NAME KEY
Protein Synthesis - REVIEW
Use your notes and Chapter 8 of the textbook for help. Study all worksheets and activities.
A. REPLICATION
Use the DNA code provided and fill in the complementary DNA strand.
1.
A T T C G A T G C
2.
T A A G C T A G C
T A C G G A T C G
3. C A G T G A C T T
A T G C C T A G C
G T C A C T G A A
B. TRANSCRIPTION
1. Which nitrogen base is used during transcription but is not used
in replication? uracil
2. Use the DNA code provided to copy an m-RNA message.
a) (DNA) A C T G G A T A C
b) A C G G A T C G T
c) T G A C A G C T A
mRNA U G A C C U A U G
U G C C U A G C A
A C U G U C G A U
C. TRANSLATION:
USE the Chart in your notes to
DETERMINE the AMINO ACID that
corresponds to the m-RNA CODE GIVEN.
mRNA CODE
AAA
GCG
GAU
CAA
CAC
UUU
7. Which two mRNA codes correspond to
histidine?
AMINO ACID
1. lysine
CAC
2. alanine
3. aspartate
4. glutamine
5. histidine
6. phenylalanine
CAU
8. How many different mRNA codes
correspond to Threonine? 4
9. Tell the amino acid sequence for the following mRNA message:
MRNA MESSAGE: A U G C C A U G G C A U
Amino acid sequence:
(start) methionine
–
proline
–
tryptophan
Polypeptide chain
-
histidine
D. Look at the m-RNA message below:
1.Match each of the tRNA/amino acid complexes with its correct mRNA codon by placing the
corresponding number in the blank.
1.
2.
3.
4.
a) 2
b) 4
c) 3
d) 1 .
2. WHAT IS THE AMINO ACID SEQUENCE FOR THE PROTEIN THAT WOULD BE
PRODUCED FROM THIS MESSAGE?
Methionine
-
phenylalanine
-
lysine
-
leucine
Polypeptide chain
E. FILL IN THE INFORMATION BELOW with the correct sequence
1.
DNA code
mRNA message
3.
DNA code
T T A C G C G C A
A A U G C G C G U
A C A C T C G G C
mRNA message U G U G A G C C G
2. DNA code
C C G A A T C G T
mRNA message
4. DNA code
mRNA message
G G C U U A G C A
G A C C G A T G T
C U G G C U A C A
5. The process occurring above is what part of protein synthesis. transcription
6. Where in the cell does this process take place?nucleus
7. What if a mutation caused a change in the code so the message read UGG instead of UGC?
How would this affect the protein produced?
UGG makes tryptophan instead of cycteine (UGC) this changes the amino acid and therefore it
changes the protein made. The result would be harmful to the organism.
8. What if a mutation caused a change in the code so the message read GGA instead of GGC?
How would this affect the protein produced?
GGA makes glycine and so does GGC. Since the same amino acid would be added to the polypeptide
chain it would NOT change the protein. The result would not be harmful.
F. MATCH THE PARTS IN THE DIAGRAM WITH THE CORRECT LABEL.
1.C RIBOSOME
2.A NUCLEUS
3.B MESSENGER RNA
4.E ANTICODON
5.G AMINO ACID
6.F CODON
7.D TRANSFER RNA
8. The process taking place in the picture is what part of protein synthesis? translation
9. Where in the cell does this process take place? cytoplasm on the ribosome
10. Another name for a protein chain is polypeptide (It is named after the type of chemical bond
that forms between the amino acids)
11. What will happen to D after it drops off its amino acid?
Leaves to go get another amino acid to bring
12. What will happen to B after its message is read?
Breaks down into nucleotides to be used again to build another message
G. Answer the following questions.
1. What is the central dogma of biology? DNA codes for RNA which codes for Proteins
It can also be DNA RNA  Transcription Translation
2. In which type of cell must a mutation occur in order for the mutation to be passed on to the
offspring?
Somatic/body cells
or
sex cells/gametes
3. How are DNA and mRNA alike?
How are DNA and mRNA different? Fill in the table below.
