All genes are not "on" all the time. using the metabolic needs of e. coli, explain why not. 2. what are the two main ways of controlling metabolism in bacterial cells? 3. feedback inhibition is a recurring mechanism throughout biological systems. in the case of e. coli regulating tryptophan synthesis, is it positive or negative inhibition? explain your choice. 4. what is a promoter? 5. what is the operator? what does it do? 6. what is an operon? ap biology reading guide chapter 18: regulation of gene expression fred and theresa holtzclaw copyright © 2010 pearson education, inc. - 2 - 7. list the three components of an operon, and explain the role of each one. 8. how does a repressor protein work? 9. what are regulatory genes? 10. distinguish between inducible and repressible operons, and describe one example of each type. 11. label this sketch of the lac operon with the terms at right. know the function of each structure.

answer by yourhope:

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hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.

registered nurse (rn): the rn is responsible for carrying out both the medical plan of care prescribed by the physician as well as the nursing care plan developed by the nursing staff. the rn assesses each resident and modifies the nursing care as needed to meet the patient's needs.