Chapter 17 Flashcards
Transcription creates an RNA molecule that is _______ to the DNA template.
complementary
what is the polymerase that makes RNA from DNA in bacteria?
RNA polymerase
DNA dependent
Template strand definition
the DNA that serve as the template for transcription (the one that RNA polymerase will read)
Non-template strand definition
coding strand, have the same sequence as the RNA, will not get copied
promoter definition
site where RNA polymerase binds to the gene
Sigma definition
binds to the promoter region of the DNa- helps RNA polymerase bind to the gene
Holoenzyme contains what?
Sigma and RNA polymerase
steps for initiating transcription in bacteria
- initiation begins- sigma binds to promoter region of DNA
- initiation continues- RNA polymerase opens the DNA helix; transcription begins
- initiation is complete- sigma is released from the promoter; RNA synthesis continues from DNA
steps for ending transcription in bacteria
- Hairpin forms- RNA polymerase transcribed a transcription- termination signal, which codes for RNA that forms a hairpin.
- Termination- the RNA hairpin causes the RNA to separate from the RNA polymerase, terminating transcription.
what are the three enzymes used for transcription in Eukaryotes?
RNA polymerase 1, 2, and 3
RNA polymerase I
genes that code for most of the large RNA molecules found in ribosomes
RNA polymerase II
protein- coding genes; also, genes that code for RNAs that function in ribosome assembly, and in processing and regulation of mRNAs
RNA polymerase III
genes that code for transfer RNAs, for one of the small rRNAs found in ribosomes, and for noncoding RNAs; also, genes that code for RNAs that function in ribosome assembly, and in processing and regulation of mRNAs
intron definition
contains no genetic information
exon definition
contains genetic information
when is the RNA functional?
- after being cut
- after going through RNA splicing
after going through RNA splicing
what is RNA splicing?
process that removes introns in Eukaryotes
what are the steps in splicing?
- snRNPs bind to start of intron and an A base within the intron.
- snRNPs assemble to form the spliceosome
- intron is cut; loop forms
- intron is released as a lariat; exons are joined together
what is the last step to making the final mRNA?
adding a 5’ cap and 3’ poly(A) tail to each spliced transcript
What is transcription?
a) Synthesis of protein, with tRNA used as template.
b) Synthesis of DNA, with RNA used as template.
c) Sythesis of protein, with mRNA used as template.
d) Synthesis of RNA, with DNA used as template.
d) Synthesis of RNA, with DNA used as template.
Which of the following would not create a frameshift in the final mRNA?
a) Deleting 2 bases from the exon of a gene.
b) Adding an extra base to the exon of a gene.
c) Deleting 1 base from the exon of a gene.
d) Deleting 6 bases from the exon of a gene.
d) Deleting 6 bases from the exon of a gene.
In what way is RNA polymerase similar to DNA polymerase?
a) Both read template DNA in the 5’-3’ direction.
b) Both read template DNA in the 3’-5’ direction.
c) Both use DNA as a template to make RNA.
d) Both use RNA as a template to make DNA.
b) Both read template DNA in the 3’-5’ direction.
What is the correct order of initiating translation?
I. mRNA binds to small ribosomal subunit
II. Met-tRNA binds to start codon
III. large ribosomal subunit binds to mRNA
IV. tRNAs enter the “A” spot
a) II, III, I, IV.
b) I, III, II, IV.
c) I, II, III, IV.
d) II, I, III, IV.
c) I, II, III, IV.
You are studying tropomyosin, a gene that is expressed in both skeletal muscle and smooth muscle. During your experiments you discover that the tropomyosin protein isolated from smooth muscle is almost twice as large as tropomyosin protein isolated from skeletal muscle. Why are the proteins different in size even though they come from the same gene?
a) Genetic recombination.
b) Unequal crossing over.
c) Differences in histone acetylation.
d) Alternative splicing.
d) Alternative splicing.
