Video Transcript
Which of the following best describes the difference between the DNA of bacteria and the DNA of eukaryotes? Our choices are: Eukaryotes do not contain any unused sections of DNA, but bacteria do. Bacterial DNA contains uracil instead of thymine. Eukaryotic DNA contains uracil instead of thymine. There are no differences between the DNA of bacteria and eukaryotes. Or bacteria do not contain any unused sections of DNA, but eukaryotes do.
This question’s asking us to identify the choice that describes the difference between the DNA of bacteria or prokaryotic cells and the DNA of eukaryotic cells. Also important to note is that this question is asking us for the answer choice that best describes the difference. This means that there may be more than one correct answer, and we’re looking for the one that is the most correct out of the choices available.
This is a drawing of a simplified bacteria or prokaryotic cell and a eukaryotic cell. In bacteria, DNA exists in a long loop, and it’s floating in the cytoplasm of the cell. In a eukaryotic cell, the DNA is linear, contained in chromosomes, and protected within the nucleus of the cell. Another notable difference between bacteria and eukaryotic DNA is that the DNA of eukaryotic cells contains sections that are not used in the production of proteins. These sections are removed before the RNA is translated. This is not the case in bacteria DNA.
Now, let’s zoom in a little farther. Here, we’ll represent the DNA as the base pairs that make up the genetic code. In the DNA of all organisms, adenine or A pairs only with thymine or T. And cytosine or C only pairs with guanine or G. These four bases may appear in any order, but the same four bases make up the DNA of all organisms. Now, let’s return to our question and answer choices.
Which of the following best describes the difference between the DNA of bacteria and the DNA of eukaryotes?
Eukaryotes do not contain any unused sections of DNA, but bacteria do. Since we know that eukaryotes and not bacteria contain unused sections of DNA, this is not the best choice because it’s false.
Bacterial DNA contains uracil instead of thymine. The four bases contained in all organisms’ DNA are adenine, thymine, cytosine, and guanine. Uracil is a base that replaces thymine in RNA. Uracil is not present in the DNA of bacteria. So, this choice is also false.
Eukaryotic DNA contains uracil instead of thymine. Once again, we know that uracil is found in RNA not in DNA. This choice is also false.
There are no differences between the DNA of bacteria and eukaryotes. Since we’ve already reviewed several differences between the DNA of bacteria and the DNA of eukaryotes, we know that this answer choice is also false.
Bacteria do not contain any unused sections of DNA, but eukaryotes do. Since we know that eukaryotes contain sections of DNA that are removed before protein production and that bacteria cells do not share this feature, this statement is true.
So, the statement that best describes the difference between the DNA of bacteria and the DNA of eukaryotes is “Bacteria do not contain any unused sections of DNA, but eukaryotes do.”
