Molecular Biology Questions and Answers – Recombination in Higher Organisms – 2

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This set of Molecular Biology Question Paper focuses on “Recombination in Higher Organisms – 2”.

1. What is the central protein of homologous recombination?
a) RecB
b) RecD
c) RecA
d) RecC
View Answer

Answer: c
Explanation: RecA is the central protein of homologous recombination. It is the founding member of a family of enzymes called the strand exchange protein.

2. What is the joint molecule?
a) RecB of the RecBCD pathway
b) B DNA
c) Z DNA
d) Rec A bound three stranded structure
View Answer

Answer: d
Explanation: The RecA bound three stranded structure is known as the joint molecule. It usually contains several hundred base pairs of hybrid DNA.

3. The RuvAB complex specifically recognizes the Holliday junction in a ATP dependent manner.
a) True
b) False
View Answer

Answer: a
Explanation: RuvA recognizes and binds to the Holliday junction and recruits RuvB protein to this site. RuvB is a hexameric ATPase thus making the process an ATP dependent one.

4. Which component cleaves the specific DNA strands at the Holliday junction?
a) RuvC
b) RuvD
c) RuvA
d) RuvB
View Answer

Answer:
Explanation: RuvC recognizes the Holliday junction. It specifically nicks two of the homologous DNA strands that have the same polarity.

5. After cleaved by RuvC the resulting ligated recombination products will only be the splice product.
a) True
b) False
View Answer

Answer: b
Explanation: Depending on which pair of strands is cleaved by RuvC the resulting recombinant product will depend. It either forms a spliced product or a patched product.

6. What is the cleavage site of RuvC?
a) 5’….A/TTTG/C….3’
b) 5’….G/TTTC/T….3’
c) 5’….T/TGCG/C….3’
d) 5’….C/ATTG/T….3’
View Answer

Answer: a
Explanation: Cleavage by RuvC takes place at sites conforming to the consensus sequence 5’….A/TTTG/C….3’. cleavage occurs after the second T in this sequence.

7. What is the source of energy during the action of SPO11?
a) Cleavage of peptide bond
b) Cleavage of amide bond
c) Cleavage of glycoside bond
d) Cleavage of phosphodiester bond
View Answer

Answer: d
Explanation: During the action of SPO11 the cleavage of DNA phosphodiester bond is stored in the bound protein-DNA linkage. By this process the DNA strands can be released.

8. What are the components of the MRX protein?
a) MreII, Rad50, Xrs2
b) Rad51, Rad52, Rad59
c) RecA, RuvC, RuvAB
d) Rad51C, WRN, BLH
View Answer

Answer: a
Explanation: MRX enzyme complex is used for the event of DNA processing. It is composed of protein subunits, MreII, Rad50 and Xrs2. The first letters of the subunits gives the complex its name.

9. Processing of the DNA at the break site occurs at the 3’ end.
a) True
b) False
View Answer

Answer: b
Explanation: Processing of the DNA at the break site occurs exclusively at the 5’ terminus. The strand ic covalently attached to the Spo11 protein.

10. How many cycles are required for the configuration of chromosomes?
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: b
Explanation: Chromosomes are configured during two division cycles. This is because meiosis involves two rounds of nuclear divisons.

11. What is non-disjunction?
a) Proper alignment
b) Sister chromatid formation
c) Failed alignment
d) Chromosome segregation
View Answer

Answer: c
Explanation: The absence of recombination leads to the failed alignment of the chromosomes in the 1st meiotic division and as a result there is a high incidence of chromosome loss. This improper segregation of chromosomes is called nondisjunction.

12. For which biological phenomenon homologous recombination is critical?
a) Mitosis
b) Meiosis
c) Fragmentation
d) Sporing
View Answer

Answer: b
Explanation: Homologous recombination is critical for meiosis during the pachytene stage of meiosis I. This is important for the introduction of genetic variations in every generations.

13. What are homologs?
a) Part of DNA
b) Pair of nucleus
c) Pair of chromosomes
d) Part of a cell
View Answer

Answer: c
Explanation: Before cell division the cell has two copies of each chromosome, one of each was inherited from either parent. These are known as homologs.

14. What is the function of the Spo11 in meiotic recombination?
a) Introduction of mutation
b) Introduction of nick
c) Introduction of DSB
d) Introduction of lesion
View Answer

Answer: c
Explanation: Spo11 gene encodes a protein that introduces DSBs in chromosomal DNA to initiate meiotic recombination. The Spo11 protein cuts the DNA at many chromosomal locations with little sequence selectivity but at a very specific time during meiosis.

15. How many subunits of Spo11 are involved in the process of cleavage of DNA?
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: b
Explanation: The two subunits of Spo11 cleave the DNA two nucleotides apart on the two DNA strands. It makes staggered double strand break by cleavage.

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Energy Engineering Questions and Answers – Applications of Biogas & Gasifier

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This set of Energy Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Applications of Biogas & Gasifier”.

1. What is the percentage at which rated power from biogas in petrol engine can be developed?
a) 45%
b) 65%
c) 75%
d) 85%
View Answer

Answer: d
Explanation: Petrol engine can be operated on biogas after initially starting with petrol. Petrol replacement of 1005 is possible and petrol engines can develop about 85% of rated power where as diesel engine can develop full power.

2. Which engine can run on dual fuel with little engine modification?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
View Answer

Answer: a
Explanation: Diesel engine can run on dual fuel with little engine modifications. Advancing the injection timing and entry of biogas with intake air, it can be achieved by providing a mixing chamber below the air cleaner which facilitates mixing of biogas with air before entering into the cylinder.

3. Which of the SI engine can be run on biogas?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
View Answer

Answer: b
Explanation: Petrol engine can run on biogas, but it is required to be started with petrol in the beginning. Petrol engine can be modified for operation on biogas including provision for entry of biogas, throttling of intake air and advancing ignition timing.

