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base
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. Dictated by specific hydrogen bonding patterns, "Watson–Crick" (or "Watson–Crick–Franklin") base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA. The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and RNA polymerase transcribes DNA into RNA. Many DNA-binding proteins can recognize specific base-pairing patterns that identify particular regulatory regions of genes.
Intramolecular base pairs can occur within single-stranded nucleic acids. This is particularly important in RNA molecules (e.g., transfer RNA), where Watson–Crick base pairs (guanine–cytosine and adenine–uracil) permit the formation of short double-stranded helices, and a wide variety of non–Watson–Crick interactions (e.g., G–U or A–A) allow RNAs to fold into a vast range of specific three-dimensional structures. In addition, base-pairing between transfer RNA (tRNA) and messenger RNA (mRNA) forms the basis for the molecular recognition events that result in the nucleotide sequence of mRNA becoming translated into the amino acid sequence of proteins via the genetic code.
The size of an individual gene or an organism's entire genome is often measured in base pairs because DNA is usually double-stranded. Hence, the number of total base pairs is equal to the number of nucleotides in one of the strands (with the exception of non-coding single-stranded regions of telomeres). The haploid human genome (23 chromosomes) is estimated to be about 3.2 billion bases long and to contain 20,000–25,000 distinct protein-coding genes. A kilobase (kb) is a unit of measurement in molecular biology equal to 1000 base pairs of DNA or RNA. The total number of DNA base pairs on Earth is estimated at 5.0×1037 with a weight of 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).
I have recently installed a new shower, I was standing on a stool and doing the final touches with silicone and the stool slipped and went straight through the shower trap base.. The tray has been mortered in and is solid all glass panels fixed so ripping it out sounds like an absolute disaster...
I have a new kitchen mixer tap and water drips out from the chrome collar around the swivel base. Can somebody please tell me if this collar should be tight as I can move it with my hand and if it while be tight would that cause water to drip as the seals inside should be ok if the tap is only a...
Hi
The aluminium plastic cover keeps coming off as one of the plastic plugs on the shower base has snapped off. I would like to remove the base which is clamped onto the shower tray.
Please see photo. Does anyone know how I can get it off, I presume it unscrews anti clockwise
but I don't see...
Hi All,
I've recently purchased a flat built in the 1930's and am having some trouble with the central heating.
Firstly it's an indirect boiler (two cisterns on the loft with expansion pipes) but only run by an electrical immersion heater.
I've replaced the old 27" immersion heater (it's...
ozhall
Thread
base
central
central heating
cold
cylinder
heating
hot
immersion
no central heating
still
Picked one up at lunchtime today, bargain.
http://www.diy.com/departments/stanley-250mm-tool-bag/141666_BQ.prd
http://www.NoLinkingToThis/p/stanley-fatmax-hard-base-tool-bag/76628
I am I'm the process of quoting for a complete oil heating system including tank and base. It will be a concrete base and I will be getting a builder in to do it as I don't want that hassle but so I know it's all done right will they have to dig out, put hardcore down, sand over that then concrete?
I seem to get water leaking from the bottom of my bathroom sink, it only seems to happen say when I have basin full of water to have a wash then when I pull the plug there seems to be water dripping from the base of sink onto floor, I cant seem to work out where the water is leaking from or how...
hughwon
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base
basin
bathroom
leak
leaking
seems
sink
waste
water
water leak
Hi All
I have moved into my first home with my wife.
We have a toilet which leaks from from a specific point at the base after flushing. I *think* the water is fresh. The amount that leaks ranges from barely visible, to a patch about palm-size. The latter seems to happen if something else in...
spaniard5
Thread
around
attach
base
dishwasher
flush
leaking
oil
toilet
water
worse
Hi all,
Just quickly...fitted a new Riello 40 burner about 5 weeks ago and all was fine until get call today to say customer had run out of oil but since oil delivery the burner was not firing up. Thought might be just a quick case of bleeding the pump but when I got there I found the base of...
Whilst checking drain hole in shower tray, I noticed that there is a good few inches of water lying in the base.
Excuse my ignorance, but is this normal or should this water have drained away.
Any advice would be appreciated.
gordmar
Thread
base
drained
inches
lying
should
shower
shower tray
tray
water
Hi all, I have a bristan java mixer tap, please see exploded diagram here. Basically it leaks whenever i move the spout into a certain position, or especially if i accidently hit the spout with something, so that it moves up-downward, from the spout base it leaks water onto the worktop.
I...
Hi. I moved into a newly built property 10 months ago. We have had a few leaks recently. My current problem is in our en suite bathroom- the toilet is leaking water, it appears on the tiled floor and seems to be coming from under the base of the toilet. Research I have done so far suggests it...
Hi,
I have just installed a new toilet but it appears to have a very small leak from the base.
I have felt all around the back and on the inlet pipe etc and it's bone dry. The waste pipe (the big pipe that takes all the stuff away) is also dry.
I have marked the water level in the pan and...
Hi can anybody help
had to change doughnut washer on downstairs loo. brought new washer and connector kit and assembled and checked for leaks with no problem. Noticed a small air bubble rising from bowl when you wee in it. have checked for blockages ect outside in main drain and ok. have...
PEE GROOVER
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around
base
check
close
connector
coupled
crack
leaking
oil
problem
toilet
Hi there.
I'm replacing an existing toilet in our downstairs cloakroom. The soil connector on the base of the new toilet is quite a bit higher than the old, so I needed to replace the soil pipework. Also wanted to make a clean start and not use filthy 20 year old pipes.
Put together what I...
Some fitter has put my HW tank on a peice of chipboard which I see is bending. How can anyone of experience do this as chipboard is not structural? Advice on what to use would be appreciated before I drain, support and renew the support.
I have a 120 firebird that I want to service and put back to factory settings (jet type, oil pressure, base air setting) and then fine tune from there
as ever customer (and unfortunetly friend) has no manuals and I cant find any manuals online to give me the definitive answer. We are not even...
ar22
Thread
air
bar
base
burner
firebird
manuals
oil
pressure
settings
Hi, if anyone can help it would be amazing - over the last week the mixer tap in my kitchen has started seeping water from its base - it has slowly got worse and is now constantly leaking.
I'm sure there is a simple solution and I don't want to have to pay a plumber to come and sort it if I can...
jk83
Thread
base
cold
help
help needed
help required
hot
included
kitchen
leak
leaking
mixer
mixer tap
pipe
please
plumber
plumbing
screw
sink
tap
taps
valve
washer
water
water tap
work
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