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Microbiology 7
Genetics
Question | Answer |
---|---|
Complete set of genetic information | Genome |
Transcription | copying info on DNA to RNA |
has a 5 prime end and a 3 prime end | single strand of DNA |
Describe the 2 strands of DNA | In a double helix and are anti-paralell |
Denaturing | The seperating of a double strand of DNA |
Transcribed from one of the 2 strands of DNA | A single strand of RNA |
3 Functional groups of RNA | messenger (mRNA), ribosonal (rRNA), transfer (tRNA) |
When double-stranded DNA is duplicated before cell division so that its info passed on to next generation | DNA replication |
When info in DNA is deciphered | expressed |
Two processes in gene expression | transcription & translation |
Serves as a temporary form of genetic information and is what is actually deciphered | RNA |
Central dogma of molecular biology | theflow of info from DNA (transcription) to RNA to protien |
composed of neucleotides | single strand DNA |
The covalent bond that joins DNA | 5 phosphates (5 prime) & 3 OH (3 Prime) |
sugar-phosphate backbone | alternating sugar / phosphate joined by A, T, G, C |
Occurs as a double-stranded helix structure | DNA |
The characteristic bonding of A to T and G to C | Base pairing |
Rules of base pairing | One strand can always be used as a templatefor synthesis of complementary, opposing strand |
Transcript | fragment of DNA synthesized by using a region of DNA strand |
RNA differs from DNA in these ways: | 1) has riboneucleotides, not deoxyneucleotides 2) contains uracil instead of thymine 3) RNA single stranded and shorter |
Are 2 complementary strands of RNA usually generated? | NO |
Hydrogen bonding of base pairs | 3 between G & C, 2 between A & T |
mRNA | Regulation of its synthesis leads to control of protien synthesis - short lived |
Replication of DNA | Semiconservative: each of 2 molecules contains 1 old strand & 1 new - Bidirectional, as replication goes in both directions in a "bubble" shape |
DNA polymerase | enzymes that synthesize DNA, using one strand as a template to generate complementary strand |
These enzymes can ONLY add neucleotides onto preexisting fragment of neucleic acid | DNA Polymerase - then fragments serve as primer |
Always enlongates chain in 5' 3' direction | DNA polermerase |
DNA gyrase | breaks strands of DNA which server to temporarily ease tension - the target of antibacterical meds |
DNA Lygase | joins 2 DNA fragments by forming covalent bond |
Helicases | unwind helix ahead of replication fork |
Okaki Fragment | neucleic acid fragment generated during discontinuos replication of lagging strand of DNA |
Primase | Synthesizes small fragments of RNA to serve as primers for DNA |
250 Neuclotides | needed for DNA replication |
Codon | 3 neucletides that code for specific amino acid |
Promoter | neucleotide sequence to which RNA polymerase binds to initiate transcription |
Ribosome | facilitates joining of amino acids durring translation |
DNA synthesized from what direction? | 5' 3' |
DNA read from | 3' 5' |
Where active replication occurs | replication fork |
Causes RNA polymerase to fall off DNA template and release newly synthesized RNA | Transcription terminator |
how is info on mRNA read? | genetic code |
Begins when ribosome binds to the ribosome binding site on mRNA, even if it is still being synthesized | Iniation of translation |
Removes introns from eukaryotic precursor RNA to generate mRNA | Splicing |
Function as the site of translation | Ribosomes - 70s & 30s subunit |
Segments of RNA that act as keys that interpret genetic code | tRNA |
Anticodon | sequence of 3 neucleotides - allows tRNA to bind w/ appropriate codon |
Facilitates the joining of amino acids during translation - made of protien | Ribosomes |
The target of antibacterial drugs | Ribosomes |
Type of RNA present in ribosomes | rRNA |
The first AUG after a binding site | Start codon |
mRNA is processed, with a cap and poly A tail attached | Eukaryotic |
contain inrons which are removed by splicing | Eukaryotic |
The mRNA MUST be transported out of the nucleus before it can be translated in cytoplasm | Eukaryotic |
mRNA is NOT processed | Prokaryotes |
mRNA does NOT contain introns | Prokaryotes |
Translation in mRNA begins as it is being transcribed | Prokaryotes |
mRNA Polycistronic: it begins at the first AUG that follows a ribosome binding site | Prokaryotes |
Employs a repressor that prevents transcrption of genes when lactose NOT available | lac operon |
Catabolite repression | prevents transcription of lac operon when GLUCOSE is available |
Could two m-RNA’s have different nucleotide sequences and yet code for the same protein? | Yes. Each amino acid has several different triplet codes. Different triplet codes might be used to code for the same amino acids in two separate m-RNA’s. |
Would a deletion of two base pairs have a greater consequence if it occurred in an intron or in an exon? | Since an intron is only a spacing sequence that does not code for any amino acid sequence, a deletion would not be expected to cause any changes. |
Sigma factors bind to | promoters |
one gene encodes: | One protien |
DNA is composed of | 4 different units |
A cell's genome is composed of | DNA |
held together by hydrogen bond | DNA strands |
adds a nucleotide to the 5' end | DNA Polymerase |
occurs in mitochondria of eucaryotes and polymerize or cut RNA | Ribozymes |
uses DNA for a template | RNA Polymerase |
Expresses only a SINGLE protien | eukaryotic mRNA |