All categories - 10 September 2006

percentage of it can be successfully shifted by the end of the year 2500 ?

2006-09-10 21:32:13 · 7 answers · asked by orsel 2 in Astronomy & Space

Can someone please help me revise this? give me advice?

One may wonder how a single cell becomes two cells, and why this is ultimately important to life. For this essay, it would be much too difficult to discuss the process of cell division, which is the biological basis of life. That being said, this essay will examine more closely the precursor to cell division, also known as DNA replication. DNA replication is the process of copying a double-stranded DNA strand on a chromosome within a cell. The process, in its totality, is a sequence of three basic steps: initiation, elongation, and termination.

To understand the process of DNA replication, you much first be familiar with the structure of DNA. Resembling a twisted ladder or a zipper, DNA is a double helix formed with nucleotides (structural units of DNA containing a base, a sugar, and one or more phosphates), a phosphate and sugar backbone, and nitrogenous bases. There are four bases, and each one will only bond with its complement. Adenine will only bond with Thymine, and Cytosine with only Guanine. The double helix is antiparallel, meaning each strand runs in a different direction.

Initiation, the first step to DNA replication is the unwinding of the double helix with the help of an enzyme called helicase. Once unwound, the DNA unzips and the bonded nucleotides are separated.

In the next stage, elongation, an enzyme called DNA polymerase is important. The DNA polymerase attaches to each strand at the replication origins, reading the nucleotides and finding the complement base. Because the leading strand runs in the same direction that it was unzipped, the DNA polymerase moves with ease down the length of the strand. Because human DNA is so very long (with up to 80 million base pairs in a chromosome) it unzips at multiple places along its length so that the replication process is going on simultaneously at hundreds of places along the length of the chain. Eventually these areas run together to form a complete chain. The lagging strand, however, runs in the opposite direction that it was unzipped, making it harder for the DNA polymerase to move down the strand, so it keeps returning to the strand until the job is done. Proof reader enzymes then run down the strand detecting and fixing errors.

To complete the replication, the new strands are paired with their corresponding original strands. This is called semi-conservative because there is one new and one old strand combined. The strands are rewound into a double helix with the help of enzymes. The cell then prepare for mitosis where a copy of the DNA will be sent to each nucleus, then cells will go through ctytokinesis, where a nucleus will be distributed to each cell. This process has provided the daughter cell with an exact copy of DNA from its parent.

DNA polymerase makes very few errors, and most of those that are made are quickly corrected by DNA polymerase and other enzymes that "proofread" the nucleotides added into the new DNA strand. If a newly added nucleotide is not complementary to the one on the template strand, these enzymes remove the nucleotide and replace it with the correct one. With this system, a cell's DNA is copied with less than one mistake in a billion nucleotides.

With DNA replication, cells will divide thus providing reproduction and life.

2006-09-10 21:31:58 · 0 answers · asked by sball124 3 in Homework Help

2006-09-10 21:31:56 · 13 answers · asked by Anonymous in Cell Phones & Plans

2006-09-10 21:31:50 · 13 answers · asked by vijaykumar n 1 in Higher Education (University +)

2006-09-10 21:31:46 · 8 answers · asked by bocandy 1 in Religion & Spirituality

2006-09-10 21:31:05 · 1 answers · asked by Joel A 1 in Other - Education

2006-09-10 21:30:47 · 48 answers · asked by shagkitten21 3 in Current Events

just wondered if you guys could spare a cyber hug????

2006-09-10 21:30:34 · 32 answers · asked by hartshorntracy 4 in Friends

I know that I can buy another copy of the visualizer from the company that made it, but I think this feature should be added to the Itunes I already own.

2006-09-10 21:30:16 · 1 answers · asked by Chris 1 in Software

2006-09-10 21:30:14 · 11 answers · asked by NONAME 3 in Singles & Dating

She refused to answer the simplest of questions and then kills herself before the where abouts of her son are known. Do you think Melinda is responsible for her sons disappearance

2006-09-10 21:30:13 · 2 answers · asked by Chad 7 in Current Events

I'm getting a pet rat. Any tips for me? It's only a small one.
I've never had a rat before so I'd like to know a bit more about them.
If you have or have had a rat can you please tell me all you know?!
(it's cream coloured and has red eyes, if this makes any difference)

2006-09-10 21:30:06 · 10 answers · asked by Anonymous in Other - Pets

I have heard that the thicker the fabric, the better; is this correct? Something like a velveteen? Should the nap face downward, or does it even matter? I was thinking to attach it at the wall, on towel bars (using velcro) or similar. I have been trying to locate the "how to" on this project, but have been unsuccessful. I am interested to know how this is usually accomplished, professionally; there is no "example" within driving distance for me to "check out". I am required to be a jack-of-all-trades or problem fixer at my place of employment. It is not possible to hire an interior decorator or acoustics specialist for this project. Help! Your advice will be greatly appreciated!

