.........................................................
Answer:
1.27 hour or 77 minutes.
Explanation:
In the given question it is provided that:
1. DNA polymerase III synthesizes new DNA at a rate of- 1000 bases/sec
2. The genome of E.coli has- 4,600,000 base pairs
To calculate the time required for replication:
Total base pairs/ speed of enzyme
= 4600000/1000
= 4600 seconds
= 4600/3600 (1 hour= 3600 seconds)
= 1.27 hour or 77 minutes.
Thus, 1.27 hour or 77 minutes is correct.
Resting membrane potential refers to the voltage across the membrane of a resting neuron. The resting membrane potential of a neuron is around -70mV. The positively charged ions like the sodium and potassium, negatively charged ions like the chloride are found on the membrane and around the neurons.
The processes that maintain a steady resting membrane potential are the-
(a) Diffusion and active transport- In diffusion, ions like the sodium and potassium move down their concentration gradient through the channels on the membrane of the neuron. In active transport the ions move against their concentration gradient using ATP as a source of energy.
(b) The Donnan effect- It is the attraction of positively charged ions like sodium and potassium and repelling of negatively charged ions like chloride by the huge impermeant negatively charged intracellular molecules.
Answer:
As light intensity increases to 800 (units), the rate of photosynthesis also increases. This is because a higher light intensity results in an increased rate of the light dependent reaction. However, when light intensity increases above 800, the rate of photosynthesis remains constant. This is because the light intensity is no longer the limiting factor, meaning that something else must be limiting the rate of photosynthesis. This could be carbon dioxide concentration or water availability. CO2 is required for the light independent stage of photosynthesis (the Calvin cycle) whereas water is required to produce H+ and e- for the electron transport chain.
Explanation:
I hope this would be enough to get the 4 marks. The main point is that the rate does not increase each time light intensity increases, because there is a limiting factor that is affecting the rate of the light independent reaction.
