Bio 230W Week 8 Learning Guide with Answers

- BIOL230W Week 8 – Segregating Chromosomes BIOL230W Week 8 – Segregating Chromosomes We have spent the first half of the semester focused on the flow of information from DNA→ RNA→ protein using cystic fibrosis as a model. Now we will spend a few weeks looking at the roles proteins play in the cell including signaling, cell division and cell cycle regulation. These processes are important to cell function and when they fail can result in the development of cancer. Learning Objectives • • • • • • • • • • • • Compare and contrast centromere, chromosome and chromatid with respect to structure, function, location, stage and phase. Compare and contrast the amount and location of DNA at each stage of the cell cycle Describe the main processes occurring in each of the four stages of the cell cycle Outline the structures and result of each phase of mitosis. Compare and contrast the polymerization of microtubules with the polymerization of DNA/RNA and proteins Differentiate the kinetochore and the centrosome Describe how the structure of microtubules contributes to its function in interphase and in mitosis. Apply the concept of “dynamic instability” to the structure and function of microtubules in mitosis. Compare and contrast the 3 different types microtubules that create the mitotic spindle with respect to attachment and function. Draw and label the different stages of mitosis (with respect to the DNA structure, microtubule structure, kinetochore, nuclear membrane and centrosome and cohesin). Define microtubule targeting agent (MTA). Outline general mechanism of how MTAs disrupt cellular processes. Mini-Lecture: Intro to Cell Cycle and Cancer Small Group Activity: Previous Knowledge Activate! Form a scaffold to which new knowledge can be attached. 1. What are the 4 stages of the cell cycle? G S G2 MitOsi ,, . , 2. Which stages are included in interphase? G1 , S , G2 3. What happens in S-phase? DNA gets Duplicated 4. In which stages would you find sister chromatids? S-Phase 5. What macromolecule makes up the centromere? Protein Centromere Is a part of DNA sequence Spacked Most tightly part of 1 BIOL230W Week 8 – Segregating Chromosomes Mini-Lecture: DNA in Interphase 6. Is G0 a part of interphase? No 7. Compared to G1, how much DNA is in the nucleus of a cell in G2? Double 8. What is the function of cohesin? A protein that connects the Sister chromatin Small group activity: DNA in Interphase 9. Using the images below indicate which stages are interphase or mitosis. 10. Given the provided cellular membranes below, draw two individual chromosomes in G1, S and G2 ONLY. Indicate the presence of euchromatin vs heterochromatin, sister chromatids, cohesion, the conesin centromere and the nuclear membrane. = - = · Sister - chromatas netero and en => = centromere chromo. auclearmembran m #" ⇌ 加川 n Immi ↑ f mi ↳ 、 Mini Lecture: DNA In Mitosis 11. What is the purpose or result of mitosis? Cells transfer replicated DNA of parent cell into the daughter cells 12. Compared to G2, how is the structure of chromosomes different in mitosis? To make In are daughter + mitosis-chromosomes highlysondensed . D See ber E 2 BIOL230W Week 8 – Segregating Chromosomes 13. Based on chromatin structure in interphase vs. mitosis, how would you expect the overall level of gene expression to differ? When transcription is > During Interphase MitosIs > - - , high overall gene expression occuring Cittle None - 14. Compared to G2, how much DNA is in the cell in prophase? The same amount 15. Compared to metaphase, how much DNA is in the cell in anaphase? Will be a single of genome after anaphase and metaphase will haveI copled stil Small Group Activity: DNA in Mitosis Go back to the cell drawing for DNA structure in interphase. NOW, use what you have learned in class today and previous knowledge to draw your interpretation of the structure of DNA in the phases of mitosis. Be sure to include the two chromosomes, sister chromatids, cohesin, the nuclear membrane and the centromere. Make sure your drawing reflects the heterochoromatic nature of the chromosomes. Prophase protometaphase m m · m Mini-Lecture: How does the DNA Move? Microtubules and Kinetochores GTB 16. Tubulin monomers polymerize when they are bound to __________ and depolymerize when they are bound to ______________. GDD cannot bind GFP Grow destab-dynamic instability 17. How might the lack of GTP affect the stability of a microtubule? + ⑪ & Microtubule will destabilize depolymerization overall Gip"cap" is lacking 18. Given your answer to Q16, in what category of protein might you place the tubulin monomer? GFP tUbulIn dimers structural proteins 19. Take a few minutes to compare and contrast the microtubule polymer with two other polymers (DNA/RNA and proteins) we have studied. Use Q. 20 and 21 to record your answers. Monomers Polarity Connecting bond Polymerizing Agent Nucleation = initiation of polymerization DNA/RNA Protein Nucleotide Amino acd) Yes 31 N-Term - gi Phosphodlester Dolymerase peptide eplus & Minus end .. No Hydrogenbonds holdsg Microtubules ¿ C term Ribosome tubulin dimer θ charge 1 θ Hydrogen Autopolymerization 3 - BIOL230W Week 8 – Segregating Chromosomes plus + minus -> not charged 20. How is the polymerization of microtubules similar to the polymerization of nucleic acids and proteins? Have polarity - 21. How is the polymerization of microtubules different from the polymerization of nucleic acids and MT are not proteins? covalent hydrogen bonds - - bonds us in MT information carriers 22. What function of microtubules is dependent on the bond that joins microtubule monomers into a polymer as described in Q21? (hint – microtubules are not permanent structures)? They have dynamic stability 23. What organelle nucleates microtubule polymers? centrosome & Group Activity: Microtubules During Interphase MSmall Go back to the cell drawing for DNA structure in interphase. Use what you have learned in class today 배 ⇌ to draw your interpretation of the location of microtubules in interphase. Be sure to include the microtubules, the centrosome(s) and nuclear membrane. prophase-formation of spindlemt Mini-Lecture: Spindle formation and chromosome attachment Metaphase- 24. What cellular event allows microtubules to invade the nuclear space during prometaphase? CENTROMERE Nuclear membrane dissolves + microtubules attach to kinetochove 25. What type of macromolecule is a kinetochore? * MSS Bind to Kinetichove Proteln 26. Centromeres and kinetochores are present during which phases of the cell cycle (G1, S, G2, M)? a. Centromere = Gl S G2 M b. Kinetochore = MDhase . , , 27. What does the + end of each of the three types of mitotic microtubules attach to? Polar = Another microtubule (on opposite pole) Kinetochore = Kinetichore Astral = to plasma membrane 4 1 -e BIOL230W Week 8 – Segregating Chromosomes 28. How does the dynamic instability of the microtubule relate to the attachment of microtubules to chromosomes? Allows for microtubules to generate force and to align at the metaphase plate 29. What provides the force to position the chromosomes at the center of the cell at metaphase? Motor proteins X-ATp : inesinpyneinθ hydrolysis > motor head binding Small Group Activity: Microtubules During Mitosis Go back to the cell cycle drawing. Use what you have learned in class today to draw your interpretation of the location of microtubules in mitosis. Be sure to include the microtubules (Polar, kinetochore and Astral), the centrosome(s), kinetochore and nuclear membrane. At Home Practice: Here are some extra cell outlines. See if you can remember all the structures and locations in the different stages of the cell cycle without looking! Try using different colors to highlight the various structures. ⇌ · Dn ↑ d ∅ - 삔 g 5