Concept explainers
To analyze:
Considering that in Arabidopsis thaliana, the approximate number of nucleosomes per nucleus is
How many nucleosomes are expected in the nucleus after completion of S phase? Explain.
Are all of the additional nucleosomes that are present after completion of S phase of the cell cycle composed of newly synthesized histone proteins? Explain.
Introduction:
During the S phase of the cell cycle, the DNA content of the cell is doubled by the
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Genetic Analysis: An Integrated Approach (2nd Edition)
- Why do eukaryotic cells need to go through the elaborate procedure of mitosis rather than simply dividing during interphase? Select as many answers as apply. 1.Daughter cells must be genetically identical to the mother cell, for homeostasis and ordered tissue growth. 2.Bivalent chromosomes must condense and be separated in an orderly fashion, to allow equal distribution of copies into daughter cells 3.Physically dividing the nucleus during interphase would likely lead to gross chromosome breakage and highly unequal assortment of genetic information into daughter cells. 4.Dividing the nucleus during interphase would have the same outcome as mitosis 5.Daughter cells must have half the number of chromosomes after mitosis than the mother cells 6.The homologous pairs of chromosomes need to be separated, to ensure copies go to the daughter cells.arrow_forwardHuman somatic cells have 46 chromosomes. Are the cells different in any way from the parent cell and what is chromosome count of each of those cells once they have finished mitosis?arrow_forwardExplain why we can say that M-phase of the cell-cycle is triggered by a positive feedback loop. a) What would the consequences be if cohesins were working normally but condensins were not? and b) what stage of the cell cycle would this cause problems in? Why is it important for the centrosome to duplicate during G1-G2 (interphase) before M phase? The kinetochores serve as a link between the sister chromatids and the microtubules attached to the mitotic spindle. a) How are microtubules still able to exhibit dynamic instability after they are bound to the sister chromatids and b) why is this important to mitosis? As the name suggests, the Anaphase-promoting-complex (APC), promotes the 4th phase of mitosis by separating the sister chromatids so they can travel to separate poles of the cell, and prevents them from being re-zipped together. Describe how APC does these two things (Hint: one involves M-cyclin and the other involves…arrow_forward
- If you expose a culture of human cells (for example,HeLa cells) to 3H-thymidine during S phase, howwould the radioactivity be distributed over a pair ofhomologous chromosomes at metaphase? Would theradioactivity be in (a) one chromatid of one homolog,(b) both chromatids of one homolog, (c) one chromatid each of both homologs, (d) both chromatids ofboth homologs, or (e) some other pattern? Choose thecorrect answer and explain your reasoning.arrow_forwardColchicine is a chemical mutagen that inhibits the spindle formation and prevents anaphase, which retains the cell’s single restitution nucleus (doubled chromosome number). Suppose that an onion (2n=16) is subjected to three consecutive rounds of colchicine treatment, what will be the resulting chromosome number of the treated onion?arrow_forwardConsider the following DNA molecule (shown in the picture) and assume this is the DNA sequence of the entire chromosomes. list the amino acid sequences of the possible protein or proteins that could be produced from this DNA sequence what would be the DNA sequence of a sister chromatid generated from this chromosome sequence? (specify the 5' nd 3' ends)arrow_forward
- 1). A diploid somatic cell from a dog (Canis lupus familiaris) has a total of 78 chromosomes (2n = 78). As in humans, sex chromosomes determine sex: XX in females and XY in males. a) What is the total number of DNA molecules in G2 of the cell cycle? b) What is the total number of sister chromatids during prometaphase? c) What is the total number of telomeres in a somatic dog cell in G1? d) What is the total number of autosomes?arrow_forwardTo identify genes controlling the cell cycle in budding yeast, a genetic screen was carried out. In this screen, haploid yeast cells were exposed to a DNA damaging agent to introduce random mutations in the genome. By culturing cells at an elevated temperature (e.g. 37 degrees), where many mutated genes lose their function, scientists identified yeast mutants that showed growth defects and arrest at specific stages of the cell cycle (e.g. in mitosis with large buds). In this screen, mutants of the cyclin-dependent kinase were identified, but not mutants of cyclins. Explain the reason for this outcome.arrow_forwardYou isolate a cell from a yeast species (a eukaryote) where n = 8, apply a chemical that forces chromosomes to condense, and then make a karyotype. You observe a cell with 16 DNA molecules. The stage of this cell: (A) [Select] [ Select] (B) [Select] and each chromosome is made up of [Select] [Select] (C) [Select] be G1 of the cell cycle, because at that stage the cell is O [Select] and so has [Select] and each chromosome is made up of [Select] and so has [Select] be Metaphase of Mitosis, because at that stage the cell is chromosomes and so has [Select] chromatid(s). and each chromosome is made up of [Select ] chromosomes chromatid(s). ✪ be Prophase II of Meiosis, because at that stage the cell is ↑ chromosomes ? chromatid(s),arrow_forward
- A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G2?arrow_forwardA crayfish strain became triploid while kept in a pet store. Pet owners released these crayfish into the wild, and they became an invasive species. These triploid animals have 2 different kinds of chromosomes (chromosome 1 and chromosome 2). To understand what kind of difficulties the crayfish triploid cells might have during the cell cycle you will draw: Cell is triploid with 2 different chromosomes ( 1 and 2) A) cell in G1 (assume chromosomes are condensed as they normally are in metaphase throughout the cell cycle) B) cell in G2 (assume chromosomes are condensed as they normally are in metaphase throughout the cell cycle) C) cell in Metaphase of mitosis D) cell in Metaphase I of the first meiotic division E) cell in Metaphase II of the second meiotic divisionarrow_forwardThe Yellow Fever vector mosquito (Aedes Aegypti) is normally 2n = 8. Please draw the following diagrams and in each of your diagrams label the following (or note the absence of): a) a pair of homologous chromosomes b) a pair of sister chromatids A) A somatic cell in this organism undergoing prophase. B) A germ cell undergoing anaphase II.arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education