BIOL 1441 1st Edition Lecture 10 Outline of Last Lecture I. MicroscopyII. Cell classificationIII. Cell sizeIV. Cell organellesOutline of current Lecture I. OrganellesII. CytoskeletonIII. Extracellular componentsCurrent LectureI. Organelles:a. Lysosomesi. Membrane sac- holds hydrolytic enzymes1. Breakdown proteins, fats, carbs, nucleic acids2. DIGESTION3. NOT detoxii. (very specialized) Proteins in the inner surface of the membrane or enzymes themselves- iii. Acidic environmentiv. Engulf smaller organisms or food particles (amoebas)1. Phagocytosis (cell eating)2. Breaks down into monomers- simple sugars, amino acids3. Pass into cytosol as nutrients for the cell4. Macrophage- immune cell, ingests mircoorganismsv. Autophagy- recycle organelles and macromolecules (eating organelles)1. Membranes fuse2. Enzymes break it down3. Returns to cytosol for reuseThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.vi. Liver cell recycles half its macromolecules each weekvii. Tay-Sachs Disease1. Genetic mutation (autosomal recessive)- rare2. Lack hydrolytic enzymes to break down lipids3. Build up in lysosome, interfere with other cellular activities4. Brain becomes impaired by accumulation of lipids5. Side effectsa. Paralysisb. Blindnessc. Die by age of 2 usuallyd. Born with it (must have gene from mom AND dad)b. Vacuolesi. Large vesicles- membrane-bound sacsii. Food vacuole- formed by phagocytosis, fuses with lysosomeiii. Contractile vacuole(protists)- pump excess water out of a cell to maintain the salt concentration, iv. Central vacuole- plants, enclosed by tonosplast (membrane)1. Organic molecules2. Inorganic ions- potassium & chloride3. Disposal sites metabolic by-products4. Pigments- color flower petals5. Store waterv. Plant Cell- Central Vacuole1. Plant growth- cell enlarge as vacuole absorb water2. Fills with water for turgor pressure3. increase volume with water but not metabolism change so no limits on sizec. Mitochondria (not part of the endomembrane system)i. Sites of cellular respirationii. Respiration- metabolic process generates ATP by extracting energy from sugars & fats, using oxygeniii. Membrane bound organelle- membrane not made by rough ER1. Made by free ribosomes in cytosoliv. Have its own DNA and ribosomesv. Cell can have hundreds-thousands mitochondria1. More active cells have more mitochondriavi. Smooth outer membrane & inner membrane folded into cristae- each is aphospholipid bilayer1. Folded membrane=more surface area when volume increasesvii. Inner membrane creates two compartments:1. Intermembrane space 2. Mitochondrial matrixviii. Mitochondrial matrix contains1. Enzymes2. Mitochondrial DNA3. Ribosomesix. Metabolic steps of cellular respiration are catalyzed in the mitochondrial matrixx. Cristae present a large surface area for enzymes that synthesize ATP, increasing productivity of respirationd. Chloroplastsi. Make ATP too/also has its own DNA and ribosomes ii. Type of organelle called a plastidiii. Only in plants and algae- contain the green pigment chlorophyll & enzymes that function in photosynthesis1. In leaves and other green organs of plants and in algaeiv. Convert solar energy to chemical energy by absorbing sunlight and usingit to drive the synthesis of organic compounds, like sugars from CO2 & H2Ov. Thylakoids- membranous sacs1. Granum- stack of thylakoidsvi. Stroma- internal fluid1. Contain ribosomes & DNAvii. Divided into 3 compartments1. Intermembrane space2. Stroma3. Thylakoid spaceviii. Replicate themselvesix. Mobile and move within the celle. Peroxisomes- DETOXIFICATIONi. Specialized metabolic compartments bounded by a single membraneii. Produce hydrogen peroxide (H2O2) & convert it to water1. Enzymes that transfer hydrogen from substances to oxygen2. Special enzymes (peroxidase) converts H2O2 to H2O iii. Use oxygen to break down fatty acids- fuel in mitochondriaiv. Liver- detoxify alcohol & drugsRH2(toxic substance) + O2 R + H2O2 (hydrogen peroxide) H2OII. Cytoskeleton a. Network of fibers extending throughout the cytoplasmb. Composed of 3 types of molecular structures:i. Microtubulesii. Microfilamentsiii. Intermediate filamentsc. Roles of the Cytoskeleton (in general)i. Support cell and maintain its shape1. Animal cells lack cell wallsii. Remarkable strength and resilience 1. Stabilized by balance of opposing forcesiii. Provides anchorage for organellesiv. Dynamic- quickly dismantled and reassembledv. Motility- cell movement & parts within the cellvi. Motor proteins bind tubules, filaments1. Slide them past one another2. Similar to how your muscles contractvii. Vesicles, organelles travel along microtubules1. Neurotransmitter molecules migrate to tips of axons2. ER transport vesicles travel to Golgiviii. Manipulate plasma membrane to form vesiclesd. Components of the Cytoskeleton (based on width)i. Microtubules- thickestii. Microfilaments- (actin filaments) thinnestiii. Intermediate filaments- middlee. Microtubulesi. PROTEIN=TUBULINii. Hollow rods 1. Tubulin dimeriii. Grow in length- add a dimer1. Disassembled as welliv. Plus side- accumulates/releases dimers higher ratev. Functions:1. Cell motility2. Separate chromosome- divisionvi. Centrosomes & Centrioles (on plus end)1. In animal cells- microtubules grow out from a centrosome (MTOC)a. Region near the nucleus, microtubule-organizing center2. Centrioles- within centrosome, each with 9 triplets of microtubules arranged in a ring (27 total)vii. Cilia and Flagella1. Microtubules control the beating of cilia & flagella2. Cilia and flagella differ in their beating patterns3. A core of microtubules sheathed by the plasma membrane4. Basal body- anchors the cilium or flagellum (Where it attaches to cell)5. 9 + 2 patterna. 9 doublets in a ringb. 2 single in the centerf. Microfilaments-PROTEIN=ACTINi. Solid rods – actin1. Twisted double chain of actin subunitsii. Linear filaments & networks1. Inside plasma membrane- cortical microfilamentsiii. Cortex-outer cytoplasmic layer (gel)iv. Functions:1. Muscle contraction2. Cell motility-psuedopodia3. Cell division-cleavage furrowv. Actin Filaments- Muscle1. Thousands of strands of actin parallel with thicker filaments- myosin2. Myosin “walks” along actin3. Contraction- actin and myosin sliding past each otherg. Intermediate Filaments- PROTEIN=KERATINi. Diverse class of cytoskeletal fibers (many different things make it up)ii. Made out of