Alterations in gene number may occur in various ways. Which of the folowing best describes a situation where gene number may be altered? Multiple Choice Crossing over during prophase is followed by metaphase and then homologous chromosome segregation during anaphase I. Metaphase Il is followed by sister chromatid segregation at anaphase Il without nondisjunction. Chromosomes undergo nondisjunction during either anaphase I or anaphase II. Because the mammalian X and Y chromosomes are non-homologous there is no crossing over between this pair.

Alterations in gene number may occur in various ways. Which of the folowing best describes a situation where gene number may be altered? Multiple Choice Crossing over during prophase is followed by metaphase and then homologous chromosome segregation during anaphase I. Metaphase Il is followed by sister chromatid segregation at anaphase Il without nondisjunction. Chromosomes undergo nondisjunction during either anaphase I or anaphase II. Because the mammalian X and Y chromosomes are non-homologous there is no crossing over between this pair.

Human Biology (MindTap Course List)

11th Edition

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cecie Starr, Beverly McMillan

Chapter20: Chromosomes And Human Genetics

Section: Chapter Questions

Problem 3CT: People with Down syndrome have an extra copy of chromosome 21, for a total of 47 chromosomes....

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crossing over within a pericentric inversion produces chromosomes that have extra copies of some genes and no copies of other genes. The fertilization of gametes containing chromosomes with duplications or deletions often result in children with syndromes characterized by developmental delay, intellectual disability, abnormal development of organ systems, and early death. Maarit Jaarola and colleagues examined individual sperm cells of a male who was heterozygous for a pericentric inversion on chromosome 8 and determined that crossing over took place within the pericentric inversion in 26% of the meiotic divisions (M. Jaarola, R. H. Martin, and T. Ashley. 1998. American Journal of Human Genetics 63:218–224). Assume that you are a genetic counselor and that a couple seeks counseling from you. Both the man and the woman are phenotypically normal, but the woman is heterozygous for a pericentric inversion on chromosome 8. The man is karyotypically normal. What is the probability that this…
Consider the following "pericentric" ("around the center") inversion. In one an individual, a simplified 8-gene sequence along one chromosome is 1234 5678 while a pericentric inversion occurred on their other homologous chromosome, resulting in the sequence 1265 4378 (the dot represents the centromere). Draw these homologous chromosomes lined up (as during crossing over, in Prophase l). If a crossover event occurred between gene locus 3 and 4 (slicing between them) on the original chromosome, what would the crossover products look like? What would be the "problem" with each of the chromosomes that result?
What structures are found in a chromosome? Group of answer choices Two structures for the mitotic spindle to bind, and two complex repetitive structures that are maintained by telomerase One structure for the mitotic spindle to bind, and two complex repetitive structures that are maintained by telomerase One structure for the mitotic spindle to bind, and one complex repetitive structure that is maintained by telomerase Two structures for the mitotic spindle to bind, and one complex repetitive structure that is maintained by telomerase.
Why do eukaryotic cells need to go through the elaborate procedure of mitosis rather than simply dividing during interphase? Select as many answers as apply. 1.Daughter cells must be genetically identical to the mother cell, for homeostasis and ordered tissue growth. 2.Bivalent chromosomes must condense and be separated in an orderly fashion, to allow equal distribution of copies into daughter cells 3.Physically dividing the nucleus during interphase would likely lead to gross chromosome breakage and highly unequal assortment of genetic information into daughter cells. 4.Dividing the nucleus during interphase would have the same outcome as mitosis 5.Daughter cells must have half the number of chromosomes after mitosis than the mother cells 6.The homologous pairs of chromosomes need to be separated, to ensure copies go to the daughter cells.
Two nonhomologous chromosomes have the following segments, where * represents the centromere: *ABCDEFG , *RSTUVWX. Name the type of chromosomal rearrangements that would produce each of the following chromosomes. *ABABCDEFG , *ABCD , GFEDCBA*RSTUVWX , *RSWVUTX , *ABCWX , *RSTUVDEFG . Which of these types of abnormalities are most likely embryonic lethal and which ones are not usually a problem for the individual carrying them? Briefly explain why.
___________ chromosome aneuploidy is usually welltolerated because only one X chromosomeremains active and because the Y chromosomehas few genes
A cell has two pairs of submetacentric chromosomes, which we will call chromosomes Ia, Ib, IIa, and IIb (chromosomes Ia and Ib are homologs, and chromosomes IIa and IIb are homologs). Allele M is located on the long arm of chromosome Ia, and allele m is located at the same position on chromosome Ib. Allele P is located on the short arm of chromosome Ia, and allele p is located at the same position on chromosome Ib. Allele R is located on chromosome IIa and allele r is located at the same position on chromosome IIb.a. Draw these chromosomes, identifying genes M, m, P, p, R, and r, as they might appear in metaphase I of meiosis. Assume that there is no crossing over.b. Taking into consideration the random separation of chromosomes in anaphase I, draw the chromosomes (with genes identified) present in all possible types of gametes that might result from this cell’s undergoing meiosis. Assume that there is no crossing over.
describe the folded fiber model of the mitotic chromosome the folded fiber model is based on each_____ consisting of single fiber wound like a skein of yarn. Each fiber consists of ___-. A cloning process occurs during the transition of _____ chromatin into more condensed chromosomes during ____ of mitosis or meiosis. Such condensation leads to 5000 folded ____ in the length of the DNA. The transition is at the end of ______ and in the beginning of ____ when the chromosomes are in the condensation process. This eventually leads to typically short and fat and chromosome. interphase, RNA and protein, prophase, protein, DNA and protein, couple of fibers, contraction, extension, chromatid, metaphase
In which stage(s) of the cell cycle, mitosis or meiosis do each of these processes occur (multiple stages apply to some) Crossing-over: Chromosome supercoiling: Separation of sister chromatids: DNA synthesis: Chromosome reduction from 2N to N: 4. A previously undiscovered single celled organism was found living at a great depth on the ocean floor. Its nucleus contains only a single, linear chromosome consisting of 7x10^6 nucleotide pairs of DNA coalesced with three types of histone-like proteins. The analysis of individual nucleosomes revealed that each unit contained one copy of each protein and that the short linker DNA had no protein bound to it If the entire chromosome consists of nucleosomes (discounting any linker DNA), how many are there and how many total proteins are needed to form them?
A phenotypically abnormal individual has a phenotypically normalfather with an inversion on one copy of chromosome 7 and a phenotypicallynormal mother without any changes in chromosomestructure. The orders of genes along the two copies of chromosome7 in the father are as follows: R T D M centromere P U X Z C (normal chromosome 7)R T D U P centromere M X Z C (inverted chromosome 7) The phenotypically abnormal offspring has a chromosome 7 withthe following order of genes: R T D M centromere P U D T R Using a sketch, explain how this chromosome was formed. In youranswer, explain where the crossover occurred (i.e., between whichtwo genes).
What type of chromosome or fragment cannot be formed by the following chromosome inversion heterozygote after segregation?
Consider the example of the fusion of chromosome 21 and 14. By itself, this fusion does not cause any phenotypic differences in the carrier individuals. However, the children of carriers have a very high rate of down syndrome, as well as low fertility. Explain why this is? Be specific about what differences in chromosome number may occur in offspring, and how this occurs. Please answer asap and in short and content should not be palgarised please answer asap Consider the example of the fusion of chromosome 21 and 14. By itself, this fusion does not cause any phenotypic differences in the carrier individuals. However, the children of carriers have a very high rate of down syndrome, as well as low fertility. Explain why this is? Be specific about what differences in chromosome number may occur in offspring, and how this occurs.