Cells, DNA & energy — organelles, replication, protein synthesis, mitosis, photosynthesis and cellular respiration.
A cutaway animal cell follows labeled cargo from rough ER through Golgi stacks into transport vesicles and across the plasma membrane. Select the nucleus, mitochondria, lysosome or cytoskeleton to inspect compartment functions.
Inspect a rectangular plant-cell cutaway with a cellulose wall, membrane, central vacuole, chloroplast grana and nucleus. Change external osmolarity to compare water uptake, turgor and plasmolysis.
Explore an antiparallel double helix with two sugar-phosphate backbones, complementary base pairs and grooves. Change GC content and helical twist, then open the base pairs to inspect hydrogen bonding.
A moving fork separates parental DNA while leading synthesis follows continuously and lagging synthesis forms Okazaki fragments. Compare helicase progress, polymerase speed and the effect of inhibiting ligase.
A nucleus-to-ribosome pathway transcribes a short DNA coding example, exports the mRNA and advances a ribosome through AUG GCU UUU GGA UAA. tRNAs deliver amino acids and the chain stops at UAA.
A model diploid cell with 2n=4 enters mitosis after S phase. Condensed chromosomes attach to spindle fibers, align at metaphase, separate at anaphase and form daughter nuclei during cytokinesis.
A chloroplast cutaway shows stacked thylakoids, light absorption, water oxidation, proton movement and ATP synthase. Follow ATP and NADPH into a separate Calvin-cycle ring in the stroma.
Separate glycolysis in the cytosol, pyruvate oxidation and the citric-acid cycle in the matrix, and electron transport on the mitochondrial inner membrane. Follow carriers, proton pumping and ATP synthase.