DNA Flashcards
how many strands in dna serve as a template for transcription
1 parental strand
describe deoxyribonucleotude
double stranded, dna, deoxyribose sugar, ATGC, phosphates
double helix, what does it provide
2 linked strands that wind around each other. provides a measure of protection
semi conservative
half of the original dna appears in the replicated dna
anti parallel
strands run in opposite directions
describe ribonucleotide
single stranded, ribose sugars, AUGC, RNA, phosphates
where is mRNA made, what does it do
made in the nucleus,
- carries genetic message from DNA in the nucleus
- to ribosome in the cytoplasm for protein synthesis
replication fork
Y shaped site where DNA is separated and synthesized
3’ and 5’ ends
DNA polymerase can only add nucleotides in the 5’ to 3’ direction (moves along the template strand in the 3’ to 5’ direction)
template strand
parental strand
leading strand
built continuously 5’ to 3’
lagging strand
synthesized in fragments
helicase
unwinds
polymerase
adds nucelotides
ligase
links fragments
ribosome
- construction site
translates mrna into polypeptide chains to assemble proteins.
trna
transfers amino acids to ribosme to make proteins
what is a cells source of supply of amino acids?
diet (essential amino acids)
codon
triplet of nitrogen bases on mrna. codes for amino acids
anticodon
trna that carries specific amino acid to complimentary base pair with codon
what happens to transfer rna after it drops off its amino acod
leaves the translation “e” site, recharged to find another amino acid to deliver
silent substitution
no effect
missense substitution
change in codon
nonsense substitution
stop codon
addition/deletion
frameshift: codons after mutation change
what are proteins, what is it made through
chains of amino acids that do jobs in our bodies made through translation and protein synthesis
Where is translation?
in the ribosome
initiation (translation)
Ribosome binds to the MRNA, entering the a site. tRNA to the start codon
elongation (translation)
- ribosome reads mrna codons
- trna brings amino acids to the ribosome in the P site, exits with the E site
- ribose forms a polypeptide chain
termination (translation)
ribosome reaches stop codon, chain released with hydrolysis from the release factor
separation (replication)
dna helicase unwinds double helix, breaking H bonds.
- single stranded binding proteins prevent re joining
complementary base pairing (replication)
dna polymerase adds nucleotides.
- rna primase begins replication by making primers. once primers are in place polymerase adds nucleotides
joining (replication)
dna ligase links fragments with phosphodiester bonds
site of replication for prokaryotes
no nucleus, replication in cytoplasm
transcription
copying genetic info from DNA to mRNA
initiation (transcription)
rna polymerase binds in the promoter region (TAA box), exposing template strand and attaches
elongation (transcription)
mRNA symthesized
termination (transcription)
rna polymerase and new rna are released, dna is reformed
how many genes are transcribed with transcription
one
rna polymerase
enzyme that does transcription
______ codons reduce errors
diverse
rna splicing
removes introns (pre rna) and reconnects exons
