1 What is a chromatid? a special region that holds two centromeres together a chromosome found outside the nucleus a chromosome in G1 of the cell cycle a replicated chromosome another name for the chomosomes found in genetics 2 What is the name for a special region on a duplicated chromosome that holds the sister chromatids together? centromere centrosome kinetichore desmosome microtubule organizer region 3 This is the longest of the mitotic stages interphase prophase 4 entromeres uncouple, sister chromatids are separated, and two new chromosomes move to opposite poles of the cell during this phase pro prophase 5 If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested (stopped)? prophase interphase 11/17/09 3:07:21 PM Page 1 of 6
6 ll of the following occur during prophase of mitosis in animal cells XPT the centrioles move towards opposite poles chromosomes are duplicated the nuclear envelope disappears the nucleolus can no longer be seen the spindle is organized 7 If there are 40 chromatids in a cell at, how many chromosomes are there in each daughter cell following cytokinesis? 20 40 10 80 60 8 ytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with a single large nucleus high concetrations of actin and myosin two nuclei but with half the amount of N two abnormally small nuclei two nuclei 9 Regarding mitosis and cytokinesis, one di!erence between higher plants and animals is that in plants the spindles contain microfibrils and microtubules, whereas animal cells do not contain microfibrils sister chromatids are identical, but they di!er from one another in animals chromosomes are attached to the spindle at prophase, whereas in animal cells they attach at a cell plate beings to form at, whereas animal cells have a cleavage furrow initiated at that stage. spindle poles contain centrioles, wehreas spindle poles in animals do not. 10 hromosomes first become visable during of mitosis. prophase pro 11/17/09 3:07:21 PM Page 2 of 6
11 ells that are in a nondividing state are in which phase? S G1 G2 G0 M 12 The correct sequence of steps in the M phase of the cell cycle is,,, prophase, pro pro, prophase,,, prophase, pro,,,, prophase,,, pro,,, prophase, pro 13 Which of the following is true concerning cancer cells? They do not exhibit density-dependent inhibition when growing in culture They are not subject to cell cycle controls When they stop dividing, they do so at random points in the cell cycle and only,, and 14 sexual reproduction and sexual reproduction are di!erent in that asexual reproducers produces genetically identical o!spring, while sexual reproducers produces genetically distinct o!spring asexual reproducers transmit 100% of their genes to o!spring, whereas sexual reproducers only transmit 50% asexual reproduction involves a single parent, whereas sexual reproduction involves two asexual reproduction only requires mitosis, whereas sexual reproduction always involves meiosis all of the above 15 What is a karyotype? 11/17/09 3:07:21 PM Page 3 of 6
a display of every pair of homologous chromosomes within a cell, organized according to size and shape the set of unique characteristics that define an individual a unique combination of chromosomes found in a gamete a system of classifying cell nuclei a collection of all the mutations present within a genome 16 The human X and Y chromosomes are both present in every somatic cell of males and females alike called the "sex chromosomes" because they determine an individual's sex. of approximately equal size almost entirely homologous, despite their di!erent names. all of the above 17 If the liver cells of an animal have 24 chromosomes, how many chromosomes do its sperm cells have? 6 24 48 12 64 18 Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes an unfertilized egg cell a sperm cell a female somatic cell a male somatic cell both and 19 In animals, somatic cells are produced by mitosis, and are produced by meiosis. spores zygotes clones diploid cells gametes 11/17/09 3:07:21 PM Page 4 of 6
20 Which of the following happens at the conclusion of meiosis I? Sister chromatids are separated The chromosome number is conserved Homologous chromosomes are separated Four daughter cells are formed The sperm cells elongate to form a head and a tail end 21 Independant assortment of chromosomes is a result of the random and independent way in which each pair of homologous chromosomes lines up at the plate during meiosis I the random distribution of the sister chromatids to the two daughter cells during II the random nature of fertilization of ova by sperm the relatively small degree of homology shared by the X and Y chromosomes all of the above 22 Which of the following statements about crossing over is INORRT? rossing over combines sections of the maternal and paternal chromosomes There are on average one to three crossover events per chromosome rossing over plays a role in both sexual and asexual reproduction rossing over increases the genetic variation beyond what is possible through independent assortment alone rossing over results in recombinant chromosomes 11/17/09 3:07:21 PM Page 5 of 6
nswer Key: Mitosis and Meiosis Review Question Key 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 11/17/09 3:07:21 PM Page 6 of 6