Transcript Cells
Cells • Mostly microscopic – Light microscopy upto 1000x • Passes light through • E.g. typical plant & animal cells – Electron microscopy upto 100000x • Scans sample with electron beam • E.g. molecules (DNA) • Prokaryotic – Bacteria and bacteria-like • Eukaryotic – Fungi, Protista, Plants, Animals Prokaryotes vs. Eukaryotes • • • • Simpler Smaller size DNA without nucleus Cell wall & other crude protective layers • Lack organelles • • • • Complex >10x larger DNA in nucleus Cell membrane – Some also have cell wall • Membrane bound organelles – specialization Nucleus • Genetic control center • DNA – Replicates during cellular division – Fibers = chromatin • Sends instructions as RNA (in nucleolus) through pores – To synthesize proteins (writes amino acid sequence) Endoplasmic Reticulum • Rough ER • Studded by ribosomes – Assembles proteins for further processing • Membrane system – Continuous with nuclear membrane • Creates compartments • Acts as highway or conveyer belt Smooth ER • Continuous with Rough ER • Lacks the ribosomes • Uses enzymes to make lipids – In sex cells, SER makes sex hormones – In liver cells, SER detoxifies – In muscle cells, SER stores and releases Calcium for muscle contraction Golgi apparatus • Shipping / Receiving department – Receives proteins from ER, modifies, packages, labels for destination, within or outside of cell Lysosomes – breakdown bodies • RER packaged enzymes • Golgi modified • Digests: – Food in vacuole – Bacteria in blood – Damaged organelle (recycles) Vacuoles • Membranous sacks w/o digestive enzymes • Carry food in • Storage – – – – – Water Chemicals Waste Pigments Poisons Contractile vacuoles • Water regulation – Water continues to seep inside • Osmotic properties and differences in concentrations – Pump out excess – Prevents cells from overswelling or burst Chloroplasts • Photosynthesis = converts solar E to glucose • Continuous double membrane/compartment system – Fluid stroma – disks or grana = solar power packs Mitochondria • Converts glucose (stored E) into cellular E (ATP) – Potential E to chemical E to Kinetic E – Via cellular respiration • Double membrane & compartment system – Fluid matrix – Folds or Cristae to increase Surface Area Cytoskeleton – structural proteins • Microfilaments – cell structure & cell contraction • Intermediate filaments – cell structure and anchoring • Microtubule – organelle support & movement Cilia & Flagella • Locomotor microtubules • Short, numerous • Long less numerous Cell Surfaces • Cell wall, plasma membrane, or capsules • Plant cell wall – Cellulose fibers for structure & support – E.g. wood is almost all cell wall material – Plasmodesmata for intercellular communication • Animal cell membranes – Tight junctions = leakproof – Anchoring junctions = strength – Gap junctions = intercellular communication