Molecular Genetics ( Part II )- Voice Lessons and obj question answers

🐘 biology-zoology.blogspot.com 🐘

---

12-ம் வகுப்பு Part-II

மாணவர்கள் நன்றாகப் படிக்கவும். நல்ல மதிப்பெண் பெற கடினமாக உழைக்கவும்

தெய்வத்தான் ஆகா தெனினும் முயற்சிதன் மெய்வருத்தக் கூலி தரும்.

---

---

Section A-மாணவர்கள் சரியான பதிலை தேர்ந்தெடுக்கவும்

---

1). Hershey and Chase experiment with bacteriophage showed that.

a ) Protein gets into the bacterial cells.    
b ) DNA is the genetic material.    
c ) DNA contains radioactive sulphur    
d ) Viruses undergo transformation

---

2) DNA and RNA are similar with respect to.

a ) Thymine as a nitrogen base.    
b ) A single - stranded helix shape    
c ) Nucleotide containing sugars, nitrogen bases and phosphates    
d ) The same sequence of nucleotides for the amino acid phenyl alanine

---

3) A mRNA molecule is produced by

a ) Replication    
b ) Transcription    
c ) Duplication    
d ) Translation

---

4) The total number of nitrogenous bases in human genome is estimated to be about

a ) 3.5 million    
b ) 350000    
c ) 35 million    
d ) 3.1 billion

---

5) "E. coli cell grown on `\ ^15N` medium are transferred to `\ ^14N` medium and allowed to grow for two generations. DNA extracted from these cells is ultracentrifuged in a cesium chloride density gradient. What density distribution of DNA would you expect in this experiment"?:

a ) One high and one low density band    
b ) One intermediate density band    
c ) One high and one intermediate density band.    
d ) One low and one intermediate density band.

---

6) "What is the basis for the difference in the synthesis of the leading and lagging strand of DNA molecules? ":

a ) Origin of replication occurs only at the 5' end of the molecules.    
b ) DNA ligase works only in 3' ---> 5' direction    
c ) DNA polymerase can join new nucleotides only to the 3' end of the growing stand    
d ) Helicases and single - strand binding proteins that works at the 5' end.

---

7) Which of the following is the correct sequence of event with reference to the central dogma?

a ) Transcription, Translation, Replication    
b ) Transcription, Replication, Translation    
c ) Duplication, Translation, Transcription    
d ) Replication, Transcription, Translation

---

8) "Which of the following statements about DNA replication is not correct"?

a ) Unwinding of DNA molecules occurs as hydrogen bonds break.    
b ) Replication occures as each base is paired with another exactly like it.    
c ) Process is known as semi conservative replication because one old strand is conserved in the new molecules    
d ) Complementary base pair are held together with hydrogen bonds.

---

9) "Which of the following statements is not true about DNA replication in eukaryotes" ?

a ) Replication begins at a single origin of replication    
b ) Replication is bidirectional from the origins    
c ) Replication occurs at about 1 million base pairs per minute    
d ) There are numerous different bacterial chromosomes, with replication occurring in each at the same time.

---

10) "The first codon to be deciphered was .................. which codes for .............. " ?

a ) AAA, proline    
b ) GGG, alanine    
c ) UUU, Phenylalanine    
d ) TTT, arginine

---

11) "Meselson and Stahl's experiment proved " ?

a ) Transduction    
b ) Transformation    
c ) DNA is the genetic material    
d ) Semi - conservative nature of DNA replication.

---

12) Ribosomes are composed of two subunits; the smaller subunit of ribosome has a binding site for .......... and the larger subunit has two binding sites for two ........?

a ) mRNA, tRNA    
b ) rRNA, mRNA    
c ) SER, RER    
d ) Lysosome, Lysozyme

---

13) An operon is a ?.

a ) Protein that suppresses gene expression    
b ) Protein that accelerates gene expression    
c ) Cluster of structural genes with related function    
d ) Gene that switched other genes on or off

---

14) "When lactose is present in the culture medium" :

a ) Transcription of `\lac   y, lac   z, lac   a ` genes occurs    
b ) Repressor is unable to bind to the operator    
c ) Repressor is able to bind to the operator    
d ) Both (a) and (b) are correct

---

---

Hi, this teacher angry over me, so I hide here

---