Plasma membrane: Figs 11-1,11-4, 11-5, 11-7, 11-11, 11-12; pp. 359-366 Are all cell membranes composed of a lipid bilayer? Yes, all cell membrane are composed of a lipid bilayer. Define hydrophilic/hydrophobic. -Hydrophilic- dissolves in water because it is “water-loving” andpolar-Hydrophobic- does not dissolve in water because it is “water-fearing”and nonpolar Define polar/non-polar.
-Polar- unequal electron distribution between 2 atoms-Nonpolar-equal electrondistribution between 2 atoms Compare the structure of phospholipids and cholesterol. How does structure affect function?Phospholipidsand cholesterol have a hydrophobic, nonpolar tail (made of fatty acids) and a hydrophilic,polar head (made of glycerol). The difference between them is thatphospholipids have a phosphate group substituted for one of the fatty acids. Phospholipids and cholesterol maintain thecell membrane’s fluidity.
In addition, Phospholipids allow forsemi-permeability of the membrane due to its amphipathic nature. Why do phospholipids spontaneously form bilayers?Bilayersare formed to prevent the hydrophilic, nonpolar tails of the phospholipids fromwater interaction and because it is energetically favorable as well. Nucleus: Nucleolus: Fig. 5-18; pg.
184§ Function?Contains ribosomal RNA to make ribosomes § Whatis its size and shape determined by? Amount ofribosomal RNANuclear Envelope: Fig. 15-7, pp.488,495§ Whatprovides structural support? Nuclear lamina§ Functionof nuclear pore complexes? Itallows molecules to come in and out of the nucleus.Ribosomes: Figs.
7-31,7-32, 7-33; pp.244-245 Are ribosomes organelles? No, because it does not have a membrane. Endoplasmic Reticulum:Figs 1-21, 15-12; pp.489,498-499 Three major functions of ER?1.
Formsproteins (made by the ribosomes) and transports them to the Golgi 2.Forms lipids3. Formssteroid hormones and extracellular signals Structural/functional difference between smooth and rough ER?SmoothER has not ribosomes, so its function is steroid hormone synthesis, lipidsynthesis, and forming extracellular signals.
Rough ER has ribosomes, so it isthe site of protein synthesis. Where are smooth and rough ER found? Bothare found throughout the cell, but the Rough ER is more concentrated near thenucleus. Is the ER connected to the nuclear envelope? To the Golgi? The ERis connected to the nuclear envelope, not the Golgi. Golgi: Figs. 1-22,15-26;pp.19, 510-511 How does the term compartmentalization apply to the Golgi?TheGolgi has cisternae, which are multiple layers within it to separate thevarious enzymes and process that occur in each layer. What is sorted by the Golgi? ProteinsLysosomes: Figs. 15-35, 15-36;pp.
19, 489, 515, 518-520 What is the significance of lysosomes having an internal pH ~5? Havinga pH of 5 is what activates the lysosomal enzymes for digestion. Define “endosome”. How does an endosome differ in structure and function from a lysosome? …from a phagosome?-Endosome- organelle that transports molecules from the plasmamembrane to the lysosome-Endosomesonly transports material (which eventually forms into a lysosome), while lysosomesand phagosomes ingest the material. Describe the three pathways to degradation in lysosomes.-Phagocytosis:process where a cell engulfs a specific substance through physical contactusing phagosomes and fused with lysosomes-Endocytosis:process where a cell engulfs a substance (not through physical contact) usingvesicles and the contents are delivered to the lysosomes via endosomes-Autophagy:Parts of an organelle are packaged into autophagosomes and sent to lysosomes foringestionMitochondria and Chloroplasts: Figs 1-16, 1-17, 1-18, 1-19, 14-1, 14-2, 14-4, 14-5, 14-6, 14-7, 14-8;pp. 448-453.
