The structure of DNA double helix and how it was discovered. Chargaff, Watson and Crick, and Wilkins and Franklin.
Log in jakduir1 8 years agoPosted 8 years ago. Direct link to jakduir1's post “What is a codon and how d...” What is a codon and how does it relate to a DNA function and structure ? • (17 votes) Natassja Ellen Brien 8 years agoPosted 8 years ago. Direct link to Natassja Ellen Brien's post “A codon is the name for a...” A codon is the name for a group of three subsequent nucleotides in RNA. Since RNA is transcribed from DNA, the DNA sequence will determine the sequence of RNA, the codons, and ultimately what amino acids come together to form a protein. If a DNA sequence (template strand) goes CTTAGG, the corresponding RNA will read GAAUCC. In this sequence there are two codons: GAA followed by UCC, which will code for amino acids. (55 votes) samarth6899 8 years agoPosted 8 years ago. Direct link to samarth6899's post “well I have 2 doubts:1) ...” well I have 2 doubts: • (9 votes) Sanjana 8 years agoPosted 8 years ago. Direct link to Sanjana's post “As far as the 2nd questio...” As far as the 2nd question is concerned , it is because the double helix should have a uniform diameter all throughout otherwise there might be problems during the supercoiling . Now if , purine is bonded to purine , both being bigger , would end up in a diameter that would be larger than that formed by the 2 pyrimidines and thus the diameter would be uneven . The fact that A will pair T and G with C was found experimentally . Manar Al-Masri 6 years agoPosted 6 years ago. Direct link to Manar Al-Masri's post “I want to make sure I hav...” I want to make sure I have these ideas true! • (5 votes) tyersome 6 years agoPosted 6 years ago. Direct link to tyersome's post “Seems mostly correct.Th...” Seems mostly correct. The one mistake I notice is that I think the word you were looking for was histones (not histamin). Note that the non-coding DNA between genes is very diverse and much of it is composed of many different families of repeated sequences including multiple types of transposons and inserted retroviral genomes. (10 votes) Big M 8 months agoPosted 8 months ago. Direct link to Big M's post “This is the point in the ...” This is the point in the High School Biology Course that everyting gets a bit complicated, I can tell • (8 votes) choui003 5 years agoPosted 5 years ago. Direct link to choui003's post “Am I understanding this c...” Am I understanding this correctly? The amount of the total bases in a cell's DNA is always the same in each organism in a species, but the amount of each type of base (A,T,G, and C) in a cell's DNA can vary between organisms in the same species. And is the double-helix form of DNA its condensed or decondensed form? Thanks! • (6 votes) Ivana - Science trainee 5 years agoPosted 5 years ago. Direct link to Ivana - Science trainee's post “Not exactly.The amount ...” Not exactly. The amount of each type of base in a cell's DNA is the same in all cells in the whole organism. Genetic code is the same, but gene expression is different. What is different is proprotion of AG to CT for each species and defined as a different number (CHargaff's rule). The condensed form is chromosomes. The double helix is always double helix, regardless of being part of Euchromatin or Heterochromatin. So, in metaphase, you can only see the condensed form of chromosomes. But you can isolate DNA (extract) by various methods and see t by the naked eye as well. Hope this helps :D (5 votes) RIP_LAW 2 years agoPosted 2 years ago. Direct link to RIP_LAW's post “What is the difference be...” What is the difference between DNA and RNA • (3 votes) FrozenPhoenix45 2 years agoPosted 2 years ago. Direct link to FrozenPhoenix45's post “I will answer you the way...” I will answer you the way I have answered this question before with other users. I hope it is adequate. There are several differences. To start, DNA stands for deoxyribonucleic acid, while RNA stands for ribonucleic acid. These names describe the sugar that makes up their backbone--DNA = deoxyribose and RNA = ribose. Second, while each has four nucleiotide bases, there is one difference. You probably know that DNA has guanine, cytosine, adenine, and thymine, and that guanine links to cytosine and adenine links to thymine. But RNA doesn't have thymine. Instead, it has uracil, a nucleiotide base with a slightly