Molecular Biology -- Rna

Front 1

what is meant by the "central dogma of molecular biology"

Back 1

RNA is synthesized from a DNA template and proteins are synthesized by RNA.

Front 2

what enzyme synthesizes RNA

Back 2

RNA polymerase

Front 3

what sugar is RNA

Back 3

ribose

Front 4

what 4 bases are typically found in RNA

Back 4

A, U, G, C

Front 5

what direction is RNA polymerized

Back 5

3' --> 5'

Front 6

is RNA singled stranded, double stranded or both

Back 6

both

Front 7

what's the purpose of secondary structures in RNA

Back 7

provides a recognizeable region of RNA (?)

Front 8

what's an RNA "hair pin"

Back 8

a secondary structure that occurs when a single strand of RNA folds back on itself to and pairs with the bases on the opposite side.

Front 9

which RNA in involved in coding proteins

Back 9

mRNA

Front 10

tRNAs

Back 10

adaptors between mRNA and proteins

Front 11

snRNAs

Back 11

fuction in a variety of nuclear processes including pre-mRNA splicing

Front 12

snoRNAs

Back 12

processand chemically modify rRNAs

Front 13

scaRNAs

Back 13

modify snoRNAs and snRNAs

Front 14

miRNAs

Back 14

regulate gene expression by blocking select mRNA translation

Front 15

What protein(s) are responsible for synthesizing RNA in bacteria?

Back 15

RNA polymerase

Front 16

describe the events that occur during prokaryotic transcription initiation

Back 16

RNA polymerase binds to a sigma factor and forms a holoenzyme which can recognize the DNA promoter. RNA polymerase then transcribes the DNA

Front 17

phosphodiester bond

Back 17

covalently bondsa phosphate and a sugar to hold nucleotides together in RNA or DNA

Front 18

RNA hairpin

Back 18

a segment of RNA that makes a hairpin turn and can be can be used to silence gene expression via RNA interference

Front 19

ribozyme

Back 19

a segment of RNA that can act as a catalyst

Front 20

describe the events that take place during elongation

Back 20

RNA is transcribed 3' to 5' until a stop codon is reached

Front 21

What events take place during termination?

Back 21

The RNA encounters a stop codon and the complex unbinds from the DNA.

Front 22

What is the significance of sigma factor? Give an example in regulation of bacterial gene expression and regulation of viral gene expression.

Back 22

Sigma factor reads the start signal. Bacteria use interchangeable sigma factors to regulate gene expression.
Viruses take over by inserting their own sigma factors into bacterial DNA.

Front 23

Describe the elements of the terminator that make termination occur.

Back 23

A/T rich nucelotide sequence that signals RNA polymerase to stop

Front 24

Describe the implications of having a “strong promoter” versus a “weak promoter.”

Back 24

A strong promoter will cause the sigma factor to bind to the DNA sequences and recognize it better. A weak promoter will bind more loosely and not recognize the sequence as well.

Front 25

How could you tell if a promoter is weak or strong?

Back 25

A strong promoter produces proteins much more rapidly.

Front 26

Consensus sequence

Back 26

the most frequent nucleotide sequence in transcription factors

Front 27

What enzyme is responsible for synthesizing mRNA in eukaryotes?

Back 27

RNA polymerase

Front 28

What is meant by DNA supercoiling? How does it form? How is it released?

Back 28

When DNA unwinds in between its' 2 fixed ends, th tension causes it to coil upon itself. It is released by topoisomerase/ DNA gyrase

Front 29

During transcription initiation, what is the role of the mediator?

Back 29

Allows activator proteins to communicate with the Pol II and TFs

Front 30

During transcription initiation, what is the role of transcriptional activator proteins?

Back 30

Bind specific sequences to attract RNA pol II to start transcription

Front 31

During transcription initiation, what is the role of histone modifying enzymes?

Back 31

Allow greater access to the DNA, facilitate formation of the transcription initiation complex

Front 32

TFIIF

Back 32

stabilizes RNA polymerase interaction with TBP and TFIIB; helps attract TFIIE and TFIIH

Front 33

TBP subunit

Back 33

recognize TATA box

Front 34

TAF subunit

Back 34

regulates DNA-binding by TBP

Front 35

TFIIB

Back 35

gets RNA in the correct position at the start site of transcription