Green fluorescent protein is commonly used to label DNA sequences. visualize the localization of proteins in living cells. photobleach other fluorescent proteins. label antibodies. Transmission electron microscopy is used to view cells in three dimensions. observe subcellular organelles and viruses. study the shapes of whole cells. view fluorescently labeled proteins in cells. If concentration of sodium and potassium ions were at the following concentrations inside and outside a cell, how could the two molecules enter the cell? Both would require active transport in order to enter the cell Sodium ions could enter by facilitated diffusion while the potassium ions would need active transport to enter the cell Both would diffuse through the membrane into the cell without going through protein channels Both would enter by facilitated diffusion through protein channels Potassium ions could enter by facilitated diffusion while the sodium ions would need active transport to enter the cell The nematode worm Caenorhabditis elegans (C. elegans) is a good model system because it allowed researchers to observe the process of fertilization better than had been possible in the past follow the developmental lineage of all the cells found in an adult from a single fertilized egg cell microscopically follow the process of how cells growing individually can aggregate to form a simple multicellular organism. identify the genes involved in differentiation of every cell type found in mammals Solution Q 1: Answer D (to label antibodies). Q 2: Answer D: (view fluorescent labeled proteins in cells.) Q 3: Answer B: sodium ion enter by facilitative diffusion and potassium ion by active transport. Q 4: Answer B: follow the developmental lineage of all the cells found in adult from single fertilized egg cell microscopically..