different chemical makeup. Thymine had the chemical formula C5H6N2O2 and uracil is C4H4N2O2. Uracil links to adenine in RNA just like thymine does in DNA Finally, DNA is double-stranded and forms a double helix structure. RNA is single-stranded and is generally straight. DNA is a complete set of instructions needed for life (unless you're a virus, but that's a whole different story/debate) and RNA is used to copy DNA and to synthesize proteins. I know this is a lot to take in, but there are several videos and articles on Khan Academy to help. Here are a few. https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/v/molecular-structure-of-rna https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/v/rna-transcription-and-translation https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/a/hs-rna-and-protein-synthesis-review Anyway, this is probably a lot, but I hope it helps! (8 votes) Katherine Butseev 8 years agoPosted 8 years ago. Direct link to Katherine Butseev's post “Why is adenine a purine b...” Why is adenine a purine base? • (4 votes) RowanH 7 years agoPosted 7 years ago. Direct link to RowanH's post “I'm not sure it is the NH...” I'm not sure it is the NH2 group which accepts protons most readily to make it a base. I think it could be the nitrogens in the rings, which I think also have lone pairs of electrons that could accept a H+. I think on the other hand the NH2 nitrogens the lone pair electrons are delocaslised so wouldn't make it very basic. (3 votes) SorensenAbigail 7 years agoPosted 7 years ago. Direct link to SorensenAbigail's post “How can you tell the heli...” How can you tell the helix is right handed? • (4 votes) Katherine 7 years agoPosted 7 years ago. Direct link to Katherine's post “You can tell if if the he...” You can tell if if the helix is right handed or left handed based on the way it twists. Here's a link to an image that shows the difference between a right and a left. Hope this was helpful! https://www.google.com/imgres?imgurl=http://1.bp.blogspot.com/-a9mozeRTQ3M/VQ7VbFXcLfI/AAAAAAAAXpc/FLsA3yb63nU/s1600/right%252Bvs%252Bleftt%252Bhanded%252BDNA.jpg&imgrefurl=http://sandwalk.blogspot.com/2015/03/on-handedness-of-dna.html&h=357&w=222&tbnid=4six7X82OnMXYM:&tbnh=160&tbnw=99&usg=__3ts8S2DUkv-GCt810cHksqyLH48=&vet=10ahUKEwjiubHonbbTAhXkzIMKHXmRDe0Q9QEIJTAA..i&docid=bxjwHpzOd_V1PM&sa=X&ved=0ahUKEwjiubHonbbTAhXkzIMKHXmRDe0Q9QEIJTAA (2 votes) Brittany Jean Czarnecki 6 years agoPosted 6 years ago. Direct link to Brittany Jean Czarnecki's post “What do the data show abo...” What do the data show about the make-up from different species? Before concluding that the pattern seen in the data is universal, which other types of organisms should tested? Why? • (4 votes) vilceusjimmy 6 years agoPosted 6 years ago. Direct link to vilceusjimmy's post “What are the four differe...” What are the four different kinds of nitrogen bases? • (1 vote) Scout Finch 6 years agoPosted 6 years ago. Direct link to Scout Finch's post “The four nitrogenous base...” The four nitrogenous bases are as follows: Adenine, Thymine, Guanine, and Cytosine. (7 votes)Want to join the conversation?
1) in the second para under the topic 'right hand helix' i couldn't understand as to why DNA is a right handed helix
2) in the second para under the topic 'base pairing' how exactly is the bigger size of purines and small size of pyramidines affecting the bond length?
It may have nothing to do with the article but I found it relevant.
Starting from zero:
We all have 2 copies of chromosomes; one from the mother and the second from the father.
Each chromosome is formed of DNA and proteins ( basically histamin) .
DNA is a double helix; 2 strands, each one has coding areas ( which are 2% and maybe less) and non-coding areas . Within the gene itself there are non-coding sequences which their name is “ introns “.
The non-coding area (outside the gene) of DNA strand has different types of sequences ; satellites and repeated sequencing .
Is that true for now?
Chromatin is composed of DNA plus associated proteins and RNAs. These other molecules organize, fold, protect, and control the DNA.
A major component of chromatin are nucleosomes — a twist of DNA wrapped around an octamer of histones.
Cytosine and Thymine are pyrimidines
Adenine and Guanine are purines.
Adenine and Thymine are a complementary pair.
Cytosine and Guanine are a complementary pair.
Hope that helps!
