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Unformatted text preview: Answers to Lecture Questions from Week of 1‐25‐10 I. What are the products of mitosis? 1. How many cells are produced at the end of a single mitotic division? Two cells are produced at the end of a single mitotic division. 2. How many different kinds of cells are produced at the end of a single mitotic division? Only one kind of cell is produced. Two daughter cells are produced, but they are identical to each other and to the parent cell that gave rise to them. Identify the mitotic phases: A. Prophase B. Telophase C. Anaphase D. Metaphase II. Six centromeres are observed in a prophase cell from a species of insect. 3. How many pairs of chromosomes does this organism contain? Three pairs 4. For each stage of mitosis, indicate the number of centromeres you would expect to find and the number of copies of chromosomes attached to each centromere. Number of centromeres Number of chromosomes Stage of mitosis: visible per cell attached to each centromere Metaphase 6 2 Anaphase 12 1 III. Haplopappus is an annual flowering plant that grows in deserts. It is of interest because its 2n number is only four. 5. This means that cells in the vegetative parts of the plant, that are not undergoing mitosis, have how many DNA molecules in their nuclei? There would be 4 DNA molecules or 4 total chromosomes in cells not undergoing division. 6. During metaphase of mitosis, how many DNA molecules would be in the nucleus? During metaphase, there would be 8 DNA molecules in the nucleus. DNA would have duplicated in the S phase of interphase prior to division. 7. You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown. A. Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle? Sample I B. Which sample might represent an animal cell in G2 phase of the cell cycle? Sample II C. Which sample might represent a sperm cell? Sample III Nerve cell in G0 would have unreplicated chromosomes; G2 phase cell would have replicated chromosomes and thus 2X the amount of DNA as the nerve cell. The sperm is haploid & contains unreplicated chromosomes, thus this sample would possess the lowest DNA quantity of all samples. 9. Referring to the labeled chromosomes below, of the given choices, which areas (A thru X) contain identical information? A. A & B B. A & C C. A & E D. A & W Answer: The chromosomes depicted here all represent replicated chromosomes; such chromosomes possess 2 sister chromatids, one being an identical copy of the other. Of the choices given, only choice B (A & C) represent areas of identical information. 10. Referring to the chromosomes above, which areas contain similar information inherited from different parents? A. A & B B. A & C C. A & E D. A & W E. A & G Answer: Choices C (A & E) and D (A & G); as mentioned above a diploid individual has 2 chromosome sets, one inherited from the mother, one from the father. A homologous chromosome pair will share the same gene loci, but the forms of each gene, i.e., alleles, may differ. For example, the gene locus for eye color will be found in the same location (locus) on each chromosome in a homologous pair, but one of the alleles may confer brown eye color, the other, blue eye color. ...
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This note was uploaded on 04/15/2010 for the course BIOL 1362 taught by Professor Loeblich during the Spring '08 term at University of Houston.
- Spring '08