Plant and animal cells carry out mitosis to form two genetically identical cells from one original cell.

1. (a)State other reasons why mitosis is important in both plants and animals.[2]
2. (b)Plant cells require microtubules to form structures that are needed for mitosis. Name one of these structures.[1]
3. (c)During the mitotic cell cycle, free nucleotides are used for the synthesis of both types of nucleic acid: RNA and DNA. Complete sentences A, B, C and D to provide information about nucleotides and the synthesis of nucleic acids. Write the correct term in the spaces provided in each sentence. A Each nucleotide has three main components: a a group, (5 carbon) sugar and a nitrogenous organic base. B The nitrogenous organic base of a nucleotide is either a purine or a C In a DNA nucleotide, the sugar is deoxyribose and in an RNA nucleotide the sugar is D The synthesis of RNA from a template strand of DNA is known as [5]
4. (d)A virus named Pandoravirus salinus was discovered in 2013 by French scientists. The virus was so large that the scientists initially thought that P. salinus was a bacterium. P. salinus was confirmed to be a virus after further research.
5. (d)(i)List three key features of viruses.[3]
6. (d)(ii)The dimensions of viruses are usually stated in nanometres (nm). As P. salinus is so big, it has been described as 1 µm long and 0.5 µm wide. Convert the width of P. salinus to nanometres. width = nm[1]