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Biology
2014-2015
Name ___________________________________
DNA, RNA, Protein Synthesis and Mutations Test Review
TEKS
5C: Describe the roles of DNA, RNA and environmental factors in cell differentiation.
6B: Recognize that components that make up the genetic code are common to all
organisms.
6C: Explain the purpose and process of transcription and translation using models of
DNA and RNA.
6D: Recognize that gene expression is a regulated process.
6E: Identify and illustrate changes in DNA and evaluate the significance of these
changes.
Summary of Topics to Review
 Structures and functions of DNA and RNA
 Nucleotide structure and how they are arranged to form DNA and RNA
 Structure and functions of they types of RNA
 Processes of protein synthesis, including transcription of DNA and translation of mRNA
 Translate codons of mRNA using Genetic Code chart
 Identify how changes in DNA may cause mutations
 Distinguish between the types of mutations
II. Questions
1. The diagram below shows a process occurring in cells. Name the process and label items 1-5 on the diagram.
Amino Acid
Polypeptide
tRNA
Ribosome
mRNA
2. What is transcription and where does it occur in the cell?
Transcription is the process of making mRNA from DNA in the nucleus. RNA polymerase opens the DNA then adds
nucleotides to create a complementary mRNA strand from the noncoding strand.
3. What is translation and where does it occur in the cell?
In translation mRNA enters the cytoplasm where it binds with a Ribosome made of rRNA. tRNAs bring amino acids to the
Ribosome; it binds codon to anti-codon to make Proteins.
4. 3 nucleotides (nitrogen bases) = 1 codon = 1 amino acid
5. Given this DNA strand, find its (refer to Genetic Code chart on page 303):
G T A C A T C T T A A C G C A T A T
mRNA: C A U G U A G A A U U G C G U A U A
amino acids: Histidine, Valine, Glutamic Acid, Leucine, Arginine, Isoleucine
tRNA:
G U A C A U C U U A A C G C A U A U
6. Label the diagrams as either proteins, DNA or RNA.
DNA
mRNA
Protein
7. In the diagram below, circle a phosphate group, circle a 5-carbon sugar, and name the two nitrogen bases present. Is this
molecule a DNA nucleotide or an RNA nucleotide?
Adenine and Thymine are the
nitrogenous bases
This is DNA because it has Thymine
and is double stranded
8. Genes made of DNA contain information for assembling _____.
a. purines
b. proteins
c. pyrimidines
d. nucleosomes
9. Name the 3 types of gene mutations.
1. Insertion
2. Deletion
3. Substitution
10. Are all mutations harmful?
No, they can be beneficial, harmful or do nothing
11. Can mutations lead to genetic variation?
Yes, mutations are how species change over time.
12. Name a genetic disorder caused by a gene mutation.
Albinism, PKU, Cystic Fibrosis, Tay-Sachs
13. Compare the following codon sequences: (6E)
GUG-UGA-CGC-UGU-CCA
And
GUG-UGA-CCG-CUG-UCC-A
Which mutation is being illustrated?
a. deletion
b. insertion
c. substitution
d. inversion
Biology
Mutations Worksheet
Name
KEY
There are several types of mutation:
DELETION (a base is lost)
INSERTION (an extra base is inserted)
Deletion and insertion may cause what’s called a FRAMESHIFT, meaning the reading “frame”
changes, changing the amino acid sequence.
SUBSTITUTION (one base is substituted for another)
If a substitution changes the amino acid, it’s called a MISSENSE mutation.
If a substitution does not change the amino acid, it’s called a SILENT mutation.
If a substitution changes the amino acid to a “stop,” it’s called a NONSENSE mutation.
Complete the boxes below. Classify each as either Deletion, Insertion, or Substitution AND as either
frameshift, missense, silent or nonsense (hint: deletion or insertion will always be frameshift).
Original DNA Sequence:
T A C A C C T T G G C G A C G A C T
mRNA Sequence:
A U G U G G A A C C G C U G C U G A
Amino Acid Sequence:
METHIONINE -TRYPTOPHAN - ASPARAGINE - ARGININE- CYSTEINE - (STOP)
Mutated DNA Sequence #1:
T A C A T C T T G G C G A C G A C T
What’s the mRNA sequence? A U G U A G A A C C G C U G C U G A (Circle the change)
What will be the amino acid sequence? METHIONINE -(STOP)
Will there likely be effects?
YES
What kind of mutation is this? SUBSTITUTION - NONSENSE
Mutated DNA Sequence #2:
T A C G A C C T T G G C G A C G A C T
What’s the mRNA sequence?
A U G C U G G A A C C G C U G C U G A
(Circle the change)
What will be the amino acid sequence? METHIONINE - LEUCINE -GLUTAMIC ACID – PROLINE
Will there likely be effects?
YES
What kind of mutation is this? INSERTION - FRAME SHIFT
Mutated DNA Sequence #3:
T A C A C C T T A G C G A C G A C T
What’s the mRNA sequence?
A U G U G G A A U C G C UG C U G A
(Circle the change)
What will be the amino acid sequence? METHIONINE-TRYPTOPHAN-ASPARAGINE- ARGININE- (STOP)
Will there likely be effects?
Mutated DNA Sequence #4:
What’s the mRNA sequence?
NO
What kind of mutation is this? SUBSTITUTION – SILENT MUTATION
T A C A C C T T G G C G A C T A C T
A U G U G G A A C C G C U G A U G A
(Circle the change)
What will be the amino acid sequence? METHIONINE-TRYPTOPHAN-ASPARAGINE- (STOP)
Will there likely be effects?
