DNA and RNA AS Flashcards
structures in a neucleotide
nitrogenous bases A,T,C or G, a deoxyribose pentose sugar backbone and a phosphate.
what reaction and bond joins parts of DNA?
condensation reaction and phosphodiester bond
adaptations of DNA
sugar phosphate backbone gives strength. coiling makes compact. long molecule for lots of information. complementary base pairs allow accurate replication. many H bonds provide strength, easily broken for replication
word for when one strand runs in the 5’ 3’ direction and the other runs in the 3’ 5’ direction.
antiparallel
what pairs with adenine
thymine
what pairs with guanine
cytosine
how many H bonds with Adenine
2
how many H bonds with guanine
3
how many bases code for an amino acid
3
name of sections of DNA which are non-coding
introns
name for discrete triplet codes
non-overlapping code
how do mutations stop enzymes from working
change in base. amino acid sequence changed. change in H/ionic bonds. tertiary structure altered and thus shape of active site
semi conservative replication
DNA strands separate
new molecules formed from one old strand and one new strand
How is RNA adapted for function?
stable
single stranded to allow bonding at the ribosome
comparison between DNA and RNA
DNA double stranded RNA single stranded
DNA deoxyribose sugar RNA ribose sugar
DNA has thymine base RNA has uracil base
Structures in RNA
nitrogenous base, A, U, C and G. ribose sugar, and a phosphate.
purpose of RNA
messenger RNA transfers the genetic code from the DNA to the ribosomes
steps in DNA replication
chains separate, breaking H bonds
with DNA helicase
each chain acts as a template
nucleotides line up with complementary bases and join to template strand
DNA polymerase joins sugar phosphate groups of adjacent nucleotides in the 5’ 3’ direction
phosphodiester bonds form
why does DNA polymerase work in the 5’ 3’ direction only
its active site only bonds to the 3’ end (5’ and 3’ end are different shapes)
