Central Dogma Flashcards
(57 cards)
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