Tag: bio-chemistry

Questions Related to bio-chemistry

In a 3.2K bp long piece of DNA, 820 adenine bases were found. What would be the number of cytosine bases

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

  1. 1480

  2. 740

  3. 560

  4. 780

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Correct Option: D

Teminious central dogma of protein synthesis is

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

  1. DNA DNA mRNA protein

  2. mRNA gRNA DNA Protein

  3. gRNA DNA mRNA Protein

  4. DNA gRNA mRNA Protein

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Correct Option: C

Central dogma of molecular biology was modified with the discovery of

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

  1. Ligase

  2. RNA polymerase

  3. DNA polymerase

  4. Reverse transcriptase

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Correct Option: D

Which one is a termination codon?

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

  1. UGU

  2. AAA

  3. UAG

  4. UUC

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Correct Option: A

Enzyme responsible for replication of HIV in macrophages is 

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

  1. RNA polymerase

  2. DNA ligase

  3. DNA polymerase

  4. Reverse transcriptase

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Correct Option: D
Explanation:

Once inside a CD$ _4$ cell ( helper T cell ), HIV releases and uses reverse transcriptase  to convert its genetic material—HIV RNA—into HIV DNA. The conversion of HIV RNA to HIV DNA allows HIV to enter the CD$ _4$ cell nucleus and combine with the cell’s genetic material—cell DNA.

So, the correct answer is 'Reverse transcriptase'

Which of the following information transfers is catalyzed the reverse transcriptase?

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

  1. RNA $\rightarrow$ RNA

  2. RNA $\rightarrow$ DNA

  3. DNA $\rightarrow$ DNA

  4. None of these

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Correct Option: C
Explanation:

Reverse transcriptase is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. A retrovirus is a type of RNA virus that inserts a copy of its genome into the DNA of a host cell that it invades thus changing the genome of that cell. Once inside the host cell cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern and thus retro (backward).

So, the correct option is ' RNA $\rightarrow$ DNA'.

Teminism is

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

  1. Central dogma reverse

  2. Central dogma of molecular biology

  3. Circular flow of hereditary information

  4. Effect of cytoplasm on functioning of DNA

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Correct Option: A

Some RNA viruses carry a gene or an enzyme that uses viral RNA as a template in the synthesis of DNA. This enzyme is 

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

  1. RNA replicase

  2. Reverse transcriptase

  3. Viral nuclease

  4. RNA polymerase

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Correct Option: B
Explanation:

Reverse transcriptase catalyzes the formation of double-stranded deoxyribonucleic acid (DNA) from a single-stranded ribonucleic acid (RNA) genome. It is called "reverse" transcriptase because it reverses the usual direction of information flow, from DNA to RNA. Reverse transcriptase enzymes can be found in viruses, which use reverse transcriptase to make more viruses.

So, the correct option is 'Reverse transcriptase'.

In cloning experiments, cDNA molecules can be obtained from an mRNA copy by

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

  1. Polymerase chain reaction

  2. Reverse transcriptase

  3. Ribozyme

  4. DNA-RNA hybridization

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Correct Option: B
Explanation:

Complementary DNA (cDNA) is a DNA copy of a messenger RNA (mRNA) molecule produced by reverse transcriptase. cDNA is often used to clone eukaryotic genes in prokaryotes.  cDNA is also produced naturally by retroviruses (such as HIV) for integration into the host's genome.

So, the correct option is 'Reverse transcriptase'.

Choose the correct answers from the alternatives given :
The central dogma of molecular biology

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

  1. states that DNA is a template for all RNA production

  2. pertains only to prokaryotes because humans are unique

  3. states that translation precedes transcription

  4. states that DNA is a template only for DNA replication

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Correct Option: A
Explanation:

During the transcription phase of the central dogma, DNA acts as the template for RNA synthesis. The RNA polymerase enzyme identifies the base on the DNA strand and adds a complementary base to the sequence. After transcription, translation of mRNA occurs that leads to the formation of the polypeptide sequence.

So, the correct option is 'states that DNA is a template for all RNA production'.