STRUCTURE OF DNA AND RNA
SOURCE: PEARSON BOOK/ CLASS POWER POINTS
Understandings:
• The nucleic acids DNA and RNA are polymers of nucleotides.
• DNA differs from RNA in the number of strands present, the base composition and the type of pentose.
• DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs.
Applications and skills:
• Application: Crick and Watson’s elucidation of the structure of DNA using model making.
• Skill: Drawing simple diagrams of the structure of single nucleotides of DNA and RNA, using circles, pentagons and rectangles to represent phosphates, pentoses and bases.
Guidance:
• In diagrams of DNA structure, the helical shape does not need to be shown, but the two strands should be shown antiparallel. Adenine should be shown paired with thymine and guanine with cytosine, but the relative lengths of the purine and pyrimidine bases do not need to be recalled, nor the numbers of hydrogen bonds between the base pairs.
Understandings:
• The nucleic acids DNA and RNA are polymers of nucleotides.
• DNA differs from RNA in the number of strands present, the base composition and the type of pentose.
• DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs.
Applications and skills:
• Application: Crick and Watson’s elucidation of the structure of DNA using model making.
• Skill: Drawing simple diagrams of the structure of single nucleotides of DNA and RNA, using circles, pentagons and rectangles to represent phosphates, pentoses and bases.
Guidance:
• In diagrams of DNA structure, the helical shape does not need to be shown, but the two strands should be shown antiparallel. Adenine should be shown paired with thymine and guanine with cytosine, but the relative lengths of the purine and pyrimidine bases do not need to be recalled, nor the numbers of hydrogen bonds between the base pairs.
nucleotides are the building blocks of nucleic acids
There are 3 major examples of nucleic acids in nature. They are adenosine triphosphate ATP, deoxyribonucleic acid DNA, and ribonucleic RNA. ATP functions as an energy storage compound. Other nucleic acids function as coenzymes.
Both DNA and RNA are polymers of nucleotides. Individual nucleotides are referred to as monomers and always consist of 3 major part: one phosphate group, one 5-carbon monosaccharide, and a single nitrogenous base. Chemical bonds occur at specific locations in order to produce a functional unit.
Both DNA and RNA are polymers of nucleotides. Individual nucleotides are referred to as monomers and always consist of 3 major part: one phosphate group, one 5-carbon monosaccharide, and a single nitrogenous base. Chemical bonds occur at specific locations in order to produce a functional unit.
All the bonds within the ncleotide involve the sharing of electrons and are therefore referred as covalent bonds. The phosphate group is the same in DNA and RNA. However there are 5 possible nitrogenous bases:
The base uracil only occurs in RNA, not DNAm and the base thymine only occurs in DNA, not RNA.
The sugars differs in the nucleotide of DNA and RNA. DNA nucleotides contain the pentose known as deoxyribose and RNA nucleotides contain ribose.
monomers into polymers
Monomers are single nucleotides in both DNA and RNA, may bond together to produce long chains or polymers. In the picture besides, each nucleotide has been drawn in a different color to emphasize the nucleotide structure. The chain has an alternative pentose-phosphate backbone, with the nitrogen bases extending outward. The importance of the order of the bases has to do with their genetic code. The nucleotides attach to one another to form a chain as a result of condensation reactions forming connected covalent bonds.
single strand or double strand
RNA is composed of a single chain or strand of nucleotides, while DNA consists of 2 separate chains or strands of nucleotide connected to one another by weak hydrogen bonds. The strands of both DNA and RNA may involve very large numbers of nucleotides. The DNA molecule is double stranded and it function as a ladder. The rungs of the ladder are made of the bases, because the ladder has 2 sides there are 2 bases making up each rung. The 2 bases are complementary to each other and are A-T, C-G and in RNA A-U, C-G.
It is essential to note that one strand of DNA has 5-carbon often referred to as the 5-prime (5') carbon, unattached and on top. At the bottom of that same strand notice that the 3- or 3-prime (3') carbon is unattached. If you look at the opposite strand of deoxyribose and phosphates, you will notice it is the opposite: the 3' carbon is at the top and the 5' is at the bottom. These 2 strands are therefore said to be antiparallel to one another. Electrical charges related to the molecules of the 2 strands cause a characteristic twisting action of the DNA ladder to produce the double helix shape that Watson and Crick described int he model proposed in the early 1950s
It is essential to note that one strand of DNA has 5-carbon often referred to as the 5-prime (5') carbon, unattached and on top. At the bottom of that same strand notice that the 3- or 3-prime (3') carbon is unattached. If you look at the opposite strand of deoxyribose and phosphates, you will notice it is the opposite: the 3' carbon is at the top and the 5' is at the bottom. These 2 strands are therefore said to be antiparallel to one another. Electrical charges related to the molecules of the 2 strands cause a characteristic twisting action of the DNA ladder to produce the double helix shape that Watson and Crick described int he model proposed in the early 1950s
Theory of knowledge:
• The story of the elucidation of the structure of DNA illustrates that cooperation and collaboration among scientists exists alongside competition between research groups. To what extent is research in secret ‘anti-scientific’?
What is the relationship between shared and personal knowledge in the natural sciences?
I think that the research in secret is not considered anti-scientific as long as when you finish it you publish so other people can know about it, and more if it is something beneficial of the human being like a cure or a new medicine. Sometimes it is better to work as a secret so you dont have the pressure of failing if something goes wrong. The scientific world is really competitive, everyone is always rushing up their experiments to be the first one to publish something out there and gain recognition. In natural sciences, shared knowledge is when everyone accepts an statement, like "the sky is blue" that is shared knowledge because everyone in the world knows it. Personal knowledge is more about your opinion, like "The best theory is mine because it explains more in depth" that is personal knowledge, because it is not sure that more people thinks the same.