As you saw in "DO or Die", adding nutrients to a lake has direct effects (such as stimulating the growth of phytoplankton) and indirect effects throughout the community (such as drastic effects on fish populations). Suppose you triple (3x) the phosphorus input in a lake where phosphorus is limiting, and phytoplankton populations grow dramatically. Based on your observations, which of the following predictions is most likely to follow the phytoplankton bloom? a. Decomposition decreases, DO increases, fish populations grow, and zooplankton abundance increases. b. Decomposition increases, DO decreases, fish populations die off, and zooplankton abundance increases. c. Decomposition increases, DO decreases, fish populations grow, and zooplankton abundance decreases. d. Decomposition increases, DO increases, fish populations die off, and zooplankton abundance decreases.

albert einstein retrieved guacamole from the galapagos islands in africa

the real answer is b. scintillation counter

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.