Answer:
The correct answer would be Light independent reactions require the energy gathered in the thylakoids.
Photosynthesis can divided into two sub-processes or reactions:
Light-dependent reaction: It converts solar energy into chemical energy that is, ATP (adenosine triphosphate) and NADPH with the help of photolysisis of water. It takes place in thyllakoid membrane of the chloroplast.
Light-independent reaction: It fixes carbon obtained from carbon dioxide into the food or glucose with the help of enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase).
It takes place in the stroma of the chloroplast and does not require the involvement of light however, it requires the products (ATP and NADPH) of the light reaction.
Fixation of 1 molecule of glucose requires 6 molecules of carbon dioxide, 9 molecules of ATP and 6 molecules of NADPH.
So, darkness indirectly affects the light-independent reaction.
Answer:
A. Molecular changes such as extracellular signals on extracellular ligands can result in quick changes in cell behaviour. One example is insulin. Upon insulin binding on the receptor on the cell membrane, the cell release GLUT4 transporters (for muscle cells) to increase uptake of glucose.
B. Slow changes in cell behaviour can be observed for other lipophilic hormones or intracellular receptors such as glucocoortoid or estrogen which reacts with receptors in the cells.
C. Insulin is required to maintain a constant blood glucose level and hence levels of insulin has to be mediated in correspondence to the blood glucose levels. Fast acting signalling is thus required for homeostasis of blood glucose levels. Where for such lipophilic hormones such as steriods, glucocortoid, these hormones tend to have a longer lasting effect and hence results in a slow change.
I believe the biggest space mission of the twenty-first century will be a manned mission to Mars, and the colonization that follows. This is the stated goal of several nations, companies, and individuals, all with considerably deep pockets. This mission will not only be a huge leap forward in space exploration, it will usher in a new era in human history in which the human race is an interplanetary civilization, a natural milestone as humanity continues to progress and advance.
Significant challenges are many and overwhelming. In terms of getting to mars, we need efficient, powerful propulsion systems and a spaceship that can not only accommodate a full crew for a mission that would likely last years, but withstand the various hazards that a long trip through space and entrance into the Martian atmosphere will entail. In terms of colonization, significant challenges will include establishing efficient and frequent travel/transport between the planets, and in the longer term, the necessity to terraform the planet (make it more like Earth) so that humans can more easily live there.
1. Exchange materials with its environment efficently
