TERM TEST #2 Flashcards
What does the central dogma of molecular biology consist of?
its the universal information flow from DNA to protein in order to convert genotype to phenotype
In prokaryotes what does the Central dogma process look like?
Transcription and translation both occur in the cytoplasm in prokaryotes and therefore, both processes happen simultaneously
in Eukaryotes what does the central dogma process look like?
transcription and process of the precursor mRNA molecules occur in the nucleus and translation occurs in the cytoplasm
what is the one gene-one enzyme (protein) hypothesis?
in 1940s Beadle and Tatum hypothesized that genes encode enzymes that function at each step of a biochemical pathway needed to make an essential nutrient
- mutating a gene encoding an enzyme would cause a block in the metabolic pathway and the organism can no longer synthesize the needed nutrient (auxotroph)
what is an auxotroph?
An auxotroph is an organism that cannot synthesize a particular essential nutrient on its own and must obtain it from its environment. This inability is due to a mutation in a gene involved in the biosynthetic pathway of that nutrient.
information flow occurs in certain places on chromosomes called what?
genes
genes encode for two types of RNA which are?
- coding RNA (mRNA): codes for protein/polypeptide
- noncoding RNA: tRNA, rRNA, snRNA, microRNA: does not code for a protein
what is the genetic code?
nucleotide information to amino acid sequence
For the genetic code information is contained in what?
4 nucleotide bases in DNA (A,T,G,C) OR RNA (A,U,G,C) sequences
if a code has one-letter words how many combination?
4 combinations
if a code has two-letter words how many combinations?
16 combinations
if a code had three-letter words how many combination?
64 combinations
If DNA has a three-letter code it is known as a what?
Triplet
if RNA has a three-letter code it is known as a ?
codon
genetic code is what ?
universal (same code in prokaryotes, eukaryotes and viruses)
why is it that the universal code can allow foreign genes to be transferred and expressed in different host organisms
The universal genetic code means that the same codons specify the same amino acids in almost all organisms. This allows it to be transmitted to different host organisms because the host’s cellular machinery can read and translate the inserted genes correctly to produce the corresponding protein
How does green fluorescent protein used from jellyfish help with for research from scientists?
main application is to monitor the spatial and temporal expression of a protein
What are the key things we need to note about template and coding DNA strands?
in general for every gene, a RNA molecule is only produced (transcription) from one of the DNA strand (Template strand)
- the other DNA strand is the non template strand or coding strand (has same 5’to3’ orientation and sequence as mRNA molecules except uracil is substituted with thymine
- the template strand is always read from 3’-5’ by the RNA polymerase
-mRNA is synthesized in the 5’to3’ direction (by the RNA polymerase)
what the order for central dogma?
- DNA replication
- Transcription
- TRANSLATION
- PROTEIN
Transcription of a gene occurs off only …?
one of the DNA strands (template) in a 5’- 3’ direction
On chromosomal maps genes are shown on the coding strand true or false?
true
on a prokaryote what are the rings labelled?
Which came first DNA or RNA?
Likely RNA because able to store genetic information (code for amino acids like DNA) can also catalyze reaction (like an enzyme)
- DNA developed late with advantages over RNA such as more stable, and double stranded allows the complementary strand to be used as a template to repair the damaged strand