Name
Class
13
Date
RNA and
Protein Synthesis
The Role of RNA
1. Complete the table to contrast the structures of DNA and RNA.
DNA
Sugar
Deoxyribose
Number of Strands
2
Bases
ATCG
RNA
Ribose
1
AUCG
2. On the lines provided, identify each kind of RNA.
a. Transfer RNA
b Messenger RNA
c.Ribosomal RNA
mRNA
RNA Synthesis
In transcription, RNA polymerase
separates the two DNA strands.
RNA then uses one strand as a
template to make a complementary
strand of RNA. RNA contains the
nucleotide uracil instead of the
nucleotide thymine.
Follow the directions.
1. Label the RNA
RNA
polymerase
2. Label the DNA.
3. Use the key to label the missing
nucleotides marked on the
diagram.
DNA
Key
DN
RN
A = Adenine
A
A = Adenine
A
C = Cytosine C = Cytosine
G = Guanine G = Guanine
T = Thymine U = Uracil
BUILD Vocabulary
Term
Definition
Exon
The part of mRNA that is spliced (reconnected) after the introns are
removed. Exons code for amino acids.
Intron
The parts of mRNA that are cut out. They do not code for amino
acids.
Messenger
RNA
A RNA copy of a DNA gene.
Ribosomal
RNA
Type of RNA that ribosomes are made of.
RNA
polymerase
Enzyme that copies the DNA gene and builds a complementary RNA
Transcription
The process of copying DNA into RNA
Transfer RNA
Type of RNA that carries a specific amino acid to the ribosome during translation
RNA Synthesis
In DNA replication a cell copies its DNA. Both strands of the double helix are used as templates
to make complementary, or matching, strands of DNA. In DNA transcription a single strand of
DNA is used as a template to generate a strand of mRNA.
Follow the directions.
Fill in the missing information. One row has been completed for you.
DNATemplate
Complementary DNA
Messenger RNA (mRNA)
TTACGG
AATGCC
AAUGCC
CCGCCG
GGCGGC
GGCGGC
TGCATC
ACGTAC
ACGUAG
TCTGAG
UCUGAG
CTATTC
GATAAG
GAUAAG
GACCGATGT
CTGGCTACA
AGACTC
CUGGCUACA
The Genetic Code
The diagram below shows the mRNA codes that
correspond to amino acids and stop codons. Read
the diagram from the center outwards. For example,
the mRNA code UAC corresponds to the amino
acid tyrosine.
Follow the directions.
In the chart below the diagram, write the name
of the amino acid that corresponds to each
mRNA code.
mRNA Code
Amino Acid
AAA
lysine
GCG
ALANINE
GAU
ASPARTIC ACID
CAA
GLUTAMINE
BUILD Vocabulary
Term
Definition
Anticodon
The three bases at the bottom of a tRNA that are complementary to a
mRNA codon
Codon
The three bases on mRNA that code for an amino acid
Polypeptide
A chain of amino acids. Proteins are made of one or more
polypeptides.
Translation
The process of “reading” the mRNA message and building the
corresponding polypeptide.
Phenylalanine
leucine
lysine
methionine
Translation
Use the diagram to answer Questions 1-3.
1. What is the anticodon for leucine? GAC
2. What is the codon for leucine? CUG
3. List the amino acids in the order they would
appear in the polypeptide coded for by this
mRNA.
MET-PHE-LYS-LEU
Types of Mutations
For Questions 1–4, match the term with its definitio
Definition
B
Term
1. The change of one base to another in a DNA
sequence
A. mutation
A
2. A heritable change in genetic information
B. substitution
D
3. A kind of mutation that can change every
amino acid that follows the point of mutation
C. deletion
4. The addition of a base to the DNA sequence
E. insertion
E
D. frameshift mutation
Types of Mutations
Gene mutations produce a change in one gene. Point mutations produce gene mutations that involve
a change in one or more nucleotides. Point mutations also occur at only one point in the DNA
sequence. The diagram below shows an original chromosome and three possible point mutations.
Follow the directions.
1. Use the words in the box to add headings to the three lower parts of the diagram.
insertion
deletion
substitution
Complete the sentences. Use the terms from the box above.
2. In a(n) substitution, one base is changed to a different base.
3. In a(n) insertion, a base is inserted into the DNA sequence.
4. In a(n) deletion, one base is removed from the DNA sequence.
Answer the questions.
5. Which of the following can result in a frameshift mutation? Circle each correct answer.
A. deletion
B. substitution
C. insertion
6. Why is a frameshift mutation more damaging than a substitution? A substitution may change a
single amino acid, but a frameshift will alter all the amino acids after an insertion or deletion.