DNA/RNA Flashcards
The HIV virus has the unique ability to do what to DNA and with what enzyme?
Produce DNA from an mRNA molecule by using reverse transcriptase
How does the location of ribosomes differ in eukaryotes and prokaryotes?
Prokatyotes - free floating or attached to plasma membrane
Eukatyotes - free floating or bound to the ER (RER)
The _____ ribosomes are the sites of protein synthesis in bacterial cells and chloroplasts, composed of 2 rRNA subunits (30s and 50s).
70s
The ____ ribosomes are the sites of protein synthesis in the cytoplasm of eukaryotic cells and composed of two rRNA subunits (40s &60s)
80s
What 5 enzymes are depended on for genetic recombination experiments?
- DNA ligases (join)
- endouncleases (internally cleaves phosphodiester bonds)
- DNA polymerase I
- Reverse transcriptase (makes DNA copy of RNA molecule)
- Exonucleases (cleave nucleotides from 3’ or 5’ end)
What technique is used to detect mutations in DNA and can also ifentify DNA restriction fragments? It combines the use of restriction enzymes and DNA probes.
Southern blot
What are 4 areas of research that are using recombinant DNA technology?
- human insulin
- anticoagulants
- erythropoietin
- human growth hormone
Name 3 bacterial cloning vectors?
- Plasmids
- bacteriophages
- Cosmids
In DNA replication, how is the new ssDNA built?
3’ to 5’
What is the purpose of RNA intermediates?
To prime DNA polymerase then are later replaced by DNA
What enzyme re-forms the coiled structure of DNA after the replication fork has passed?
DNA gyrase
2 main differences between DNA and RNA
DNA - deoxyribonucleic acid - double stranded
RNA - ribonucleic acid - single stranded
What is the backbone of nucleic acids made up of?
Alternating phosphate and pentose units, with a purine or pyrimidine base attached to each
What enzyme catalyzes the formation of uric acid from purine bases?
Xanthine oxidase
what enzyme in purine and pyrimidine synthesis has made it a target for antimetabolites used in chemotherapy?
tetrahydrofolic acid (TFA)
What is the third position in a codon known as?
“wobble” position , 3rd position can change and sometimes it still accounts for the same AA
Name 3 AA that only have 1 codon
- Tryptophan
- Methionine
- Selenocysteine
Initiation codon
AUG
An _______ is a specific sequence of 3 nucleotides in a tRNA complementary to a codon for an AA in a mRNA. tRNA and mRNA are paired ________.
Anticodon
Antiparallel
How many H bonds between G and C?
How many H bonds between A and T?
3 in G-C
2 A-T (weaker so aids in release of newly formed RNA from DNA template)
The A-T base pair promotes what in DNA but not so in RNA?
Helix stabilization
Which is larger, purines or pyrimidines?
Purines
Which base pairs give DNA a higher melting temperature?
G-C
Is the DNA/RNA backbone hydrophobic or hydrophilic?
Hydrophilic and highly polar
Bases are hydrophobic and use van der waals interactions
The ribose phosphate portion of purine and pyrimidine nucleotides comes from PRPP. PRPP is synthesized from ATP and ribose 5 phosphate, which is primarily formed by what?
pentose phosphate pathway
Which type of RNA is least adundant?
mRNA (rRNA most abundant)
Which RNA is the template for protein synthesis and contains the codon?
mRNA
What is the group of enzymes that ensures that the correct AA is attached to the tRNA with the correct anticodon. Highly specific, no error checking
Amino acyl-tRNA synthetase
