Unit 6 Flashcards
What is a polymerase?
An enzyme that makes polymer DNA
DNA Replication process
1) Helicase unwinds DNA strands
2) Topoisomerase relaxes supercoiling in front of the replication fork
3) DNA polymerase requires RNA primers to initiate DNA synthesis
4) DNA polymerase synthesizes new strands of DNA continuously on the leading strand and discontinuously on the lagging strand
5) Ligase joins the fragments on the lagging strand
Is replication semiconservative?
Yes, replication is a semiconservative process where one strand serves as a template for a new strand of complementary DNA
What are the combinations in nucleotide base pairings for DNA?
T and A, C and G
What are the combinations in nucleotide base pairings for RNA?
A and U, T and A, C and G
Purines
G and A; double ring structure
Pyrimidines
C,T, and U; single ring structure
What direction is DNA synthesized?
5’ to 3’ direction
What are plasmids?
small extra-chromosomal, double stranded, circular DNA molecules
Where is genetic info stored?
its stored in and passed to subsequent generations through DNA molecules (in a minority of cases, through RNA molecules)
What is the difference between Prokaryotes and Eukaryotes?
Prokaryotic organisms typically have circular chromosomes and no nucleus. Eukaryotic organisms have multiple linear chromosomes and a nucleus.
What is transcription?
Writing something word for word
What is translation?
writing something word for word in a different language
What is transcription initiation?
When RNA polymerase binds to the DNA template strand to begin transcription
What is transcription elongation?
RNA polymerase adds RNA nucleotides (A, C, U, G) to the growing RNA strand
What is transcription termination?
RNA polymerase reaches a stop codon
What is translation initiation?
mRNA binds to a ribosome and translation begins at a start codon
What is translation elongation?
tRNA brings an amino acids to go bind an anticodon to a codon to mRNA; adds amino acid to growing polypeptide/protein
What is translation termination?
RNA polymerase reaches a stop codon
What is the central dogma of molecular biology?
DNA → RNA → Protein
Transcription: DNA is transcribed into messenger RNA (mRNA) in the nucleus.
Translation: mRNA is translated into proteins by ribosomes in the cytoplasm.
What are introns? Exons?
Introns are sections of a gene that do not code for proteins.
Exons are sections of a gene that code for proteins.
What is alternative slicing?
Excision of introns and slicing and retention of exons can generate different versions of the resulting mRNA molecule.
How does genetic information flow from RNA to DNA to proteins in a cell?
Genetic information flows from a sequence of nucleotides in DNA to a sequence of bases in a mRNA molecule to a sequence of amino acids in protein
Describe the function of the mRNA molecule and the tRNA molecule
mRNA molecules carry info from DNA to the ribosome. tRNA molecules bind specific amino acids and have anti-codon sequences that base pair with the mRNA