Video Transcript
The image provided shows an amoeba, a single-celled organism, as viewed under a microscope. An amoeba can reproduce by replicating its genetic material and splitting in half to produce two new cells. Which principle of cell theory does this process support? (A) Cells are the smallest biological structure within an organism. (B) Cells cannot function in groups and must work individually. (C) All living organisms are made up of more than one cell. Or (D) all cells are made from preexisting cells.
Cell theory is one of the unifying theories of biology. Without understanding what a cell is, we would be severely lacking in our knowledge of biology. Cell theory was developed over hundreds of years by many key scientists. It has three principles. So let’s look at each one to see which best describes this dividing amoeba cell. The first principle is that all living things are made of at least one cell. This amoeba here is indeed made of one cell, but this doesn’t describe the process that the cell is going through to divide and produce another cell. We can eliminate answer choice (C) as there are also organisms which are single celled like the amoeba in this question.
The second principle states that cells are the basic unit of life. This is very true since all life is made up of cells. And these cells themselves are made up of smaller biological structures like organelles, such as this mitochondrion here. Whether you’re multicellular and made up of trillions of cells, like humans, or a single-celled organism, like this amoeba, we’re all made up of cells. But again this doesn’t describe the process of this amoeba dividing to form a new cell. Based on what we’ve discussed with this principle, we can eliminate answer choice (A) that cells are the smallest biological structure within an organism.
The final principle is that all cells come from preexisting cells. It’s amazing when you think of how we were all a single cell at one point that divided into what we are today. And indeed, this amoeba here is also undergoing this process of dividing to produce a new cell. So answer choice (D) looks like the correct answer. Answer choice (B) states that cells cannot function in groups and must work individually. This statement is incorrect. For instance, the cells of an organ like our heart need to function together to effectively transport blood throughout our body. Therefore, the process of this amoeba reproducing to make two new cells is supported by the principle of cell theory that states that all cells are made from preexisting cells.
