Biology 1406 Exam #3 Top Rated Questions and Answers Graded A

Cell division is used for which of the following ? - Reproduction of single-celled organisms, growth of multicellular organisms, repair and replacement of cells, and sperm and egg production Asexual and sexual reproduction differs in that sexual reproduction_____________ - Can produce great variation among the offspring (Meiosis) Asexual Reproduction ____________ - Produces offspring genetically identical to the parent (Mitosis) Most of the time, DNA is in the form of____________ - Euchromatin When the DNA condenses, it becomes ____________ - Heterochromatin Histones are - Proteins around which DNA is coiled In eukaryotes, chromosomes are tightly coiled due to the association of histone proteins and DNA. Three structures are known as - Nucelosomes What is the protein complex that holds sister chromatids together? - Cohesins Condensin - Condenses DNA What is the "Waist" of the chromosome, where the sister chromatids are joined together called? - Centromere Immune system cells enter a resting phase after undergoing mitosis. When activated- for example, by an infection-- they can reenter the sequence of events in the cell cycle that leads to cell division. What would be the correct sequence of events? - G1, S, G2, M When examining cells in the laboratory, you notice that a particular cell has half as much DNA as the surrounding cells. It appears that this cell's cell cycle halted at checkpoint______. - G1 which of the following statements correctly describes the timing of DNA synthesis? - DNA is synthesized in the S phase of interphase which of the following shows the cell cycle in the correct chronological order? - interphase, prophase, prometaphase, metaphase, anaphase, telophase (IPPMAT) A human somatic (Body) cell contains _____ chromosomes. - 46 (diploid) What would be the immediate consequence of destroying a cell's centrosomes? - the mitotic spindle would not form What does the mitotic spindle do in Mitosis? - Pull chromosomes apart Where do the spindle fibers attach to the chromosomes during Mitosis and Meiosis? - Kinetochore What happens in Interphase? - Copy of DNA, Cell grows, 2 centrosome form What happens in Prophase of Mitosis? - Nuclear Envelope disappears, Chromosomes or chromatin condense, spindle forms and attach to kinetochores. What happens in metaphase of Mitosis? - Align in the center What happens in Anaphase of Mitosis? - Sister chromatid separate What happens in Telophase of Mitosis? - Nuclear Envelope reforms, Chromosome Uncondensed, During cytokinesis, in animals a_____ forms and in plants________ forms? - Cleavage Furrow, Cell plate What are the 4 things that control cell division? - Density- dependent inhibition, growth factors, anchorage dependence, (G1, G2, M check points) How does the cell cycle control system regulate cell division? - triggers & coordinates key events (director of a movie) True or False: If a cell doesn't have enough cyclins when it reaches a checkpoint, it won't move on to the next phase of cell division. - True What enzyme reacts with cyclin to trigger events in the cell division cycle by phosphorylating specific target proteins? - CDK (Cycline dependent Kinase) If the DNA has been damaged, then it causes an increase in a transcription regulator called _____ which stimulates the transcription of a CDK inhibitor_______ that prevents the cell from entering the S Phase of interphase. - P53, P21 Apoptosis is.... - Programmed Cell Death