7 structure of DNA

what does DNA stand for?

deoxyribonucleic acid

what’s the function of DNA?

codes for the sequence of amino acids in the primary structure of a protein, which in turn determines the final 3D structure and function of protein

why is it essential for cells to carry a copy of the genetic code?

so it can be passed down onto new cells without being damaged

what’s the monomer that makes up DNA called?

a nucleotide

what’s a nucleotide made out of?

• deoxyribose (a pentose sugar)

• a nitrogenous base

• one phosphate group

what types of nitrogenous bases are there?

• guanine

• cytosine

• adenine

• thymine

what are polymers of these nucleotides called?

polynucleotides

how are polynucleotides formed?

a condensation reaction between the deoxyribose sugar and the phosphate group, creating a phosphorite bond

what are phosphorite bonds?

strong covalent bonds that help ensure that the genetic code isn’t broken down

what does the polynucleotide having a sugar phosphate ‘backbone’ describe?

the strong covalent bonds between the sugar and phosphate groups that hold the polymer together

describe the structure of DNA

the polymer occurs in pairs that are joined together by hydrogen bonds between the bases. these two chains twist, creating a double helix structure

what can hydrogen bonds only form between?

complementary base pairs

what are the complementary base pairs?

cytosine and guanine

adenine and thymine

how many hydrogen bonds do adenine and thymine form?

2 hydrogen bonds

how many hydrogen bonds do cytosine and guanine form?

3 hydrogen bonds

why are the complementary base pairs important?

they help maintain the order of the genetic code when DNA replicates

what structures does DNA have?

• sugar phosphate backbone and double helix

• double stranded

• weak hydrogen bonds

• large molecule

• complementary base pairing

how does a sugar phosphate backbone and double helix relate to the function of the DNA?

provides a stable structure

how does being double stranded relate to the function of DNA?

so replication can occur using one strand as a template

how does weak hydrogen bonds relate to the function of DNA?

for easy unzipping of the two strands in a double helix during replication

how does being a large molecule relate to the function of DNA?

to carry lots of information

how does complementary base pairs relate to the function of DNA?

allows identical copies to be made