Three barr bodies. Bio Chapter 15 B Flashcards 2022-12-11

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Barr bodies, also known as sex chromatin bodies, are small, dense structures that are found within the nucleus of female cells. These structures are made up of compacted DNA and proteins and are formed during the process of chromosomal inactivation.

There are three Barr bodies in female cells because females have two X chromosomes, while males have one X chromosome and one Y chromosome. During the development of female cells, one of the X chromosomes is randomly inactivated and becomes a Barr body. This process is necessary to ensure that females and males have the same number of active X chromosomes, which helps to maintain genetic balance.

The presence of Barr bodies can be detected through a cytogenetic technique called "Barr body counting." This technique involves staining cells with a special dye and examining them under a microscope. If three Barr bodies are present, it indicates that the cell is from a female individual. If only two Barr bodies are present, it may indicate that the individual is a male with a genetic disorder known as Klinefelter syndrome, which is characterized by the presence of extra X chromosomes.

Barr bodies have important implications for understanding genetic disorders and the role of X-chromosome inactivation in human development. They also provide insight into the evolution of sexual dimorphism and the mechanisms that have allowed for the development of different physical and behavioral traits in males and females.

Overall, Barr bodies are an important and fascinating aspect of genetic and cellular biology, and their study continues to yield important insights into the complex processes that shape human development and evolution.

The number of Barr body in XXXX female isA. 1B. 2C. 3D. 4

three barr bodies

D 4:3 male to female. E Three out of four. C The involved gene was on an autosome. C Recombination did not occur in the cell during meiosis. A The two genes are likely to be located on different chromosomes. At fertilization, meiosis II process commences and produces a secondary oocyte, the second polar body and third polar body. B All of the offspring have combinations of traits that match one of the two parents.

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bio ch.15 Flashcards

three barr bodies

Which is the most probable cause? The SRY gene is found on the Y chromosome. In which of the following groups would you expect this to be significantly higher? This is because the total number of Barr bodies is calculated as one less than the total number of X chromosomes. SRY is A a gene present on the Y chromosome that triggers male development. E reflect the frequency of crossing over between X and Y chromosomes. D an autosomal gene that is required for the expression of genes on the X chromosome.

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Number of Barr bodies in XXXXY is A) 1B) 2C) 3D) 4

three barr bodies

The nucleus has a double membrane called the nuclear envelope The nuclear lamina is also found within the nucleus, which is kind of a mesh network which adds support to the nucleus. Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome because A the frequency of crossing over varies along the length of the chromosome. C It may explain the transmission of Duchenne muscular dystrophy. Both males and females should have the same quantity of X-chromosome gene expression. B The gene involved is on the Y chromosome.


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Bio Chapter 15 B Flashcards

three barr bodies

D The gene order on the chromosomes is slightly different in every individual. The loss of Tsix expression on the future inactive X chromosome results in an increase in levels of Xist around the Xic. C It allowed scientists to see the DNA present within chromosomes. A An increase in non-disjunction. B Some abnormal gametes may be formed.

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Triple X syndrome

three barr bodies

A 2:1 male to female B 1:2 male to female C 1:1 male to female A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. A It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele. Barr body is an inactive chromosome while the polar body is a small haploid cell formed during oogenesis. D The entire Drosophila genome has approximately 400 map units. C An autosomal gene that is required for the expression of genes on the Y chromosome. The heterozygote is tortoiseshell. Centers for Disease Control and Prevention.

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Difference Between Barr Body and Polar Body

three barr bodies

B One member of the couple carried a translocation. B All will carry the same translocation as the father. What is Barr body in female? A 0% B 25% C 33% D 50% E 75% 44 A phenotypically normal prospective couple seeks genetic counseling because the man knows that he has a translocation of a portion of his chromosome 4 that has been exchanged with a portion of his chromosome 12. The X chromosome is shared by both men and females. If this is the case, the child has a mosaic form of triple X syndrome, and only some cells have the extra X chromosome. Errors such as translocations may place a gene in close proximity to different control regions. C Chromosomes were not distinguishable during interphase.

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Barr Body

three barr bodies

For example, people with Klinefelter syndrome 47,XXY karyotype have a single Barr body, and people with a 47, XXX karyotype have two Barr bodies. A space probe discovers a planet inhabited by creatures who reproduce with the same hereditary patterns seen in humans. D Other male-specific factors influence eye color in flies. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female? C two genes work together to control a specific characteristic. D Abnormal meiosis has occurred.

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How many Barr bodies will there be in an individual who is 47 XXY?

three barr bodies

National Center for Learning Disabilities. B All of the offspring have combinations of traits that match one of the two parents. D X chromosomes in males generally have more mutations than X chromosomes in females. So, their total number of Barr bodies is zero. E Other female-specific factors influence eye color in flies. E 3:1 male to female. E Both of the characters are controlled by more than one gene What does a frequency of recombination of 50% indicate? D There will be three extra gametes.

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