Ascientist wants to test how much of an acid can be added to a solution before
the ph of the solution changes to below a certain point. the starting ph of the
solution is 6.0, and the scientist wants to know when the ph of the solution
changes to below 4.0.
which ph indicator should the scientist use?
a
cresol red, which changes from yellow to purple around a ph of 7.2
b. thymolphthalein, which changes from colorless to blue around a ph of
9.3
c. methyl yellow, which changes from yellow to red around a ph of 4.0
d. methyl violet, which changes from violet to yellow around a ph of 2.0

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

the answer would be..

b. sucking