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Honors Biology Ch. 4 Notes Cell
Honors Biology Ch. 4 Notes Cell 4.1 Microscopes designs: light and e- emitting: scanning and transmission images: o light: mag. 1,400x (Cyclosis; Chloroplasts at 1,250x) o Fantastic Vesicle Traffic o SEM: surfaces mag. 100,000x o TEM: internal mag. 200,000x magnification: increase in apparent size resolution: a measure of the clarity of an image 4.2 Cell Theory: 1. All living organisms are composed of one or more cells 2. Cells are the basic units of structure and function in an organism 3. cells come only from the reproduction of existing cells History: fig. 4.2a discovery of cells required invention of microscope 1. Hooke: 1665, first microscope, cork, CELLS, “Little boxes” 2. Leeuwenhoek: 1673, Dutch trader, better lenses, Protists: spirogyra, Vorticella, “Wee little beasties” 3. Cell theory: 150 years later Mrs. Loyd [email protected] Page 1 of 11 9/21/16 http://loydbiology.weebly.com 4.2 Limits to cell size http://www.cellsalive.com/howbig.htm Lower limit: Minimum volume for necessary DNA, protein (enzymes), internal structure to survive and reproduce. Upper limit: s.a. by the square (plasma membrane or “supply”) vol. by cube (metabolism or “demand”) Large cells have more surface area than small cells, but large cells have much less surface area relative to their volume than small cells of the same shape. fig. 4.2b 4.3 Comparing Prokaryotic similarities differences 4.4 Eukaryotic Plasma membrane Ribosomes Cytoplasm Enzymes DNA Smaller max, No membranebound organelles, circular chromosomes antibiotics Larger max, Organelles, Compartmentalized, Linear chromosomes cytoskeleton Compartmentalization Structure: created by internal membranes of organelles cellular metabolism occurs in compartments enzymes imbedded in organelle membrane allows certain chemical conditions simultaneous, different processes Mrs. Loyd [email protected] Page 2 of 11 9/21/16 http://loydbiology.weebly.com 4.4 Organelles unique to each PLANTS Plastids like chloroplasts Cell wall Central vacuole ANIMALS centrioles 4.4 Structure and Function of 4 functional areas: 1. Manufacturing nucleus ribosomes endoplasmic reticulum Golgi apparatus 2. Hydrolysis (breakdown) lysosomes vacuoles peroxisomes 3. Energy Processing chloroplasts (plants) mitochondria (both plants and animals, yeast and fungus) 4. Structure, movement, communication among cells cytoskeleton microtubule polymerization/depolymerization Motor Proteins hauling a vesicle along cytoskeleton Fantastic Vesicle Traffic A Day in the Life of a Motor Protein plasma membrane: leaflets are different in structure Harvard, Inner Life of the Cell: Plasma membrane leaflets, rafts, microtubules etc. cilia, flagella Bacterial Flagellum: advanced structure cell wall 4.5 Structure of membranes correlates with functions Boundary that controls traffic into and out of the cell Main component: phospholipids fig. 4.5a o polar (hydrophilic) phosphate “head” o nonpolar (hydrophobic) fatty acid “tails” phospholipid bilayer self-assembles in water o heads face out o tails face in toward each other away from water Embedded in membrane are proteins o hydrophobic interiors (align with tails) o hydrophilic exteriors (align with heads) Permeability: o Pass easily: O2 and CO2 both nonpolar like membrane interior o o Water passes thru aquaporins (protein passageway) Channels: for charged, hydrophilic, or large particles Mrs. Loyd [email protected] Page 3 of 11 9/21/16 http://loydbiology.weebly.com MANUFACTURING AND BREAKDOWN 4.6 nucleus: nuclear envelope: nucleolus: chromatin nuclear pore: 4.7 ribosomes: rRNA + protein small subunit: large subunit: free in cytoplasm: bound to ER: 4.8 Endomembrane System: Membranes physically connected or connected by transfer of membrane by vesicles. Work together in the synthesis, storage, and export of molecules. Includes: nuclear envelope endoplasmic reticulum Golgi apparatus lysosomes vacuoles plasma membrane 4.9 Endoplasmic Reticulum (E.R.) is a biosynthetic factory Smooth E.R. lacks ribosomes. Synthesis of: lipids oils phospholipids steroids Abundant in (Structure/Function): ovaries and testes steroid hormones liver detoxify store calcium ions (muscle contraction) Rough E.R. has ribosomes studding outside surface Synthesis of: Phospholipid to be added to membrane Ribosomes on ER produce proteins that will be: used within the membrane of the cell transported to other organelles secreted by the cell (pancreas cells’ R.ER insulin) fig. 4.9b Abundant in (Structure/Function): (pancreas cells’ R.ER insulin) Mrs. Loyd [email protected] Page 4 of 11 9/21/16 http://loydbiology.weebly.com 