Tag: bio-chemistry

Quizzes (82) Questions (1918)

Questions Related to bio-chemistry

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

Reverse transcriptase is

  1. RNA dependent RNA polymerase

  2. DNA dependent RNA polymerase

  3. DNA dependent DNA polymerase

  4. RNA dependent DNA polymerase
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.

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

A codon is read in

  1. 3 5 direction

  2. 5 3' direction

  3. 3 6' direction

  4. 6' 3' direction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Codons are read in the 5' to 3' direction on the mRNA molecule during translation. This is the same direction as RNA synthesis during transcription. The ribosome moves along the mRNA from 5' end toward 3' end, reading each codon sequentially. Options A and C have incorrect notation (3' 5', 3' 6'). Option D has non-standard notation (6'). Option B is correct.

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

Which of the following is correctly matched?

  1. Ligase- Breaking DNA strand

  2. Flame cells- Roundworms

  3. Rous Sarcoma- Reverse transcriptase

  4. Thyroxine- Adrenal
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.
Multiple choice bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

Reverse transcriptase occurs in virus

  1. HIV

  2. Influenza virus

  3. Vaccinia virus

  4. All the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.

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

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

  1. UGU and GUG

  2. UUG and GGU

  3. GUG and UGU

  4. UGG and GUU
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A repeating UGUGUG... sequence produces codons UGU and GUG. UGU codes for cysteine and GUG codes for valine, matching the observed peptide.

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Griffith discovered transformation, Gamow proposed the triplet nature of the genetic code, and Miescher first isolated nucleic acids (nuclein). All are correct.