Central Dogma Flashcards
What are the difficulties of having the 2’ OH?
- DNA molecules cannot undergo auto-catalytic cleavage
- DNA has a wider/shallower major groove for protein access
- DNA is less rigid, easier to store so long
Why is thymine used instead of uracil?
- Cytosine can easily degrade to uracil
What is the function of having dsDNA?
- Information storage
- Stability
- Ease of packaging
- Long double strand
- Flexibility allows for easier storage
What are important functions of RNA?
- Temporary messages - mRNA
- Enzymatic reactions - ribosomes
- Translator/ adaptor tRNA
DNA and RNA are _____.
Directional
DNA stands are _______ to one another.
Antiparallel
Genomes vary in _____
Size
List the genomes from smallest to largest.
a. Amoeba Dubia
b. Average Bacterium
c. Carsonella Ruddi
d Humans
Carsonella ruddi, average bacterium, humans, amoeba dubia
What nucleotides match together in watson crick franklin pairing?
G to C
A to T
Microbial genomes are mostly ______.
Genes (coding sequences)
What allows for transcription?
RNA polymerase
How does RNA polymerase know where to start? What recognizes this?
Promotors
Sigma subunit recognizes
Promotor strength can _____.
Vary
How is promoter strength determined?
how well sigma subunit binds
What are the difference components of the RNA polymerase structure?
2 alpha
beta
beta prime
omega
sigma
What are the 4 steps of transcription?
- Recognition
- Formation of open complex
- Elongation
- Termination
How does recognition work in bacteria?
omega subunit recognizes special sequence and guides RNA polymerase to bind to promotor and transitions to an open complex.
How does elongation work?
RNA polymerase makes a new strand in the 5’ to 3’ direction as it moves down DNA random nucleotides enter the channel. After about 20 nucleotides emerge from polymerase sigma falls off
What is the rate of elongation?
45 bp per second
Template strand is the _______ strand
The coding strand is the _______ strand.
copied strand
coded strand
How does termination work?
Recognizes termination signal and releases complex
What is Rho-independent termination
Hairpin loop structure followed by a run of As
Causes polymerase to fall off
What is Rho-dependent termination?
Binds to open sequence of RNA and hydrolyzes ATP as it walks down RNA and causes termination
Prokaryotic mRNAs contain multiple ____.
Genes
Genes that are transcribed together are called______.
operons
mRNA that encodes for more then one gene is called _____.
polycistronic
What do operons code for?
Genes that are involved in related cellular function?
What is an example of an operon?
Degradation of lactose
Which of the following have a SINGLE RNA Polymerase
a. bacteria
b. archaea
c. eukarya
Bacteria and archaea
TRUE or FALSE? Bacteria and Archaea have the same RNA polymerase structure?
FALSE - structures vary
Which of the following have a MULTIPLE RNA Polymerases
a. bacteria
b. archaea
c. eukarya
Eukarya
TRUE or FALSE? Bacteria and Eukarya have the same RNA polymerase structure?
FALSE - Eukarya polymerase similar to archaea
Name the promotors used for the following
a. bacteria
b. archaea
c. eukarya
a. Pribnow Box
b. TATA Box
c. TATA Box
Which of the following structures have introns
a. bacteria
b. archaea
c. eukarya
Archaea and eukarya
How would you describe the mRNA between Bacteria v Archaea?
Similar family (often polycistronic) and unstable
How would you describe the mRNA between Bacteria v Eukarya?
Different
Eukaryotes monocistronic
5’cap and poly A tail
Eukaryotic relatively stable
What proteins are responsible for guiding RNA polymerase to TATA box?
TBP
TFB
What is the difference between archaea splicing vs eukayotic splicing?
The both splice introns but in eukaryotic pre-mRNA 5’cap and poly A tail are added
What is translation?
Going from nucleotides to amino acids
What is the most conserved process in biology?
Translation
What type of code is used for translation?
base triplets
genetic code is ________ and ________.
Universal and redundant
What is the importance of the wobble rule?
More then one triplet may code for the same amino acids and the wobble of the last base pair is not as important
What works as the translator in RNA translation?
tRNA synthetase
What is the requirement for tRNA synthetase?
Must be charged with the correct amino acid
What are the steps of initiation?
- 30S subunit + mRNA + IF (intiation factors)
- mRNA - Shine - Dalgarno sequence that binds to 16S RNA to set up reading frame
- fMet-tRNA enters p sight
- 50S is added and second charged tRNA enters A site help from EF
What are the steps of elongation?
- Peptide bond forms and peptide is translocated to tRNA at A site
- Ribosome advances by moving peptidyl - tRNA to P sight and moving empty initiator tRNA to E site
- New charged tRNA enters A site, Peptide bond formation continutes
- Termination occurs at a stop condon with RF
How do mutations effect translation and transcription?
- block translation
- stop transcription
What are the products of translation?
String of AA
What might the synthesized string of AA need after translation?
- Protein folding
- Cofactor insertion
- Multimer formation
How does translation termination differ in eukaryotic organisms?
occurs when RNA polymerase reaches a polyadenylation signal
In eukaryotes is translation simultaneously like transcription
No
How does translation initiation differ in eukaryotic organisms?
- No shine Dalgarno sequence
- Start from first AUG
- Methioinine inserted
How does translation initiation differ in prokaryote organisms? (special exceptions)
GUG UUG can serve as start codons
TRUE or FALSE? in Prokayotes the Shine Dalgarno is always necessary?
FALSE
What is the foundational difference in prokayotes when it comes to translation?
2 starts
2 proteins
one gene
In prokaryotic organisms Ribosome and tRNA ______.
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