Several temperature-sensitive mutant strains of E. coli

Question

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.

Supercoiled strands remain after replication, which is never completed.

Accepted Answer

Hi everyone. Let's look at our next question here. It says determine the incorrect statement about single stranded binding proteins. Well let's recall what the single strand of providing proteins would do a quick definition here. Single stranded binding proteins bind to single strands of DNA. With very high affinity versus double strands of D. N. A. They follow immediately after the healing case. And this prevents the two strands that have just been separated from the by the case from joining and reforming that double helix. So with that in mind let's look at our answer choices, remembering that we are looking for the incorrect statement. So when we look at choice a. It says they catalyze the separation of double stranded DNA and two single strands. Um Well this is false. That is hell a case that comes along and catalyze is that separation by breaking the hydrogen bonds between the bases. So that is right away. Are incorrect statement. So we're gonna go ahead and highlight that as that is not what single stranded binding proteins do. So now let's go along and look at our other answer choices. Choice B. Says they bind to the newly separated individuals D. N. A. Strands. Well as we saw here that is true, they bind to that single strand immediately after the pillowcase. So this is true and that's why it's not a correct answer. Choice C. Says they stabilize the unwound D. N. A. And that's also true. Um by binding there they prevent it from reforming the double helix DNA prefers to be in that double helical confirmation. Um So by the fact that they keep it in a single stranded state that's essentially stabilizing that state. So that is another true statement and therefore not our answer. And finally, Choice D. They prevent the re enabling of the two separated strands. And we saw that in our definition they do prevent the two strands from joining and reforming. So that is another true statement and not our answer. So again, determine the incorrect statement about single stranded binding proteins. And that's choice A. They catalyze the separation of D. S. D. N. A into two single strands. See you in the next video.

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.
Supercoiled strands remain after replication, which is never completed.

Key Concepts

DNA Replication Process

Role of DNA Topoisomerases

Temperature-Sensitive Mutations

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