Mesquite trees can grow in soil containing few nutrients. Once mesquite trees have been growing in an area for a certain amount of time, the soil is found to be enriched with nitrogen compounds, making it fertile enough for the growth of crops. Which of the following is probably true of mesquite trees? (A) They have a symbiotic relationship with nitrogen-fixing bacteria. (B) They obtain useable nitrogen directly from the atmosphere and pass it on to the soil. (C) They take in atmospheric nitrogen during photosynthesis and use it to build glucose molecules. (D) All of these are probably true

the answer will be a) proteins i believe

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.