MCBG - Intro To DNA Flashcards
What is the width of a strand of DNA?
2 nanometres
What are the circular cores of nucleosomes called?
Histones
What is the name given to tightly ravelled nucleosomes?
Solenoids
What do genes carry?
The code for proteins. They have a chromosomal location.
How many chromosomes does a human have?
22 pairs plus two sex chromosomes, XX or XY
What is the difference between a nucleotide and a nucleoside?
Base + sugar + phosphate = nucleotide
Base + sugar = nucleoside
What are polynucleotides?
Linear polymers of nucleotides
What is the difference between the sugar on DNA and RNA?
On DNA is termed “deoxyribose” and has H on 2’ carbon. On RNA has OH group and is termed “ribose”.
What is the difference between a purine and a pyrimidine?
Purines have two rings, pyrimidines have one ring.
Which bases are purines?
Adenine and guanine
Which bases are pyrimidines?
Cytosine, uracil, thymine.
Which pair of bases has three hydrogen bonds rather than the usual two?
G-C
What catalyses DNA replication?
DNA polymerase
In which direction does DNA replication occur?
5’ to 3’
What are Okazaki fragments?
Short sections of replicated DNA that form in the 5’ to 3’ direction on the lagging (top) strand during DNA replication.
