Nucleic Acids Flashcards
U1L7
What are the two types of Nucleic Acids?
DNA (Deoxyribonucleic)
RNA (Ribonucleic)
What is DNA?
DNA holds the genetic information of a cell. It is located in the nucleus of the cell.
DNA works with RNA to determine the sequence of Amino Acids in proteins (primary structure).
What are the 4 Nitrogenous bases of DNA?
Adenine (A)
Cytosine (C)
Thymine (T)
Guanine (G)
There are all based on two chemical structures, Purines and Pyrimidines.
What is the purpose of Nucleotides?
Nucleotide monomers essentially link together to make nucleic acid polymers.
What are the three parts of a nucleotide?
Nucleotides have 3 groups:
Phosphate
Deoxyribose (sugar)
Nitrogenous Base (A,C,T,G)
How do nucleotides link?
Nucleotides link through Condensation reactions. These reactions form phosphodiester linkages.
How do DNA strands work?
DNA is double stranded.
One strand is attracted to the other complimentary strand from Hydrogen Bonds.
Adenine pairs with Thymine causing 2 hydrogen bonds whilst Cytosine pairs with Guanine causing 3 hydrogen bonds.
Both of these strands run in OPPOSITE directions (hence antiparallel double helix).
The H-bonds and phosphate/sugar backbone cause the DNA to twist.
What’s RNA?
RNA is similar to DNA with the exception that it’s:
Single stranded
Has a Uracil nitrogenous base instead of Thymine
Uses ribose sugar as a backbone instead of deoxyribose.
What’s the process from DNA to protein?
Because DNA cannot survive outside the nucleus without being digested by enzymes.
DNA gets transcribed in to a single strand RNA molecule which leaves the nucleus and attaches to ribosomes.
Ribosomes then translate the molecule into Polypeptides which go on to form proteins.
How much DNA do we have?
ALOT.
46 chromosomes in 23 homologous pairs.
Over 3 billion base pairs (ACTG).
These are packaged tightly into chromosomes using histone proteins.
