11 + 12 Flashcards
what is DNA composed of?
nucleotides- 5C sugar, phosphate and nucleobase
prokaryote’s DNA vs eukaryote’s?
P: supercoiling reduces its size
NAP helps DNA to fold into coil
Compaction evident when cell is lysed
E: wrapped around histone protein
< lvl of compaction
final lvl of compation not after mitosis & meiosis
core genes vs variable vs unique in E.coli?
shared by all strain vs found in a single strain/ species vs unique to 1 strain . species
purpose: in metabolism, growth and reproduction / not essential for growth and reproduction / ?
DNA polymerase reads in _____ but moves in ____
3’ to 5’ ; 5’ to 3’
______ moves along continuous synthesis while _____ moves _______, creating _______ fragments
leading, lagging & discontinuous, Okazaki
transcription vs translation?
In first: gene is copied into complementary mRNA
in second: ribosome reads mRNA to produce polypeptide using am.a
make mrNA vs polypeptide
what is mRNA?
carries genertic info for ribosome to read
encoded in a series of 3 base pair codons which specify an amn.a
AUG _> methionine
what is rRNA?
RIBOSOMAL: transcribed but not translated
combined with 50 proteins to form ribosome
what is tRNA?
TRANSFER: anticodon binds to mRNA codon with specific am.a attached
transfer to the growing peptide chain
How is RNA made?
With RNA polymerase: reads 3’-> 5’ like DNA polymerase but only 1 strand is transcribed
Compare DNA vs RNA?
1/ large 2x-stranded mole vs small, single stranded molecule
2/ deoxyribose vs ribose
3/ molecular inheritance vs gene expression
eukaryote vs prokaryote replication?
(1) presence of intron is removed prior to translation in E vs no intron in P
(2) translation and transcription is couipled in P & occurs at the same time
Describe DNA replication?
(Keywords:
(1) origin of replicaiton, replication fork
(2) DNA polymerase, strand, proofread
(3) replication factories, termination protein, 180
(1) initiation: anabolic employs imilar mechaism to P & E
begins @ origin of replication: DNA helcase unwinds 2 strands, forming a replciation fork
(2) elongation: DNA polymerase copies template strand semiconservative rep: each chromo has 1 old + 1 newly synthesized strands
=> proofread reduces error
(3) termination: replication factories ends at 180 from oriC
termination protein cause repl. facgtories to detach
2 DNA moelcules separate
Prokaryotes usually have singular ___ chromosome / ____/ while eukaryotes have _____ chromosomes and ___ copies of each /___/
circular / haploid / more than 2 / 2 / haploid
2 ways to identify mutations?
negative selection: identity nutr mutation
positive selection: abtibiotic resisistant one
what does Amex test use?
auxophobi His- strain of bacteria
which is larger: insertion sequence or transposoons
the latter- bgigger and carries more DNA
if ______moved to ______, create a mutation at the point of ____ & ____. if moved to plasmid, maybe transferred to a _______
transposable elements, chromosomes, excisions and insertion. different cell.
spontaneous vs induced mutation?
1st: results from a natural phenomena: errors uncorrected during DNA replication
2nd: mutagens (e.g UV light)
mismatch repair vs nucleoid excision repair?
during DNA replication, DNA polymerase may left some errors uncorrected. cut off that DDNA, unwines and puts correct codon
some mutagens target the double helix. recognizes that distortio, small regions digested and made new w/ complementary strand
describe transformation
describe transduction
describe the conjugation
describe Hfr.
