chapter 14

Question 1

are all eukaryotic genes colinear?

Answer 1

no, because some eukaryotic genes have introns that are not translated

Question 2

which is the most precise definition of a gene?

Answer 2

the entire DNA sequence that is required to transcribe and encode a single RNA molecule

Question 3

what is the shine-dalgarno sequence ?

Answer 3

the ribosome binding site in bacterial RNA

Question 4

what is necessary for the addition of the poly(A) tail?

Answer 4

the consensus sequence, AAUAAA

Question 5

which is not found in a slice some that is actively splicing ?

Answer 5

DNA

Question 6

alternative splicing produces

Answer 6

mRNAs of different lengths form the same pre-mRNA

Question 7

which not a type of pre-mRNA processing in eukaryotes?

Answer 7

3’ mRNA degradation

Question 8

how would the deletion of the shine-dalgarno sequence affect a bacterial mRNA?

Answer 8

translation would not occur

Question 9

classify each description as true one introns only, tru of exons only, or true of both introns and exons

Answer 9

introns only: generally absent from bacterial genomes & removed from initial mRNA strand prior to translation
exons only: code for a protein & part of the final mRNA strand
both introns and exons: present in the DNA used as the template for transcription & present in eukaryotic genomes

Question 10

in what order would the RNA polymerase encounter the elements in the DNA sequence of the gene ?

Answer 10

earliest encountered 
promoter
5' UTR 
start codon 
splice acceptor site 
stop codon 
3' UTR 
last encountered

Question 11

what is the function of the splicesome?

Answer 11

the splice some removes the introns and joins the exons to form the mature transcript

Question 12

which description applies to alternative mRNA splicing?

Answer 12

processing of exons in mRNA that results in a single gene coding for multiple proteins

Question 13

what statements regarding RNA splicing is correct?

Answer 13

noncoding introns are edited out and removed

Question 14

why can alternative splicing of messenger RNAs (mRNAs) be advantageous for eukaryotic organisms?

Answer 14

increases the variety of proteins that can be produced

Question 15

how do the nucleus and ribosomes work together to generate a protein?

Answer 15

in the nucleus, DNA is transcribed to mRNA, which ribosomes use as instructions to synthesize a specific protein

Question 16

identify which statements apply to the ribosome, RNA polymerase II, or both in eukaryotic cells

Answer 16

ribosome: reads RNA sequence to make proteins, made of two RNA- protein subunits, & found in the cytoplasm
RNA polymerase II: found in the nucleus & reads DNA sequence to make mRNAs
both: has protein components