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Online MCQ Assignment
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Multiple choice question for engineering

Set 1

1. Which macromolecule is not abundantly found though being of critical importance for biological mechanism?
a) Proteins
b) Lipids
c) Nucleic acids
d) Polysaccharides

View Answer

Answer: b [Reason:] Though lipids is of essential use in the cell for the formation of cell wall it is a micro molecule and is generally found in association with either phosphate or polysaccharide. In case of the other three they are all macromolecules and are of essential use for the cell. For example: proteins such as, enzymes regulates biological functions, nucleic acids carry genetic information and polysaccharides functions as either storage of energy or acts as structural polymers.

2. Which of the following is wrongly paired?
a) Proteins – peptide bond
b) Nucleic acid – hydrogen bond
c) Polysaccharide – glycosidic bond
d) Phospholipids –phosphate linkage

View Answer

Answer: b [Reason:] Nucleic acids, that is, DNA and RNA show phosphodiesterase linkage which is the major type of linkage. Without the phosphodiester bonds between the phosphate and adjacent 3’OH sugar molecule the backbone will not be formed. Therefore, the nucleotides would not be able to attach and bond to form a nucleic acid.

3. With respect to nucleosides which of the following is paired correctly?
a) Purine – Adenosine, Thymidine
b) Purine – Guanosine, Thymidine
c) Pyrimidine – Uridine, Cytidine
d) Pyrimidine – Uridine, Adenosine

View Answer

Answer: c [Reason:] As we know purines have a fused ring structure with 9 element backbones ring structure. They are of two types Adenosine and Guanine. Again, the other three residues cytidine, Thymidine and Uridine are pyrimidines having a ring structure of 6 elements in the core backbone. Thus the correct pair among the above options is pyrimidine – uridine, cytidine.

4. Which of the following is not a component of the nucleic acid backbone?
a) Pentose sugar
b) Phosphate group
c) Nucleotide
d) Phosphodiesterase bond

View Answer

Answer: c [Reason:] A nucleic acid backbone is mainly composed of a pentose-phosphate unit which acts as a monomer. The repeat of this monomer is attached together by the phosphodiesterase linkage, thus, giving rise to the backbone. The nucleotides attached to the sugar moieties forms the side chain which gives rise to the hydrogen linkage with its complementary strand.

5. According to Chargaff’s rule the two strands of DNA has ___________
a) Same molecular weight
b) Same amount of A and G
c) Different amount of A and G
d) Different molecular weight

View Answer

Answer: d [Reason:] According to Chargaff’s rule the two strands have equal number of A and T residues and equal number of G and C residues. Thus when in one strand A is more automatically in the other T is more. Thus, A being a pyrimidine has a higher molecular weight than T, which is a purine, and so the two strands have different molecular weight. The same happens in case of G and C also.

6. In one strand of a double stranded DNA the rate of occurrence of A is 3 times C in consecutive 10 bases. So how many G will be there in 100 base pairs of a DNA duplex?[Consider G=T in one strand].
a) 30
b) 20
c) 40
d) 60

View Answer

Answer: c [Reason:] Let’s consider C = 1 Therefore, A = 3C = (3*1) = 3 Now, A+C = (3+1) = 4 Again G = T [given] And A+C+G+T = 10 [given] Now replacing T with G and putting the value of A+C We get, 4 + 2G = 10 2G = 6 G = 3, T = 3, A = 3, C = 1 Thus in 100 bases in one strand there are (3*10 = 30) G residues Now for the complementary strand G = C residues [Chargaff’s rule] Therefore, C = G = 1 residue in every 10 bases That is, G = 1*10 = 10 in 100 bases Therefore total number of G residues = 30 + 10 = 40 in 100 base pairs of a DNA duplex.

7. In a diploid organism with 30,000 bases haploid genome contains 23% A residues. What is the number of G residues in the genome of this organism?
a) 16000
b) 16200
c) 16500
d) 14200

View Answer

Answer: b [Reason:] By Chargaff’s rule, A = T = 23% Therefore, G + C = [100 – (A+T)] G + C = [100 – 46] G + C = 54 G = C = 27 [By Chargaff’s rule] Therefore, G = 27% Now, each cell is diploid thus it contains (2*30,000 = 60,000) bases So, G = 27% of 60,000 G = 16,200 bases.

8. Which of the following is not a characteristic of nucleotide bases?
a) Planar
b) Heterocyclic
c) Aliphatic
d) Ubiquitous

View Answer

Answer: c [Reason:] The nucleotide bases have a 6 member ring structure as one component which is common for all five bases. Thus, they are considered as aromatic molecules due to the presence of a benzene ring structure which provides the molecules with an aromatic property.

