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9
votes
1answer
1k views

Are all Y-chromosomes the same?

Since the Y-chromosome can only pass from male to male child, it would seem to pass intact. Thus, a boy's Y-chromosomes would, I guess, be the same as his father's. Going backwards, would not all men ...
7
votes
1answer
193 views

Why and how is DNA synthesis so much faster then RNA synthesis?

DNA synthesis in E. coli is 20x faster than RNA synthesis at 1000nt/s vs 50nt/s. (Mirkin'05) I find that perplexing since DNA polymerization has better proofreading than the RNA variety, which ...
6
votes
1answer
84 views

Why doesn't telomerase activity cause DNA to get longer each time a cell undergoes DNA replication?

Telomerase extends the ends of the lagging strands in order for all of DNA to be be copied. Doesn't this also mean that DNA gets progressively longer each time it undergoes replication? Why is this ...
5
votes
1answer
76 views

How do mutations actually occur?

DNA replication seems so mechanical- the DNA polymerase just running along the template strand. I just don't understand how mutations can arise. When it comes to substitutions, I get that a wrong ...
4
votes
1answer
1k views

Does DNA polymerase always go the same direction?

I read that mutations are more likely to occur on "the strand that DNA polymerase replicates discontinuously". Does DNA polymerase always go replicate the same strand discontinuously, and if so, ...
3
votes
2answers
400 views

How are DNA segments selected in PCR?

I understand that in PCR we're able to amplify only selected portions of the DNA... however despite reading it from multiple sources, I cannot figure out how this selection actually takes place. I ...
3
votes
1answer
93 views

DNA content doubling in interphase

Why does the DNA content of a cell get doubled in interphase? Why doesn't it become tripled or quadrupled? What's stopping it from doing so?
3
votes
1answer
56 views

Does DNA polymerase I require a $3^\prime$ end?

DNA polymerase III adds nucleotides in the $5^\prime \rightarrow 3^\prime$ direction because it can only add nucleotides to the $3^\prime$ end of the previous nucleotide. This is why it requires a ...
3
votes
1answer
53 views

How does the splicing enzyme recognize where to splice the introns?

When the DNA from the nucleus is transcribed to an mRNA, the mRNA is spliced by an enzyme before it goes outside through the nuclear pore. What is the name of this enzyme and how does it recognize ...
3
votes
1answer
58 views

Why do some bacteria have an asymmetric replication?

Our teacher said that Bacillus subtilis has an asymmetrical replication fork. I know that this happens only in some strain of the bacteria . She asked us to find an explication for this mechanism , ...
3
votes
0answers
20 views

What would the resulting karyotype be if someone with Klinefelter syndrome fertilized an “empty” egg?

Endoreduplication: is a form of nuclear polyploidization that results in multiple, uniform copies of chromosomes. This process is common in plants and animals, especially in tissues with high ...
2
votes
1answer
959 views

ATP required for cell processes [closed]

I haven't been able to find anything that tells me how much ATP is needed for DNA replication, transcription, and translation in humans, just papers that mention ATP used in those processes. I need ...
2
votes
1answer
108 views

Specific numbers of nucleotides in Okazaki fragments

Okazaki fragments are formed during replication of the lagging DNA strand. What determines the length of these fragments?
1
vote
2answers
203 views

What errors can occur during DNA replication?

When there is an error in copying DNA (a mutation), what exactly goes wrong? If G goes with C and A goes with T, I don't see how that part can mess up. Is the idea that when the double helix is ...
1
vote
1answer
104 views

The Semi-Conservative Model of DNA Replication: Question

My Campbell's Biology textbook contains the following diagram related to the semi-conservative model of DNA replication proposed by Watson and Crick. I have highlighted where my confusion arises in ...
1
vote
5answers
119 views

Can your immune system's cells destroy you? (Critical thinking and Fictional sense)

In an imaginary sense, If you alone were replicated into 2 so that there should now be 2 of "you" (meaning you both have the same DNA). Then let's say one of you shrunk to the size of a bacteria, and ...
1
vote
1answer
40 views

How RNA primer on leading strand is removed during DNA replication and how the gap is filled? [closed]

Please can you explain me how the gap created by the removal of primer on 5'-3' leading strand is filled.
1
vote
1answer
38 views

Why isn't the RNA in bacteria always split up and replicating?

Isn't helicase always free floating in bacterial cells, and the DNA without a nuclear membrane and uncoiled and freefloating and so why doesn't the helicase keep breaking the double helix of DNA? ...
1
vote
0answers
30 views

From an information perspective, are both strands of DNA necessary?

I am learning about the genetic code, replication, and transcription, and I have a question about whether or not both strands of DNA are really "necessary". In replication, at a high level, we are ...
1
vote
0answers
15 views

Does any specific property decide which DNA strand acts as leading strand template?

Of the two strands of DNA, the one that unwinds in the 3' to 5' direction constitutes the leading strand template, with the other strand of course acting as the lagging strand template. Is there any ...
1
vote
0answers
78 views

Does cancer cells come from same process as evolution? [duplicate]

Here is how I understand it: DNA replication is not 100% perfect and error can happen, this error can be good(evolution) or bad(cancer properties). But its not the only source of cancer cells - DNA ...
0
votes
2answers
289 views

DNA sequence from the middle of a gene

Someone gives you a short DNA sequence that comes from the middle of a gene. 5'- TCTAACTGATTAGC -3' 3'- AGATTGACTAATCG -5' From this sequence, determine the ...
0
votes
2answers
48 views

“Prime” structure of DNA Double Helix: Confusion

In this video on DNA replication, the diagram shows the unwound DNA as still being anti-parallel, but the first diagram in this post on Biology SE shows that the individual strands are 5'____5' and ...
0
votes
1answer
92 views

Difference between PCR for linear template and a plasmid?

I believe PCR can be conducted both on a linear template and a plasmid, and I was wondering how these procedures differ in what enzymes are used, how the enzymes work on the template, primers used ...
0
votes
1answer
83 views

In the future, it is plausible that we can change the physical appearance of a living animal by editing DNA?

http://www.independent.co.uk/news/science/revealed-scientists-edit-dna-to-correct-adult-genes-and-cure-diseases-9273555.html This article explains that scientists managed to change the DNA of adult ...
0
votes
0answers
21 views

Separate replication origin and terminus vs making them one and the same

The classical picture of bacterial reproduction has a replication origin on one side of the circular chromosome and a replication termination area on the opposite end. This essentially creates two ...
0
votes
1answer
64 views

How does RNA polymerase achieve higher processivity?

DNA polymerase uses a sliding clamp in order to replicate DNA. RNA polymerase does not require one. What allows RNA polymerase to hold on to DNA just like DNA polymerase?
0
votes
1answer
81 views

Why do you need primers in PCR? [duplicate]

I have read that DNA polymerase requires a primer to bind to the DNA, but I am confused as to why this is the case. When DNA undergoes replication in the cell, there are no primers in the nucleus so ...
-6
votes
1answer
84 views

Two 20 million yr old fossils of Hummingbirds found "The amazing thing about the fossil is that it's essentially a modern hummingbird

does this only mean that the Hummingbird is perfect in creation and needs no change to survive? http://news.bbc.co.uk/2/hi/science/nature/3691169.stm