Chapter 15 BIO PLQ

25 July 2022
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question
A child was taken to the doctor for excessive bleeding. The mother feared her daughter had hemophilia, although no one else in the family had ever exhibited signs of the disease. In addition, her daughter exhibited slight intellectual impairments, unusually large (hammer) toes, odd facial features, low platelets, and poor hand-eye coordination. Upon examination of the child's karyotype, the doctor noticed that one copy of chromosome 11 was slightly shorter than the other. What conclusions can the doctor make? The daughter has hemophilia. The daughter will not survive to be an adult. The daughter inherited her hemophilia as a sex-linked trait, so it never manifested itself before. The daughter has a chromosomal deletion that was probably inherited from one of her parents. The daughter has a chromosomal deletion that was probably the result of a germ-line mutation in one of her parents gametes.
answer
The daughter has a chromosomal deletion that was probably the result of a germ-line mutation in one of her parents gametes
question
Which of the following mutations will NOT alter the amount of genetic material of a chromosome? deficiency inversion and simple translocation duplication simple translocation inversion
answer
Inversion
question
During crossing over in meiosis, an unequal exchange of genetic material occurs. This would most likely produce a deficiency in one homologue and a duplication in the other homologue. a duplication in one homologue and an inversion in the other homologue. a deficiency in one homologue and an inversion in the other homologue. a reciprocal translocation. a deficiency in both homologues.
answer
A deficiency in one homologue and a duplication in the other homologue.
question
Which of the following statements about sister chromatids is TRUE? Sister chromatids are exact copies of each other and are formed just prior to cell division. After mitosis, sister chromatids contain the same genes, but they may have different alleles. Sister chromatids are produced during mitosis. All of these statements about sister chromatids are TRUE. Sister chromatids are held together by complementary base pairing of DNA at the centromere.
answer
Sister chromatids are exact copies of each other just prior to cell division.
question
Place the following events of mitosis in the correct order. I. Sister chromatids align on the metaphase plate. II. The cleavage furrow forms. III. The nuclear membrane breaks up. IV. Sister chromatids condense. V. Sister chromatids separate. -I, II, III, IV, V -IV, III, I, V, II -III, II, I, IV, V -III, IV, I, V, II -IV, I, III, V, II
answer
IV, III, I, V, II
question
Meiosis I produces ________, and meiosis II produces _________ cells. two haploid, 4 haploid two diploid, two haploid two haploid, two haploid two somatic, two gametic two diploid, 4 haploid
answer
two haploid, 4 haploid
question
Why are sex chromosome aneuploidies less detrimental than autosomal aneuploidies? In females, all but one X-chromosome is inactivated; in males, the Y chromosome contains very few genes, so extra or missing copies do not cause huge abnormalities. Gene expression of the sex chromosomes is not dosage-dependent as it is for the autosomes. All of these are TRUE. Sex chromosomes do not contain genes that are important for anything other than sex determination. Sex chromosomes are only found in gametes, they do not occur in diploid cells.
answer
In females, all but one X-chromosome is inactivated, in males, the Y chromosome contains very few genes, so extra or missing copies do not cause huge abnormalities.
question
Mitosis results in the formation of two genetically identical daughter cells. This is because the chromosomes pair up (synapse) in prophase as a counting mechanism. the number of chromosomes needs to be reduced before cytokinesis. daughter cells are initially haploid, but they duplicate their chromosomes to become diploid again. after replication, the material is compared and corrected to be identical. all the genetic material is duplicated then segregated equally to the daughter cells.
answer
All the genetic material is duplicated then segregated equally to the daughter cells.
question
Why must the life cycle of sexually reproducing species alternate between haploid and diploid stages? -Haploid cells cannot grow independently of diploid cells. -Meiosis must occur at some point in the life cycle to prevent a reduction of chromosomes in each generation. -Mitosis must occur at some point in the life cycle to prevent a reduction of chromosomes in each generation. -Meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation. -The diploid stage allows for genetic recombination.
answer
Meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation.
question
At the end of meiosis I -the cells are diploid and the homologous pairs are in separate cells. -the cells are haploid and the homologous pairs are in separate cells. -cells are haploid. -the homologous pairs are in separate cells. -cells are diploid.
answer
The cells are haploid and the homologous pairs are in separate cells.
question
The first division of meiosis is called a reduction division. This is because -the chromosomes are much more highly condensed than in mitosis. -the mother cell is diploid, but the products of the first division are haploid. -the products of the first division are diploid but then they discard some chromosomes. -the purpose of meiosis is to divide into four smaller cells. -the number of chromosomes per cell stays the same after the first division.
answer
The mother cell is diploid, but the products of the first division are haploid.
question
Which of the following is NOT a true difference between mitosis and meiosis? During telophase of meiosis I, daughter nuclei are haploid; during telophase of mitosis, daughter nuclei are diploid. During anaphase I of meiosis, homologous chromosomes are separated; during anaphase of mitosis, sister chromatids are separated from each other. As a result of mitosis, daughter cells are identical to each other; as a result of meiosis, daughter cells are genetically different from each other. During prophase of mitosis, chromosomes are condensing; during prophase II of meiosis, chromosomes are already condensed from meiosis I. During cytokinesis associated with meiosis II, four daughter cells are produced; during cytokinesis associated with mitosis, two daughter cells are produced.
answer
During prophase of mitosis, chromosomes are condensing; during prophase II of meiosis, chromosomes are already condensed from meiosis I
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The process by which haploid cells are produced from diploid cells is called reduction. mitosis. fertilization. sexual reproduction. meiosis.
answer
meiosis
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Which of the following statements about the cell cycle is correct? In actively dividing cells, the S and G2 phases are collectively known as interphase. The phases of the cell cycle are G1, S, and M phases. When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase. The cell cycle is a sequence of replications and divisions that produces a new cells. During G2 phase, the cell grows and copies its chromosomes in preparation for cell division.
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When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase.
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During interphase, a eukaryotic cell would be expected to ______ replicate its DNA and prepare for mitosis. grow, replicate its DNA, and prepare for mitosis. replicate its DNA. grow in size. grow and replicate its DNA.
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Grow, replicate its DNA, and prepare for mitosis.
question
Which of the following occurs during metaphase? the "beads on a string" structure is visible. chromosomes are much shorter than they were in interphase. heterochromatin is converted to euchromatin. chromosomes undergo gene transcription. chromosomes are about 30 nm wide.
answer
chromosomes are much shorter than they were in interphase.
question
Colchicine is a toxin that binds to tubulin proteins and prevents microtubules from elongating. What effect might this have on dividing cells? Cells will be able to complete mitosis, but cytokinesis will not occur. The cell will not be able to move past the restriction point, so DNA will not be replicated. Replicated chromosomes will not be able to stick together, so sister chromatids will not properly sort into daughter nuclei. Sister chromatids will not be properly separated into separate daughter cells. Chromosomes will not be able to condense, so mitosis will not occur.
answer
Sister chromatids will not be properly separated into separate daughter cells.
question
The formation of the bivalent during meiosis aids the alignment of sister chromatids in a single row along the metaphase plate. occurs during meiosis I and meiosis II. ensures that the resulting haploid cells will have the same combination of homologous chromosomes as the original diploid cell. contributes to the genetic diversity of a species. is required for the pairing of homologous chromosomes.
answer
Contributes to the genetic diversity of a species.
question
When a gamete that is lacking a sex chromosome due to nondisjunction has fused with a gamete carrying an X chromosome, this type of abnormality leads to ________. Triple X syndrome Klinefelter Syndrome Edward Syndrome Down Syndrome Turner syndrome
answer
Turner syndrome