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CSIR NET Genes and Proteins — practice questions — page 2

Explore 62 free Genes and Proteins questions in CSIR NET Biology. Open each question or exercise to read its content, reference answers and available explanation.

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Genes and Proteins questions and exercises with answers

Showing questions 31–60 of 62.

Which set of products belongs to RNA polymerase III?Read the answer and worked solution →Which eukaryotic promoter element is essential and works by binding transcription factors?Read the answer and worked solution →What do the GC-rich and octamer boxes contribute to a eukaryotic promoter?Read the answer and worked solution →How do enhancers and silencers differ from the basal transcription factors?Read the answer and worked solution →How much DNA is wound around the eight histones of a single nucleosome?Read the answer and worked solution →What terminates transcription of a gene read by RNA polymerase I?Read the answer and worked solution →Where do the promoters of genes transcribed by RNA polymerase III lie?Read the answer and worked solution →Which modification is added to the 5' end of a eukaryotic pre-mRNA?Read the answer and worked solution →Which feature of a processed eukaryotic mRNA is recognized by the factors that begin translation?Read the answer and worked solution →About how many adenine residues does poly-A polymerase add to a pre-mRNA?Read the answer and worked solution →What is true of the intron sequences of a eukaryotic gene?Read the answer and worked solution →Why must every intron be removed with single-nucleotide accuracy?Read the answer and worked solution →What are spliceosomes made of?Read the answer and worked solution →Where are introns removed from a pre-mRNA, and what becomes of them?Read the answer and worked solution →Which processing step adds stability to pre-tRNAs and pre-rRNAs?Read the answer and worked solution →Mature rRNAs make up roughly what fraction of a ribosome?Read the answer and worked solution →What is the anticodon of a tRNA?Read the answer and worked solution →An E. coli ribosome is described as 70S. Which two subunits give that value?Read the answer and worked solution →Which pair of subunits makes up a mammalian ribosome?Read the answer and worked solution →Which ribosomal subunit binds the mRNA template, and which one binds the tRNAs?Read the answer and worked solution →In which directions does a ribosome read the mRNA and build the polypeptide?Read the answer and worked solution →What is a polysome?Read the answer and worked solution →How many types of tRNA exist in the cytoplasm, depending on the species?Read the answer and worked solution →What does the Shine-Dalgarno sequence do in an E. coli mRNA?Read the answer and worked solution →In the Kozak consensus around a vertebrate start codon, which bases can occupy the R position?Read the answer and worked solution →Which ribosomal site does the initiator tRNA occupy as the initiation complex forms?Read the answer and worked solution →In what order does a charged tRNA pass through the three compartments of the ribosome?Read the answer and worked solution →What kind of catalyst is peptidyl transferase, and where does it sit?Read the answer and worked solution →What does a signal sequence do for a newly made protein?Read the answer and worked solution →What do chaperone molecules do during protein folding?Read the answer and worked solution →

Worked practice questions

Which set of products belongs to RNA polymerase III?

  1. All rRNAs other than the 5S rRNA
  2. Nuclear pre-mRNAs and their introns
  3. The 18S and 28S rRNAs alone
  4. 5S rRNA, tRNAs and small nuclear RNAs
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Correct answer: D. 5S rRNA, tRNAs and small nuclear RNAs

1. RNA polymerase III transcribes structural RNAs rather than messages. 2. Its products are the 5S rRNA, the transfer RNA precursors and the small nuclear RNAs. 3. Those small nuclear RNAs go on to splice pre-mRNAs and to regulate transcription factors. 4. Every rRNA other than the 5S is made by RNA polymerase I, so that option belongs to the first enzyme. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 15 "Genes and Proteins", section 15.3 Eukaryotic Transcription_

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Which eukaryotic promoter element is essential and works by binding transcription factors?

  1. The GC-rich box
  2. The octamer box
  3. The CAAT box
  4. The poly-A signal
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Correct answer: C. The CAAT box

1. The CAAT box has the sequence GGCCAATCT and sits at approximately -80 in the mouse thymidine kinase promoter. 2. It is an essential promoter sequence and its role is to bind transcription factors. 3. The GC-rich box and the octamer box are nonessential, so they can be missing and transcription still proceeds. 4. Those two only raise the efficiency of initiation and may appear several times in one promoter. 5. The poly-A signal acts on the transcript during processing rather than on the promoter, so it is not a promoter element at all. 6. Only the CAAT box satisfies both conditions in the question. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 15 "Genes and Proteins", section 15.3 Eukaryotic Transcription_

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What do the GC-rich and octamer boxes contribute to a eukaryotic promoter?

  1. They are essential for any transcription at all
  2. They mark the exact spot where synthesis starts
  3. They terminate transcription at the end of a gene
  4. They raise the efficiency of transcription initiation
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Correct answer: D. They raise the efficiency of transcription initiation

1. The GC-rich box is GGCG and the octamer box is ATTTGCAT, and both may appear several times in one promoter. 2. They bind cellular factors that increase the efficiency of transcription initiation. 3. Both are nonessential, which rules out the option calling them required. 4. The initiation point is fixed by the +1 site and the nearby TATA box, so these boxes do not mark it. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 15 "Genes and Proteins", section 15.3 Eukaryotic Transcription_

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