Question

1. The researchers find that despite the lack of light. the cells appear to continue to not just divide. but increase in multiplication rate. They speculate this is most likely due to a decrease in reactive oxygen species produced by the plant while growing in the dark. A. What are reactive oxygen species (you may need to look this up)? B. Hypothesize why more reactive oxygen species are produced in the light compared to the dark. C. Why would the presence of reactive oxygen species slow down cell division? 2. Hypothesize how these plant cells are growing in the dark. In your hypothesis please in clude the likely electron source and the likely carbon source for these plant cells (after all you can?t grow without harvesting energy from somewhere) 3. With this information what two 'Lifestyles' do you believe these Arabidopsis cells are capable of switching between?

Answer 1

1. A) Reactive oxygen species have oxygen in them and are are chemically reactive molecules. Ex hydroxyl radical and singlet oxygen. Reactive oxygen species are formed during metabolism.

B) Reactive oxygen species are produced more during photosynthesis and photosynthesis take place during light.

C) Excess reactive oxygen species causes programmed cell death and thereby it affects cell division.

2. Plant cells can be grown in darkness, because the nutrient media on which its grown provides all the necessary ingredients for its growth.

3 The plant cells can grow both in environment having light as well as dark environment as it shows growth in both environments.