Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
52 Cards in this Set
- Front
- Back
|
Transcription
|
Process of synthesis of complimentary RNA strand from DNA
|
|
|
What is the template for the transcription of RNA from DNA?
|
A gene
|
|
|
What is the product of transcription?
|
Single stranded RNA
|
|
|
Where does RNA transcription occur in prokaryotes?
|
Nucleoid region of the cytoplasm.
|
|
|
What are the four types of RNA?
|
Messenger RNA
Transfer RNA Ribosome RNA Primer RNA |
|
|
What are the purines in RNA? What are the pyramidines?
|
(A,G) and (C, U) no T
|
|
|
In RNA you will find deoxyribose sugars? (T/F)
|
False. They have ribose sugars. Still non ATP b/c no T.
|
|
|
What is the outcome of Transcription?
|
DNA nucleotide sequence is copied to RNA sequence.
|
|
|
How does RNA polymerase differs from DNA polymerase?
|
1. RNA pol. adds ribonucleotides instead of deoxyribose nucleotide.
2. Built in helicase activity no need for helicase enzyme 3. Doesn't require a primer. 4. Poor proofreading activity 5. RNA polymerase is slower than DNA polymerase III 6. RNA pol transcribes only one of the DNA strands. |
|
|
Transcription Requirement
|
1. Template DNA -- a. Promoter sequence b. Terminator sequence (ends transcription)
2. RNA nucleotides (A,C,G,U) 3. Sigma factor 4. RNA polymerase |
|
|
What are the 3 steps of transcription?
|
1. Initiation: polymerase binds to template
2. Elongation: polymerase moves along the template (generates sequence) 3. Termination: polymerase disassociates, releases template along with the newly synthesized RNA |
|
|
What are the two types of termination processes in bacteria?
|
1. Rho dependent
2. Self-determination |
|
|
Self-Termination
|
Self-termination occurs when RNA polymerase transcribes a terminator sequence of DNA composed of two symmetrical series: one that is very rich in guanine and cytosine bases, flowed by a region rich in adenine bases.
|
|
|
Rho dependent termination
|
This type of termination depends on a termination protein called Rho, that binds to a specific RNA sequence near the end of an RNA transcript.
|
|
|
What is a codon?
|
Triplet of nucleotide which codes for a specific amino acid.
|
|
|
How many possible codons are there?
|
64
|
|
|
How many codons code for an amino acid?
|
61
|
|
|
There are 64 possible codons and 61 actual code for an amino acid. There other three code for what?
|
They are stop codons and stop translation
|
|
|
What is codon degeneracy?
|
Some amino acids are coded for by more than one codon.
|
|
|
What is the advantage of an amino acid being coded for by more than one codon?
|
It allows for the correct amino acid to be coded for despite a different 3rd amino acid. It essentially allows for errors since the RNA polymerase doesn't have good proofreading
|
|
|
Anticodon
|
Present only in t-RNA molecule. Forms hydrogen bonds with codons (on mRNA).
|
|
|
t-RNA
|
Has clover leaf like structure with loops and stems. Delivers amino acid to ribosomes; has acceptor arm where amino acid attaches. Some unusual bases are present (dihydouridene, pseudanidine)
|
|
|
How many t-RNA are there for each amino acid?
|
At least one could be more
|
|
|
Translation
|
Involves decoding the sequence of mRNA to amino acid sequence of proteins.
|
|
|
Is there a t-RNA for the stop codons?
|
No. Because they are non-sense codons.
|
|
|
Ribosomes
|
Provide platform where codons of mRNA are transformed into amino acid sequence of proteins. Has small and large subunit.
|
|
|
What are the three sites of the large subunit?
|
Large subunit has P, A, and E site. A is acceptor site. E is exit site. These are only in the large subunit.
|
|
|
What are the three steps of translation?
|
Initiation, elongation, termination.
|
|
|
What's the first A.A. In translation for humans?
|
In human cells the first amino acid is AUG (methionine)
|
|
|
What's the first A.A. In bacteria for translation?
|
Formyl methionine
|
|
|
What is the source of energy for translation?
|
GTP
|
|
|
What are the 3 horizontal gene transfer processes?
|
Transformation, Transduction, and bacterial conjugation.
|
|
|
What does it mean for a cell to be competent?
|
The cells have the ability to take up DNA from their environment. It results from alterations in the cell wall and cytoplasmic membrane that allow DNA to enter the cell.
|
|
|
The stages of transduction
|
1. Phage injects it's DNA
2. Phage enzymes degrades host DNA 3. Cells synthesizes new phases that incorporate phage DNA and mistakenly some host DNA 4. Transducing phage injects donor DNA 5. Donor DNA is incorporated into recipients chromosome by recombination. |
|
|
What is transformation?
|
A recipient cell takes up DNA from the environment such as DNA that might be released by dead organisms.
|
|
|
When is transformation more effective?
|
When recipient and donor cells are closely related.
|
|
|
Cells can be made to transfer artificially (T/F)
|
True.
|
|
|
Competence can be artificially enduced. (T/F)
|
True
|
|
|
What bacteria are naturally competent?
|
Streptococcus, staphylococcus, bacillus, and neisseria. The can pick up bacteria by transformation
|
|
|
How is DNA polymerase and RNA polymerase similar?
|
Both use DNA template
|
|
|
What are the types of transduction?
|
1. Generalized transduction
2. Specialized transduction. |
|
|
Conjugation
|
A complex process where DNA is transferred by pili and occurs when bacteria are in close contact.
|
|
|
What is transferred during conjugation?
|
Either plasmid or the complete genome can be transferred.
|
|
|
What is synthesized in the recipient cell during conjugation?
|
The second strand of the transferred plasmid.
|
|
|
A cell with sex pili is called?
|
Male: F+ cell
|
|
|
What is synthesized in the recipient cell during conjugation?
|
The second strand of the transferred plasmid.
|
|
|
What bacteria do we study for conjugation?
|
E. Coli
|
|
|
A cell with sex pili is called?
|
Male: F+ cell
|
|
|
What do you call a cell without the sex pili?
|
F- : female.
|
|
|
Transduction is mediated by...
|
Virus (bacteriophages or phages)
|
|
|
How does conjugation differ from transformation?
|
1. Contact between donor and recipient cell is required
2. Conjugating cells must be of opposite mating type (+) (-) 3. Larger piece and quantity of DNA is transferred. |
|
|
What is sigma factor
|
In bacteria, it's a polypeptide subunit of RNA polymerase that is necessary for recognition of they promoter to begin transcription.
|
