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Gene Expression REVIEW Packet
Transcription & the Big picture
1. Fill-in-the-blank General Summary
Like DNA, ribonucleic acid (RNA) is a ________________ acid—a molecule made of nucleotides linked together.
RNA differs from DNA in three ways. First, RNA consists of a __________________ strand of nucleotides instead of
the two strands found in DNA. Second, RNA nucleotides contain the five-carbon sugar ________________ rather than
the sugar deoxyribose found in DNA nucleotides. And third, RNA has a nitrogen base called ________________
(abbreviated as U) instead of the base ________________ (T) found in DNA. No thymine (T) bases are found in RNA.
Like thymine, uracil is complementary to ________________ whenever RNA base-pairs with another nucleic acid.
2. Defining and comparing Replication and Transcription
a-Define the following processes:
-Replication
-Transcription
b-Comparing the two processes. Think about this, and try to give 2 items for each box:
How are these two processes SIMILAR
How are these two processes DIFFERENT?
3. RNA vs DNA
Decide if each statement describes DNA only, RNA only, both, or neither. Then check the appropriate column or
columns (or neither!)
DNA
a
b
c
d
e
f
g
h
i
j
k
RNA
made of nucleotides
single strand of nucleotides
double helix
contains amino acids
contains uracil
contains thymine
contains adenine
contains sugar
contains deoxyribose
contains ribose
contains phosphate
l
m
n
o
p
q
r
s
t
DNA
is a nucleic acid
contains a base that pairs
with adenine
used as a template for
making nucleic acid
used in transcription
used in replication
used in translation
does not leave the nucleus
leaves the nucleus
has more than one form
RNA
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4. Location, location, location…
•Where within the cell does each of the following occur?
a-replication? ____________________________
b-transcription? ____________________________
c-translation? ____________________________
5. Transcription Practice
•Transcribe mRNA from the following DNA segments:
a-CTCCGAT
b-TAACGTAGTTC
c-ATTGCTAGT
#6
6. Transcription Labeling #1 
In transcription, RNA polymerase splits the two halves of a
strand of DNA. RNA then uses one half as a template to
make a copy of the other half. RNA contains the nucleotide
uracil instead of the nucleotide thymine. Label the DNA and
RNA. Then, label the missing nucleotides marked on the
diagram.
7. Transcription Labeling #2 
•Label the following items:
-RNA polymerase
-DNA coding strand
-DNA non-coding strand
-mRNA
#7
8. RNA Labeling
a-Label these 3 types of RNA molecules
b-Circle the molecule in charge of bringing amino acids to the ribosome.
c-Put an X on the molecule that represents a temporary copy of DNA.
9. Big Picture review
a-Groups of _____ nitrogen bases are translated into amino acids. These trios bases are called _____________________,
and they are located on ___RNA molecules. Amino acids are the building blocks of ________________________.
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Translation
10. Translation Labeling #1
•Review: During translation, transfer RNA(tRNA) anticodons
match to messenger RNA(mRNA) codons. Each tRNA
molecule can carry one particular amino acid. The amino acids
are joined to form a polypeptide (protein).
•The Diagram: Below is a strand of mRNA that needs to be
translated into protein, and the 4 tRNA’s that will match up
with it.
a-Below the four tRNA anticodons, write the numbers 1-4 to show
the order in which they would appear to match the codons in the
mRNA strand.
a-Order of tRNA’s 
b-Below the mRNA, identify which amino acid would be brought
to make the protein. (Be Careful! Before you do this, make sure
to read the TITLE of the table in the notes.)
b-Amino acids:
________ ________ ________ _______
11. Translation Labeling #2
•First, locate these 2 items
and label them:
A-mRNA segment
leaving the nucleus
B-mRNA segment at the
ribosome
•Then label the following
items:
C-tRNA
D-ribosome
E-a codon
F-an anticodon
G-use the table to
identify the three
specific amino acids on
the 3 tRNA’s)
H-nucleus
12. Bio-Math Challenge: Alien codons
a-With codons being 3 bases long, there are _________ different combinations. Since there are only _______ amino acids,
there is quite enough for each amino acid to have its own “word” to stand for it.
b-If you discovered a planet whose residents had 2-base codons, what is the maximum number of amino acids they could use?
