Active transport is the energy-requiring process of pumping molecules and ions across membranes against a concentration gradient.
Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell
At least 75% of the history of the earth
From the energy of photons(light).
Photons give their energy to electrons and through the processes of the light reactions and electron is added to NADP+ to become NADPH.
Answer:
Cell differentiation and cell division both work together by starting out with a somatic cell(basic cell) and cell differentiation gives it the specific instructions in the DNA to enable it to perform its function, then cell division comes in also known as mitosis, and it makes the cell with the whole package included with its function
Explanation:
If a lot of tryptophan is present, the operon will be repressed.
Under intermediate amounts of tryptophan, the change to stop codons would cause the ribosome to stall and therefore would mimic as if there were no tryptophan present.
If no tryptophan present, the operon would be maximally expressed.
a - True. The ribosome would always be stalled in the leader sequence - so this wouldn't matter. However, the operon would still be transcribed because the repressor would be active (remember Trp operon is controlled both by attenuation and repression). True as long as there's not much tryptophan to activate the repressor!
b- True - With no tryptophan the repressor isn't engaged and the ribosome is stalled in the leader sequence.
c- Matters about how much tryptophan is available. So True if there's lots of tryptophan available.
d- I would choose this one as all of the above could be true depending on the levels of tryptophan.
