DNA

Chapter 1. DNA Extraction and the Central Dogma of Molecular Biology Post-Lab

Lab 12 Post-Lab Questions
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You must read each slide, and complete any questions on the slide, in sequence.

DNA Extraction and the Central Dogma of Molecular Biology Post-Lab

A. Review of DNA Structure: Fill in the blank

1. Name the sugar found in DNA

2. Number of strands in DNA

3. The term to describe the shape of DNA

4. The nucleotide that pairs with cytosine

5. The nucleotide that appears with adenine

6. The term used to describe the opposite orientation of 2 strands of DNA

7. The two molecules that form the sides of the DNA ladder

8. The chemical bonds joining complementary nitrogenous bases (steps of the ladder)

9. The chemical bonds joining one nucleotide to another (sides of the ladder)
Correct.
Incorrect.

B. Review of DNA Replication: Fill in the blank

1. Enzyme that unwinds DNA

2. Enzyme primes DNA

3. Enzyme adds DNA to the growing strand

4. Enzyme that removes the RNA primer

5. Enzyme that joins the DNA fragments together
Correct.
Incorrect.

C. Review of RNA Structure and Transcription

1. Name of the sugar found in RNA

2. Number of strands and RNA

3. List three types of RNA

4. The template for RNA synthesis

5. Term for synthesis of RNA

6. Location of RNA synthesis
Correct.
Incorrect.

D. Translation of RNA to a Protein

1. The organelle needed for translation and joins amino acids together

2. Which RNA carries the instructions from DNA to the cytoplasm?

3. Which RNA brings in amino acids?

4. Location of RNA translation
Correct.
Incorrect.

In the diagram below, fill in the missing bases on the second (template) DNA strand, and then fill in the bases on the RNA strand. The RNA strand should be complementary to the template DNA strand.

Table 1: Please fill in the missing bases below according to the rules of base pairing. Type your answers in all capital letters, leaving no spaces between letters.

Coding DNA A A C G C C T A T C G A C
Template DNA
RNA

A. Transcribe this DNA sequence to mRNA:

GAG | TGG | TAC | ATG | TCA | TCC | AGC | ACT

  1. The DNA sequence above has been re-written in Table 2 below. Transcribe and translate the DNA sequence, recording your answers in the boxes below. Look for punctuation codons (start and stop) because it signals the ribosome when to start and when to stop.

Table 2: Normal DNA: Transcribe and translate the amino acid sequence. Pay attention to punctuation codons. Type your answers in all capital letters.

Code word 1 2 3 4 5 6 7
DNA G A G T G G T A C A T G T C A A G C A C T
mRNA
Amino acids
  1. What would happen to the protein if 3rd base code word 4 in the DNA sequence above were changed from a “G” to a “C” as in the example below?

Table 3: Mutated DNA: Transcribe and translate the amino acid sequence. Pay attention to punctuation codons. Type your answers in all capital letters.

Code word 1 2 3 4 (mutation) 5 6 7
DNA G A G T G G T A C A T C T C A A G C A C T
mRNA
Amino acids

B. Consider the following hypothetical gene. Indicate the sequence of the bases in the mRNA produced during transcription, and the sequence of the amino acids in the polypeptide produced during translation.

Table 4: Effect of Mutation: Original Sequence

Code word 1 2 3 4 5 6 7
DNA T A C G G C A G T C C T T C T G C A A C T
mRNA
Amino acids

Table 5: Effects of Mutation: Base Substitution

Code word 1 2 3 4 5 6 7
DNA TAC TGC AGT CCT TCT GCA ACT
mRNA
Amino acids

Table 6: Effects of Mutation: Base Addition

Code word 1 2 3 4 5 6 7
DNA TAC GGC CAG TCC TTC TGC AAC T
mRNA
Amino acids /TqcnA==

Table 7: Effects of Mutation: Base Deletion

Code word 1 2 3 4 5 6 7
DNA TAC GCA GTC CTT CTG CAA CT
mRNA
Amino acids /TqcnA==

Question 1. Based on the three examples on the previous page, which mutation(s) is/are potentially the most serious? Please justify your answer.
Base addition and deletion are the most serious because they completely change the amino acid sequence from that point on. This means that the protein will have a different shape and no longer function.

Question 2. What does the DNA look like when it is dissolved in solution?

A.
B.
C.
Correct.
Incorrect.

Question 3. What does the DNA look like when it precipitates out of solution?

A.
B.
C.
Correct.
Incorrect.

Question 4. Where is DNA located in a eukaryotic cell?
Correct Answers: nucleus, mitochondrion, and chloroplast
Correct Answers: nucleus, mitochondrion, and chloroplast

Question 5. In order to isolate the DNA, what do you have to lyse? Check all that apply

A.
B.
C.
D.
Correct.
Incorrect.

Question 6. Why it is important that we isolate DNA?
DNA is isolated for a variety of reasons. You can test an individual for genetic disease, analyze forensic evidence, or study a gene with a pure sample of DNA that was isolated from a cell.

Question 7. Why is a deletion or addition referred to as a “frame-shift” mutation?
The insertion or deletion of nucleotide base pairs shifts the reading frame and the way the sequence is read.

Question 8. Where does a mutation take place?

A.
B.
C.
Correct.
Incorrect.

Question 9. Refer back to section 2, when you filled out Table 1. The coding DNA would

A.
B.
C.
Correct.
Incorrect.

Question 10. Based on the following mRNA sequence, where would translation begin? UGACGGCAAAUGACGCCUGAUUAAAAAAAAAAAAAAAAA

A.
B.
C.
Correct.
Incorrect.

Question 11. Explain how a single mutation can alter the hemoglobin protein? How does this mutation affect individuals who have inherited this hemoglobin mutation.