DNA and chromosomes

whats the basic structure of DNA called

a double stranded helix (bc it has two strands binded by nucleotides through hydrogen bonds and curves )

what do nucleotides make up and whats the structure

dna, they have a phosphate group, a sugar (deoxyribose in dna and ribose in rna ) and a nitrogenous base.

how many carbons are in deoxyribose in dna

5 carbons. and there is no oxygen at carbon 2

what are nucleotides linked together by

phosphodiester covalent bond (the next nucleotide binds onto the Oxygen molecule at the end of the 3rd carbon on the deoxyribose (3’ end), and 5’ end of new nucleotide binds with phosphate bond in phosphate group

what is the significance of the 2nd carbon in the deoxyribose compared to ribose

it is bonded to a hydrogen

what are the nitrogenous bases and what ring structures do they have

A and G have double ring structures, while T and C have single ring structures

what are the amount of hydrogen bonds that bring together the nitrogenous bases

A and T have 2 hydrogen bonds while G and C have 3 (the more bonds the higher the melting point where the dna denatures)

where would the 3 prime and 5’ end often be

at the end of the oxygen in deoxyribose and the 5’ end would be the phosphorus in the phosphate group

what is the backbone of a nucleic acid

it is the sugar phosphate backbone. made of the phosphorus base and the deoxyribose.

what is significant in the 5' prime and 3' prime end when speaking of both strands

they are anti parallel

how is dna able to fit inside a nucleus

proteins bind to dna to fold It very tight to fit. making chromosomes

what are the top and bottom of a chromosome called and the middle

a telomere is top notch bottom while middle is centromere

whats a duplicated chromosome look like

its 2 chromatid arms, forming an X shape

how many chromosome pairs do humans have

22 plus a sex chromosome so 23 (a chromosome pair has one chromosome from mom and one from dad)

as histones are bonded with dna and form chromatin, what does the initial compaction form

nucleosomes which are just one chromatin and dna wrapped

as dna is negative charge and histones are positive what does this mean

makes it attract and wrap around each other

draw the dna structure or don’t

what's inside each histone octamer

there's 4 diff histones and 2 copies of each. equaling 8 histone proteins

what are the two pathways to open up dna after it has condensed with proteins

1. chromatin remodling complex

2. modification of histone tails

what are the ends of a chromosome called

telomere

what do the centromere and the telomere of a chromosome tend to be

they tend to be condensed which is called heterochromatin

what are the parts of a chromosome that tend to be loose called

euchromatin, this is where important genes will go bc its easier to get access to them

how many hydrogens are in a deoxy

10

how many oxygens are in a deoxy

4