Cells & Tissues — One‑Page Cheat Sheet
Learning goals
- Understand cell structure, cellular metabolism, cell cycle/division, and tissue types.
Cell fundamentals
- Cell: basic unit of life (somatic vs germ).
- Main parts: Plasma membrane, Cytoplasm (cytosol + organelles), Nucleus.
Plasma membrane & transport
- Composition: phospholipids, glycolipids, cholesterol, proteins.
- Functions: selective permeability, signaling, structural support.
- Transport types:
- Passive: diffusion, osmosis, facilitated diffusion (no ATP). [pages 8–13]
- Active: ATP‑dependent pumps (e.g., Na+/K+ pump).
- Secondary active: uses ionic gradients to cotransport.
- Vesicular: endocytosis (pinocytosis, phagocytosis, receptor‑mediated) & exocytosis. [pages 16–17]
- Tonicity: hypertonic = shrink, hypotonic = swell, isotonic = no net change.
Organelles (quick roles)
- Rough ER: protein synthesis. Smooth ER: lipid synthesis, detox, Ca2+ storage.
- Mitochondria: ATP production; Krebs & ETC.
- Golgi: modifies/packages proteins.
- Lysosomes: digestion. Peroxisomes: oxidation/detox.
- Ribosomes: translate mRNA → protein.
- Cytoskeleton: microfilaments, intermediate filaments, microtubules; microvilli/cilia/flagella for specialization. [pages 25–26]
Genetics & protein synthesis
- DNA (double helix); RNA: mRNA, rRNA, tRNA. [pages 34–35]
- Transcription: DNA → mRNA in nucleus (RNA polymerase).
- Translation: mRNA → polypeptide on ribosomes (initiation, elongation, termination). Codons specify amino acids. [pages 38–40]
- Mutation: base change → altered mRNA/protein.
Cellular metabolism — ATP production
- Glycolysis (cytosol): 2 ATP + 2 pyruvate.
- Krebs cycle (mitochondria): small ATP + CO2.
- ETC / oxidative phosphorylation: bulk of ATP; O2 = final electron acceptor. [pages 31–32]
Cell cycle & division
- Interphase: G0, G1 (growth), S (DNA replication), G2 (prep).
- Mitosis: prophase → metaphase → anaphase → telophase → 2 identical diploid somatic cells. [pages 47–48]
- Meiosis: two divisions → 4 unique haploid gametes.
- Differentiation: stem cells → specialized cells.
Tissues — 4 primary types
- Epithelial: protection, absorption/secretion.
- Connective: support, binding, transport.
- Muscle: contraction.
- Nervous: signal transmission.
High‑yield facts to memorize
- Na+/K+ pump — maintains membrane potential; uses ATP.
- ATP sites: glycolysis (cytosol), Krebs + ETC (mitochondria). [pages 31–32]
- Transcription vs Translation: nucleus vs cytoplasm/ribosomes. [pages 37–38]
- Start codon: AUG; Stop codons: UAA, UAG, UGA.
Exam tips
- Identify gradient + ATP requirement for membrane transport problems. [pages 8–15]
- DNA replication = S phase. Know G1/G2 checkpoints. [pages 45–46]
- For protein synthesis, trace DNA → mRNA → tRNA/amino acid → polypeptide. [pages 37–40]
