Tag: bio-chemistry

Questions Related to bio-chemistry

Reverse transcriptase is

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. RNA dependent RNA polymerase

  2. DNA dependent RNA polymerase

  3. DNA dependent DNA polymerase

  4. RNA dependent DNA polymerase

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Correct Option: D
Explanation:

Reverse transcriptase is an RNA dependent DNA polymerase enzyme which means it uses RNA primers to synthesize DNA molecules. Reverse transcriptase enzyme used to generate complementary DNA (cDNA) from an RNA template by the process called reverse transcription. Retroviruses contain reverse transcriptase enzyme which converts their RNA genome into cDNA that can be incorporated into the host genome. 

So, the correct answer is 'RNA dependent DNA polymerase'.

A codon is read in

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. 3 5 direction

  2. 5 3' direction

  3. 3 6' direction

  4. 6' 3' direction

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Correct Option: B

Which of the following is correctly matched?

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. Ligase- Breaking DNA strand

  2. Flame cells- Roundworms

  3. Rous Sarcoma- Reverse transcriptase

  4. Thyroxine- Adrenal

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Correct Option: C
Explanation:
a)  Restriction enzyme causes breaking DNA strand. Ligase helps in joining two DNA fragments.
b) Flame cells are absent in roundworms. 
c) Rous sarcoma virus (RSV) is a retrovirus causes sarcoma in chickens. The virus contains a reverse transcriptase which is a DNA polymerase that uses RNA as its template. This enzyme reverse transcribes RNA into cDNA and incorporation into the host genome.
d) Thyroxine is produced by the thyroid gland. 
So, the correct answer is 'Rous Sarcoma- Reverse transcriptase'.

Reverse transcriptase occurs in virus

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. HIV

  2. Influenza virus

  3. Vaccinia virus

  4. All the above

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Correct Option: A
Explanation:

HIV (Human Immunodeficiency Virus) is a retrovirus with a viral envelope, matrix proteins and core. The viral core consists of two single strands of RNA. Retroviruses containing RNA genome have reverse transcriptase enzyme that synthesizes a DNA copy (cDNA) of viral RNA. This cDNA can be introduced in the hosts' genome and allowed to replicate to form viral proteins. Influenza and vaccinia viruses are not retroviruses.

Thus, the correct answer is option 'HIV'.

The two strands of DNA are held together by 

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. Peptide bonds

  2. Phosphodiester bonds

  3. Hydrogen bonds

  4. S-S bonds

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Correct Option: C

Khorana et al synthesised RNA with copolymer of UGUGUGUGUG... It produced a peptide with alternate cysteine and valine. The codons for the two are

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. UGU and GUG

  2. UUG and GGU

  3. GUG and UGU

  4. UGG and GUU

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Correct Option: A

Reverse transcription was discovered by

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. Beadle and Tatum

  2. Temin and Baltimore

  3. Watson and Crick

  4. Khorana

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Correct Option: B

Find out the correct answers out of the following discoveries
1. Griffith-Transformation
2. Gamow-Triplet code
3. Miescher-Nucieic acid

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. 1, 2 and 3 correct

  2. 1 and 2 correct, 3 false

  3. 1 correct, 2 and 3 false

  4. 1 and 3 correct, 2 false

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Correct Option: A

Who proposed central dogma ?

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. Watson and Crick

  2. Beadle and Tatum

  3. Klug

  4. Crick

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Correct Option: D

Enzyme needed for production of DNA from RNA is

bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

  1. RNA polymerase

  2. Reverse transcriptase

  3. DNA helicase

  4. DNA polymerase

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Correct Option: B