paper 1: Nucleic Acids and DNA Replication Flashcards
what does DNA stand for
deoxyribonucleic acid
what does RNA stand for
ribonucleic acid
what does DNA do in the body
holds genetic information which codes for proteins
what does RNA do in the body
transfers genetic information from DNA to ribosomes
draw the structure of a DNA/ RNA nucleotide
what is the difference between the structure of DNA and the structure of RNA
- the pentose sugar for DNA is deoxyribose, for RNA it’s ribose
- the bases for DNA can be A, C, G, T but for RNA its A, C, G, U.
what are the names of the organic bases in DNA
adenine, thymine, cytosine, guanine
what are the names of the organic bases in RNA
adenine, uracil, cytosine, guanine
describe the formation of polynucleotides
- nucleotides join together by condensation reactions
- to form a phosphodiester bond between the phosphate group of one nucleotide and the pentose sugar of another
- to make the sugar-phosphate backbone
- which is strong and stable
what is the word used to describe the phosphate backbones running in opposite directions
anti-parallel
what does the 3’ and the 5’ relate to
the carbon number of the deoxyribose
describe an RNA strand
relatively short, single stranded polynucleotide strand
why must DNA be replicated accurately
so each daughter cell recieves an exact copy of DNA
when does DNA replication take place
- during cell division
describe the 3 stages of DNA replication
stage 1: DNA helicase breaks hydrogen bonds between complimentary bases in the polynucleotide strand. this causes the DNA helix to unwind and separate
stage 2: new DNA nucleotides are attracted to exposed bases on the template strands and hydrogen bonds form between complimentary bases.
stage 3: DNA polymerase joins the adjacent nucleotides together via a condensation reaction to form phosphodiester bonds.