Name: ________________________
Date: _____________
5A Gene Expression
Study Guide
Part I
1. Compare DNA and RNA, include BOTH structure and function.
2. What are the roles of the three types of RNA? Fill in the table:
Type of RNA
mRNA
“______________” RNA
rRNA
“______________” RNA
tRNA
“______________” RNA
Picture
Function
3. Use the following gene to complete the tasks below:
DNA/gene
T A C
T T C
G G A
A T A
G C A
A C T
Transcribe the gene into mRNA
__________|___________|____________|____________|____________|__________
Translate the mRNA into a polypeptide
__________|___________|_____________|___________|____________|__________
What are the tRNA anticodons that match with the mRNA codons?
__________|___________|_____________|___________|____________|__________
4. Complete the following table:
Location
Starting Molecule
Product
Transcription
Translation
5. What enzyme allows for transcription to occur? ________________________
6. What is the first codon read on an mRNA strand called? ____________________ What three letters make this
codon? ____________
7. What is the codon called that tells the ribosome that the polypeptide is complete? ______________________
8. tRNAs bring in the correct amino acids according to the message in the mRNA. This happens because each tRNA
has an _______________________ that pairs with a specific _____________ on the mRNA.
9. What types of bonds connect the amino acids in the polypeptide? ____________________
10. Use the word bank to label the diagram below:
mRNA
tRNA
start codon
stop codon
anticodon
ribosome
polypeptide
11. Think!!
a. A mRNA strand with 66 nucleotides codes for a polypeptide _____ amino acids in length.
b. A protein 300 amino acids in length was made from an mRNA strand _______ nucleotides in length.
Part II
1. What are the three types of gene mutations? ________________________________________________
2. Create each of the gene mutations one at a time using the gene below. EACH TIME MAKE THE MUTATION AT
THE 4TH BASE. Show how it will affect the resulting polypeptide.
Original Gene:
TAC
GTG
AAC
GCA
Transcribe the original: _____ ______ ______ ______
Translate the original: _____ ______ ______ ______
Substitution
Insertion
Deletion
Gene with mutation
Resulting mRNA
Resulting polypeptide
3. Which two gene mutations are frameshift mutations? ___________________________________
4. Why are these more problematic types of mutations?
___________________________________________________________________________________
5. Describe each of the chromosomal mutations shown below:
- ________________________________________________________________________
-________________________________________________________________________
-_________________________________________________________________________
-_________________________________________________________________________
6. Why can some mutations be helpful, others harmful, and others make no difference at all?
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
7. Roughly how much of the DNA codes for protein? __________What is the rest of the DNA called? ____________
8. What does it mean for a certain gene to be “turned on”?
___________________________________________________________________________________________
___________________________________________________________________________________________
9. Turning on and off genes allows cells to _________________________________ (have a certain job role).