biochem notes

Essay by ashxoxxoxoUniversity, Bachelor'sA+, November 2014

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- Nucleotides come together to form nucleic acid.

- There is a linkage between the 5' PO4- group and the 3'OH group. (3'5' phosphor-diester bond links nucleotides together).

Invariant region: The backbone which is highly negative due to the phosphate group… there is a repeating unit (found in both DNA and RNA) [carbohydrate- phosphate- carbohydrate-…]

Varibal eregion: different series of nitrogenous bases connected to the backbone. This is how genetics is passed on generations.

Polymers are measured in base pairs. (humans have 3 trillion pb in DNA The DNA is 1% of the cell).

Major types of RNA: Ribosomal RNA (rRNA)- Transfer RNA (tRNA)- Messanger RNA (mRNA)… they are heterogeneous and have different shapes and densities. A cell is 5-10% of the cell mass.

Nucleic acids have acidic regions

The variable region is aromatic. It is hydrophobic. They are not protonated and they are uncharged. Therefore they do not act as acids/ bases.

There is difference between the charge of the bases and the backbone (negatively charged) this rises polarity.

In an aqueous environment, the backbone is more accessible to the solvent while the bases cluster together and away from the water.

Even though they are hydrophobic, the nitrogenous bases of the variable region is still capable of hydrogen bonding.

Adenine hydrogen bonds to Thymine (2 H bonds)

Guanine hydrogen bonds to Cytosine (3 H bonds)

1 polycyclic to 1 monocyclic

Antiparallel direction of the backbone (5' PO4 to 3' OH)

Asides from hydrogen bonding, there are also vanderwaal interactions. Hydrophobic interaction of the bases above and below the nitrogenous bases referred to as the stacked bases interaction…the pi orbitals between the bases interact with the other bases above and below it on the same strand.

Therefore 2 types of interactions

DNA exists as a double helix… Watson and...