Answer
396.9k+ views
Hint: In identifying a chromosome from a set, secondary constrictions are useful. A knob-like structure at the top, called a satellite chromosome (SAT chromosome), is formed due to secondary constriction. DNA is called rDNA in a secondary constriction which forms rRNA. SAT chromosomes (13,14,15,21,22) contain NORs.
Complete answer:
In both chromosomes, primary constriction is present. But in all chromosomes, secondary constriction is not present. Secondary constriction is also known as the area of the nucleolar organiser since NOR is involved in the nucleolus creation.
In addition to primary constriction / centromere, secondary constriction may be observed on a chromosome. During Anaphase, chromosomes can bend only at the site of primary constriction. In identifying a chromosome from a set, secondary constrictions are useful. In a cell at anaphase, there are either 0, 1 , 2, 3, or 4 secondary constriction sites. "Many parts of these constrictions imply the development of nucleolus sites and are known as" nucleolar organising areas. The nucleolus is the nucleus connected to the NOR zone of the secondary constriction field. The number of NORs in humans is equal to the number of nucleoli. The number of NORs in humans is 10. NOR occurs (13,14,15,21,22) in SAT (satellite chromosome) chromosomes.
Hence, option D: 5 is the correct answer.
Note: Each cell usually contains 23 pairs of chromosomes in human beings, for a total of 46. In both males and females, 22 of these pairs, called autosomes, look the same. The 23rd pair varies between males and females, the sex chromosomes.
Complete answer:
In both chromosomes, primary constriction is present. But in all chromosomes, secondary constriction is not present. Secondary constriction is also known as the area of the nucleolar organiser since NOR is involved in the nucleolus creation.
In addition to primary constriction / centromere, secondary constriction may be observed on a chromosome. During Anaphase, chromosomes can bend only at the site of primary constriction. In identifying a chromosome from a set, secondary constrictions are useful. In a cell at anaphase, there are either 0, 1 , 2, 3, or 4 secondary constriction sites. "Many parts of these constrictions imply the development of nucleolus sites and are known as" nucleolar organising areas. The nucleolus is the nucleus connected to the NOR zone of the secondary constriction field. The number of NORs in humans is equal to the number of nucleoli. The number of NORs in humans is 10. NOR occurs (13,14,15,21,22) in SAT (satellite chromosome) chromosomes.
Hence, option D: 5 is the correct answer.
Note: Each cell usually contains 23 pairs of chromosomes in human beings, for a total of 46. In both males and females, 22 of these pairs, called autosomes, look the same. The 23rd pair varies between males and females, the sex chromosomes.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Why Are Noble Gases NonReactive class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let X and Y be the sets of all positive divisors of class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x and y be 2 real numbers which satisfy the equations class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x 4log 2sqrt 9k 1 + 7 and y dfrac132log 2sqrt5 class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x22ax+b20 and x22bx+a20 be two equations Then the class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
At which age domestication of animals started A Neolithic class 11 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Which are the Top 10 Largest Countries of the World?
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write a letter to the principal requesting him to grant class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill in the blanks A 1 lakh ten thousand B 1 million class 9 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)