Define chemiosmotic coupling.Chemiosmotic coupling- process where the energy that is formed as electronspass through the ETC is used to create a proton gradient, forming ATP asprotons pass through this gradient Why is plasticity of mitochondria needed? It isneeded to accommodate to each of the cell’s metabolic requirements to createthe proper amount of energy needed. Compare/contrast the structure/function of mitochondria and chloroplasts.-Similarities:-both take part in metabolic processes -both have doublemembrane -both have circular DNA-Differences:-mitochondria takes part in oxidative phosphorylation, while chloroplasts take part inphotosynthesis -mitochondria found in plant &animal cells, while chloroplasts only found in plant cells -chloroplasts havephotosynthetic pigments, while mitochondria does not -chloroplasts have an extracompartment (thylakoid) -mitochondria are smaller,chloroplasts are larger Purpose of a double membrane?To increasethe surface area needed for metabolic processes to occur, so more energy can begenerated. Why is it postulated that mitochondria/chloroplasts contain DNA? Does it code for the same proteins as nuclear DNA?It is postulatedthat mitochondria/chloroplasts contain DNA due to the Endosymbiotic Theory,which states that they were engulfed by Eukaryotic cells (which also containedDNA). It does not code for the same proteins as nuclear DNA. Why are mitochondria mostly maternally inherited in higher animals? What is the significance of this?Mitochondriais maternally inherited because it is passed through the egg from the mother tothe offspring. This is significant because we can trace back the lineages ofvarious animals using this mitochondrial DNA.
How are mitochondria made? Mitochondriacan be made through mitochondrial DNA, or through cell division (usingmitochondrion). Peroxisomes: pp.19,489-490, 498 Function? Use hydrogen peroxide to break down fatty acids. How do peroxisomes function differently from lysosomes?Peroxisomesbreak down substances, while lysosomes ingest waste productsCytoskeleton: Fig 1-26,17-1, 17-2, 17-5; pp.21, 565-566Ø Define”cytoskeleton”.-Cytoskeleton- composed of proteins which provide shape and structure toa cellØ Formicrofilaments, microtubules, intermediate filaments–Microfilaments: -Majorproteins: actin -Size(diameter): 3-6 nm -Stability:are stable -Functions:muscle contraction, cytokinesis, pseudopod formation -Microtubules: -Major Proteins: tubulin -Size (diameter): 20-25 nm -Stability: are stable -Functions: compose mitotic spindles,cilia, flagella; used for intracellular transport-Intermediate filaments: -Major Proteins: many different proteins -Size (diameter): 10 nm -Stability: most stable of the three -Function: provide structure for the cell Extracellular matrix (ECM) structures: Figs 20-2, 20-3, 20-5,20-8, 20-19, 20-20, 20-21, 20-22, 20-31; pp.683, 686, 688, 694-695§ Doplant cells have an ECM? Yes, plant cells have anECM. § Howdoes a tissue differ from a cell? Tissues are made of similar cells that share a commonfunction.
§ Define”connective tissue”.Connectivetissue- connects othertissues/organs with a matrix (composed of elastic tissue, cartilage, of fattytissue)§ Listthe 3 major components of connective tissue. What are two main proteins associated with connective tissue? -3 major components:1. fibers2. ground substances3. cells – 2 main proteins= reticularproteins & collagen§ Whatcomprises the extracellular matrix of bone? Cartilage? Tendon? Blood?-Bone’sETC: water, minerals, collagen fibers -Cartilage’sETC: proteoglycan, elastin fibers, collagen fibers-Tendon’sETC: collagen, proteoglycans, water -Blood’s ETC: contains plasma(proteoglycans, water, minerals, fibers)§ Describethe structure of epithelial tissue.The epithelial tissue contains cells that are packedtogether as sheets that are closely connected. It also contains glands,junctions, and the basal lamina.
§ Whatis a basal lamina? Function?The basal lamina a layer beneath the epithelium whichcontains the extracellular matrix secreted by the epithelial cells. Itsfunction is to separate the epithelial cells from other tissues and also actsas a selectively permeable filter. § Describethe functions of at least 3 different cell junctions.
Cytosol: Fig 1-25; pp.21-22 Is the cytosol liquid? No, it is considered more of a water-based gel than a liquid. Describe the internal environment of the cell.
Is it static?Thecell’s internal environment is not static. It has various molecules andproteins that are constantly in motion. Ø List three ways plant cells differ from animalcells. Panel 1-2, pg. 251)Plant cells have a chloroplast, while animal cells do not.2)Plant cells have a cell wall, while animal cells do not3)Plant cells have vacuoles, while animal cells do notØ Describe the main difference between prokaryoticand eukaryotic cells. pp.
12-22Eukaryoticcells contain membrane-bound organelles (which includes the nucleus), whileprokaryotic cells do not.