Biology
The cell
Prokaryotes vs eukaryotes, organelles, membranes.
Basics
Cell theory
All organisms are made of cells; cells come from cells; cells carry hereditary information. Prokaryotes lack a nucleus (bacteria, archaea); eukaryotes have a nucleus and membrane organelles.
Cell membrane
A phospholipid bilayer with proteins. Selectively permeable: small nonpolar molecules cross easily; ions and large polar molecules need channels or carriers. Osmosis is net water movement.
Main organelles
Mitochondria: ATP. Chloroplasts: photosynthesis (plants, algae). Ribosomes: protein synthesis. ER and Golgi: processing and secretion. Lysosomes: breakdown. Nucleus: DNA.
Formulas
Surface-to-volume
As a cell grows, relative surface area falls and exchange gets harder.
Symbols
-
SAsurface area -
Vvolume -
rradius
Osmotic pressure (van’t Hoff)
More solute particles pull water toward that side.
Symbols
-
Πosmotic pressure -
ivan’t Hoff factor -
cmolarity
Key table
| Prokaryote | No nucleus, 70S ribosomes, peptidoglycan wall (bacteria) |
|---|---|
| Eukaryote | Nucleus, 80S ribosomes, membrane organelles |
| Animal vs plant | Plant: wall, vacuole, chloroplast. Animal: centrioles, no wall |
In this field
Genetics and molecular biology
DNA, transcription/translation, Mendel, meiosis.
Metabolism
Photosynthesis, respiration, ATP, enzymes.
Evolution and ecology
Natural selection, phylogeny, trophic levels, cycles.
Human physiology basics
Homeostasis, circulation, nerves, immunity.
Plants and development
Plant tissues, hormones, developmental stages.
Immunity and microbes
Pathogens, innate and adaptive immunity, antibiotics and vaccines.
Nervous and endocrine systems
Neurons, synapses, hormones, and homeostasis — fast electrical and slower chemical signals.
Molecular lab sketch
Restriction enzymes, electrophoresis, PCR, and sequencing — a short principle sketch.
Population ecology
Exponential and logistic growth, carrying capacity, life history, predator–prey sketch.
Life’s diversity
Domains, a phylogeny sketch, homology versus analogy, and binomial names.
Biological macromolecules
Carbohydrates, lipids, proteins, and nucleic acids — structure and role sketches.