Select the correct answer. Protein X is produced in the liver cells of the body. However, this protein is not produced within the intestine. Which statement best explains why? A. The gene for protein X is present in the intestinal cells, but it is not expressed. B. The gene for protein X is not present in the intestinal cells. C. The gene for protein X is present in the liver cells, but it is not expressed. D. The gene for protein X is not present in the liver cells.

The first signs of cellular differentiation occur in the blastocyst. why is cellular differentiation important for the development of a fully formed human infant?

Mouse liver cells were homogenized and the homogenate subjected to equilibrium density-gradient centrifugation with sucrose gradients. fractions obtained from these gradients were assayed for marker molecules (i. e., molecules that are limited to specific organelles). the results of these assays are shown in the figure. the marker molecules have the following functions: cytochrome oxidase is an enzyme involved in the process by which atp is formed in the complete aerobic degradation of glucose or fatty acids; ribosomal rna forms part of the protein-synthesizing ribosomes; catalase catalyzes decomposition of hydrogen peroxide; acid phosphatase hydrolysis monophosphoric esters at acid ph; cytidylyltransferase is involved in phospholipid biosynthesis; and amino acid permease aids in transport of amino acids across membranes. a) name the marker molecule and give the number of the fraction that is most enriched for each of the following cell components: lysosomes; peroxisomes; mitochondria; plasma membrane; rough endoplasmic reticulum; smooth endoplasmic reticulum.

Amniocentesis is a process in which amniotic fluid is taken from the mother's womb to identify any genetic abnormalities in the fetus. how would the discovery of the human genome contribute to this process?