nucleic acid and their functions Flashcards
what is a nucleotide made up of
phosphate group, pentose sugar and nitrogenous base
what happens to release ATP energy
ATPase component in ribosomes breaks bond between the middle
how does ATP turn into ADP and into ATP again
ATP —- ADP hydrolysis, energy for cells exit
ADP—ATP phosphorylation (addition of phosphate)
what are the purine bases and whats their structure
adenine and guanine with double ring structure
what are the pyrimidine bases and whats their structure
thymine/uracil and cytosine with single ring structure
what type and how many bonds are between A-T/U and C-G
A-T/U with 2 hydrogen bonds
C-G with 3 hydrogen bonds
what is the structure of DNA
double stranded with alternating sugar phosphate backbone and complementary base pairing
structure of RNA
ribose sugar is single stranded and contains uracil
function of mRNA
genetic code of one gene - one gene codes for polypeptide
function of rRNA
found in cytoplasm, component in ribosomes
structure of tRNA
single stranded molecule - clover leaf anticodon to transport amino acid to ribosomes
give a brief summary of DNA replication
- DNA helicase breaks hydrogen bonds and DNA unwinds
- DNA ploymerase catalyses the addition of free nucleotides to bases forming two identical DNA molecules. each strand acts as a template
what is semi conservative hypothesis
each new strand of DNA formed is composed of original strand and newly synthesized strand
what is conservative replication
one DNA molecule would consist entirely of the original parental DNA while the other would be entirely new
what is dispersive replication
both DNA molecules would contain a mixture of old and new DNA segments with parental DNA being broken down and dispersed into the newly synthesized strands
how did meselson and stahl prove semi- conservative replication
they centrifuged bacterial DNA. bacterium eschericha coli
give a brief summary of transcription
- DNA helicase breaks hydrogen bonds and DNA is unzipped
- RNA polymerase attaches to DNA (only one strand acts as a template)
- RNA nucleotide align and DNA bonds to complementary nucleotides
- results in synthesis of mRNA
- DNA rejoins to form helix and mRNA moves through nuclear pores to ribosomes
give a brief summary of translation
- ribosomes act as framework moving along mRNA
- mRNA contains codons which each codes of an amino acid
- tRNA attach its specific amino acid molecule to complementary anticodon
- peptide bonds form via condensation reaction
