Bacteria 1 (MJC)

Genetic recombination in bacteria leads to variation.
Which process involves the use of viruses to initiate this recombination?

1) Conjugation
2) Plasmid replication
3) Transduction
4) Transformation

Which of the following structures are present in both a bacteria and a human somatic cell?

1) Cell wall, nucleus and flagella
2) Slime layer, ribosomes and mitochondria
3) Sex pili, chloroplast and ribosomes
4) Ribosomes, cell membrane and cytoplasm

How are mitosis and binary fission identical?

1) Both processes give rise to 2 identical daughter cells.
2) Both processes involve anaphase.
3) Both processes gives rise to 2 identical nuclei
4) Both processes involve the replication of DNA at a single origin of replication.

Genetic recombination in bacteria does not involve the

1) random uptake of free DNA
2) insertion of a plasmid via vesicles
3) formation of prophages
4) accidental uptake of bacterial DNA by a bacteriophage during the packaging process

How is the trp operon different for the lac operon?

1) Trp operon produces polycistronic mRNA while lac operon produces monocistronic mRNA
2) Repressor binds to the operator in the trp operon while the activator binds to the operator in the lac operon
3) Trp operon is repressible while the lac operon is inducible
4) Trp operon is active in the presence of tryptophan while the lac operon is active in the absence of glucose.

A mutation that makes the regulatory gene of an inducible operon nin-functional would result in

1) continuous transcription of the operon's genes
2) reduced transcription of the operon's genes
3) accumulation of large quantities of a substrate for the catabolic pathway controlled by the operon
4) irreversible binding of the repressor to the promoter

A particular operon that encodes enzymes that together manufacture an essential amino acid. If the regulation of the operon is like that of the trp operon,

1) the amino acid inactivates the repressor
2) the enzymes produced are called inducible enzymes
3) the repressor binds to the operator in the absence of the amino acid
4) the amino acid acts as a corepressor

Which type of control of gene expression is commonly found in both the prokaryotes and eukaryotes?

1) post translational
2) post transcriptional
3) transcriptional
4) translational

Bacteria can undergo sexual reproduction to result in genetic variation.
Which of the following is NOT an example of sexual reproduction.

1) Transformation
2) Conjugation
3) Binary fission
4) Transduction

A bacteria cell can undergo either generalised transduction or specialised transduction.
The main difference that separates the two types of transduction is

1) Generalised transduction involves a temperate phage while specialised involves the use of a bacteriophage.
2) Generalised transduction involves homologous recombination but not specialised transduction
3) Generalised transduction involves excising the prophage DNA from the bacteria DNA while specialised transduction involves the host cell's degraded DNA to be randomly packaged within a capsid.
4) Generalised transduction does not involve the viral DNA to be integrated into the bacterial chromosome but specialised do.

Which of the following is NOT a feature of the bacterial chromosome?

1) It is circular in nature.
2) It undergoes supercoiling.
3) It is associated with histones to make it compact.
4) It is double-stranded.

Repressible enzymes are needed for the regulation of certain operons such as the trp operon.
Which of the following is an advantage of repressible enzymes?

1) It ensures that the cell does not synthesize a protein until it is needed.
2) It ensures that the cell does not waste energy synthesizing unneeded proteins.
3) It does not utilise a lot of energy for its' synthesis.

The function of an operator region in the operon is to

1) prevent gene expression when the repressor binds to it
2) code for the function proteins in the operon
3) serve as a binding site for RNA polymerase so as to initiate transcription
4) code for the repressor protein to inhibit gene expression

Conjugation involves the use of the sex pili found on the external surface of bacteria cells. What is the function of this pilus?

1) It is needed for the replication of DNA at the origin of replication.
2) It is needed for the integration of the F plasmid into the bacteria chromosome.
3) It is needed for the fusion of two bacteria cells together.
4) It is needed to form a cytoplasmic bridge to allow for the transfer of the F plasmid between two bacteria cells.

The availability of glucose controls the expression of genes in the lac operon.
How does glucose affect the expression of genes in the lac operon?

1) It serves as a corepressor where it binds to the inactive repressor to activate it.
2) It binds to the active repressor to inactivate it, allowing transcription of the gene to occur.
3) It binds to operator region and prevents the binding of RNA polymerase to the promoter region, thus inhibiting transcription.
4) It inhibits the synthesis of cAMP and hence prevents the activation of CRP needed to enhance the binding of RNA polymerase to the promoter region.