Kingdom of Saudi Arabia
‫اململكة العربية السعودية‬
Ministry of Higher Education
‫وزارة التعليم العايل‬
Salman Bin Abdul-Aziz University
‫جامعة سلمان بن عبد العزيز‬
College of Applied Medical
‫كلية العلوم الطبية التطبيقية‬
Sciences
Final Practical Examination 1
Course Title: Gene and molecular technology
Course Code: MLAB 475
Year: 1433/1434
Year: 4th
Level: seventh
Time allowed: 2 hour
Date: 16 -02-1434
Number of papers: 5
Number of questions: 6
Student Name : …………………………………………………………………………………………
Student Number: ……………………………………………………………………………………..
Question no
QI
QII
QIII
QIV
QIV
QIV
Total
Question
Scores
Multiple choice
Mention
Compare
Complete
Short essay
Label
Student
Scores
3
6
5
5
8
3
30
Prepared by: Ms. Ghannimh ALghuwainem
Signature:
ANSWER ALL THE FOLLOWING QUESTIONS
3
Part 1: choose the correct answer
1. Which of the technique (s) probe is used for ?
a. Sequencing
b. PCR
c. Hybridization
d. A and B
2. Which of element (s ) NOT used in PCR reaction
a. Deoxynucleotides
b. Dideoxynucleotides
c. Polymerase enzyme
d. Primer
3. Denaturation step is a part of
a. Northern blot
b. Southern blot
c. Western blot
4. The type of probe used in Western blotting is
a. Antibody
b. RNA probe
c. DNA probe
5. In DNA organic extraction procedure for DNA extraction, using of Nonionic detergent, Salt, Buffer and EDTA is for
a. Destruction of cell membrane
b. Precipitation of the cell components
c. Removing proteins from the cell
d. releasing DNA into solution
6. In DNA organic extraction procedure for DNA extraction, the material
used to digest unwanted extra protein is
a. Phenol
b. Chlorform
c. Proteinase K
d. Isopropanol
6
Part 2: answer the questions
1. Mention four of the components found in DNA sequencing reaction
matrix ( 2)
DNA polymerase, nucleotides, dideoxyneuleotides, ssDNA, primer, Mg,
buffer
--------------------------------------------------------------------------------------2. Mention 4 examples of sample used for DNA extraction ( 2)
Blood, Semen, Saliva, Urine, Hair, Teeth,Bone,Tissue, Cigarette Butts
Envelope & Stamps, Fingernail Clippings,Chewing Gum, Bite Marks
.--------------------------------------------------------------------------------------3. The reason of using Formaldehyde in Northern blotting procedure is (1)
Even though RNA is single stranded, it can have small regions that can
form base-paired secondary structures. This treatment prevents this from
occurring
----------------------------------------------------------------------------------------4. The reason of using restriction enzyme in southern blotting and
Denaturation step is to (1)
Because DNA is double strand (dsDNA) and denaturation allows
complementary DNA probe to binds to the ssDNA
-----------------------------------------------------------------------------------------
Part 3: complete the table
5
1. Compare between PCR and DNA replication according to:
DNA replication
Helicase
PCR
Heat 95 C
Reaction site
In vivo
In vitro
Feature of primer
RNA primer
DNA primer
Method of denaturation
step
2. Compare between PCR and DNA sequencing according to
Primer type / numbers
Type of template (
sample)
PCR
2 types ( forward and
reverse)
dsDNA
DNA sequencing
1 only either forward or
reverse
ssDNA
Part 4 : fill in the blanket with correct words to complete the
principle of electrophoresis
5
1. Electrophoresis is a technique used to separate macromolecules as protein and nucleic
acids according to differences in size and charge
2. DNA is negatively charged and it can be separated through a gel called agarose which
is extracted from seaweed.
3. When the DNA is exposed to an electrical field, the particles migrate from anode (-)
toward the cathode (+) electrode
4. A dye called Ethidium bromide has the ability to binds to DNA and fluoresces under
UV light, allowing the visualization of DNA on a Gel.
5. The smaller size of DNA move faster than large DNA
Part 6 : Short essay
8
A- Describe the step of polymerase Chain Reaction PCR ( 3). Explain
your answer with a diagram
Answer :
Step
1
Denaturation of DNA
(1/4)
95C
(1/4)
the DNA is
denatured the two
strands are separated
(1/4)
Step2 Primer annealing (1/2) 40the primers anneal
65C
(or bind to) their
(1/4)
complementary
sequences on the
single strands of
DNA (1/4)
Step Extension (1/4)
72C
DNA polymerase
3
(1/4)
Extends the DNA
chain by adding
nucleotides to the 3’
ends of the primers.
(3/4)
In a PCR reaction, the following series of steps is repeated 2040 times
Diagram
Denature (heat to
95oC)
Lower temperature to
56oC Anneal with
primers
Increase temperature
to 72oC DNA
polymerase + dNTPs
Total
3/4
1
1+ 1/4
1/4
1+ 1/4
B- Illustrate the steps of Western Blot. (3+ 1/2)
 This method is used to detect Protein in a serum sample
1. Electrophoresis step : protein in a sample is separated moved from – to +
according to its size (1)
2. Blotting : transfer the protein from the gel into a membrane ( nylon )
(3/4)
3. Adding probe : antibody labeled with enzyme is added (1)
4. Detection step :by adding substrate color changed band detection
(3/4)
Part 6 : Analyze the pictures
A- Label the pointed items to complete the steps of Southern blotting
procedure
A cleavage by Restriction enzyme
B gel electrophoresis
C blotting
D hybridization by DNA probe
3
B- Analyze the autoradiography showed down that present a manual DNA
sequencing result and extract
a. The complementary synthesized sequence
b. The template of DNA that used
for Sequencing
SEQUENCE READ
3' CGAGATTGACTCAGTAACG 5'
TEMPLATE
5' GCTCTAACTGAGTCATTGC 3'