Question

which genes are present in the liver cells?

• half the number of genes is present in the liver cells.
• all the genes are present in the liver cells.
• liver cells do not require any genes.
• only the genes needed by the liver cells are present in those cells.

Explanation:

In a multicellular organism, almost every cell (including liver cells) contains the entire genome (all genes) of the organism. However, different cells express (use) only the genes they need for their specific functions. But the question is about which genes are present (not expressed). All cells in an organism (barring exceptions like red blood cells in mammals which lose their nucleus) have the full set of genes. So among the options, "All the genes are present in the liver cells" is correct. The first option is wrong as cells don't have half the genes. The third is wrong as cells need genes for function. The fourth is about gene expression (which genes are used), but the question is about presence; all genes are present, but only some are expressed.

Answer:

B. All the genes are present in the liver cells (assuming the option with "All the genes are present in the liver cells" is labeled as B, adjust the label as per the actual option numbering in the question, but the key is the text "All the genes are present in the liver cells" is the correct choice)