Nuceloides and Nucleic Acids Flashcards
What is a nucleic acid
many nuleotides
what is a single nucleotide formed from
pentose monosaccharide
phosphate group
nitrogenous base
how are nucleotides joined
condensation reactions form a polynucleotide
phosphate group on carbon 5 of pentose, covalently bonds with hydroxyl group on third carbon
bonds in in poly nuelotides
phosphodiester
Sugar in DNA
deoxyribose
what are pyrimidines
smaller bases
single carbon ring
thymine and cytosine
what are purines
larger bases
double carbon ring
adenine and guanine
what is the double helix
two strands of polynucleotides
held by hydrogen bonds
antiparallel
base pairing rules
Complementary base pairing
Adenine and thymine-2 hydrogen bonds
Cytosine and guanine-3 hydrogen bonds
pyrimidine binds to purine
How is RNA different from DNA
ribose
thymine replaced by uracil
why do cells require energy
synthesis
transport
movement
what is adenine triphosphate made of
nitrogenous base (adenine) pentose sugar (ribose) 3 phosphate groups
what is phosphorylation
reattaching the phosphate group (condensation)
properties of ATP
small water soluble easily regenerated hydrolysis- releasing energy condensation- storing energy
how is the structure of DNA suited to is role
base sequence code, allowing DNA to be copied and transcribed
2 strands so is more compact
what is transcription
the copying of the genetic code from DNA onto mRNA- produces shorter RNA molecules
what is translation
the assembly of a polypeptide from the genetic code on the mRNA
what does the ribosome do during translation
act as the binding site for mRNA and tRNA
how is DNA replicated
semi-conservative replication
DNA helicase separates strands
DNA helicase fully separates strands
free RNA nucleotides attract to their complementary bases
what is the genetic code
DNA codes for a sequence of amino acids
what is the code in the base sequence called
triplet code
what is a sequence of 3 bases called
codon
what 2 things is the genetic code
universal
degenerate
