Cell Specialization: Same DNA, Different Jobs

0:00Nearly every cell in your body has the same DNA. So how do cells do such different jobs?

0:07Your cells all come from stem cells, which are unspecialized: not yet shaped for one job.

0:14Its DNA, the full set of instructions, is kept in the nucleus, the cell's control centre.

0:22A gene is a section of DNA with the instructions for making a protein.

0:27To specialize, a cell switches some genes on and keeps the rest switched off.

0:34This is called differentiation, and it gives each cell a shape that fits its job.

0:40A red blood cell is a flexible disc with no nucleus once mature, leaving more room for oxygen.

0:47A nerve cell has long, thin branches that carry electrical signals around the body.

0:53A muscle cell is a long fibre whose protein strands slide together, so it contracts, or shortens.

1:01Stem cells can still become many types. Your body keeps some, for example to make new blood cells.

1:08In a plant leaf, two guard cells open and close a pore, called a stoma, to let gases in and out.

1:16A root hair cell grows a long, thin hair into the soil, giving a large surface area to absorb water.

1:24Compare an amoeba. It is unicellular, just one cell, so that cell must move, feed, remove waste and reproduce.

1:34You are multicellular: your many cells share the work, so each type can specialize.

1:40Same DNA, different genes switched on, so each cell's shape fits its job.