Based on your understanding of genetic code, explain the formation of any abnormal haemoglobin molecule. What are the known consequences of such a change?
Due to point mutation in $\beta$-globin chain of haemoglobin molecule, glutamic acid (Glu) is replaced by valine (Val) at the sixth position.
Under stress condition erythrocytes lose their circular shape and become sickle-shaped. As a result, the cells cannot pass through narrow capillaries. Blood capillaries are clogged and thus affect blood supply to different organs.
Sometimes cattle or even human beings give birth to their young ones that are having extremely different sets of organs like limbs/position of eye(s) etc. Comment.
Sometimes cattle or even human beings give birth to their young ones that are having extremely different of organs like limbs/position of eye etc. It happens due to the disturbance in coordinated regulation of expression in sets of genes, which are associated with organ development.
In a nucleus, the number of ribonucleoside triphosphates is 10 times the number of deoxy $x 10$ ribonucleoside triphosphates, but only deoxy ribonucleotides are added during the DNA replication. Suggest a mechanism.
DNA polymerase enzyme is highly specific to recognise only deoxy ribonucleoside triphosphates. Therefore, it cannot hold RNA $\beta$-nucleotides.
Name a few enzymes involved in DNA replication other than DNA polymerase and ligase. Name the key functions for each of them.
The enzymes involved in DNA replication other than DNA polymerase and ligase are listed below with their functions.
(i) Helicase - Opens the helix
(ii) Topoisomerases - Removes the super coiling of DNA
(iii) Primase - Synthesises RNA primer
(iv) Telomerase - To synthesis the DNA of telomeric end of chromosomes.
$$ \text { Name any three viruses which have RNA as the genetic material. } $$
In some viruses, RNA is the genetic material.
e.g., Tobacco mosaic viruscs, QB bacteriophage, HIV, influenza virus, etc.