Central Dogma of Molecular Biology Flashcards
How does a single faulty gene result in the dramatic appearance of this albino raccoon?
Most likely had a mutation in the protein Tyrosine which codes for melanin (dramatic changes in appearance are caused by mutations)
Gene expression
The process by which DNA directs protein synthesis in two stages, transcription and translation
Transcription
The synthesis of RNA under the direction of DNA
Translation
The synthesis of proteins under the direction of RNA
Why did the Nobel Prize in 1958 go to Bradley and Tatum?
Because of their work in 1941 that revealed the fundamental relationship between genes and proteins - that genes regulate enzymatic events
What is the one-gene-one enzyme hypothesis?
That the function of a gene is to dictate production of a specific enzyme
Later was revised to the one-gene-one protein then one-gene-one polypeptide hypothesis
How is RNA different from DNA?
RNA used the sugar ribose instead of the deoxyribose in DNA
RNA had the nitrogenous base uracil instead of thymine
What is the triplet code?
A series of non-overlapping, three-nucleotide words
Can one species read the DNA code from a second species?
Yes because the genetic code is universal
Transgenic
The introduction of foreign DNA into the genome of an organism
What are the three steps of transcription?
Initiation, Elongation, Termination
Initiation
Involving the attachment of RNA polymerase to the promoter and the start of RNA synthesis
RNA synthesis begins after RNA polymerase attaches to the promoter
Elongation
As the newly formed RNA strand grows
Using the DNA as a template, RNA polymerase adds free RNA nucleotides one at a time
Termination
When RNA polymerase reaches the terminator DNA and the polymerase molecule detached from the newly made RNA strand and the gene
RNA synthesis ends when RNA polymerase reaches the termination DNA sequence
X-chromosome inactivation
One X-chromosome is inactivated by addition of methyl groups
What we’re the first (and only) permitted farmed GMO animal on the USA?
Transgenic salmon (AquaBounty)
Inserted a growth hormone producing gene form Chinook salmon under the control of promoter from a cold-adapted fish species to produce Atlantic salmon that grow fast year round
Messenger RNA (mRNA)
Encodes amino acid sequences and conveys genetic messages from DNA to the translation machinery of the cell
Whats the difference In DNA translation in prokaryotes and eukaryotes?
Prokaryotes - it occurs in the same place that mRNA is made
Eukaryotes - mRNA must exit the nucleus via nuclear pores to enter cytoplasm
Introns
Interrupting sequences that separate exons
Exons
The coding regions
RNA splicing
Removes introns and joins exons to produce a continuous coding sequence
Alternative RNA splicing
Produces different mRNAs from the same transcript, results in the production of more than one polypeptide from the same gene, and is very common in humans
RNA processing
Enzyme in the eukaryotic nucleus modify pre-mRNA before export to cytoplasm
What does the Pfizer mRNA vaccine use instead of uracil?
Uridine analogy 1-methyl-3’-pseudouridylyl
What did The Human Genome Project reveal about not human genomes?
That most of the human genomes does not consist of genes
What was early estimates of human gene numbers based on?
Sequencing mRNA molecules, cDNAs arising from splice variants were often counted as separate genes
Transfer RNA
A strand of RNA that forms a structure that:
Picks up a specific amino acid and using a special triplet of bases called an anticodon, inserts the amino acid at the appropriate position in the coding sequence
Where does translation occur?
On the surface of the ribosome
Ribosomes role in translation:
Ribosomes coordinate the functioning of mRNA and tRNA and, ultimately the synthesis of polypeptides
Ribosomes have two subunits: small and large
Each subunit is colosseum of divisional RNAs and proteins
What are the three phases of translation?
Initiation, Elongation, and Termination (same as transcription)
Initiation (RNA)
Brings together mRNA , a tRNA bearing the first amino acid, and the two subunits of a ribosome
Elongation (RNA)
The messenger RNA moves between the two ribosomal subunits and the polypeptide chain grows as more tRNA is brought in
Termination (RNA)
The ribosome reaches a stop codon in mRNA and the release factor promotes hydrolysis
