Question

Some plants with genetic defects are unable to photorespire. These plants end up being damaged under intense light. Researches identify this as evidence that photorespiration is a protective mechanism in plants. Why might a disabling of the photorespiratory pathway lead to cell damage and how might the process of photorespiration mitigate this damage?

3.In which stage are the sister chromatids separated?

Group of answer choices

Telophase

Anaphase

Metaphase

Prometaphase (late prophase

8.Cytokinesis in plant cells is different than cytokinesis in animal cells.
a) Explain why it has to be different, and
b) briefly describe the processes in the two different cell types.

Note: You can use page 262 in your textbook to help with this questions.

Answer 1

1. Cell organelles involved in photorespiration = Peroxisomes, chloroplast, and mitochondria
Peroxisomes contain a special enzyme known as peroxidase. It catalyzes the degradation of hydrogen peroxide and provides protection against oxygen free radicals.
2 H2O2 ------> 2 H2O + O2
Excess light intensity cause solarization (Photo-oxidative damage of pigment molecules) and produces free radicals. These free radicals are sequestered by peroxisome and provide protection against excess light intensity.

2. Anaphase is characterized by contraction of spindle fibers and separation of sister chromatids

3. Cytokinesis is different in plants and animals
Plants = Cell-plate method
It occurs in a centrifugal manner

Animals = Constriction method
It occurs in a centripetal manner