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17

Actually, no. There are also recombination prone regions of the Y chromosome that recombine and exchange material with X chromosomes, and these are called pseudoautosomal regions (PARs). Y chromosomes can be used similarly to mitochondrial DNA to build up profiles of ancestry, but the sequences used for this purpose lie outside PARs, in the non-recombining ...


7

Note: In your PCR program you always set extension time. Case: Product length = 500bp PCR extension time = 50sec Assuming that polymerase adds 1000 nt/min Cycle 1: Strand that binds FP: extends ~800nt to the right (as per the polymerization rate): 300 bp ahead of RP complementary site. This product is lets say P1 Strand that binds RP: extends ~800nt ...


5

So in mitosis, the cell has to split itself into two cells; each daughter cell has a functional genome that may again split into more daughter cells. The cell replicates the DNA before dividing, so the error in replicating 3x or 4x is that upon division, the daughter cells will have more DNA than the initial cell, and every generation will have more DNA than ...


4

Hummingbirds were not created, they evolved. Ancestors of a modern species need not be that morphologically different from their progeny, even over a time span of millions of years. And organism will fill a niche based on its fitness to survive in the niche. If there are strong selective pressures in the environment to maintain the traits that we see today,...


4

I will assume that you are referring to humans, though much of the research to elucidate telomerase function was performed in yeast. The first reason is that only a small subset of somatic cells express telomerase. Most somatic cells are terminally differentiated and mitotically inactive, so they are not called upon to replicate their DNA and divide. And ...


4

Summary: In bacteria or organisms with only one well defined replication origin and a circular chromosome, yes for a given DNA region the same strand is replicated discontinuously. In high order animals, which replicate chromosomes using several origins of replication (ori), this is less clear as the way ori are recognized is still not fully understood but ...


4

I'm not completely clear when you say "what makes the replication terminate when the polymerase reaches the primer at the other end" since when you perform a PCR you go through three phases. The denaturation, whereby the two DNA strands become single stranded, then the annealing, which is when primers attach to their appropriate matching site (but the ...


4

There are many way in which DNA can be damaged. As already pointed out in the comment by @skymninge, the Wikipedia page on DNA repair, as well as the mutation page detail some of the things that can go wrong. You say: If G goes with C and A goes with T, I don't see how that part can mess up. This, however, would imply that the four bases are ...


3

TCT AAC TGA TTA GC T CTA ACT GAT TAG C TC TAA CTG ATT AGC AGA TTG ACT AAT CG <<< this is the ORF A GAT TGA CTA ATC G AG ATT GAC TAA TCG If the sequence comes from the middle of a gene we assume it should encode an open reading frame. For this sequence only 1/6 frames does not include a stop codon (shown above in italics). So in standard format,...


2

On the sequence alone, you can answer neither of these questions because: from the sequence alone you don't know anything about the gene or the promoter. the same is true for the orientation and the codons, since you don't know if the code is in frame or not. If one base is cut-off from the original sequence, your codons shift, and don't show the original ...


2

For DNA replication and transcription you need NTPs. In a dsDNA purine content will be same as pyrimidine content. I am considering that all nucleotides are synthesized de novo which would consume more ATP than getting nucleotides from the salvage pathway.                  &...


2

The length of Okazaki fragments is not necessarily a tight distribution. The lengths are determined by the spacing between adjacent sites where DNA primase has synthesized a short RNA primer on the lagging strand at an active DNA replication fork. In E. coli, as I recall, this occurs on an average of once per 1000 nt. DNA polymerase holoenzyme then uses ...


2

There's not much difference between them. The same enzyme and condition can be used whether the template is circular or linear. You can amplify plasmids, but PCR intrinsically generates linear DNA fragments even if you use circular DNAs.


2

Mutation of DNA can be caused by an exogenous or endogenous source. Many external factors like irradiation or chemicals induce mutations. Some endogenous mutations arise from oxidative stress, insufficient DNA repair or spontaneous mutations on the molecular level. There are many mechanisms for DNA repair like base excision repair, nucleotide excision ...


2

I believe the reason you are having trouble understanding the concept is due to a poor usage of colors in the diagram. Don't focus on the colors, but on the concept. It's the same for both replication events. Each strand of a double helix is used as a template to make a new complimentary strand, giving rise to two new DNA helices from the original. In each ...


2

DNA Pol I does require the 3' end of a previous nucleotide to initiate elongation. Regarding Okazaki fragments, this is accomplished by the annealing of small RNA primers to the lagging strand part of a replication fork. DNA Pol I extends the lagging strand off of the 3' end of those primers, generating the Okazaki fragments. The RNA primers are later ...


2

There are two factors that involve the ability of enzymes to process RNA. 1) Structure see wikipedia 2) Binding affinitya Let's take a look at the splicing process: The active 'sites' (GU,A & AG) need to be in spatial proximity (point one), and the enzyme needs to be able to bind there, aka forming hydrogen bonds with the nucleotides, which is mostly ...


1

These terms are quite similar and, for many, confusing: Chromatin Chromosome Chromatid But they are not synonyms. According to "Molecular Cell Biology", Lodish, 4th ed: Chromatin: Complex of DNA, histones, and nonhistone proteins from which eukaryotic chromosomes are formed. Thus: Chromosome: In eukaryotes, the structural unit of the genetic ...


1

The group of cellular enzymes that remove RNA primers include the proteins FEN1 (flap endonuclease 1) and RNase H. The enzymes FEN1 and RNase H remove RNA primers at the start of each leading strand and at the start of each Okazaki fragment, leaving gaps of unreplicated template DNA. Once the primers are removed, a free-floating DNA polymerase lands at the 3'...


1

DNA strands always have one 3' end and one 5' end (since each nucleotide has one of each and a strand is formed by connecting the 3' side of one nucleotide to the 5' side of another nucleotide). In a double helix DNA molecule, the two strands run in opposite directions. The Pearson Education diagram in the post you referenced has one pair of the strand ...


1

A single, unwound strand of DNA runs 5' to 3', the video is correct. When wound properly, the strands run in reverse directions, 5' to 3' for the first, 3' to 5' for the other. That diagram is not helpful, though the post itself is quite good.


1

Bacterial DNA replication is initiated at the oriC by DnaA in E. coli. Think about ways in which DnaA binding or activity can be regulated in a way that inhibits or permits DNA replication. In recently replicated bacterial DNA, the DNA is hemimethylated (parental strand has a methyl group, daughter strand doesn't): An inhibiting protein binds to ...


1

The replication fork itself is always asymmetric. This is true for all organisms and is due to the fact that DNA polymerases can only add nucleic acids to the 3'-OH end of DNA. This leads to different mechanisms for the replication of the so called leading and lagging strands. You can find more details on wikipedia https://en.wikipedia.org/wiki/...


1

This article explains that scientists managed to change the DNA of adult laboratory mice with an inherited liver disease, thereby curing them of the disease. Yes, Read about CRISPR-CAS9 method of gene editing. This is not the only method which can achieve this. There are many others like TALEN or Zinc Finger. If we used this same method to edit our ...


1

The immune system recognizes patterns - incase of innate immunity and shapes - incase of active immunity. I am making a few assumptions: The Shrinking would result in a smaller version of "the person" - meaning he/she is a bacteria sized person capable of executing all actions that a human can do. The shrunk person is placed inside the blood vessel or ...


1

This is a very interesting question. As others have alluded to, the body generally recognises self and non-self. However, as with any biology it's not that simple. Even leaving aside autoimmune disorders, the body doesn't always attack non-self and doesn't always leave self alone. Think of a pregnancy - the foetus is non-self, and yet the body doesn't reject ...



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