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Post by melanie on Apr 15, 2012 20:20:10 GMT -5
What/Where is the origin of replication? - The origin of replication is where proteins bind to a specific site on DNA signalling the start of replication.
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Post by Miss DiFederico on Apr 15, 2012 20:21:12 GMT -5
Which property of DNA makes semiconsertive replication possible? a) complimentary b) double helix c) antiparallel d) made of monomers
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Post by melanie on Apr 15, 2012 20:23:26 GMT -5
Which cell's DNA has more origins of replication eukaryotes or prokaryotes? Why? Eukaryotes have multiple origins of replication where as prokaryotes only have one (usually) This is because DNA in eukaryotes is longer and linear. If there are multiple origins of replication the replicating process is sped up
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Post by melanie on Apr 15, 2012 20:31:40 GMT -5
Hey guys I just realised this is a very basic question but nonetheless I think its important because it gives meaning to our whole unit... Why is DNA replication necessary?
-Cells can give rise to a new generation of cells through DNA replication and cell division. This is essential because without it growth, repair and regeneration of cells and tissues would not be possible
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seema
New Member
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Post by seema on Apr 15, 2012 21:05:48 GMT -5
Hey guys, for the most recent practice question Miss DiFederico posted, I feel like the answer is A)complementary but I'm not sure...any one think its that answer or a different one?
You are right. The answer is A. If DNA was not complimentary, it would not be possible for replication to occur. If adenine could be paired with thymine or cytosine, there would be no way of knowing which pair to make at which time. So because adenine can only be paired with thymine, the DNA poly III always knows which base to add. Think of it like a married couple. If you knew I was married to Nick Carter, then every time you saw me you could expect to find Nick somewhere nearby. But if all you knew was that I was married to a Backstreet Boy, then there would be 4 possible men to expect and no way of predicting who you would find.
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Post by melanie on Apr 15, 2012 21:11:12 GMT -5
Hi Seema I was going to go with A too it seems like the best fit
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seema
New Member
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Post by seema on Apr 15, 2012 21:19:37 GMT -5
Thanks Miss and thank you Melanie! It makes a lot of sense now and thats a great analogy I must say
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Post by Andrea on Apr 16, 2012 18:36:21 GMT -5
Hey miss! The test was great, we all appreciated that very much. Also, I just wanted to say that I hope your interview went well!
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Post by Miss DiFederico on Apr 16, 2012 21:12:19 GMT -5
Glad to hear everything went well. You all worked very hard and will deserve the marks you receive. The fact that the help folder has been viewed 388 times tells me everyone put in a great deal of effort so it is only natural that it should pay off. Keep up the good work everyone!
Also, my interview went very well. Thank you for asking, Andrea.
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Post by melanie on Apr 22, 2012 17:20:33 GMT -5
Hi everyone, I guess I'll start and post some practice questions for this test right now. Good luck to all of you with studying What enzyme is used in transcription? a.) DNA polymerase I b.) RNA polymerase I c.) RNA polymerase II d.) RNA helicase Answer C How does transcription differ from translation? - Transcription occurs in the nucleus where mRNA is formed and DNA and RNA polymerase II are used. Translation occurs in the cytoplasm where mRNA binds to a ribosome and tRNA brings appropriate amino acids that match what the mRNA codons say. Proteins are formed. Why can DNA not leave the nucleus? DNA is vital to the survival of an organism. If it were to leave the nucleus it could be damaged by the causatic environment in the cytoplasm= not good -> I think it would also be good to know the steps associated with transcription and translation and all of those summary and comparison charts in the notes and textbook.
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Post by Miss DiFederico on Apr 22, 2012 19:59:54 GMT -5
Thank you Melanie. Everyone please remember to post your practise questions!!
Which of the following is not true about RNA polymerase II? a) reads DNA 3’ to 5’, build 5’ to 3’ b) uses both DNA strands as templates from transcription c) does not need a primer d) begins at the TAC sequence
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Post by Lisa Kim on Apr 22, 2012 20:46:24 GMT -5
What is the difference between lac operon and trp operon?
lac operon- regulates the production of B-galactosidase and other proteins involved in the metabolism of lactose. -It consists of a cluster of three genes under the control of one promotor and one operator. -The Lacl repressor protein binds to the operator when lactose levels are low. -High levels of lactose induce the operon
trp operon- it regulates the production of the amino acid tryptophan - it consists of a cluster of five genes under the control of one promotor and one operator - the corepressor tryptophan binds to the trp repressor protein, and the complex binds to the operator when tryptophan levels are high - high levels of tryptophan repress the operon.
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Post by Lisa Kim on Apr 22, 2012 20:49:18 GMT -5
And alsooo..... i think the answer to the multiple choice Miss posted is b). :$ Someone correct me if i'm wrong please
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Post by melanie on Apr 22, 2012 21:17:04 GMT -5
I agree with you lil' kim
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seema
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Post by seema on Apr 23, 2012 16:45:45 GMT -5
Question: Show and describe the differences between DNA and RNA
Answer: DNA: double stranded, long (millions of base pairs), one type of DNA, 4 bases: adenine, thymine, cytosine, guanine where A makes 2 H bonds with T and C makes 3 H bonds with G. Also, DNA is too long to leave the nucleus so it stays there.
RNA: single stranded, much shorter than DNA, 4 bases: adenine, uracil, cytosine, guanine where A bonds to U and C bonds to G. RNA can leave the nucleus to enter the cytoplasm.
There is also a structural difference between RNA and DNA where DNA is a deoxyribose sugar having an oxygen on its 2' carbon, whereas RNA is a ribose sugar and has a hydroxyl group on its 2' carbon.
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