Reading 6

Question 1

What is the nucleotide substrate for RNA polymerase?

Answer 1

ribonucleotide triphosphates

Question 2

Where within a eukaryotic cell does the process of transcription occur?

Answer 2

nucleus

Question 3

What does the enzyme RNA polymerase do?

Answer 3

adds ribonucleoside triphosphates to the growing new pre-mRNA

Question 4

Define the term polycistronic RNA?

Answer 4

where a single terminator is present at the end of a group of several genes that are transcribed together

Question 5

What is the function of the Shine-Dalgarno sequence?

Answer 5

sequence on the 5` untranslated region that serves as the ribosome binding site during translation

Question 6

What is the function of the Kozak sequence?

Answer 6

sequence that plays a role in initiation of the translation process

Question 7

Eukaryotes have many types of RNA polymerases. How do they differ from each other?

Answer 7

-1: synthesizes pre-rRNA
-2: synthesizes precursors of microRNA, snRNA, and mRNA
-3: synthesizes tRNA

Question 8

What is a promoter, and what does it do?

Answer 8

gives ribosome somewhere to bind

Question 9

What is an intron?

Answer 9

non coding, intervening sequences

Question 10

What is an exon?

Answer 10

coding region

Question 11

Describe how the 5’ and 3’ ends of most eukaryotic pre-mRNAs modified.

Answer 11

-5 cap: extra modified nucleotide as well as methyl groups, increases stability -3 poly A tail: lots of adenine, stability

Question 12

Describe the two-step process of splicing.

Answer 12

-pre-mRNA is cut at the 5 splice site, intron folds back forming a lariat -cut at 3 splice site, exons attach, intron lariat leaves

Question 13

What is alternative splicing?

Answer 13

a single pre-mRNA is processed in different ways to produce different proteins from same DNA