Genome Structure Flashcards
What does DNA stand for?
deoxyribose nucleic acid
What makes up the backbone strands of DNA
deoxyribose sugars and phosphate groups
What make up the ‘bases’ of DNA?
nucleotides
are the bases and backbone in DNA hydrophobic or hydrophilic?
backbone = hydrophilic
bases = hydrophobic
What links the phosphate/sugars together to make up the backbone of DNA?
a phosphodiester bond - links the C3 of a sugar to the C5 of the next sugar - these are covalent bonds and they are the strongest bonds in DNA
What nucleotide bases ‘pair’ together?
Adenine with Thymine (uracil)
Guanine with Cytosine
What regions of DNA are more thermodynamically stable?
The GC-rich regions
What is the length of DNA in every human cell?
1.8 meters of DNA in each cell - subdivided into 46 individual molecules - each about 3.8 cm long
During what phase of cell division can we do a G banded karyotyping?
We can do this in metaphase as they different chromosomes are splitting
What is Chromatin?
coiled nucleosomes
What is the centromere?
it is the “belt” on DNA - where two sister chromatids fuse and where they mitotic spindles attach
what are the origins of replication?
They are the point at which DNA synthesis is initiated
What are the telomeres?
telomeres ‘cap’ the ends of chromosomes and act as a buffer from degradation - they maintain the structural integrity
What is the difference between heterochromatin and euchromatin?
heterochromatin = highly condensed, no transcription occurs here
euchromatin = extended, active transcription, gene rich areas
What percentage of our genome codes for genes?
5% of our genome
