Cell Division

Question 1

state the stages of mitosis

Answer 1

stage 1:
growth - before a cell can divide it needs to increase the number of sub-cellular structures such as ribosomes.
DNA synthesis - DNA replicates to form 2 copies of each chromosome.

stage 2:
mitosis - one set of chromosomes is pulled to each end of the cell and the nucleus divides. The cytoplasm and cell membranes divide to form 2 cells identical to the parent cell

stage 3:
cytokinesis - two daughter cells are made with full set of DNA

Question 2

how can stem cells from meristem plants be used to produce clones of plants quickly and economically.

Answer 2

rare species - can be cloned to protect from extinction

crop plants - with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.

Question 3

state the advantages of using human embryo stem cells.

Answer 3

embryos produced by therapeutic cloning have the same genes as the patient, this means that the stem cells from the embryo are not rejected by the patients body. - they can be used to medical treatments

Question 4

state the disadvantages of using human embryo stem cells.

Answer 4

they have risks such as transfer of viral infections.

some people may also have objections to use stem cells for ethical and religious reasons.