Name
KEY
Date
Period
#
Transcription / Translation Guided Reading
KEY CONCEPT
Transcription converts a gene into a single-stranded RNA molecule.
MAIN IDEA: RNA carries DNA’s instructions.
Label each of the processes represented by the arrows in the diagram below. Write where each of these
processes takes place in a eukaryotic cell in parentheses.
1. Replication (Nucleus)
DNA
RNA
2. Transcription(nucleus)
Proteins
3. Translation(cytoplasm)
____________
Fill in the table below to contrast DNA and RNA.
DNA
RNA
4. Contains the sugar deoxyribose
Contains the sugar ribose
5. Has the bases A, C, G, T
Has the bases A, C, G, and U
6. Typically double-stranded
Typically single-stranded
MAIN IDEA: Transcription makes three types of RNA.
7. What enzyme helps a cell to make a strand of RNA?
RNA Polymerase ____________________________________________________________________________________
8. The following sentences summarize the three key steps of transcription.
Circle the word or phrase that best completes the sentence,
i. A large transcription complex, including RNA polymerase and other proteins, assembles at
the start of a gene / nucleus and begins to unwind the DNA / RNA.
ii. Using one strand of the DNA as a template, DNA polymerase / RNA polymerase strings
together a complementary strand of RNA.
iii. The RNA strand attaches to / detaches from the DNA as it is transcribed, and the DNA zips
back together.
9. Write the basic function of each type of RNA in the chart below.
Type of RNA
Function
mRNA
Intermediate message that is translated to form a protein
rRNA
Forms part of ribosomes
tRNA
Brings amino acids from cytoplasm to a ribosome to help make the
growing protein
MAIN IDEA: The transcription process is similar to replication.
10. Check the appropriate boxes to identify whether each of the following processes is true of transcription, true of
replication, or true of both transcription and replication.
Transcription
Replication
Both
i. is catalyzed by large enzymes
X
ii. is highly regulated by the cell
X
iii. involves complementary base pairing of
the DNA strand
X
iv. involves unwinding of the DNA double
helix
X
v. occurs within the nucleus of eukaryotic
cells
X
11.Check the appropriate boxes to identify whether each of the following end results is true of transcription, true of
replication, or true of both transcription and replication.
Transcription
i. makes a double-stranded copy of all the DNA
in a cell
ii. makes a single-stranded complement of only a
particular DNA sequence.
X
X
iii. occurs only once during each round of the cell
cycle
iv. occurs repeatedly throughout the cell cycle to
make proteins, rRNAs, and tRNAs, as needed
by a cell
Replication
X
X
Both
12.How does the name of each type of RNA tell what it does?
mRNA - is a form of the DNA message that tells the cell what type of protein to make
rRNA – is a key component of ribosomes
rRNA - transfers, or carries, amino acids from the cytoplasm to the ribosome
13.What is transcription?
The process of copying a sequence of DNA to produce a complementary strand of RNA
Section 5: Translation
KEY CONCEPT
Translation converts an mRNA message into a polypeptide, or protein.
MAIN IDEA: Amino acids are coded by mRNA base sequences.
1. What is translation?
The process that converts an mRNA message into a polypeptide, or protein
2. What is a codon?
Sequences of three nucleotides that code for an amino acid
3. Would the codons in Figure 5.1 be found in a strand of DNA or RNA?
RNA
4.What is a reading frame?
The order in which nucleotides are read; they are read as a series of three, nonoverlapping nucleotides
Refer to Figure 5.1 to complete the table below.
Codon
Amino Acid or Function
5. AGA
Arginine (Arg)
6. UAG
Stop codon
7. UGG
tryptophan (Trp)
8. GGA
Glycine (Gly)
MAIN IDEA: Amino acids are linked to become a protein.
9. Ribosomes and tRNA molecules are the tools that help a cell translate an mRNA message into a polypeptide.
10. The small subunit of a ribosome holds onto the mRNA strand.
11. The large subunit of a ribosome has binding sites for tRNA.
12. A tRNA molecule is attached to an amino acid at one end and has an anticodon at the other end.
13. Place the following sentences into the cycle diagram below to outline the steps of translation.
i. The ribosome pulls the mRNA strand the length of one codon. The first tRNA exits the ribosome, and another
codon is exposed.
ii. The ribosome forms a peptide bond between the amino acids. It breaks the bond between the first amino acid
and tRNA.
The ribosome forms a peptide bond between the amino acids. It breaks the bond between the first amino acid and
tRNA.iii. An exposed codon attracts a complementary tRNA bearing an amino acid.
A.
Ribosome assembles at the
start codon of mRNA strand.
An exposed codon attracts a
complementary tRNA bearing an
amino acid.
B.The ribosome forms a peptide
C.
bond between the amino acids. It
breaks the bond between the
first amino acid and tRNA.
The ribosome pulls the mRNA
strand the length of one codon. The
first tRNA exits the ribosome, and
another codon is exposed.
When the ribosome
encounters a stop codon, it
falls apart and the protein is
released.
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
14. AGG, GCA, and GUU are examples of
codons
.
15. A(n) anticodon is a set of three nucleotides on a tRNA molecule that is complementary to an mRNA codon.
16. A
stop codon indicates where translation is to stop.