page 09 16. Eukaryotic chromosomes end in repetitive non-coding sequences of DNA called telomeres. Telomeres protect the coding DNA but become shorter with each round of DNA replication. The shortening of telomeres explains why many cells have a limited number of cell divisions and is associated with the ageing processes in organisms. Rapidly dividing cells may use an enzyme called telomerase to increase the lengths of telomeres. Parasitic infections often increase the rate of cell division. A student made the following predictions: 1. Parasitic infections can lead to faster ageing. 2. Telomerase activity will be low in cancer cells. 3. There is a positive correlation between telomere length and age. 4. Telomerase activity will be high in yeast cultures where there is a high reproductive rate. Which of these predictions are consistent with the information given? A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4 [Turn over