When does DNA replication take place?
DNA replication occurs in the S-phase of the cell cycle, where helicase unwinds the DNA strand, allowing the formation of two identical double DNA strands using single strands as templates.
Previous Year Papers
Why are okazaki fragments formed on lagging strand only?
1. Fragments on the lagging strand are created during DNA synthesis. 2. Synthesis occurs in the 5′ to 3′ direction toward the replication fork. 3. These fragments enable replication on only one of the two strands. 4. This enhances the efficiency of DNA replication.
Which enzyme does remove supercoils from replicating DNA?
super-helix relaxing enzyme(Topoisomerase) alleviates supercoiling in replicating DNA.
What is genome?
The genome, found in an organism’s DNA or RNA, encompasses genes and non-coding sequences. It holds all information necessary for an organism’s construction and maintenance. In humans, each cell with a nucleus contains a complete genome of over 3 billion DNA base pairs.
Why the genetic code is considered as commaless?
The triplet codes on m-RNA are positioned consecutively without gaps or spaces, making the genetic code regarded as devoid of commas.
What is the function of an RNA primer during protein synthesis?
The RNA primer attracts matching nucleotides from the nucleoplasm, facilitating the construction of a complementary mRNA strand.
With the help of neat labelled diagram, describe the structure of chromosome.
1. Chromosomes represent the densely packed form of DNA, facilitated by histone proteins H1, H2A, H2B, H3, and H4, visible during metaphase in cell division. 2. Eukaryotic chromosomes have two arms, termed p-arm and q-arm, with a central constriction called the centromere where spindle fibers attach during cell division. 3. The centromere’s location categorizes chromosomes … Read more
In the answer for inheritance of X-linked genes, Madhav had shown carrier male. His answer was marked incorrect. Madhav was wondering why his marks were cut. Explain the reason.
Males, with a single X and a Y chromosome, cannot be carriers for X-linked recessive disorders, as they lack another X chromosome to mask the expression of such genes. In females, having two X chromosomes allows them to be carriers without displaying physical traits, as one X can compensate for the recessive gene on the … Read more
What is parthenogenesis? Explain the haplo-diploid method of sex determination in Honey bee.
Parthenogenesis is a form of asexual reproduction where embryos develop from unfertilized female gametes. Examples include honey bees, Aphis, wasps, and ants. The haplo-diploid method of sex determination in honey bee are: In honeybees, sex determination operates through haplodiploidy. Three distinct types of individuals emerge:Diploid queens (2n = 32), fully functional females originating from fertilized … Read more
Define test cross and explain its significance.
A cross between F1 offspring and its homozygous recessive parent is called a test cross. Significance of testcross 1. Genotype Identification: Test cross helps determine the genotype of a plant expressing dominant traits, revealing whether it is homozygous or heterozygous. 2. Understanding Genetic Composition: It is a valuable tool for discerning the genetic makeup of plants, … Read more