9. Which of the following factors do not provide to the separation of DNA fragments during electrophoresis?
a) Chargaff’s rule
b) Matrix density
c) Ethidium bromide
d) Size

View Answer

Answer: c [Reason:] Ethidium bromide only helps in tagging the DNA molecules to make the visible under the UV radiation due to its fluorescence property, but does not take any part in the separation of DNA molecules during electrophoresis.

10. Which one of the following is not a function of a nucleotide?
a) Nucleic acid monomer
b) Ribozyme
c) Energy carrier molecules
d) Receptors

View Answer

Answer: d [Reason:] Nucleotides do not form receptor molecules. Receptor molecules are generally polysaccharide molecules or protein molecules which can have structural configurations. Energy carrying nucleotide molecules such as ATP helps binding and unbinding of signal molecules to these receptors thus facilitating different biological functions.

Set 2

1. How many types of DNA libraries are possible?
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: b [Reason:] There are two types of DNA libraries that can be produced. They are genomic DNA library and cDNA library that is produced from the reverse transcription of the mRNAs produced.

2. In the following type of libraries pick the odd one out.
a) A DNA library
b) B DNA library
c) cDNA library
d) Z DNA library

View Answer

Answer: c [Reason:] cDNA library lacks DNA fragment from the genomic DNA. This type of library is produced by the action of reverse transcriptase on the mRNA molecule to synthesize complementary DNA molecule without the intervening introns.

3. Which enzyme is involved in the synthesis of the DNA over an RNA template?
a) DNA polymerase
b) Reverse transcriptase
c) Klenow fragment
d) RNA polymerase

View Answer

Answer: b [Reason:] Reverse transcriptase is the enzyme that is involved in the reverse transcription of mRNA molecule. Thus it is used to produce the DNA copy from the mRNA transcript to form the cDNA library also known as the RNA library.

4. For the construction of DNA library what is the range of genomic DNA that has to be cloned into the vector?
a) Less than 100 bases
b) 100 to 1000 bases
c) Less than 100 to mega bases
d) Less than 10 bases

View Answer

Answer: c [Reason:] To construct a DNA library the target DNA is digested with a restriction endonuclease. This provides us with the desired range of fragments that can be incorporated within the vector and also the whole genome can be preserved within bacterial cells.

5. Which of the following enzymes is responsible for the digestion of the RNA strand in the RNA-DNA hybrid?
a) RNase A
b) RNase H
c) DNase
d) Exonuclease

View Answer

Answer: b [Reason:] When making a cDNA library the DNA copy is made from an RNA template thus leading to the formation of the RNA-DNA hybrid. Thus for the production of the chimera molecule the RNA template needs to be hydrolysed which is provided by RNase H enzyme whereas RNase A enzyme removes RNA primer from the in case of replicating the lagging strand.

6. cDNA is synthesized from __________
a) Protein chain
b) tRNA
c) mRNA
d) DNA

View Answer

Answer: c [Reason:] cDNA contains only coding sequences of the genomic DNA. Instead of starting with genomic DNA, mRNA is transcribed into DNA sequences by the action of reverse transcriptase.

7. During storage of DNA fragments for making library, larger fragments are having more chances of getting lost.
a) True
b) False

View Answer

Answer: a [Reason:] During the making of DNA library storing of larger fragments become complicated and while replication it might get lost. Thus average insert size taken is less than the insert size capacity of the vector.

8. What is the characteristic of the DNA that is used for the construction of library?
a) Naked DNA
b) Plasmid
c) Plasmid and naked DNA
d) Plasmid is preferred over naked DNA

View Answer

Answer: c [Reason:] Those libraries which are constructed using plasmid containing cells. Although naked DNA can also be inserted in the plasmid containing cells as the host transforms the naked DNA as per requirement.

9. What is the state of phage cloning vector that is used for the construction of library?
a) Packaged phage
b) Unpackaged phage
c) Packaged and unpackaged phage
d) Packaged and unpackaged phage are used but unpackaged phage is favored

View Answer

Answer: b [Reason:] Packaged phage is the one that contains viral genome but unpackaged phage is the one that does not contain any genetic material. If the phage is devoid of any genetic material it is easier to introduce desired DNA fragment and its integration into the host without the development of any infectious effect. Thus unpackaged phage is favored over packaged phage.

10. Which enzyme is used to avoid ligation of separate DNA?
a) Kinase
b) Phosphatase
c) Endonuclease
d) Ligase

View Answer

Answer: b [Reason:] Phosphatase is used to avoid ligation of separate DNA segments. Phosphatase is used to remove the terminal phosphate groups thus preventing the ligation.

