You would be unlikely to see which of the following human cells dividing? Nerve cell Skin cell Cancer cell Cell from embryo The person credited with first recognizing that living cells cannot arise spontaneously, but arise only from previously existing cells is ____________________. Louis Pasteur Robert Hooke Anton van Leeuwenhoek Rudolf Virchow Sister chromatids ___________________. Are created when DNA is replicated Are attached at the centromere prior to division Are separated during mitosis All of the above If an intestinal cell in a grasshopper contains 24 chromosomes, a grasshopper sperm cell would contain ________ chromosomes. 3 6 12 48 Mitosis & cytokinesis result in the formation of _______________; meiosis & cytokinesis result in the formation of _________________. 4 diploid cells … 4 haploid cells 2 diploid cells … 4 haploid cells 2 diploid cells … 2 diploid cells 4 haploid cells … 2 diploid cells A human somatic cell contains ________ chromosomes? 23 47 46 n The function of the cell cycle is to produce daughter cells that ____________. Have the same number of chromatids as the parent cell had chromosomes Have a random assortment of maternal and paternal chromosomes Have the same number of chromosomes as the parent cell but not the same genetic information Are genetically identical to parent cell (assuming no mutation has occurred) The complex of DNA and protein that makes up a chromosome is properly called ____________. A chromatid A chloroplast Chromatin Chromoplast The region of a chromosome holding two double strands of replicated DNA together is called ____________. A centromere A centriole A chromatid An aster “Cytokinesis” refers to _______________. Division of the entire cell Division of the nucleus Division of the cell outside the nuclear material Reduction in the number of chromosomes If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle? 15 30 45 60 A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in a cell doubled _______________. Between prophase and anaphase During the M phase of the cell cycle Between the G2 phase and prophase Between G1 and G 2 phases DNA replication occurs ______________. In prophase of both mitosis and meiosis In metaphase of meiosis only In the S phase of interphase in both somatic and reproductive cells In the cytokinesis portion of the cell’s life cycle At which point in the cell cycle do centrosomes begin to move apart to two poles of the cell in a dividing human liver cell? S phase Prophase Metaphase Anaphase One event occurring during prophase is ___________. The synthesis of a new nuclear envelope. Cytokinesis The beginning of the formation of a spindle apparatus Division of the centromere During anaphase of mitosis _________________. The centromeres divide The centrioles are at the opposite poles Identical chromatids move to opposite poles All of the above Which of the following represents a mismatch or incorrect description? Prophase: chromosomes become more tightly coiled Anaphase: there is movement of the chromosomes to the poles Metaphase: the nuclear envelope disappears Telophase: chromosomes become more extended In animal cell mitosis, the cleavage furrow forms during _______________. Anaphase G1 phase Cytokinesis prophase Which one of the following processes does NOT occur in dividing bacteria? Mitosis Replication of DNA Separation of the origins of replication Binary fission During binary fission in a bacterium ____________. The 2 DNA molecules divide in half to form 4 DNA fragments The origins of replication move apart The 2 DNA molecules attach to the centrioles The 2 DNA molecules break up into plasmids The function(s) of meiosis is (are) ______________. Decreases the chromosome number to haploid Introduce genetic variability into the daughter cells Ensure that each daughter cell get a single copy of each cell’s chromosomes All of the above Chromosomes of diploid organisms that are NOT involved in sex determination are called __________. Autosomes Mitotic chromosomes Heterochromosomes nucleosomes The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit? 22 11 44 132 What is the typical result when a diploid cell undergoes meiosis? 2 diploid cells 2 haploid cells 4 diploid cells 4 haploid cells A karyotype is _______________. The physical traits a person has A photograph of all a person’s chromosomes A list of all the genes a person carries All the possible gametes a person could produce Two chromosomes in a nucleus that carry genes for the same traits in the same loci, but specify different versions of the same traits, are called _____________. Chromatic chromosomes Sister chromatids Homologous chromosomes Differentiated chromosomes At the end of telophase I of meiosis and cytokinesis, there are _____________. 2 diploid cells 2 haploid cells 4 haploid cells 4 diploid cells Synapsis occurs during ______________. Prophase I Anaphase I Cytokinesis Prophase II During anaphase II ________________. Chromosomes line up in one plane Sister chromatids separate and migrate toward opposite poles Nuclei re-form Homologues separate and migrate toward opposite poles During anaphase I ________________. Homologues separate and migrate toward opposite poles Nuclei re-form Sister chromatids separate and migrate toward opposite poles The cell is haploid Regions of chromosomes where non-sister chromatids cross over are called ___________. Chiasmata Kinetochores Centromeres centrioles Which one of the following occurs in meiosis, but not mitosis? The cells formed have the same combination of genes as found in the initial cell Homologous chromosomes separate The nuclear envelope disappears A spindle apparatus forms Mitosis and meiosis differ in several ways. Meiosis, but not mitosis, _____________________. Changes the chromosome number of the daughter cells Results in 4 (rather than 2) daughter cells Involves 2 bouts of cell division Is correctly described by all of these statements Why is crossing over important? It prevents variation in gametes It is necessary for the attachment of chromosomes to the spindle It ensures that homologous chromosomes pair It allows the exchange of genes between homologous chromosomes Meiosis is more complicated than mitosis because it carries our more complicated functions. Meiosis must __________________. Undergo 2 rounds of cytokinesis Decrease the chromosome number to haploid Ensure that each daughter cell gets a complete set of chromosomes Introduce genetic variation among the daughter cells