4.10 Golgi apparatus (Camillo Golgi) “Receiving”: vesicles with protein from ER merge on (“front” or cis face) Modifies: adds tags (PO4-3) or “address labels” protein “matures” “Shipping”: Vesicle with finished protein pinches off forming vesicle from “end or loading dock” or trans face. 4.11 Lysosomes (“recycling center”) Lyse = breakdown or split Digestive enzymes Acidic environment Membrane compartment Uses: protists fig 4.11a engulf food in food vacuole merge with lysosome digest food building blocks go to cytoplasm White blood cells (WBC) Ingest bacteria into vacuoles lysosomal enzymes dumped in rupture bacterial wall Recycle 4.11b animal cells, damaged organelles, cell fluid apoptosis: fig.27.13a,b Mrs. Loyd [email protected] Page 5 of 11 9/21/16 http://loydbiology.weebly.com 4.12 Vacuoles: membranous sacs with variety of functions Types: Food Central (plants) Pigments (flower petals) Contractile Vacuole fig 4.12b 4.13 Endomembrane System fig. 4.13 Structural connections vs. Functional connections Endocytosis Peroxisome (NOT part of Endom. System) Breakdown of fatty acids for fuel detox. of alcohol and other harmful substances ENERGY-CONVERTING ORGANELLES 4.14 Mitochondria: “Powerhouse of the cell” fig 4.14 chemical energy (sugar) ATP cellular respiration Structure fits function Double membrane, inner convoluted (cristae) increases surface area for protein enzymes that make ATP. Innermost space = matrix (lower H+ conc.) contains: ribosomes, mtDNA, enzymes Innermembrane space (higher H+ conc.) 4.15 Chloroplasts (solar energy chemical energy) fig 4.15 Double membrane, flattened, interconnected sacs (thylakoids) Outer membrane: Intermembrane space: ? Inner membrane: Stroma: clDNA, ribosomes, enzymes, (lower H+ conc.) Thylakoid membrane: chlorophyll molecules embedded Thylakoid space: (higher H+ conc.) Mrs. Loyd [email protected] Page 6 of 11 9/21/16 http://loydbiology.weebly.com 4.16 Endosymbiosis Chloroplast and Mitochondrial similarities to prokaryotes: 1. DNA 2. ribosomes (bacterial-like) 3. split like binary fission 4. double membranes, inner like prokaryotes Evolution 1. Mitochondria probably evolved first (heterotrophic prok) 2. Chloroplast evolved from Mitochondria (autotrophs and photosynthesis evolved later) 3. Similar chemistry of homologous spaces, location of DNA & ribosomes, and fossil record support this. 4. Large Prok. ingested smaller Mitoch. Prok. and/or Photosyn. Prok. but did not digest. Smaller Prok. may have been parasitic. These links play best in Firefox. Cytoplasmic streaming of chloroplasts Flagella and Cilia Amoeboid motion (Amoeba), same motion type in HD Paramecium ingesting food Vorticella feeding Stentor feeding and reacting Mrs. Loyd [email protected] Page 7 of 11 9/21/16 http://loydbiology.weebly.com Honors Biology Ch. 5 Notes Membranes MEMBRANE STRUCTURE AND FUNCTION 5.1 Fluid Mosaic model of the plasma membrane “Fluid” The molecules can migrate through the layer that they are in but they will very seldom flip-flop. “Mosaic” The pattern or collection of molecules (phospholipids and proteins) that makes up the plasma membrane. 5.1 Describe the diverse functions of membrane proteins 50 different types of proteins found in RBC’s. Six Functions: 1. Support: (see graphic) a. integrins give the membrane a stronger framework. b. Span the membrane and attach to the cytoskeleton on the inside and the extracellular matrix (ECM) on the outside 2. cell-cell recognition: (see graphic) a. glycoproteins (sugar-protein) b. glycolipids (sugar-phospholipid) c. “glyco” or sugar acts as ID tags i. embryo sorts cells into tissues and organs ii. immune system to recognize and reject foreign cells like bacteria 3. intercellular junctions: 4. enzymes (see below) 5. signal transduction (see below) 6. transport (see below) 5.1 Relate the structure of phospholipid molecules to the structure and properties of cell membranes. Selective Permeability: Membranes allow some substances to cross more easily than others. Molecules that can move across plasma membrane are soluble in lipid (phospholipid tails are hydrophobic-“like dissolves like.”) Molecules that Move across easily Molecules that need proteins to get across membrane Small, nonpolar molecules Larger, nonpolar charged Small polar (water) actually, aquaporins help it move across. 