In eukaryotic cells, chromosomes are composed of ____. A) DNA and RNA B) DNA onl
ID: 102334 • Letter: I
Question
In eukaryotic cells, chromosomes are composed of ____. A) DNA and RNA B) DNA only C) DNA and proteins D) DNA and phospholipids If there are 20 duplicated chromosomes in a cell, how many centromeres are there? A) 10 B) 20 C) 30 D) 40 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 density-dependent. B) Cancer cells are no longer anchorage-dependent. C) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities. D) Transformation introduces new chromosomes into cells. The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in _____. A) telophase B) prophase C) prometaphase D) metaphase Neurons and some other specialized cells divide infrequently because they ____. A) no longer have active nuclei B) have entered into G_0 C) can no longer bind Cdk to cyclin D) show a drop in MPF concentration Which of the following does NOT occur during mitosis? A) condensation of the chromosomes B) replication of the DNA C) spindle formation D) separation of the spindle poles Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ____. A) an animal cell in the process of cytokinesis B) a plant cell in the process of cytokinesis C) an animal cell in the S phase of the cell cycle D) a plant cell in metaphase Several organisms, primarily protists such as diatoms, have what are called intermediate mitotic organization. These protists are intermediate in what sense? A) They reproduce by binary fission in their early development and by mitosis when they are mature. B) They use mitotic division but only have circular chromosomes. C) They maintain a nuclear envelope during division. D) None of them form spindles What is the most probable hypothesis about these intermediate forms of cell division? They represent a form of cell reproduction, which must have evolved completely separately from those of other organisms. B) They rely on totally different proteins for the processes they undergo. C) They may be more closely related to plant forms that also have unusual mitosis. D) They show some but not all of the evolutionary steps toward complete mitosisExplanation / Answer
1. Eukaryotic cells contain only DNA not RNA.prokaryotic cell may contain DNA or RNA.
So the right answer is option (b) DNA only.
2.there is no duplication of centromere occur in chromosome duplication before anaphase.before that two copies are attached to each other at the centromere.during anaphase the centromere devides
So the right answer is option (b) 20
3. In malignant tumor there is mutations in genes. These mutaion enable them to skip the cell cycle check points as a results there is uncontrolled cell division and growth resulting tumors.
So the righr option is (c)
4.the answer should b (D) because in this phase there is attachment of spundle fibre to centromere.
5.have entered Go. so right option is (B)
6.(B)replication of DNA which occurs in s phase
7. (B) plant cell present a sell plate before cell divide into two.
Cell plate formation only occur in plants.