Tag: the search for genetic material

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Questions Related to the search for genetic material

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Find out the correct options
1. Frederick Griffith - Transformation
2. Gamow - Triplet code
3. Meselson - Isolated DNA

  1. 1, 2, 3 correct

  2. 1, 2 correct

  3. 2, 3 correct

  4. 1, 3 correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is correct because Frederick Griffith discovered bacterial transformation in Streptococcus pneumoniae. Statement 2 is correct because George Gamow proposed that the genetic code consists of a combination of three nucleotides (triplet code). Statement 3 is incorrect because Meselson, along with Stahl, proved semi-conservative DNA replication, whereas isolation of DNA was done by Friedrich Miescher.

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

In Griffiths experiment, the conversion of R- type to S-type of Diplococcus pneumoniae when mixed with heat-killed S-type is called

  1. Mutation

  2. Transduction

  3. Transfection

  4. Transformation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transformation is the process by which bacteria take up naked DNA from their environment, as demonstrated by Griffith's experiment with S and R strains of Streptococcus pneumoniae.

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Which of the following is true with reference to transformation in bacteria
i) Transfer of genetic material is mediated by F factor
ii) Uptake of DNA fragments from the surrounding environment and expression of that genetic information in recipient cell 
iii) Transformation experiments were the basis to propose chromosomal theory of inheritance
iv) Transformation was discovered by Griffith in Streptococcus pneumonia

  1. i, iv

  2. ii, iii, iv

  3. iii, iv

  4. ii, iv
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement ii is correct (definition of transformation) and iv is correct (Griffith's discovery). Statement i refers to conjugation, and iii is historically incorrect as transformation was not the basis for the chromosomal theory of inheritance.

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

A molecule that acts as a genetic material must fulfill the traits given, except

  1. It should provide the scope for slow changes that are required for evolution

  2. It should be able to generate its replica

  3. It should be able to express itself in the form of Mendelian characters

  4. It should be unstable structurally and chemically
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Genetic material must be stable to store information accurately over generations. If it were unstable, it could not reliably pass on traits.

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Escherichia coli in which both the strands are labelled with $^{15}N$ is transferred to $^{14}N$ medium and allowed to replicate for two generations. Find the number of hybrid DNA molecules in the second generation

  1. Four

  2. Eight

  3. One

  4. Two
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In semi-conservative replication, after one generation, all DNA is hybrid. After two generations, half the DNA is hybrid and half is light (14N-14N). Starting with one 15N-15N molecule, after two generations, you have four molecules: two hybrid (15N-14N) and two light (14N-14N).

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Beside direct chemical analysis DNA and RNA can be detected by which of the following method?
a. Photometric procedures
b. Staining reactions
c. Enzyme digestion
Select the correct answer using the codes given.

  1. $1, 2$ and $3$
  2. $1$ and $2$
  3. $2$ and $3$
  4. $1$ and $3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA and RNA can be detected using photometric procedures (like UV absorbance), staining reactions (like Feulgen stain for DNA), and enzyme digestion (using DNase or RNase to confirm identity).