4. What does CNG stands?
a) Converted natural gas
b) Compressed natural gas
c) Compressed Non-soluble gas
d) Compressed natural gasoline
View Answer

Answer: b
Explanation: Compressed natural gas (CNG) (methane stored at high pressure) is a fuel which can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. CNG combustion produces fewer undesirable gases than the fuels mentioned above.

5. What is the full form of VRA?
a) Vibration resistant appliance
b) Vehicle Refueling Appliances
c) Volatile removal assembly
d) Validated requirement authority
View Answer

Answer: b
Explanation: Vehicle refueling appliance is abbreviated as VRAs. Certified natural gas compressors for refueling the vehicles are commercially available. These allow refueling at home and work. After upgrading with the above-mentioned technologies, the biogas (transformed into biomethane) can be used as vehicle fuel in adapted vehicles.

6. A device for converting substances (chemically or physically) into gas is called ______
a) Gasifies
b) Biogas plants
c) Draughts
d) Gas chambers
View Answer

Answer: a
Explanation: The word Gasification implies converting a solid or liquid into a gaseous fuel without leaving any solid carbonaceous residue. Gasifier is a equipment which can gasify a variety of biomass such as wood waste, agricultural waste like stalks, and roots of various crops. The gasifier is essentially a chemical reactor where various complex physical and chemical processes take place.

7. How many types of gasifiers are there?
a) 2
b) 3
c) 4
d) 5
View Answer

Answer: c
Explanation: There are four types of gasifiers namely:
1. Up draught or counter current gasifier.
2. Down draught or co-current gasifier.
3. Cross draught gasifier.
4. Fluidized bed gasifier.

8. Which is the oldest and simplest type of gasifier?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: a
Explanation: The oldest and simplest type of gasifier is the counter current or up draught gasifier. The major advantage of this type of gasifier are its simplicity, high charcoal burnout and internal heat exchange leading to low gas exit temperatures and high equipment efficiency.

9. Which is the gasifier that can be operated in small scale/amounts?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: b
Explanation: It is actually the advantage of this system that it is capable of handling very small amounts for operation. Installations below 10 KW can under certain conditions be economically feasible. The reason is the very simple gas cleaning train which can be employed when using this type of gasifier.

10. Which gasifier has better tar converting capacity?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: c
Explanation: A solution to the problem of tar entrainment in the gas stream has been found by designing co-current or down draught gasifiers, in which primary gasification air is introduced at or above the oxidation zone in the gasifier.

11. Which gasifier has a minimum tar converting capability?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: b
Explanation: A disadvantage of cross draught gasifiers is their minimal tar converting capacity and the consequent needs for the high quality charcoal. It is because of the uncertainty of charcoal quality that a number of charcoal gasifiers employ down draught principle, in order to maintain at least a minimal tar cracking capability.

12. Which gasifier equipment has inability to operate on a number of unprocessed fuels?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: c
Explanation: Down draught gasifier or co-current gasifiers equipment lies in its inability to operate on a number of unprocessed fuels. In particular, fluffy, low density materials give rise to flow problems and excessive pressure drop and the solid fuel must be pelletized before use.

Sanfoundry Global Education & Learning Series – Energy Engineering.

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Solution for N Queens Problem using Backtracking in C

What is N Queens Problem?

The N Queens problem is:

How can N queens be placed on an NxN chessboard so that no two of them attack each other?

The eight queens puzzle is the problem of placing eight chess queens on an n x n chessboard so that no two queens threaten each other.

Thus, a solution requires that no two queens share the same row, column, or diagonal. The eight queens puzzle is an example of the more general n queens problem of placing n non-attacking queens on an n×n chessboard, for which solutions exist for all natural numbers n with the exception of n=2 and n=3.

A possible solution for N Queens problem is:

 

n queens problem

Algorithm:

  •     Place the queens col­umn wise, start from the left most column
  •     If all queens are placed.
    return true and print the solu­tion matrix.
    Else
    Try all the rows in the cur­rent column.
  •         Check if queen can be placed here safely if yes mark the cur­rent cell in solu­tion matrix as 1 and try to solve the rest of the prob­lem recursively.
  •         If plac­ing the queen in above step leads to the solu­tion return true.
  •         If plac­ing the queen in above step does not lead to the solu­tion , BACKTRACK, mark the cur­rent cell in solu­tion matrix as 0 and return false.
  •     If all the rows are tried and noth­ing worked, return false and print NO SOLUTION.

 

C program for N Queens problem using Backtracking:

 

OUTPUT:

N queens problem

C Program to Print Map of India

Today I’m going to be little proud as I’m ready to write a C program to print map of India. This program is little complicated and in the end I’m going to share the logic behind the code.

 

This will be our output:

C Program to Print Map of India

 

Now let’s write the program.

 

C program to print map of India:

#include <stdio.h>
main()

{

int a,b,c;

int count = 1;

for (b=c=10;a=”- FIGURE?, UMKC,XYZHello Folks,

TFy!QJu ROo TNn(ROo)SLq SLq ULo+

UHs UJq TNn*RPn/QPbEWS_JSWQAIJO^

NBELPeHBFHT}TnALVlBLOFAkHFOuFETp

HCStHAUFAgcEAelclcn^r^r\tZvYxXy

T|S~Pn SPm SOn TNn ULo0ULo#ULo-W

Hq!WFs XDt!” [b+++21]; )

for(; a– > 64 ; )

putchar ( +c==’Z’ ? c = c/ 9:33^b&1);

return 0;
}

For explanation see: http://stackoverflow.com/questions/3533348/how-does-this-code-generate-the-map-of-india