Give descriptions for the following terms: nucleosome

Question

Accepted Answer

Welcome back, everyone. Here's our next question. Which of the following statements is incorrect. Regarding nucleosome twice. A nucleosome are composed of an October of histone proteins. Two copies each of H two A H, two B H three and H four that are wrapped by about 147 base pairs of DNA. Choice B, the histone proteins and nucleosome are positively charged while DNA is negatively charged, allowing for electrostatic interactions that hold the two components together. Choice C nucleosome play a critical role in regulating gene expression and choice D the linker histone H one is part of the histone omer that wraps around DNA in nucleosome. Well, let's look through our statements, remembering that we're looking for one that is incorrect or untrue. So we look at choice A, we're looking at the composition of nucleosome. And this is a correct statement. This is true. There is an oom of histone proteins, two copies each of the ones mentioned that are wrapped by about 147 base pairs of DNA coiled around that core. So choice A is correct and therefore not our answer. So we'll eliminate that choice. B, the histone proteins are positively charged DNA is negatively charged. That's what holds the two components together, those electrostatic interactions. That is also true. And so therefore cannot be our answer. So I see nucleosome play a critical role in regulating gene expression. This one is true also because nucleosome are part of the packing arrangement of DNA into chromatin. That is an important part of gene regulation because it can be either very, very densely packed or very loosely packed. And the densely tightly packed chromatin is not accessible for transcription. And therefore those genes do not get expressed. The loosely packed chromatin, there are genes and they are able to be transcribed. And so just by the physical arrangement tightly or loosely packed, it controls access to the DNA for gene expression. So that's not our answer choice. And then finally, d the linker histone H one is part of the histone omer. This one is our incorrect statement. This is false. Therefore, that will be our answer because the linker has shown H one along with link or DNA, as we can guess by the name linker is not part of the histone oer. It's not part of that bead aspect of the beads on a string structure but is the string. And I put string in quotation marks as being a non scientific term that holds the nucleosome together. So again, the incorrect statement regarding nucleosome is choice d the link or histone is part of the histone Otto that wraps around DNA in nucleosome. See you in the next video.

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Give descriptions for the following terms: nucleosome

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