(Forget about stop codons for now.) ______
c-Let’s say these aliens had only 2-base codons, but they also had a 5th base (let’s call it Biligine). THEN how many amino
acids could they accommodate? (Forget about stop codons again.) __________
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13. Translation practice
a-Identify the process responsible by writing its name in column B.
b-Complete column C by writing the mRNA nitrogen bases that would match up with the DNA bases in column A. Because
you’re making RNA, you should use the letters A, U, C & G.
c-Identify the process responsible by writing its name in column D.
d-Complete column E by writing the correct bases for the tRNA anticodon that bonds to each codon from column C.
e-Complete column F by writing the name of the correct amino acid that is coded by each base sequence. Use the table in your
notes to translate the mRNA (not tRNA!!) base sequences to amino acids for column F.
A
B
C
D
E
F
DNA (base
sequence)
Name of the process
of converting from
DNA  mRNA
mRNA
codon
Name of the process of
converting from
mRNA  protein
tRNA
anticodon
Amino acid
AAT
UUA
GGG
ATA
AAA
14. Big Picture Labeling 1
Label this diagram
using the word bank:
Word Bank
Nucleus
Cytoplasm
mRNA leaving
through Nuclear
Pore
DNA
DNA unzipping
mRNA (label 2x)
Transcription
Growing Protein
tRNA
individual Amino
Acids
Ribosome
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15. Decoding DNA
Complete the table below showing sequences of DNA, mRNA codons, anticodons, and corresponding amino acids. Use the list
of mRNA codons in the table in your notes to help you complete this exercise. Remember that the genetic code is based on
mRNA codons. Some have been done for you.
DNA
mRNA codon
Anticodon
Amino Acid
GAT
UAU
UUC
Tryptophan (trp)
16. Explanations!
a-Describe the structure of the tRNA molecule. Label its anticodon, too 
______________________________________________________________________________________________________
______________________________________________________________________________________________________
_____________________________________________________________________________________________
b-Explain why specific base-paring is essential to the processes of transcription and translation.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
__________________________________________________________________________________________
c-The structure (shape) and function (job) of a protein is determined by its sequence of what?
17. Big Picture Labeling 2
Label the following items on the diagram:
a-tRNA
b-amino acids attached to a tRNA
c-ribosome
d-growing protein chain
e-mRNA
f-a codon
g-an anticodon
h-free-floating amino acids
i-a tRNA that has just given up its amino acid and hasn’t
replaced it yet
j-peptide bond (pick one)
*What process is shown here?
________________________________________
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Mutations!
18. Types of mutations
•ABOVE THE ARROWS each of these diagrams shows a strand of normal DNA, plus the strand of mRNA transcribed from it,
and the protein strand made
from that.
•BELOW THE ARROWS, a
slightly mutated piece of
DNA is shown, along with the
corresponding mRNA and
protein strands.
•Label which of the 3 examples
represents which types of
mutations 
A-substitution
B-insertion
C-deletion
19. Mutation Practice
a-Determine how the mutations below will affect each amino acid
sequence. Use your translation chart to complete this table. In the
space provided, write the names of the amino acids that
correspond to each mRNA sequence and mutation given. An
example is provided for you.
b-What kind of mutation occurred to the mRNA sequence in item d?
Explain.
e.g.
a
b
c
d
original
mRNA Sequence
UGU- CCG
Amino Acid sequence
cysteine-proline
mutated
UGC-CGC
cysteine-arginine
original
GAA-CGU
mutated
GAU-CGU
original
AUC-UGC
mutated
AUC-UGG
original
UGU-CCU-CCU
mutated
UGU-UUC-CCU
original
GGG-UUA-ACC
mutated
GGU-UAA-CC
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