5.2 Explain how the properties of phospholipids spontaneously form membranes. One of the first organic molecules to form on early Earth Mrs. Loyd [email protected] Page 8 of 11 9/21/16 http://loydbiology.weebly.com Spontaneously self-assemble into simple membrane “bubbles” without help from DNA “membrane-bound sacs” surrounding beneficial chemistry (protobiont) was important stepping stone to first cell. Hydrophilic heads “love” water inside and outside cell Hydrophobic tails “fear” water and huddle together “Like dissolves like” 5.3 Define diffusion and describe the process of passive transport. Diffusion: Particles spread out evenly in an available space, from high concentration to low due to thermal motion (heat). NEVER requires energy. Passive Transport: The diffusion of a molecule across a membrane from high to low concentration or down its concentration gradient. Small, nonpolar molecules like O2 and CO2 diffuse easily. Small, polar water diffuses easily. Large, polar molecules and ions can diffuse across using a transport protein (facilitated diffusion). Passive Active HL LH No energy Uses Energy Examples: Diffusion endocytosis osmosis exocytosis Facilitated Na+/K+ pump Diffusion-Glucose 5.4 Explain how osmosis can be defined as the diffusion of water across a membrane. Osmosis is a special case of diffusion, it is specifically for water. It is defined as water moving across a membrane from HL concentration. Predicting how water will move across a membrane will be your main challenge in this chapter. 5.5 Distinguish between hypertonic, hypotonic, and isotonic solutions. Hyper = “over” like “hyperactive” Hypo = “under” like “hypodermic needle” Iso = “same” like “isosceles triangle” Tonic = solute These terms are relative. We will always be comparing one side of a membrane to the other side. (outside a cell vs. inside the cell.) STEPS in determining the direction of osmosis Latin Solute English Solute English Water Place your L, then HL Decide if water is entering or leaving the cell (Draw a PICTURE!) Determine the results Determine what will happen hypertonic “over” salty “under” watery HL use next figure 5.5 Explain how animal and plants cells change when placed into hypertonic or hypotonic solutions. Complete your “Osmosis Worksheet” to practice. Mrs. Loyd [email protected] Page 9 of 11 9/21/16 http://loydbiology.weebly.com 5.6 - 5.8 Compare the processes of facilitated diffusion and active transport. Facilitated Diffusion: uses a protein embedded in the membrane to facilitate, or help, a substance diffuse across the membrane. Example: Glucose has its own protein in the cell membrane for this purpose. It is diffusion, so the sugar moves from HL concentration of sugar. Active Transport: USES ENERGY LH Moves molecules against their concentration gradient. Examples: o endocytosis o exocytosis o Na+/K+ pump 5.9 Distinguish between exocytosis, endocytosis, phagocytosis, pinocytosis, and receptor-mediated endocytosis. This short video explains the sodium-potassium pump, exocytosis and phagocytosis. < 4min. https://www.youtube.com/watch?v=2-icEADP0J4 This short video focuses on the sodium-potassium pump. 1:28 min. https://www.youtube.com/watch?v=P-imDC1txWw Mrs. Loyd [email protected] Page 10 of 11 9/21/16 http://loydbiology.weebly.com LT8a I can use a neuron (nerve cell) to describe how passive and active transport work together to maintain homeostasis. Cells specialize to fit their form to their function. Skin cells are broad and flat to serve as a shield for protection. The cells of our inner ear have cilia to pick up vibrations so we can hear. Nerve cells are elongated to carry impulses long distances. Neuron Structure Know parts and functions. Action Potentials Varying force of sensory input is transmitted as greater or fewer numbers of action potentials. The amplitude of the A.P. does not change. The action potential is “All or None.” Conduction of an Action Potential The movement of the ion channels to send the action potential along the length of the neuron is like a stadium wave. To participate in a stadium wave you: 1. remain sitting until the wave reaches you. 2. the person next to you begins to stand and you follow just after 3. you stand and throw up your hands 4. bring your hands down, sit down 5. watch the wave move around the stadium 6. wait for another wave. Use the following events to align with the analogy. a) Na+/K+ pump returns ions to original position, repolarizing the axon. b) Na+ ions flood in, a local change (permeability to ions) c) triggering depolarization of neighboring membrane d) Impulse moves along axon to synaptic terminals e) Resting membrane potential X 2 These two videos describe an action potential and the synapse. https://www.youtube.com/watch?v=WffFL7ykbqE&list=PLqlJYrIFRy9Wg0S3MUQIB83aXd6-dPCnN&index=52 https://www.youtube.com/watch?v=CltFCbbi0Vw&list=PLqlJYrIFRy9Wg0S3MUQIB83aXd6-dPCnN&index=53 Mrs. Loyd [email protected] Page 11 of 11 9/21/16 http://loydbiology.weebly.com