2006-09-10 21:29:58 · 3 answers · asked by tama 2 in Do It Yourself (DIY)

2006-09-10 21:29:44 · 17 answers · asked by volga 1 in Earth Sciences & Geology

2006-09-10 21:29:40 · 6 answers · asked by Emily_sweet 1 in Wrestling

2006-09-10 21:29:39 · 18 answers · asked by Anonymous in Religion & Spirituality

Just want to let the People in America that i'am thinking of them on this most HORRIFIC date in History,From the Uk

2006-09-10 21:29:33 · 10 answers · asked by Anonymous in Other - Society & Culture

I mean is the Magic Kingdom to kiddy for these ages or what? I'm talking about out of all the parks from Disney .....like Animal Kingdom and so forth? Thx!

2006-09-10 21:29:29 · 8 answers · asked by Anonymous in Orlando

2006-09-10 21:29:29 · 16 answers · asked by Anonymous in Movies

2006-09-10 21:29:29 · 10 answers · asked by gelboy_777 1 in China

I am a Resident Advisor at a unitiversity for a freshman's dorm. I have one resident who is very uncomfortable about her roommate who has guys sleep over a lot of the time. She does not want to confront her roommate about the situation because she does not want tension with her roommate. As the RA, my job is to cite people who break these types of violations. I have not yet caught her roommate in order to give a citation, but have been in my office when she was about to bring a guy in after visiation hours until she saw me in my office on the hallway. Her boyfriend lives faraway and I feel bad for both of the residents in the situation because one has to feel uncomfortable with strange men in the room and the other does not have a place to allow her boyfriend. How do I talk to both of them? I know that I need to be fair to the one who is uncomfortable with strange men in her room,but how do I address the other roommate?

2006-09-10 21:29:10 · 3 answers · asked by soulplane 1 in Higher Education (University +)

to me it seems as if the law enforcement policies in the uk are going over the top, why do we have civilians in uniform patrolling our streets when it should be the police which is their job, and they are paid.
we need the police to get out of their fancy cars and back on the streets because a visible prescence is far more effective than cameras that do not work,and civilians who think they are cops walking the streets are a recipe for disaster, how long before someone is killed, train these people to be police instead of giving them a uniform and sending them out to enforce laws the know nothing about

2006-09-10 21:29:04 · 9 answers · asked by mentor 5 in Law Enforcement & Police

2006-09-10 21:28:56 · 6 answers · asked by orion 3 in Other - Society & Culture

more correct in writing English not in spoken En....

2006-09-10 21:28:49 · 8 answers · asked by mesnowz 1 in Words & Wordplay

I konw a lot of English girls think C.Ronaldo is hot, but Kaka I think is better looking and his footworks are just as good, its just that he plays in SERIE A so obviously Ronaldo who plays in the Premiership will be more known in the UK

2006-09-10 21:28:48 · 6 answers · asked by won l 1 in Celebrities

and it takes me ages to wake up. I feel 'floppy'.
Anyone else with the same symptoms?
Is this normal with these drugs?

2006-09-10 21:28:13 · 8 answers · asked by fatface 2 in Other - Diseases

My List:

1. Beethoven
2. Mozart
3. J.S. Bach
4. Mahler
5. Shostakovich

2006-09-10 21:28:08 · 4 answers · asked by Anonymous in Music

Like someone make a accussation, that thing u did not do,and put u into trouble,create problem for you what shall I do

2006-09-10 21:28:04 · 3 answers · asked by sadihan bin salahudin s 1 in Other - Health

Only sensible answers please.
I want to know what they think fossils are.
Do they not believe that people were shorter 500 years ago? Why do they think doors on old houses and graves were smaller? Do they not take this as evidence of the population changing over time?
Do they believe that there were ice ages? WHat do they think happened to plants and animals during this period?

2006-09-10 21:27:59 · 10 answers · asked by Bebe 4 in Biology