Which of the following could have an effect on the expression of a gene? A. the concentration of the end product of a metabolic pathway within a cell B. the number of mRNA transcripts that are produced C. the rate at which ribosomes attach to mRNA to begin translation D. all of these

## Step 1<br />The expression of a gene refers to the process by which the information stored in a gene is used to produce a functional product, such as a protein. This process can be influenced by several factors.<br /><br />## Step 2<br />Option A suggests that the concentration of the end product of a metabolic pathway within a cell can affect gene expression. This is true because if there is an excess of a certain product, the cell may respond by reducing the production of the enzymes that produce that product, which in turn affects the expression of the genes that produce those enzymes.<br /><br />## Step 3<br />Option B suggests that the number of mRNA transcripts that are produced can affect gene expression. This is also true because the more mRNA transcripts are produced, the more likely the gene is to be expressed.<br /><br />## Step 4<br />Option C suggests that the rate at which ribosomes attach to mRNA to begin translation can affect gene expression. This is true because the faster the ribosomes attach to the mRNA, the more quickly the gene is expressed.<br /><br />## Step 5<br />Given that all the options A, B, and C can affect gene expression, option D, which states "all of these", is the correct answer.