11. Partial digestion is preferred for the fragmentation of DNA.
a) True
b) False

View Answer

Answer: a [Reason:] For the partial digestion all fragments of DNA needs to be represented. Thus partial digestion is preferred over the complete digestion.

12. The ordered steps for the construction of library involves __________
i) Vector preparation
ii) Amplification
iii) Ligation and introduction into the host
iv) Isolation of genomic DNA
v) Fragmentation of DNA
a) iv, v, i, iii, ii
b) v, iv, i, iii, ii
c) i, ii, iii, iv, v
d) ii, iii, iv, v, i

View Answer

Answer: a [Reason:] The order of the steps is: i) Isolation of genomic DNA ii) Fragmentation of DNA iii) Vector preparation iv) Ligation and introduction into the host v) Amplification.

13. What is the significance of “c” in cDNA library?
a) Copy DNA
b) Cut DNA
c) Cell DNA
d) Clone DNA

View Answer

Answer: a [Reason:] In cDNA library mRNA sequences are converted into double stranded DNA copies called cDNA. Thus significance of “c” in cDNA library is copy DNA as it is the copy of RNA segment in the form of DNA and not fragmented DNA itself.

14. mRNA can be readily separated from lysed eukaryotic cells adding magnetic beads. What is the sequence of this magnetic bead?
a) Oligo G
b) Oligo A
c) Oligo T
d) Oligo C

View Answer

Answer: c [Reason:] mRNA is used in the construction of cDNA library. The magnetic beads that is used for magnetic separation of mRNA molecules is oligo T sequence.

15. What is the significance of SI nuclease?
a) DNA synthesis
b) Cleavage of hooks
c) Degrades RNA
d) Annealing the primer

View Answer

Answer: b [Reason:] SI nuclease is the enzyme which is used in cDNA library. SI nuclease cleaves the hook which is extended by DNA polymerase I into complementary strand during cloning the cDNA library.

Set 3

1. What is a context switch?
a) Kernel switches from executing one process to another
b) Process switches from kernel mode to user mode
c) Process switches from user mode to kernel mode
d) None of the mentioned

View Answer

Answer: a

2. Pid of init process
a) 0                         
b) 1
c) 32767              
d) none of the mentioned

View Answer

Answer: b

3. What is the default maximum number of processes that can exist in Linux?
a) 32768       
b) 1024                
c) 4096       
d) unlimited

View Answer

Answer: a

4. How do you get parent process identification number?
a) waitpid
b) getpid()
c) getppid()
d) parentid()

View Answer

Answer: c

5. Parent process id of a deamon process is_________________.
a) 2
b) 3
c) 4
d) 1

View Answer

Answer: d

6. The process which terminates before the parent process exits becomes
a) Zombie
b) Orphan
c) Child
d) None of the mentioned

View Answer

Answer: a

7. Return value of fork() system call can be:
a) -1,<0, 0
b) -1,>0, 0
c) -1,<0
d) none of the mentioned

View Answer

Answer: b

8. If the fork() system call returns -1, then it means?
a) No new child process is created
b) The child process is an orphan
c) The child process is in Zombie
d) none of the mentioned

View Answer

Answer: a

9. Fork returns _____ to parent process on success
a) 0 
b) child process id
c) parent process id
d) none

View Answer

Answer: b

10. How many times printf() will be executed in the below mentioned program?  

 
 main() 
 {
      int i;<br><br>       
      for (i = 0; i < 4; i++)      
      fork();
      printf("my pid = %dn", getpid());
}

a) 4
b) 8
c) 16
d) 32

View Answer

Answer: c

11. What is the output of the below code?
 

 
 void exit_handler1();   
 void exit_handler2();    
 int main() 
 {     
	int pid;        
	atexit(exit_handler1);      
	atexit(exit_handler2);     
	pid = fork();       
	if(pid == 0) 
	{        
		_exit(0);      
        } 
        else 
	{          
		sleep(2);            
		exit(0);     
	}     
	return 0;    
}

a) Only child executes the exit_handler 1 and 2
b) Only parent executes the exit_handler 1 and 2
c) Both parent and child executes the exit_handler 1 and 2
d) Neither parent nor child executes the exit_handler 1 and 2

View Answer

Answer: b

12. What is output of the following program?

 int main() 
 {     
	fork();       
	fork();        
	fork();       
	if (wait(0) == -1)          
	printf("leaf childn");  
 }

a) “leaf child” will be printed 1 times
b) “leaf child” will be printed 3 times
c) “leaf child” will be printed 4 times
d) “leaf child” will be printed 8 times

