1) What is the final result of mitosis in a human?A) genetically identical 1n somatic cells B) genetically identical 2n somatic cellsC) genetically identical 2n gamete cells D) genetically different 2n somatic cells
2) Some cells have several nuclei per cell. How could such multinucleated cells be explained?
A) The cell underwent repeated cytokinesis but no mitosis.B) The cell underwent repeated mitosis with simultaneous cytokinesis.C) The cell had multiple S phases before it entered mitosis.D) The cell underwent repeated mitosis, but cytokinesis did not occur.
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3) FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to _____.
A) the microtubule-organizing center of eukaryotic cellsB) the cleavage furrow of eukaryotic animal cellsC) the mitotic spindle of eukaryotic cellsD) the cell plate of eukaryotic plant cells
4) Movement of the chromosomes during anaphase would be most affected by a drug that prevents _____. A) nuclear envelope breakdown
B) shortening of microtubules
C) elongation of microtubules
D) formation of a cleavage furrow
Use the following information to answer the questions below.The unlettered circle at the top of the figure shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A to E show various combinations of these chromosomes.
5) What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis?
A) B B) C C) D D) E
6) In the figure above, G1 is represented by which numbered part(s) of the cycle?
A) I or V B) II or IV C) III only D) V only
Use the data in the accompanying table to answer the following questions.The data were obtained from a study of the length of time spent in each phase of the cell cycle by cells of three eukaryotic organisms designated beta, delta, and gamma.
Minutes Spent in Cell Cycle Phases
8) Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that ____.
A) gamma contains more DNA than betaB) beta is a plant cell and gamma is an animal cellC) beta and gamma contain the same amount of DNAD) beta cells reproduce asexually
Use the following information to answer the questions below.Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and, therefore, can be assayed to track their incorporation. In a set of experiments, a student—faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times.
9) The research team used their experiments to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that _____.
A) infection causes lymphocytes to divide more rapidlyB) infection causes lymphocyte cultures to skip some parts of the cell cycleC) infection causes cell cultures in general to reproduce more rapidlyD) the presence of the pathogen made the experiments too contaminated to trust the results
10) The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?
A) spindle attachment to kinetochoresB) cleavage furrow formation and cytokinesisC) spindle formationD) cell elongation during anaphase
11) Density-dependent inhibition is explained by which of the following?
A) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor.B) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.C) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.D) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors.
12) Exposure of zebrafish nuclei to meiotic cytosol resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?
A) They are involved in the disassembly and dispersal of the nucleolus.B) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere.C) They are involved in the disassembly of the nuclear envelope.D) They assist in the movement of the centrosomes to opposite sides of the nucleus.
13) Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
A) Cancer cells are no longer anchorage-dependent.B) Cancer cells are no longer density-dependent.C) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.D) Transformation introduces new chromosomes into cells.
14) Quaking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
A) 19 B) 38 C) 10 D) 9
15) Which of the following is true of a species that has a chromosome number of 2n = 16?
A) Each diploid cell has eight homologous pairs.B) The species is diploid with 32 chromosomes per cell.C) A gamete from this species has four chromosomes.D) The species has 16 sets of chromosomes per cell.
16) Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common?I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores
A) II, III, and IV
B) I, II, III, IV, and V
C) II, IV, and V
D) I, II, and IV
17) In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? A) length, centromere position, and staining pattern onlyB) length and position of the centromere onlyC) length, centromere position, staining pattern, and traits coded for by their genesD) They have nothing in common except that they are X-shaped.
18) How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? They have _____. A) the same number of chromosomes and half the amount of DNA.B) half the number of chromosomes and half the amount of DNA.C) half the amount of cytoplasm and twice the amount of DNA.D) half the number of chromosomes and one-fourth the amount of DNA.
19) If meiosis produces haploid cells, how is the diploid number restored for those organisms that spend most of their life cycle in the diploid state? A) fertilization B) DNA replication C) synapsis D) reverse transcription
Refer to the drawings in the figure below of a single pair of homologous chromosomes as they might appear during various stages of either mitosis or meiosis, and answer the following questions.
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20) Which diagram represents anaphase I of meiosis?
You have isolated DNA from three different cell types of the same organism, determined the relative DNA content for each type, and plotted the results on the graph shown in the figure below. Refer to the graph to answer the following question(s).
21) Which sample might represent an animal cell in the G2 phase of the cell cycle?