DNA STRUCTURE Flashcards
What does DNA stand for?
deoxyribonucleic acid
what is the role of DNA?
codes for the sequence of amino acids in the primary structure of a protien, which determines the final 3D structure and function of a protiem
what it is and its shape
describe the structure of DNA
a polymer in a double helix shape
what is the monomer that makes up DNA called
nucleotides
what is a nucleotide made up of?
deoxyribose, a nitrogenous base and one phosphate group
what is a deoxyribose
a ribose sugar
In DNA , what can the nitrogenous bases be?
the base pairings
guianine, cytosine, adenine and thymine
what does cytosine pair with
guanine
what is the A+T pairing
adenine and thymine
what is the polymer of the nucleotides called?
polynucleotide
how are polynucleotides formed?
condenstation reactions
polynucleotides
what are the condensation reactions between?
deoxyribose sugar and the phosphate group
what bond is formed between the sugar and phosphate group
a phopshodiester bond
describe phosphodiester bonds
strong covalent bonds
what do phosphodiester bonds help ensure
that the genetic code is not broken down
what does the polynucleotide have
in terms of structure
a sugar phosphate backbone
What does a sugar - phosphate ‘backbone’ describe?
the strong covalent bonds between the sugar and phosphate groups that hold the polymer together
where can hydrogen bonds only form between
complimentary base pairs
how many hydrogen bonds form between adenine and thymine
2 hydrogen bonds
how many hydrogen bonds form between cytosine and guanine
3 hyrdrogen bonds
what do they help?
why are complimentary base pairings important
they help maintain the order of the genetic code when DNA replicates
why is helping maintaining the order of the genetic code important
it reduces the chance of mutations
how the DNA structure links to its function
sugar phosphate backbone (covalent bonds)
allows it to be stable
how the DNA structure links to its function
double helix
helps prevent damage
how the DNA structure links to its function
double stranded
so replication can occur using one strand as a template
how the DNA structure links to its function
weak hydrogen bonds
easy separation of the two strands in a double helix during replication
how the DNA structure links to its function
large molecules
to carry lots of genetic information
how the DNA structure links to its function
complimentary base pairings
allows identical copies to be made
