BIOL 303 Study Guide - Midterm Guide: Xist (Gene), Chromosomal Inversion, X-Inactivation

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tangerbil959

18 Mar 2017

School

USC, SC, Carolina, South Carolina

Department

Biological Sciences

Course

BIOL 303

Professor

Waldman

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Document Summary

Genetics exam 2 study guide answer key: the female is the homogametic sex. Females have 2 x chromosomes so their chromosomes do not determine the sex of the progeny. The males are the hete(cid:396)oga(cid:373)eti(cid:272) se(cid:454) (cid:271)e(cid:272)ause the(cid:455) ha(cid:448)e the (cid:862)u(cid:374)like(cid:863: the y chromosome designates maleness in humans. Three genes on the y chromosome are the sry gene, the par gene or region, and the msy region. It is the sex-determining region of the chromosome. The par or pseudoautosomal region is where the x and y pair in meiosis. The msy region is the male-specific region of the chromosome. It makes up the majority of the y chromosome: dosage compensation is the process that equalizes the expression of the x and y chromosomes. It prevents over expression of x. barr bodies are inactivated x chromosomes that are inactivated as a part of dosage compensation. They are only associated with females: the lyon hypothesis explains x inactivation.

Related Questions

11) CIRCLE ALL CORRECT ANSWERS: Human males are hemizygous for

a) Sxl gene b) pseudoautosomal region of the Y c)SRY d) gene for testis determining factor e) Xist gene

12) The X inactivation center codes for

a) gonadal ridges to form ovaries b) gonadal ridges to form testes c) RNA d) testosterone e) protein enhancing transcription of sex linked genes

13) CIRCLE ALL CORRECT ANSWERS: The pseudoautosomal region is found on

a) autosomes in males b) autosomes in females c) X chromosome d) Y chromosome e) both the X and Y chromosome f) could occur in fruit flies

14) Comparing two monozygotic XX twins to two monozygotic XY twins

a) XX are more identical b) XY are more identical c) monozygotic twins do not occur

EXPLAIN YOUR ANSWER:

15) CIRCLE ALL CORRECT ANSWERS: Butterflies and Habrobracon differ in

a) which sex is homogametic b) which sex is monoploid c) one has sex chromosomes and the other does not d) one produces some gametes by mitosis, the other does not

I need help correcting the paragraph below (filling in the bold words- using the answer choices given at the bottom):

The explanation of the male tortoiseshell cat has two components: one is that it is tortoiseshell, and the other is that it is a male. The former is explained by the fact that the cat has both an X and a Y chromosome and is hemizygous at a fur color locus on the X-chromosome. Because of the X-chromosome-inactivation mechanism of dosage compensation in mammals, one of these chromosomes is randomly chosen for inactivation early in development in a cell-independent manner. Thus the animal is mosaic forSRY gene expression, resulting in expression of one X-linked fur-color allele in some cells and the other in other cells. The second component, that the cat is male, is explained by the fact the cat has both an X and a Y chromosome , which contain(s) the SRY which determines male sexual development. Thus, the XXY cat is a male that is mosaic for X-linked gene expression, resulting in a male tortoiseshell cat.

Answer choices: (used onece, more than once, or not at all) has two X chromosomes, has a Y chromosome, has both an X and a Y chromosome, hemizygous, homozygous, heterozygous, Y-chromosome, X-chromosome, X and the Y chromosomes, dosage compensation, gene compensation, allele compensation, early in development, late in development, cell-independent, cell-autonomous, cell-interdependent, autosomal, Y-linked, X-linked, testosterone gene, PAR, SRY

The explanation of the male tortoiseshell cat has two components: one is that it is tortoiseshell, and the other is that it is a male. The former is explained by the fact that the cat------and is--------at a fur color locus on the-------- . Because of the -inactivation mechanism of---------------in mammals, one of these chromosomes is randomly chosen for inactivation------- in a-------manner. Thus the animal is mosaic for---------gene expression, resulting in expression of one-----------fur-color allele in some cells and the other in other cells. The second component, that the cat is male, is explained by the fact the cat-----------, which contain(s) the which determines male sexual development. Thus, the XXY cat is a male that is mosaic for----------gene expression, resulting in a male tortoiseshell cat.

has two X chromosomes

has a Y chromosome

has both an X and a Y chromosome

hemizygous

homozygous

heterozygous

Y-chromosome

X-chromosome

X and the Y chromosomes

dosage compensation

gene compensation

allele compensation

early in development

late in development

cell-independent

cell-autonomous

cell-interdependent

autosomal

Y-linked

X-linked

testosterone gene

PAR

SRY

BIOL 303 Study Guide - Midterm Guide: Xist (Gene), Chromosomal Inversion, X-Inactivation

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