DNA
mRNA
Double stranded (helix)
Shape
Single strand
A,T,C,G
A, U, C, G
Deoxyribose
Nitrogen
bases
Sugars
Nucleus
Location
Nucleus  cytoplasm
Ribose
4. Name the two main parts of protein synthesis and where in the cell they take place.
1) transcription- mRNA transcribes DNA’s message in the NUCLEUS
2) translation- mRNA takes DNA’s message to a RIBOSOME in the CYTOPLASM and
translates it to a protein
5. Transcription: DNA to mRNA:
a. How many strands of mRNA are transcribed from the two “unzipped” strands of DNA? 1
b. If the following were part of a DNA chain, what mRNA bases would pair with it to
transcribe the DNA code onto mRNA? G-G-A-T-C-G-C-C-T-T-A-G-A-A-T-C
CCU – AGC - GGA – AUC - UUA - G
c. If DNA is described as a double helix, how should mRNA be described? A single strand
d. How are the accuracy of DNA and mRNA codes assured? Enzymes like RNA polymerase
and DNA polymerase check or proof read to ensure there are no mistakes, The base pairs
also are complimentary, so there is a puzzle-like mechanism that checks to be sure there is a
match.
6. Translation: mRNA to PROTEIN:
a. Name and describe the three types of RNA’s involved in protein synthesis?
1) mRNA – takes DNA’s message to the ribosome, codons on the mRNA code for the amino
acid
2) rRNA – ribosomal RNA – associates with proteins to form ribosomes in the cytoplasm
3)tRNA (transfer RNA) – brings amino acids to ribosomes, has an anticodon that matches like
a puzzle piece to the codons on mRNA to be sure that the correct amino acid is brought
b. Why is mRNA needed during transcription?
DNA cannot leave the nucleus
c. Where must an mRNA attach before protein production can begin? On a ribosome
d. How many bases are needed to specify an mRNA codon? 3
e. What is an anticodon? It is a 3 base unit on tRNA that is a compliment to the codon on
mRNA
f. If a strand of mRNA contain the sequence, U-A-G-C-U-A-U-C-A-A-A-U, what tRNA
anticodons would be needed to translate the sequence? AUC – GAU – AGU - UUA
g. What is the difference between an amino acid and a protein? An amino acid is the
monomer or building block of protein. A protein is many amino acids bonded together
h. What type of bond is formed between amino acids? polypeptide
7. Label the drawing.
Help can be found in your biology textbook chapter 8.
mRna, amino acid, anti-codon, codon,
protein, tRNA, ribosome
G
E
D
A
.
A. tRNA
B. codon
C. mRNA
F
C
D. amino acid
E. protein, (polypeptide chain)
B
F. anitcodon
G.ribosome
8. Which cellular function does this model represent?
A. Transcription
B. Translation
C. Transformation
D. DNA replication
H. Gene Regulation and Mutation
1. What is a mutation? How does it occur? A permanent change in a cell’s DNA, A mutation in
a gene (and amino acid) sequence chain change the protein that is made
2. Types of Mutations- describe
a. Point – or Substitution (base pair substitution) – one nucleotide base is replaces another,
point mutations affect only one codon, so they affect only one amino acid in a peptide chain,
it can be harmless or cause a severe issue like Muscular dystrophy
b. Insertion the ADDITION of one or more bases into a nucleotide sequence, can change
many amino acids in the peptide chain thus changing the protein, causes a “frameshift”
EXAMPLE: Crohn’s disease inflammation of intestinal tract
c. Deletion one or bases is removed from a nucleotide sequence, a different amino acide is
put into the peptide chain. Causes a “frameshift” Example is cystic fibrosis a disease where
abnormally thick mucus in lungs, intestines, and pancreas
3. Which two mutations result in a frameshift?
Insertion and deletion
4. Describe what happens in a frameshift mutation.
In a frameshift, the nitrogen bases shift to the left or right when bases are added or
deleted, resulting in new codons and therefore different amino acids – changes the protein
5. Chromosomal Mutations
a. How do chromosomal mutations effect the organism? Affects the entire chromosome and
changes the number of genes in a chromosome or the organization of the chromosome
b. Describe the mutation that causes sickle-cell.
It is a single amino acid change. It is genetic so it occurs in the sex-cell or gametes.
It will be present in all of the cells of the offspring.
c. Describe the result of the mutation on the cell. What does it do to the cell?
The shape of the cell is changed from plump and round to flat. It cause the red blood cell to
not be able to carry oxygen throughout the body as well as a normal cell can. This can lead to
the symptoms of sickle cell.
6. Body-cell v. Sex-cell Mutation
a. What is a somatic cell? Body cell – all of the cells in the human body except the
sex cells (sperm or egg)
b. Compare and contrast mutations in body cells vs. sex cells Somatic cell mutations are not
passed on to the next generation. Mutations in sex cells are passed on to the organism’s
offspring and will be present in every cell of the offspring.
c. Identify the two main types of mutagens.
High-energy forms of radiation (X-Rays and gamma rays) and chemicals
d. Which is not a type of mutation?
A. base substitutions
B. insertions
C. RNA interference
D. duplication