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BY 123Dr. CusicSession 7 WorksheetWhere do we find plastids? Only in plants and algaeWhat are the two types we called about in class? Leucoplasts:Colorless plastids that are found in storage parenchyma and other colorless tissues are refereed to as leucoplasts. Most of them act as storage organelles. Based on the kind of substance they store they are further classified into amyloplasts. Chromoplasts:All plastids containing different colored pigments are grouped under chromoplasts, of which green colored ones are called chloroplasts. Depending upon the dominant pigments present in plastids, they are further classified into Rhodoplasts rich in red pigment i.e. phycoerythrin. Phaeoplasts and Xanthoplasts contain yellow pigments i.e. xanthophylls, carotinoids. Compare prokaryotic and eukaryotic flagella. ? Prokaryotic flagella are smaller and simple in structure, whereas eukaryotic flagella are larger and complex in structure.? Prokaryotic flagella are made up of flagellin protein while eukaryotic flagella are made up of tubulin.? The movement of prokaryotic flagella is proton driven, whereas the movement of eukaryotic flagella is ATP driven.? Prokaryotic flagella have rotator movement, whereas eukaryotic flagella have blending movement.? Unlike the prokaryotic flagella, eukaryotic flagella have 9+2 arrangement of microtubules.? Prokaryotic flagella are located outside of the plasma membrane, whereas the flagella in eukaryotes are covered with the plasma membrane.What are plant cell walls made of? Bacteria? Fungi? Cellulose; not rigid like a plant cells, but flexible and gooey composed of peptidoglycan; can have a cell wall made of chitinExplain primary and secondary cell walls, middle lamina, and plasmodesmata . With very few exceptions, plant cells always form cell walls. The cell walls contains layers of cellulose fibers interspersed within a hemicellulose packing. Together, these substances yield a very strong but pliable supportive layer for plant cells. Adjacent cell walls are cemented together by botanic "glues" or pectins in a layer called the middle lamella.The cell wall forms outside the plasma membrane initially as a thin primary cell wall. Thereafter, the primary cell wall may thicken or a more durable secondary cell wall can form between the primary cell wall and plasma membrane.Plant cells remain in contact with one another via plasmodesmata, membrane lined channels that extend through cell walls to link adjacent cells. Plasmodesmata facilitate intercellular communication and transport.What are the 3 classes of cytoskeleton? Tell me about each one.1. Microfilaments – filaments, thin fibers, composed of actin, little balls in a long chain like a necklace. a. Maintain cell shapeb. Change in cell shape – Pseudopodium = false foot Amoeba c. Muscle contractions – myosin is the motor moleculed. Cell streaming – cell moves components arounde. Cell Division – cleavage furrow2. Microtubules - little tubes, protein = tubulin, kinesin is the motor molecule, microtubules are like freeways for organelle movementa. Chromosome movementb. Cell Shapec. Cell motilityd. Organelle movement3. Intermediate filaments – intermediate in size in between microfilament and microtubules. a. Maintain cell shapeb. Nuclear laminac. Anchorage of nucleus and other organellesWhat are the 3 main types of functions in animal cells? Tell me about them. Give an example. What’s an aquaporin? Why do we have it if water diffuses across membranes?Aquaporins: the Cell's Water ChannelsWater moves in and out of cells by osmosis through the cell membrane. However, it was long suspected that there was an additional mechanism for moving water across the cell membrane. The 1992 discovery of aquaporins by Peter Agre, membrane proteins facilitating water transport in and out of cells. To date, 13 variants of aquaporins have been discovered in humans. A single human aquaporin transports water, one molecule at the time, at the rate of about 3 billion water molecules per second, in accordance with the prevailing osmotic gradient (the water moves in a direction away from a low and toward a high concentration of salt and nutritional substances). In doing so, aquaporins allow cells to regulate their volume and internal osmotic pressure.What is the name of the special type of peroxisome found in the fat storing tissue of a germinating seed?GlyoxysomeWhat is the endosymbiotic hypothesis? What evidence justifies this line of thinking?Chloroplasts and mitochondria used to be free-living prokaryotic cells. However, these bacteria were taken in another cell and used as an embysimbiont. Now they both depend on each other. The evidence that supports this hypothesis is that both mitochondria and chloroplast contain their own exclusive circular DNA and ribosomesThe Chloroplast contains 3 distinct spaces. What are they?1. Intermembrane Space – between outer and inner membrane2. Stroma – space within the inner membrane3. Thylakoid space – Space inside the granum The part of the chloroplast that resembles a single penny is called _________. The part of the cell that resembles a stack of pennies is called the _________.Thylakoid… GranumA mitochondrion contains 3 distinct spaces. What are they?1. Outer membrane space – outside the mitochondria2. Inner membrane space – between the outer membrane and inter membrane3. Mitochondrial matrix – space inside the Cristae13. Both Eukaryotic flagella and cilia are made of ________. Is there a difference in their arrangement? What sort of arrangement do basal bodies and centrioles display?Microtubules. No, both Flagella and cilia exhibit a doublet “9 + 2 arrangement” of microtubules. Basal Bodies and centrioles display a triplet “9 + 0 arrangement” of microtubules.14. Explain the mechanism involved in a sodium-potassium pump?A sodium potassium pump is a form of active transport. First we must note that the concentration of sodium is higher outside the cell than inside and the concentration of potassium is higher inside the cell than outside the cell. The purpose of this pump is to return the cell back to its natural state regarding the concentrations of K+ and Na+. Initially, the carrier holds 3 sodium ions from the inside of the cell. Once the 3 sodium’s are bound to the ATP phosphorylates the pump causing it to undergo a conformational change. This phosphorylation causes the pump to change shape dumping the 3 sodium ions outside the cell. The cell then picks up 2 Potassiums and they bind to the pump. Dephosphorylation causes another conformational change that causes the pump to bring in the 2 K+ ions from the outside to the inside. Now it is back to the Na+ accepting phase and the process begins again.15. Voltage across the membrane is called the _________ _________.Membrane potential16. Voltage is _______ of ________ across the membrane.Separation of Charge17. If a molecule is uncharged you only have to take its ____________ gradient into account..... If a molecule is charged you must take into account its __________ gradient and _________ potential also known as its _____________ gradient.Chemical,…..Chemical and membrane potential….. electrochemical gradient ................
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