Purines - ANSWER Bases with a double-ring structure.
Adenine and Guanine
Pyrimdines - ANSWER Bases with a single-ring structure (cytosine, thymine,
... [Show More] uracil)
How polynucleotides form - ANSWER mononucleotides join together by condensation reaction between the deoxyribose sugar group of 1 mononucleotide and a phosphate group of another mononucleotide. This forms a phosphodiester bond.
Complementary base pairing - ANSWER A complements T (forming 2 hydrogen bonds)
C complements G (forming 3 hydrogen bonds)
Structure of DNA - ANSWER A single strand of DNA has two different ends. Due to the orientation of the deoxyribose sugar, there are two ends:
The starting point of a single DNA strand is known as the 5' (five prime) end.
The end point of a single DNA strand is known as the 3' (three prime) end.
DNA is made up of two complementary polynucleotide chains and the two strands are antiparallel. One strands goes from 5' to 3', and the opposite strand goes from 3' to 5'.
Hydrogen bonds hold the polynucleotide chains together. The hydrogen bonds form between complementary base pairs on two nucleotides.
Features of DNA - ANSWER The sugar-phosphate backbone of the structure provides strength.
Coiling gives it a compact shape.
The sequence of bases allows it to be stored as long molecules.
Double helix protects the hydrogen bonds, which makes the molecule stable.
Many hydrogen bonds gives stability, preventing the code from being corrupted.
Hydrogen bonds allows chains to be split for replication, transcription and expression.
Comparing between DNA and RNA - ANSWER Both are polynucleotides.
RNA is single-stranded, whereas DNA is double stranded (double helix)
RNA is relatively shorter than DNA
RNA has a ribose sugar group whereas DNA has a deoxyribose sugar group.
RNA contains uracil in replacement of thymine.
rRNA - ANSWER Combines with proteins to form ribosomes.
Ribosome = 50% RNA + proteins
mRNA - ANSWER Copies the genetic code from the DNA and takes it to the ribosomes.
It is complementary to DNA (the antisense/coding strand)
A copy of the other DNA strand (the sense strand)
Easily broken down and exists when needed to make a protein. [Show Less]