-phyll | Greek | Leaf | chlorophyll, mesophyll |
-plasm | Greek | Formed material | cytoplasm, nucleoplasm, protoplasm |
-sis | Greek | Process, condition | osmosis, mitosis, meiosis, photosynthesis |
-troph | Greek | Feeding, nourishment | autotroph, heterotroph, eutrophication |
-vore | Latin | Eating | herbivore, carnivore, omnivore |
When you encounter an unfamiliar biology term, try breaking it into prefix + root + suffix. Example: photosynthesis → photo (light) + syn (together) + thesis (placing/arranging) = "placing things together using light." The meaning follows from the parts.
This glossary defines the major terms introduced in Chapters 1 through 28. Chapter references indicate where each term first appears or is treated most fully. Terms are defined at a level appropriate for high school biology — precise but accessible. For molecular and biochemical detail beyond this level, consult the MGU Chemistry series or a university-level reference.
Answers are selected from each chapter's Concept Check, practice problems, and Review Questions sections. For genetics problems involving Punnett squares and probability, work through the setup completely before checking here — the process matters as much as the result. For data interpretation questions, your answer may be phrased differently and still be correct if your reasoning is sound.
Chapter numbers indicate where each topic is introduced or treated in most depth. Topics that run throughout the course (such as homeostasis, cells, and evolution) list the chapters where they receive the most focused discussion. For brief definitions, see Appendix J (Glossary). For reference tables, see Appendices C through H.
This textbook is the biology volume of the MGU Science Series, designed to follow Physical Science and to serve students studying biology before, during, or after High School Chemistry. It does not assume advanced chemistry, calculus, or prior anatomy.
The series is built on the principle that understanding comes before procedure. Students who understand why a process works — why cells need ATP, why populations evolve, why homeostasis matters — are better prepared for advanced study, for making health decisions, for engaging with environmental issues, and for appreciating the living world around them.
The 28 chapters are grouped into six parts: Foundations of Biology (Chapters 1–5), Cells and Energy (Chapters 6–11), Genetics and Biological Information (Chapters 12–16), Evolution and Diversity of Life (Chapters 17–22), Human Biology and Homeostasis (Chapters 23–26), and Ecology and Earth Systems (Chapters 27–28). Appendices A through L support the chapters as a reference library students can return to throughout their studies.
Typography: Playfair Display (headings), Source Serif 4 (body), DM Mono (labels and data). The MGU Science Series also includes Physical Science, High School Chemistry, and High School Physics.