Download Q1. Choose the most correct answer(10pts): 1

Lecturer: Dr. Raida W. Khalil
Faculty of Science,Department of
Biotechnology & Genetic Engineering
Internal Examiner:
Student Name:
Student Number:
Course Name: Applied Molecular Biology
1st Semester: 2013/2014
Course Number: 240484
Date: 14 /11/2013
1st Exam
Section: 1
Time: 11:10
Number of Questions:
Duration:50 minutes
Mark:
Number of Pages:
/20
NB: Strictly Use the provided Space only!!!
‘ It is better to understand a little than to misunderstand a lot’
Q1. Choose the most correct answer(10pts):
1- Main problem in gene analysis is the uniform nature of DNA molecule itself
a. True
b. False
2-Until 1940s, many scientists favoured proteins due to:
a- proteins less abundant in cells b. Protein too simple to convey complex information cprotein carries hereditary information
d-Non of the above
3-Nuclein isolated by Miescher revealed the following characteristic:
a-Contained phosphorus and no sulphur b- its characteristics differ from protein
c-form long nucleic acid molecules
d- a and b
4-The model below is:
a-Trinucleotide Model of the Nucleic Acid structure proposed by Levene and Simms 1926
b-Tetranucleotide Model of the Nucleic Acid structure proposed by Levene and Simms 1926
c- Four-nucleotide unit that repeated many times to form long nucleic acid molecules
d- b and c
5-The conclusion of Griffith(1928) experiment is:
a-Heat-killed S bacteria(virulent) transform Live R bacteria(avirulent) into S ones
All the best, Dr. Raida Khalil
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b- Transforming principle is polysaccharide capsule or compound required for capsule
synthesis
c- Heat-killed R bacteria(virulent) transform Live S bacteria(avirulent) into R ones
d- a and b
6-Avery, MacLeod & McCarty(1944) demonstrated that :
a-DNA and RNA are the transforming Agent b- DNA and Protein are the transforming
Agent
c-DNA is the transforming agent
d-a and c
7-‘protein has no function in phage multiplication, and that DNA has some function’(1952),
this saying is belong to:
a-Watson and Crick b-Avery, MacLeod & McCarty c- Griffith d- Hershey and Chase
8- Chargaff Experiment(1952) showed ratios of 4 bases equal, but not random:
a-True
b-False
9- Franklin(19530 improved X-ray data from highly purified samples of DNA and confirmed:
a-3.4 nm distance between stacked bases
b-Suggested structure of DNA sort of helix
c-Proposed a model for structure of DNA
d-No correct answer
10-Double-helix model(Watson and Crick,1953) proposed by relaying onto Franklin’s X-ray
diffraction pattern only:
a-True
b-False
QII. Hershey-Chase experiment depended on radioactive labels on the DNA and Protein, so
what were the two different labels? And why ?(2 pts)
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QIII. Separated DNA strands can be induce to renature or anneal. Several factors influence
annealing among them are( 1 pt):--------------------------------------and------------------------Q1V How many proteins of average size could be encoded in a virus with a DNA
genome having 12,000 bp? assuming no overlap of genes and consider the average mass of
an amino acid is about 100 D. (That means an average protein of about 40,000 contains 400
amino acids).(2 pts)
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QV. The restriction enzymes BamHI and PstI cut their recognition sequences as shown in
Figure 1-----NB: Please show your answers on the Figure (5 pts)
A-Indicate the 5’ and 3’ ends and type of protruding end of the cut DNA molecule?
B-How would the ends be modified if you incubated the cut molecules with DNA polymerase
in the presence of all four dNTPs?
C-after the reaction in part B, could you join the BamHI ends together by DNA ligase? And
could join the PstI ends together by DNA ligase?
All the best, Dr. Raida Khalil
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D- will joining of the ends in part C regenerate the BamHI sit? Will it regenerate the PstI
site?
Figure 1:5’--G GATCC-3’
3’--CCTAGG-5’
5’--CTGCAG--3’
3’--GACGTC--5’
BamHI
PstI
--G
-- CCTAG
--CTGCA
--G
GATCC-G—
G-ACGTC--
Bonus Question: Drop your proposed question and its proper answer?
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All the best, Dr. Raida Khalil
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