Tag: biology

Quizzes (1160) Questions (12174)

Questions Related to biology

Multiple choice expression of gene inherited changes biology

In processing of eukaryotic hnRNA during protein-synthesis tailing involvesof RNA

  1. Addition of adenylate residues at 3' end

  2. Addition of methyl guanosine triphosphate at 3' end

  3. Addition of methyl guanosine triphosphate 5' end

  4. Removal of introns
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the processing of eukaryotic hnRNA, tailing (polyadenylation) involves the addition of a long chain of adenylate residues (poly-A tail) to the 3' end of the transcript to protect it and aid in export.

Multiple choice expression of gene inherited changes biology

In operon model, the function of regulator gene is to produce

  1. Repressor

  2. Inducer

  3. Corepressor

  4. DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The regulator gene in an operon system codes for a repressor protein, which is responsible for binding to the operator site to inhibit transcription of the structural genes.

Multiple choice expression of gene inherited changes biology

The enzyme peptidyl transferase of prokaryotes resides in 

  1. 50 S ribosome

  2. 30 S ribosome

  3. 40 S ribosome

  4. 60 S ribosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In prokaryotes, the peptidyl transferase activity, which catalyzes the formation of peptide bonds during translation, is an intrinsic function of the 23S rRNA component of the 50S ribosomal subunit.

Multiple choice expression of gene inherited changes biology

Prokaryotic enzyme with 5'--> 3 exonuclease property is

  1. DNA polymerase I

  2. DNA polymerase II

  3. DNA polymerase III

  4. Both A and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA polymerase I is unique among the prokaryotic DNA polymerases because it possesses 5' to 3' exonuclease activity, which is essential for removing RNA primers during DNA replication.

Multiple choice expression of gene inherited changes biology

Which of the following DNA polymerase of prokarytoes have both 3' - 5' and 5' - 3' exonuclease activity

  1. DNA Pol-II

  2. DNA Pol-I

  3. DNA Pol-IV

  4. DNA Pol-III
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

DNA polymerase I is the only prokaryotic DNA polymerase that possesses both 3' to 5' exonuclease activity (for proofreading) and 5' to 3' exonuclease activity (for primer removal).

Multiple choice expression of gene inherited changes biology

Prokaryotes can be distinguished from eukaryotes as they lack

  1. RNA

  2. Ribosomes

  3. Gene discontinuity

  4. Unique DNA sequences
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Prokaryotes lack split genes, meaning their coding sequences are continuous and do not contain introns. Eukaryotic genes are frequently interrupted by non-coding introns.

Multiple choice expression of gene inherited changes biology

In eukaryotes, which of the following genes synthesise heterogeneous nuclear RNA 

  1. Holandric genes

  2. Split genes

  3. A-genes

  4. Z-genes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Split genes are genes that contain introns, which are transcribed into hnRNA (pre-mRNA) and subsequently removed during RNA splicing to produce mature mRNA.

Multiple choice expression of gene inherited changes biology

The smallest unit of DNA capable of coding for the synthesis of a polypeptide is the ___________.

  1. Operon

  2. Promoter

  3. Cistron

  4. Replicon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A cistron is defined as the functional unit of DNA that codes for a specific polypeptide chain. An operon is a cluster of genes, a promoter is a regulatory region, and a replicon is a unit of replication.

Multiple choice expression of gene inherited changes biology

In eukaryotes, removal of RNA polymerase III from nucleoplasm will affect transcription of  

  1. mRNA

  2. hnRNA

  3. tRNA

  4. 5.8 S rRNA

  5. 18 S rRNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In eukaryotes, RNA polymerase III is responsible for transcribing small RNAs, including tRNA and 5S rRNA. Therefore, its removal would specifically affect the transcription of tRNA.