Genetics Flashcards
What is a Barr body?
A Barr body is an inactivated X chromosome present in female somatic cells.
Where is the Barr body located in a cell?
It is found attached to the inner nuclear membrane.
Which staining technique helps visualize Barr bodies?
Barr bodies can be seen using Feulgen staining.
What is the significance of Barr bodies in sex determination?
Barr body presence confirms a female karyotype (46,XX).
Which anatomical structure contains cells that show Barr bodies?
Buccal mucosal cells and epithelial cells of females.
How many Barr bodies are present in Turner syndrome (45,X)?
None (since only one X chromosome is present).
How many Barr bodies are present in Klinefelter syndrome (47,XXY)?
One (since one X chromosome is inactivated).
What is the structure of a chromosome?
A chromosome consists of two sister chromatids joined by a centromere.
What are the types of chromosomes based on centromere position?
Metacentric, Submetacentric, Acrocentric, and Telocentric.
Which chromosome type is not found in humans?
Telocentric chromosomes.
Which chromosome type has equal arms?
Metacentric chromosomes.
Which chromosome type has a very short p-arm?
Acrocentric chromosomes.
Name an example of an acrocentric chromosome in humans.
Chromosomes 13, 14, 15, 21, and 22.
Which organ is commonly used for karyotyping in a live patient?
Peripheral blood (lymphocytes).
At which stage of the cell cycle is karyotyping performed?
Metaphase.
Which staining technique is commonly used for karyotyping?
Giemsa staining (G-banding).
Which inheritance pattern involves both parents being carriers but not affected?
Autosomal recessive.
Which inheritance pattern is seen in father-to-son transmission?
Y-linked inheritance.
Which inheritance pattern is common in structural protein mutations?
Autosomal dominant.
Which type of inheritance is always passed from the mother?
Mitochondrial inheritance.
What is a structural abnormality of chromosomes involving the exchange of genetic material?
Translocation.
What is the most common translocation seen in karyotyping studies?
Robertsonian translocation.
Which part of the chromosome is crucial for its attachment to spindle fibers?
Centromere.
What are the non-coding DNA sequences at the chromosome ends?
Telomeres.
What happens if telomeres become too short?
The cell undergoes senescence or apoptosis.
What is Klinefelter syndrome?
A genetic disorder where males have an extra X chromosome (47,XXY).
What is the anatomical feature commonly seen in Klinefelter syndrome?
Small testes with infertility.
Which hormone is typically reduced in Klinefelter syndrome?
Testosterone.
What is the typical karyotype of a male with Klinefelter syndrome?
47,XXY.
What are the common skeletal features in Klinefelter syndrome?
Long limbs and tall stature.
Which part of the body is commonly affected by hypogonadism in Klinefelter syndrome?
Testes.
