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Taxol is a drug used to treat cancer. Research scientists investigated the effect of
injecting taxol on the growth of tumours in mice. Some of the results are shown in
Figure 3.The scientists measured the volume of the tumours. Explain the advantage of
using volume rather than length to measure the growth of tumour - Answer Tumours
vary in shape.
Taxol is a drug used to treat cancer. Research scientists investigated the effect of
injecting taxol on the growth of tumours in mice. In cells, taxol disrupts spindle activity.
Use this information to explain the results in the group that has been treated with taxol.
- Answer As chromosomes cannot attach to spindle the chromatids cannot separate to
opposite ends of the pole. Mitosis slows down as a result.
explain what the cell cycle is and why it does not occur in some cells from multicellular
organisms - Answer Not all cells in multicellular organisms retain the ability to divide.
Explain what happens during G1, S and G2 phases of interphase. - Answer In G1 cells
grow and new organelles are formed. Protein synthesis also occurs. In S, DNA replication
occurs. In G2 cell continues to grow and organelle synthesis occurs.
Why would scientists investigating mitosis choose to study bone marrow cells over
neurones? - Answer Neurones do not undergo mitosis but bone marrow cells do.
Explain the role of spindle fibres - Answer The spindle is necessary to equally divide the
chromosomes in a parental cell into two daughter cells during both types of nuclear
division: mitosis and meiosis.
, Explain what the mitotic index is - Answer The ratio between the number of cells in a
population undergoing mitosis to the number of cells in a population not undergoing
mitosis.
Explain how cancer treatments such as chemotherapy often work to inhibit stages of the
cell cycle. - Answer Chemotherapy targets G1 by preventing the synthesis of enzymes
needed for DNA replication. If these enzymes aren't produced then the cell won't be
able to enter the synthesis stage, disrupting the cell cycle forcing the cell to undergo
apoptosis
Explain how cancer treatments such as radiotherapy often work to inhibit stages of the
cell cycle - Answer Radiation damages the DNA. At several points in the cell cycle, the
DNA is checked for damage. If severe damage is detected then the cell will kill itself
preventing further tumour growth
describe the process of binary fission in prokaryotic cells - Answer The circular DNA is
replicated once and the plasmids can be replicated multiple times. The cells get bigger
and the DNA loops move to opposite poles of the cell. The cytoplasm begins to divide
and new cell walls begin to form. The cytoplasm splits and 2 daughter cells are produced
each with one copy of the circular DNA but variable copies of the plasmids
explain what binary fission is and the organisms which carry out binary fission - Answer
In binary fission the cell replicates its genetic material before physically splitting into 2
daughter cells. Prokaryotes carry out binary fission
Explain why viruses are not classified as being living organisms - Answer Viruses don't
grow, and they can't use energy. They can't reproduce on their own as they require host
cells to replicate.
Explain how a bacteriophage, replicates after infecting a bacterial cell. - Answer A
bacteriophage binds to the cell wall of a bacterial cell.The bacteriophage injects its
genetic material into the bacterium.The bacteriophage genome replicates using the