नमस्कार विद्यार्थी मित्रांनो To examine the presence or absence of Barr body in the given sample हे प्रॅक्टिकल Experiments to be performed - PART A मधील आहे. याचाच अर्थ तुम्हाला हे प्रॅक्टिकल Exam मध्ये Examiner ला Performe करून दाखवायचे आहे. म्हणूनच प्रॅक्टिकल Exam च्या दृष्टीने हे Experiment अतिशय महत्त्वाचे आहे. या ब्लॉग मध्ये आपण Practical Book मधील या Experiment Number - 12 ची उत्तरे पाहणारं आहोत. ही उत्तरे काळजीपूर्वक वाचून आपल्या Practical Book मध्ये लिहा किंवा तुमच्या कॉलेजमधील संबंधित विषय शिक्षकांची मदत घ्या.
12. To examine the presence or absence of Barr body in the given sample.
Aim :- To observe Barr bodies in squamous epithelial cells obtained from the inner lining of the cheek (Buccal smear).
Requirements :- Cotton buds, slide, saline solution, 70% alcohol, Giemsa/Methylene blue stain, compound microscope, etc.
Procedure :-
1. Clean the mouth by rinsing and gargling with water, several times.
2. Take a sterile cotton bud and dip it in a normal saline solution.
3. Rub it on the inner lining of the cheek several times.
4. Smear the bud on a clean slide and allow it to dry.
5. Place the slide in a petridish. Layer it with a fixative (70% alcohol).
6. Allow it to stand for a few minutes.
7. Drain off the extra fixative.
8. Stain the smear with Giemsa / Methylene Blue and wait for 10 minutes.
9. With the help of a dropper gently wash off the excess stain with water.
10. Place a coverslip and observe first under low power and then under high power of the microscope.
Observation :-
1. Barr body is seen attached on the inner side of the nuclear membrane of the cell.
2. A Barr body (named after its discoverer Dr. Murray Barr) is the condensed, inactive X chromosome found in the female somatic cell. The chromatin body is made inactive by a process called lyonization.
3. The number of Barr bodies seen in a cell is one less than the number of X chromosome in the somatic cell. Hence only one barr body is seen in the cell of a normal female and never in the cell of a normal male.
Result :-
In female 1/In male 0 number of Barr body is seen in the slide.
Figure :-
Questions
1. What is a 'Barr body'?
Ans :- A Barr body is a small, densely staining structure in the cell nucleus of females, consisting of an inactive X chromosome. It is considered a marker of genetic femaleness.
2. Which stain is used for staining of Barr body?
Ans :- The stains commonly used for staining a Barr body are Giemsa or Methylene blue.
3. How many Barr bodies occur in a normal somatic cell of the human female?
Ans :- In normal somatic cells of a human female, there is typically one Barr body.
4. How many Barr bodies can be seen in Turner's female?
Ans :- In Turner's syndrome females, no Barr bodies are present.
5. will there be a Barr body in male with Klinefelter's syndrome?
Ans :- In males with Klinefelter syndrome, there is typically one Barr body present.
6. A child suffering from Down's syndrome has 47 chromosomes? How many barr bodies can be seen in the cell of a female with Down's syndrome child?
Ans :- In a female with Down syndrome, who has 47 chromosomes, there would typically be one Barr body present.
Multiple Choice Questions
1. Barr body is...
a. Inactive X - chromosome
b. Inactive Y - chromosome
c. Active X - chromosome
d. Active Y - chromosome
Ans :- a. Inactive X - chromosome
2. The number of Barr body seen in a cell is...
a. One more than the number of X - chromosome
b. One less than the number of X - chromosome
c. One more than the number of Y - chromosome
d. One more than the number of Y - chromosome
Ans :- b. One less than the number of X - chromosome
3. How many Barr bodies are seen in the somatic cell of an individual suffering from the Turner's syndrome?
a. 1
b. 2
c. 3
d. 0
Ans :- d. 0
4. Barr body is found in...
a. Somatic cell in normal male
b. Somatic cell in normal women
c. Germinal cells in women
d. Man with Down's syndrome
Ans :- b. Somatic cell in normal women
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