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WorksheetsQuiz 6: Topic 6 - Expression of Biological Info.
Total questions: 40
Worksheet time: 24mins
If the sequence of bases along one side of a DNA molecule is 3’-AAGCT-5’, then the complementary sequence of bases on the other side of the DNA molecule is …
3’-AAGCT-5’
3’-GGTAC-5’
5’-UUCGA-3’
5’-TTCGA-3’
In the Meselson-Stahl experiment, it was confirmed that DNA replication is___________ as was predicted by the Watson and Crick double-helix model.
conservative
dispersive
hybrid
semiconservative
In DNA replication, the helix is unwound by which type of enzyme?
topoisomerase
primase
DNA polymerase
helicase
What is the role of DNA polymerase?
To synthesize a short RNA primer.
To remove RNA primer and fills the gaps with RNA nucleotides.
To elongate the strand by adding new deoxyribonucleotides one by one from the nucleoplasm.
To join the Okazaki fragments to form a lagging strand.
Synthesis of a new DNA strand usually begins with
A RNA primer
A DNA primer
An Okazaki fragment
A DNA ligase
The information carried by DNA is incorporated in a code specified by the:
Phosphodiester bonds of the DNA strand.
Number of separate strands of DNA.
Size of a particular chromosome.
Specific nucleotide sequence of the DNA molecule.
During DNA replication, enzymes needed in the process are
RNA polymerase
DNA polymerase
Topoisomerase
Peptidyl transferase
The role of topoisomerase in DNA replication is
To stabilize the helical structure
To unwind the double helix
To form a new DNA leading strand
To form the Okazaki fragment
Which of the following are the CORRECT base pairs of complementary DNA strands?
A – T, C – G
G – C, T – A
C – T, A – G
A – U, A – T
Transcription is the transfer of genetic codes from a DNA molecule to …
an RNA molecule.
a sequence of amino acids in a protein molecule.
a second DNA molecule.
a ribosomal subunit.
After transcription takes place, the DNA molecule …
disintegrates into its component nucleotides.
moves to a ribosome.
replicates itself.
reassociates to form its original structure.
Which of the following is NOT true of a codon?
It consists of three nucleotides.
It may code for the same amino acid as another codon does.
It never codes for more than one amino acid.
It extends from one end of a tRNA molecule.
Which of the following is a characteristic of uracil?
The ability to bond with adenine
The ability to bond with guanine
It is a purine
The ability to bond with cytosine
The function of mRNA is to …
carry specific information from DNA and programmes protein synthesis.
hold a group of ribosomes together.
transfer the genetic codes to ribosomal RNA.
transfer the genetic codes to DNA.
The function of tRNA is to …
form a site for protein synthesis.
transcribe the genetic code.
transport specific amino acids to specific sites on the mRNA.
synthesize amino acids.
Use FIGURE 1 to answer the corresponding questions.
The component labelled B is:
DNAase
DNA polymerase
RNA primase
RNA polymerase
Use FIGURE 1 to answer the corresponding questions.
The transcription process begins at the area labeled:
A
D
E
G
Use FIGURE 1 to answer the corresponding questions.
The transcript in the figure is labelled:
D
C
G
H
The portion of the molecule in the FIGURE 2 that contains the anti-codon is:
1
2
3
5
Refer to FIGURE 2.
The portion of the molecule labelled 5 is:
the attached amino acid.
a single-stranded region.
the anti-codon.
the codon.
Translation is the …
movement of mRNA through the nuclear membrane.
transfer of genetic codes to an mRNA molecule.
transfer of genetic codes to a tRNA molecule.
transfer of genetic codes from an mRNA to a sequence of amino acids in a polypeptide.
In all organisms, the AUG codon is a code for
the initiation of translation
the termination of chain elongation
the amino acid valine
a termination tRNA molecule
The signal to start translation is the initiator codon, usually AUG, which is the codon for
methionine.
tyrosine.
leucine.
no amino acid.
After reaching the stop codon, no more amino acids are added to the newly formed polypeptide. Instead, a molecule of _____________ is added.
tRNA
ribosome
amino acid
water
After RNA processing, an mRNA molecule travels from the ______________ to the ______________, where it joins with a _________________.
nucleus … ribosome … cytoplasm
ribosome … cytoplasm … nucleus
cytoplasm … nucleus … ribosome
nucleus … cytoplasm … ribosome
Following peptide bond formation between the amino acid in the A site on the ribosome and the growing polypeptide chain, the tRNA in the A site:
releases the growing polypeptide chain.
picks up another amino acid to add to the chain.
moves to the P site of the ribosome.
forms a peptide bond with A site of the ribosome.
Translocation is the process whereby the ____________ moves in order to place the tRNA bound to the growing polypeptide chain in the ____________ site, thereby freeing the ____________ site for a new aminoacyl-tRNA.
mRNA; A; P
ribosome; P; A
tRNA; P; A
ribosome; A; P
Which of the following statements are NOT TRUE about protein synthesis?
Translation occurs on the ribosomes.
Functional ribosome unit has P site and A site.
Translation occurs in 5’ to 3’ direction of mRNA.
5’ end of mRNA binds to the bigger unit of ribosome to start the
protein synthesis.
If a human gene mRNA was placed into a cell of yeast, it would be:
degraded immediately.
translated into a chain of random amino acids not resembling the protein in humans.
translated into the protein that is found in humans.
integrated into the genome of the yeast.
The anticodon in tRNA for Methionine is UAC. How many methionine molecules are coded by the DNA template shown below?
3’ T A C C A T C A T T A C A C T C A T 5’
1
2
3
4
The lac operon, described in 1961 by Francois Jacob and Jacques Monod, is transcribed when …
lactose is needed by the cell.
lactose is available to the cell.
lactic acid is needed by the cell.
lactic acid is available to the cell.
What is the function of lactose of the lac operon?
Binds to the promoter and prevents the repressor from binding to the operator
Binds to the operator and prevents the repressor and prevents the repressor from binding to the promoter
Binds to the repressor and prevents it from binding to the promoter
Binds to the repressor and prevents it from binding to the operator
The enzyme attached to the promoter in the lac operon is …
DNA polymerase.
RNA polymerase.
helicase.
ligase.
lac operon is activated when
The promoter is blocked
The repressor is inactive
Lactose is absence
Glucose is present
What is the function of the operator in the lactose operon of E. coli?
Provides attachment site for RNA polymerase.
Provides attachment site for lactose protein.
Provides attachment site for repressor protein.
Provides attachment site for allolactose
Which of the following genes are located in the operon of Escherichia coli?
lacZ
Operator
Promoter
lacI
The FIGURE 2 shows the structure of an operon and the induced process of enzyme synthesis for the metabolism of lactose.
What are the substances represented by P, Q, R and S?
P: Structural gene Q: Operator R: Promoter S: Regulator gene
P: Promoter Q: Structural gene R: Operator S: Repressor protein
P: Regulator gene Q: Repressor protein R: Operator S: Structural genes
P: Regulator gene Q: Repressor protein R: Structural genes S: Operator
In the absence of molecule X,
gene P is not expressed.
Q is attached to R.
transcription of structural genes occurs.
enzymes are produced.
Describe the amino acid activation process and state the enzyme involved.
Process where amino acid binds to tRNA.
Forming aminoacyl-tRNA.
Requires energy in the form of ATP.
Catalysed by aminoacyl-tRNA synthetase.
Which end of tRNA acts as the amino acid binding site?
3’ end // 3’ OH end
5’ end // 5’ OH end
anticodon
phosphate group
