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IBD Biology (Unit 8 : Nucleic Acids & Proteins) Quiz sobre DNA In Protein Synthesis -The Genetic Code, criado por cloud.berry em 07-05-2014.

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DNA In Protein Synthesis -The Genetic Code

Questão 1 de 32

1

In stage one of the process by which the information of the gene is used to determine how the protein molecule is constructed, a copy of the code is made by building a molecule of mRNA which is catalysed by RNA polymerase, involving complementary base paring with the antisense strand as a template. The mRNA strand then leaves the nucleus through pores in the nuclear membrane and passes to the ribosomes in the cytoplasm to be 'read'.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 2 de 32

1

The second stage of protein synthesis occurs in the ribosomes in the cytoplasm, and AAs are activated for protein synthesis by combining with short lengths of tRNA, with a different tRNA for each of the 20 AAs. One end of each tRNA molecule is a site where a particular AA can attach and at the other end there is an anticodon.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 3 de 32

1

Anticodons are made up of a sequence of 3 bases which are complementary to the the codon of mRNA that codes for the specific AA.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 4 de 32

1

Translation is stage 3 and occurs in the ribosomes in the cytoplasm, where a protein is assembled one AA residue at a time as a ribosome moves along the mRNA reading the codons.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 5 de 32

1

Complementary anticodons of the AA-tRNA slot into place and are temporarily held in position by hydrogen bonds. While there the AAs of neighbour AA-tRNAs are joined by peptide linkages.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 6 de 32

1

Genes function (are expressed) only in cells they relate to, when they are needed.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 7 de 32

1

In eukaryotes, genes are only transcribed if an RNA polymerase enzyme binds to a region of DNA situated close to the gene known as a ___ .

Selecione uma das seguintes:

  • promoter

  • expressor

  • transcriber

Explicação

Questão 8 de 32

1

What are the special features of promoters in eukaryotic chromosomes?

Selecione uma ou mais das seguintes:

  • some permit repeated, unrestricted binding of RNA polymerase, resulting in continuous expression of a gene

  • some require a regulatory protein to be present and bound, prior to binding of RNA polymerase & gene expression

  • some regulatory proteins must first be activated by reaction with a steroid hormone or some other metabolite, before binding of RNA polymerase & gene expression

  • some do not permit binding of RNA polymerase, resulting in no expression of specific genes.

Explicação

Questão 9 de 32

1

The steps of the expression of a gene begin when the genetic informaiton in DNA is transcribed into a molecule of mRNA by complementary base paring. The RNA polymerase binds to a promoter region (the 'start' signal for transcription) located immediately before the gene.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 10 de 32

1

Highlight the characteristics that apply to the sense strand and leave the once that apply to the antisense strand blank.

Selecione uma ou mais das seguintes:

  • Carriers the promoter sequence of bases to which RNA polymerase binds and begins transcription.

  • Has the same base sequence as the mRNA.

  • Carries the terminator sequence of bases at the termination of each gene that causes RNA polymerase to stop transcription.

  • Is the template sequence for transcription by complementary base paring by RNA polymerase.

  • Has the same base sequence as the tRNA.

  • Is read in the '5 -> 3' direction and mRNA synthesis occurs in the opposite direction.

Explicação

Questão 11 de 32

1

RNA polymerase draws on a pool of free nucleotides.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 12 de 32

1

As the RNA trand is formed, it falls away from the antisense strand and hydrogen bonds re-form between the two DNA strands. The process continues until a base sequence known as the inhibitor is reached, causing both RNA polymerase and the completed mRNA strand to be freed from the site of the gene.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 13 de 32

1

The sections of DNA that carry meaningful information are called introns and the intervening lengths f DNA are called exons.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 14 de 32

1

When a split gene is transcribed into mRNA, the sequence of introns continues to exist exactly as it occurred in the DNA, and so an enzyme catalysed reaction known as ___ removes the introns to shorten the length of mRNA which is now described as mature before it moves out into the cytoplasm.

Selecione uma das seguintes:

  • post-transcriptional modification

  • pre-transcriptional modification

  • post-prescribed modification

Explicação

Questão 15 de 32

1

The AA activation process by ehich AA are combined with tRNA occurs in the cytoplasm and requires ATP.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 16 de 32

1

It is this tRNA, once attached to its AA, which facilitates the translation of the three-base sequences of each codon of mRNA into a sequence of AAs in a protein.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 17 de 32

1

The codon located on one end of the tRNA is complementary to the codon of mRNA that codes for that specific AA.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 18 de 32

1

An AA is attached to its tRNA by enzyme action specific to that AA, which allows recognition by a specific tRNA activating enzyme which attaches a specific AA to the tRNA and ensure they'r ein the right sequence.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 19 de 32

1

Translation occurs in the ribosomes which are organelles made up of a large and small subunit which are both composed of ___ and protein. During translation, the mRNAs bind with the ___ subunit where also occur the three sites where the tRNA's interact.

Selecione uma das seguintes:

  • rRNA | small

  • mRNA | big

  • tRNA | small

Explicação

Questão 20 de 32

1

At the 1st site, codons of the incoming tRNA bind to specific tRNA AAs through their anticodons by complementary base paring.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 21 de 32

1

At the 2nd site, the tRNA leaves the ribosome following transfer of its AA to the growing protein chain.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 22 de 32

1

At the 3rd site, the AA attached to its tRNA is condensed with the growing polypeptide chain by formation of a peptide linkage.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 23 de 32

1

The structure of mRNA, ribosomes and their growing protein chain, is called a polyphosphome.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 24 de 32

1

Other ribosomes that synthesis proteins to be excreted from the cell or packages in lysosomes are located where?

Selecione uma das seguintes:

  • bound to the membranes of the rER.

  • bound to the membranes of the sER.

Explicação

Questão 25 de 32

1

post-transcriptional modifications refer to processing steps that some proteins (inactive precursors) needs to go through in order to be activated.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 26 de 32

1

post-transcriptional modifications refer to processing steps that some proteins (inactive precursors) needs to go through in order to be activated.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 27 de 32

1

The central dogma of molecular biology refers to the one-way flow of coded information from the nucleus to the cytoplasm.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 28 de 32

1

An exception to the central dogma of molecular biology is the enzyme secreted by the HIV nucleic acid -reverse transcriptase, which catalyses the copying of the RNA strand to form a DNA double helix which enters the host nucleus and becomes attached to a hsot chromosome.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 29 de 32

1

Reverse-transcriptase can be extracted from retroviruses and used in genetic modification for the synthesis of a DNA strand, complementary to an existing RNA strand.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 30 de 32

1

DNA ligase occurs with nucleic acid in the nucleus of all organisms and is used for..

Selecione uma das seguintes:

  • joining together DNA molecules during replication of DNA.

  • breaking DNA into shorter lengths.

Explicação

Questão 31 de 32

1

Polymerase occurs in the same place as ligase and is used for..

Selecione uma das seguintes:

  • synthesising nucleic acid strands, guided by an antisense strand of nucleic acid.

  • synthesising DNA strands complementary to an existing RNA strand.

Explicação

Questão 32 de 32

1

Restriction enzymes found in the cytoplasm of bacteria can be used for breaking DNA molecules into shorter lengths at specific nucleotide sequences.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

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