BIO 140.01 - Module 3-1: Gene Expression - Transcription

DNA, RNA

Transcription uses a ___ template to produce an ___ molecule

RNA

“Messenger of the instructions”

mRNA

Contains the instructions to make proteins

tRNA

Carries and transfers the amino acids during protein synthesis

rRNA

Component of ribosomes where protein synthesis occurs

Ribozyme

RNA molecules that can catalyze reactions

False

T or F: Prokaryotic and eukaryotic mRNA undergoes post-transcription modification

False

T or F: tRNA ends are capped so it can safely exit out of the nucleus

mRNA transcription

First step of gene expression

Gene

Sequence of DNA that holds the instructions for producing a specific protein

Deoxyribo, Double, deoxyribose

Fill in the blanks: DNA: ___nucleic acid, ___-stranded, Sugar is ___

Ribo, Double, Ribose

Fill in the blanks: RNA: ___nucleic acid, ___-stranded, Sugar is ___

True

T or F: Both strands of DNA contain coding sequences.

False

T or F: The coding sequence for one gene is found on both strands.

True

T or F: Only one strand of DNA is used as a template

False

T or F: The sense strand and the template strand are the same.

Sense strand

DNA strand that contains the sequence for the proteins

Anti-sense strand

Complementary strand which is used as the template to make mRNA

Promoter sequence

Short sequence before the gene that is recognized to begin transcription

Transcription factor

Promoter sequence is recognized and bound to by ____

Sigma factor

Transcription factor in prokaryotes

TTGACA, TATAAT (Pribnow box)

Promoter sequence in prokaryotes

TFIID

Transcription factor in eukaryotes

TATA box

Promoter sequence in eukaryotes

Transcription factor

This dictates where the RNA polymerase should bind

Template or anti-sense

RNA polymerase binds to the ___ strand

False

T or F: Helicase creates the transcription bubble by breaking the hydrogen bonds between bases and unwinding DNA

3’-5’

RNA polymerase moves down the template strand in a ___ direction

5’-3’

RNA polymerase synthesizes mRNA in a ___ direction

False

T or F: As an all around enzyme, RNA polymerase will spontaneously cease mRNA transcription without any marker

Terminator sequence

Sequence that signals RNA polymerase to terminate transcription and causes it to dissociate from DNA

Hairpin loop

Prokaryotic mRNA sequence will form a ____ after termination to destabilize the transcription complex

Rho factor

This is sometimes required in prokaryotic mRNA transcription termination to help release RNA from DNA

True

T or F: Hairpin loops in mRNA are due to intermolecular base pairing.

True

T or F: RNA polymerase terminates transcription once it reaches a terminator site

Cleavage stimulation factor

This cleaves pre-mRNA off the transcription complex

False

T or F: In prokaryotes and eukaryotes, the resulting mRNA strand must be edited before it can exit the nucleus and be used for protein synthesis

Splicing, capping the ends

Two main steps in post-transcription modification

Exons

Protein-coding sequences

Introns

Noncoding sequences that are edited out of the mRNA

Spliceosome

Excises the introns out of the mRNA strand and joins exons together

True

T or F: according to alternative splicing, different cells may splice the same pre-mRNA differently to produce the variations of the same protein. One example of this is the variations of muscle tissue.

5’ methylguanosine cap

Term for the 5’ cap of mRNA

3’ polyadenylate tail or 3’ poly-A tail

Term for the 3’ cap of mRNA