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DNA Structure & Packaging Video Lecture | Biology Class 12 - NEET

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FAQs on DNA Structure & Packaging Video Lecture - Biology Class 12 - NEET

1. What is the structure of DNA?
Ans. DNA (deoxyribonucleic acid) is a double-stranded molecule that forms a twisted ladder or helical structure known as the double helix. It consists of two long strands made up of nucleotides, which are composed of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The two strands are held together by hydrogen bonds between the complementary base pairs (adenine with thymine and cytosine with guanine).
2. How is DNA packaged in the cell?
Ans. DNA packaging in the cell involves a process called DNA condensation or supercoiling. The DNA molecule is wrapped around proteins called histones to form structures called nucleosomes. These nucleosomes, in turn, fold and coil to form a chromatin fiber. The chromatin fiber further condenses and coils to form a compact structure known as a chromosome. This packaging allows a large amount of DNA to be compactly organized within the cell nucleus.
3. What is the importance of DNA packaging?
Ans. DNA packaging is crucial for several reasons. Firstly, it allows the long DNA molecule to fit within the limited space of the cell nucleus. Secondly, it helps protect the DNA from damage and prevents tangling or breaking of the DNA strands. Additionally, the organization of DNA into chromosomes aids in the regulation of gene expression, as certain regions of the DNA become more or less accessible for transcription and DNA replication. Lastly, DNA packaging plays a role in the transmission of genetic information from one generation to the next during cell division.
4. How does DNA packaging affect gene expression?
Ans. DNA packaging plays a significant role in gene expression. The degree of packaging, from loosely packed chromatin to highly condensed chromosomes, affects the accessibility of DNA to various cellular machinery involved in gene regulation. Loosely packed regions of DNA, known as euchromatin, are accessible for transcription and gene expression. In contrast, tightly packed regions, known as heterochromatin, are less accessible and typically associated with gene silencing. Therefore, DNA packaging can influence which genes are active or silenced in a particular cell type or during specific developmental stages.
5. Can alterations in DNA packaging affect human health?
Ans. Yes, alterations in DNA packaging can have significant implications for human health. Abnormal DNA packaging can lead to changes in gene expression patterns, which may contribute to the development of diseases such as cancer. For example, alterations in the packaging of specific regions of DNA can result in the activation of oncogenes or the silencing of tumor-suppressor genes. Furthermore, mutations or dysregulation of proteins involved in DNA packaging can lead to disorders known as chromatinopathies, which are associated with developmental abnormalities, intellectual disabilities, and other genetic disorders.
87 videos|294 docs|185 tests
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