View Answer

Answer: c

13. Which niceness value among the following indicate most favorable scheduling?
a) 0      
b)  19    
c)  5       
d)  -20

View Answer

Answer: d

14. The maximum time slice that can be given to a process in Linux (where tick is 10ms) is
a) 150ms  
b) 10ms   
c) 300 ms   
d) 600ms

View Answer

Answer: d

15. Nice can be used by an ordinary process to
a) increase the priority of a process
b) decrease the priority of a process
c) increase or decrease the priority of a process
d) none of the mentioned

View Answer

Answer: b

Set 4

1. If a signal is received by a process, when will it be processed?
a) It is processed immediately
b) It is processed when process is switching to kernel mode
c) It is processsed in the next timeslice given to the process
d) None of the mentioned

View Answer

Answer: b

2. Which signal is generated when we press control-C?
a) SIGINT
b) SIGTERM
c) SIGKILL
d) SIGSEGV

View Answer

Answer: a

3. Which signal is generated when we press ctrl-Z?
a) SIGKILL
b) SIGSTOP
c) SIGABRT
d) SIGINT

View Answer

Answer: b

4. Which signal is sent when the Child process terminates?
a) SIGINIT
b) SIGKILL
c) SIGSTOP
d) SIGCHLD

View Answer

Answer: d

5. Which of the following signal cannot be handled or ignored?
a) SIGINT
b) SIGCHLD
c) SIGKILL
d) SIGALRM

View Answer

Answer: c

6. Another signal that cannot be caught is:
a) SIGPIPE
b) SIGHUP
c) SIGSTOP
d) SIGUSR1

View Answer

Answer: c

7. When real interval timer expires which signal is generated?
a) SIGINT
b) SIGCHLD
c) SIGKILL
d) SIGALRM

View Answer

Answer: d

8. Signals are handled using which system call?
a) kill
b) signal
c) both
d) none

View Answer

Answer: b

9. Default action of SIGSEGV is
a) Terminate
b) Core dump + Terminate
c) Stop
d) Cont

View Answer

Answer: b

10. The kill system call is used to
a) Send shutdown messages to all by superuser
b) Send a signal to a process
c) Kill processes
d) Stop the processes

View Answer

Answer: b

11. What is the output of the below code?

    void sig_handler ( int signum) {
        printf(“Handled the signaln”);
    }
 
    int main() {
        int pid;
        signal (SIGKILL, sig_handler);
        pid = fork();
        if (pid==0) {
            kill(getppid(), SIGKILL);
            exit(0);
        } else {
            sleep(20);
        }
        return 0;
    }

a) Error child cannot send a SIGKILL signal to parent
b) Parent goes to the signal handler, prints handled the signal and goes back to sleep
c) Parent goes to the signal handler, prints handled the signal and exits
d) Parent exits without going to the signal handler

View Answer

Answer: d

Set 5

1. Each process has unique
a) fd table
b) file table
c) inode table
d) data block table

View Answer

Answer: a

2. File descriptor table indexes which kernel structure?
a) struct file
b) strruct fs_struct
c) files_struct
d) struct inode

View Answer

Answer: a

3. What is the default number of files open per user process?
a) 0
b) 1
c) 2
d) 3

View Answer

Answer: d

4. The file system information is stored in
a) Boot block
b) Super Block
c) Inode Table
d) Data Block

View Answer

Answer: b

5. Switch table is used by
a) device special file
b) directory file
c) fifo
d) link file

View Answer

Answer: a

6. What is the use of fcntl function?
a) locking a file
b) reading the file descriptor flag
c) changing the file status flag
d) all of the mentioned

View Answer

Answer: d

7. Which function can be used instead of the dup2 to duplicate the file descriptor?
a) read()
b) open()
c) stat()
d) fcntl()

View Answer

Answer: d

8. printf() uses which system call
a) open
b) read
c) write
d) close

View Answer

Answer: c

9. read() system call on success returns
a) 0
b) -1
c) number of character
d) none

View Answer

Answer: c

10. Which system call is used to create a hard link?
a) hardlink
b) link
c) symlink
d) ln

View Answer

Answer: b

11. namei() is
a) ANSI C library function
b) C library function
c) System call
d) kernel routine

View Answer

Answer: d

12. dup2(1,0)
a) closes the stdout and copies the stdin descriptor to stdout
b) closes the stdin and copies the stdout descriptor to stdin
c) will produce compilation error
d) None of the mentioned

View Answer

Answer: b