YES
What kind of mutation is this? SUBSITUTION - NONSENSE
Original DNA Sequence:
mRNA Sequence:
T A C A C C T T G G C G A C G A C T
A U G U G G A A C C G C U G C U G A
Amino Acid Sequence: METHIONINE-TRYPTOPHAN-ASPARAGINE-ARGININE-CYSTEINE- (STOP)
Mutated DNA Sequence #5:
T A C A C C T T G G G A C G A C T
What will be the corresponding mRNA sequence? A U G U G G A A C C C U G C U G A
What will be the amino acid sequence? METHIONINE-TRYPTOPHAN-ASPARAGINE- PROLINE - ALANINE
Will there likely be effects?
What kind of mutation is this? DELETION – FRAME SHIFT
YES
1. Which type of mutation is responsible for new variations of a trait? FRAME SHIFT AND MISSENSE
2. Which type of mutation results in abnormal amino acid sequence? FRAME SHIFT, NONSENSE, AND MISSENSE
3. Which type of mutation stops the translation of the mRNA? NONSENSE
Sickle Cell Anemia
Sickel cell anemia is the result of a type of mutation in the gene that codes for part of the hemoglobin molecule.
Recall that hemoglobin carries oxygen in your red bloods cells. The mutation causes the red blood cells to become
stiff and sickle-shaped when they release their oxygen. The sickled cells tend to get stuck in blood vessels,
causing pain and increased risk of stroke, blindness, damage to the heart and lungs, and other conditions.
Analyze the DNA strands below to determine what amino acid is changed and what type of mutation occurred.
Normal hemoglobin DNA
Normal hemoglobin mRNA
C A C G T G G A C T G A G G A C T C C T C
G U G C A C C U G A C U C C U G A G G A G
Normal hemoglobin A.A. sequence VALINE-HISTIDINE-LEUCINE-THREONINE-PROLINE-GLUTAMIC ACIDGLUTAMIC ACID
-------------------------------------------------------------------------------------------------------------------------------Sickle cell hemoglobin DNA
Sickle cell hemoglobin mRNA
C A C G T G G A C T G A G G A C A C C T C
G U G C A C C U G A C U C C U G U G G A G
Sickle cell hemoglobin A.A. sequence VALINE-HISTIDINE-LEUCINE-THREONINE-PROLINE-VALINEGLUTAMIC ACID
http://staff.fcps.net/einman/biology/MutationsWS.doc
PROTEIN SYNTHESIS WORKSHEET
PART A. Read the following and take notes on your paper:
Protein synthesis is the process used by the body to make proteins. The first step of protein synthesis is called
Transcription. It occurs in the nucleus. During transcription, mRNA transcribes (copies) DNA. DNA is
“unzipped” and the mRNA strand copies a strand of DNA. Once it does this, mRNA leaves the nucleus and
goes into the cytoplasm. mRNA will then attach itself to a ribosome. The strand of mRNA is then read in order
to make protein. They are read 3 bases at a time. These bases are called codons. tRNA is the fetching puppy.
It brings the amino acids to the ribosome to help make the protein. The 3 bases on tRNA are called anti-codons.
Remember, amino acids are the building blocks for protein. On the mRNA strand, there are start and stop
codons. Your body knows where to start and stop making certain proteins. Just like when we read a sentence,
we know when to start reading by the capitalized word and when to stop by the period.
Ribosome
tRNA
mRNA
PART B. Answer the following questions on your paper:
1. What is the first step of protein synthesis?
a. unzipping of DNA
2. What is the second step of protein synthesis?
a. Produce mRNA
3. Where does the first step of protein synthesis occur?
a. Nucleus
4. Where does the second step of protein synthesis occur?
a. Cytoplasm
5.
Nitrogen bases are read 3 bases at a time.
6. The bases on the mRNA strand are called Codons.
7. The bases on tRNA are called anti-codons
mRNA
DNA
8. What is the start codon?
a. AUG
9. What are the stop codons?
a. UGA, UAG, UAA
10. A bunch of amino acids put together makes a polypeptide.
PART C. Use your codon chart to determine the amino acid sequence. Remember to read through the
strand and ONLY start on AUG and STOP when it tells you to stop. Follow example below:
Example:
DNA  AGA CGG TAC CTC CGG TGG GTG CTT GTC TGT ATC CTT CTC AGT ATC
mRNA  UCU GCC AUG GAG GCC ACC CAC GAA CAG ACA UAG GAA GAG UCA UAG
protein 
start - glu – ala –thre – hist – asp -glu-threo-stop
acid
1.
acid
DNA  CCT CTT TAC ACA CGG AGG GTA CGC TAT TCT ATG ATT ACA CGG TTG CGA TCC ATA ATC
mRNA  GGA GAA AUG UGU GCC UCC CAU GCG AUA AGA UAC UAA UGU GCC AAC GCU AGG UAU UAG
protein  - Met- Cys- Ala- Ser- Hist- Ala- Iso- Arg- Tyr- Stop - - -
2. DNA  AGA ACA TAA TAC CTC TTA ACA CTC TAA AGA CCA GCA CTC CGA TGA ACT GGA GCA
mRNA  UCU UGU AUU AUG GAG AAU UGU GAG AUU UCU GGU CGU GAG GCU ACU UGA CCU CGU
protein  - - Met- Glu- Asp- Cys- Glu- Iso- Ser- Gly- Arg- Glu- Ala- Thre- Stop acid
acid
The rest is not completed, but you get the picture.
acid