Advertisements
Advertisements
Questions
Describe the structure of a nucleosome.
With the help of a suitable diagram describe the structure of a nucleosome
Describe the structure of a nucleosome, with the help of a well-labelled diagram.
Advertisements
Solution 1
In eukaryotes, the packaging of the DNA helix is very complex, as the amount of DNA is very high. When we analyse the structure of the eukaryotic chromosome, we find that it is composed of DNA and proteins. These proteins, known as histones, are basic in nature and are positively charged. Thus, they can easily interact with the negatively charged DNA molecule. The histone proteins first organise to make a unit of eight molecules, which is known as a histone octamer. The negatively charged DNA molecule gets wrapped around this positively charged histone octamer. This complex structure is called a nucleosome. In a typical nucleosome, around 200 base pairs of DNA are present.
Solution 2
The nucleosomes in chromatin are seen as ‘beads-on-string’. Histones are proteins that are rich in the basic amino acid residues, such as lysines and arginines, which carry the positive charge in their side chains. Eight molecules of histones (two each of H2A, H2B, H3 and H4) get organised to form a histone octamer. DNA is negatively charged, and it is wrapped around the positively charged histone octamer to form the nucleosome. Around the octamer, the DNA molecule is wrapped in 1 and 3/4th turn. The DNA is called core DNA (146 bp), and small segments of DNA linking the octamer are called linker DNA (54 bp). Each nucleosome contains 200 bp of DNA helix.
APPEARS IN
RELATED QUESTIONS
In an octamer of the nucleosome, core DNA consists of ______ base pairs.
Attempt any TWO of the following:
With the help of a suitable example illustrate ‘Palindrome’.
Short Answer Question:
Write a short note on DNA packaging in the eukaryotic cell.
Write a note on the packaging of DNA in Eukaryotes.
Explain the formation of a nucleosome.
Repeating units of chromatin are known as ____________.
The length of DNA can be calculated by ______.
The octamer of histone protein is made of ______.
Nucleosome core is made of ______.
Histone proteins are ______.
A stretch of euchromatin has 200 nucleosomes. How many bp will there be in the stretch and what would be the length of the typical euchromatin?
Read the following and answer from given below:
In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.
Name the linkage present between the nitrogen base and pentose sugar in DNA.
Read the following and answer from given below:
In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.
The double helix structure of DNA was proposed by ______
Read the following and answer from given below:
In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.
The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of the B-DNA duplex produces ______
Which one of the following cell organelle is considered as ‘Cell within a cell’?
Plasmid has been used as vector because ______.
Which process occurs in the regulation of gene expression in prokaryotes but does not occur in the regulation of gene expression in eukaryotes?
During translation initiation in prokaryotes, a GTP molecule is needed in:
Watson and Crick proposed the 'Double Helix' structure of DNA based on data produced by ______
______ are the amino acids of histones.
Distinguish between heterochromatin and euchromatin. Which of the two is transcriptionally active?
The most abundant prokaryotes helpful to human in making curd from milk and in the production of antibiotics are the ones categorised as ______ .
Total ATP production during EMP pathway is ______.
Nucleosomes are the repeating units of chromatin the part between adjacent nucleosomes is called ______ .
Histones are enriched with ______.
Statement I: In prokaryotes, the positively charged DNA is held with some negatively charged proteins in a region called nucleoid.
Statement II: In eukaryotes, the negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome.
In the light of the above statements, choose the correct answer from the options given below:
