The endosymbiotic hypothesis concerns the origin of mitochondria and chloroplasts, two organelles contained within various eukaryotic cells. According to this hypothesis, these organelles originated as separate prokaryotic organisms that were taken inside a primordial eukaryotic cell.
Water treatment is any process that improves the quality of water to make it more acceptable for a specific end- use. The end use may be drinking, industrial water supply, irrigation,river flow maintenance, water recreation or many other uses, including being safely returned to the enviroment
Answer:
a. repressor
b. regulator
c. operator
Explanation:
All constituent genes of an operon are transcribed in a coordinated manner, such as polycistronic mRNA, that is, multigenic, which is sequentially translated into proteins by ribosomes. The initiation of transcription can be regulated positively or negatively. The genes under negative control are constantly expressed unless they are "disconnected" by a repressor protein that will prevent gene expression by binding to a specific DNA sequence called operator, preventing RNA polymerase from initiating transcription in the promoter.
Those genes whose expression is under positive control will not be transcribed unless an activating protein is present which binds to a specific DNA sequence and helps RNA polymerase in the initial steps of transcription.
Answer:
2.6 billion years old
Explanation:
Initial:
100% k-40
0% ar-40
After 1.3 billion years:
50% k-40
50% ar-40
After 2.6 billion years:
25% k-40
75% ar-40
So the rock is 2.6 billion years old.
