Genetics

Question 1

What is a Barr body?

Answer 1

A Barr body is an inactivated X chromosome present in female somatic cells.

Question 2

Where is the Barr body located in a cell?

Answer 2

It is found attached to the inner nuclear membrane.

Question 3

Which staining technique helps visualize Barr bodies?

Answer 3

Barr bodies can be seen using Feulgen staining.

Question 4

What is the significance of Barr bodies in sex determination?

Answer 4

Barr body presence confirms a female karyotype (46,XX).

Question 5

Which anatomical structure contains cells that show Barr bodies?

Answer 5

Buccal mucosal cells and epithelial cells of females.

Question 6

How many Barr bodies are present in Turner syndrome (45,X)?

Answer 6

None (since only one X chromosome is present).

Question 7

How many Barr bodies are present in Klinefelter syndrome (47,XXY)?

Answer 7

One (since one X chromosome is inactivated).

Question 8

What is the structure of a chromosome?

Answer 8

A chromosome consists of two sister chromatids joined by a centromere.

Question 9

What are the types of chromosomes based on centromere position?

Answer 9

Metacentric, Submetacentric, Acrocentric, and Telocentric.

Question 10

Which chromosome type is not found in humans?

Answer 10

Telocentric chromosomes.

Question 11

Which chromosome type has equal arms?

Answer 11

Metacentric chromosomes.

Question 12

Which chromosome type has a very short p-arm?

Answer 12

Acrocentric chromosomes.

Question 13

Name an example of an acrocentric chromosome in humans.

Answer 13

Chromosomes 13, 14, 15, 21, and 22.

Question 14

Which organ is commonly used for karyotyping in a live patient?

Answer 14

Peripheral blood (lymphocytes).

Question 15

At which stage of the cell cycle is karyotyping performed?

Answer 15

Metaphase.

Question 16

Which staining technique is commonly used for karyotyping?

Answer 16

Giemsa staining (G-banding).

Question 17

Which inheritance pattern involves both parents being carriers but not affected?

Answer 17

Autosomal recessive.

Question 18

Which inheritance pattern is seen in father-to-son transmission?

Answer 18

Y-linked inheritance.

Question 19

Which inheritance pattern is common in structural protein mutations?

Answer 19

Autosomal dominant.

Question 20

Which type of inheritance is always passed from the mother?

Answer 20

Mitochondrial inheritance.

Question 21

What is a structural abnormality of chromosomes involving the exchange of genetic material?

Answer 21

Translocation.

Question 22

What is the most common translocation seen in karyotyping studies?

Answer 22

Robertsonian translocation.

Question 23

Which part of the chromosome is crucial for its attachment to spindle fibers?

Answer 23

Centromere.

Question 24

What are the non-coding DNA sequences at the chromosome ends?

Answer 24

Telomeres.

Question 25

What happens if telomeres become too short?

Answer 25

The cell undergoes senescence or apoptosis.

Question 26

What is Klinefelter syndrome?

Answer 26

A genetic disorder where males have an extra X chromosome (47,XXY).

Question 27

What is the anatomical feature commonly seen in Klinefelter syndrome?

Answer 27

Small testes with infertility.

Question 28

Which hormone is typically reduced in Klinefelter syndrome?

Answer 28

Testosterone.

Question 29

What is the typical karyotype of a male with Klinefelter syndrome?

Answer 29

47,XXY.

Question 30

What are the common skeletal features in Klinefelter syndrome?

Answer 30

Long limbs and tall stature.

Question 31

Which part of the body is commonly affected by hypogonadism in Klinefelter syndrome?

Answer 31

Testes.