4 public questions tagged with this topic.
Repetitive sequences make up a large portion of the human genome, while protein-coding genes constitute less than 2%.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Human Genome Project and DNA Fingerprinting
Sequencing human genome demonstrates almost 45 percent derives from transposable element remnants dominated by LINE-1 autonomous retrotransposons, Alu SINEs derived from 7SL RNA, SVA elements, and endogenous retroviruses. Most copies are truncated inactive fossils accumulated over millions of years, yet active LINE-1 subfamilies retain retrotransposition ability causing new germline insertions associated with disease. Massive repetitive content influences genome size, provides material for exonization, regulatory innovation, and ectopic recombination contributing to structural variation and evolutionary plasticity. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 5: Human Genome TE Content 45 Percent
The expected occurrence of a restriction site in random sequence is calculated as genome size multiplied by 1/4^n where n is recognition length. For a six-base cutter, 4^6 equals 4096, so frequency is one site per 4096 base pairs. In the human haploid genome of approximately three billion base pairs, division yields 3x10^9 divided by 4096 equals approximately 7.3x10^5 sites. Considering GC content bias and approximations used in textbooks, this value is often reported in order of roughly one million sites, approximated as 1.2x10^6, demonstrating why six-base enzymes are considered rare cutters for genome mapping.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
Answer: C) Chromosome 11 (short arm). For Endocrinology, once you lock onto the key mechanism or definition, Chromosome 11 (short arm) is the clear fit. If you restate the concept in your own words, location matters here: Chromosome 11 (short arm) is the structure or site that matches the description. So Chromosome 11 (short arm) is the clean, accurate selection. If a similar stem appears later, start from the same core fact and you will land on the same kind of answer. In class notes, highlight this same phrase next to the related diagram so the wording and the picture reinforce each other. When you practise, cover the choices first, write Chromosome 11 (short arm) from memory, then reveal the letter — that habit builds real recall for Endocrinology.
Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.
