Question 1

β-galactosidase is encoded by the ___________.
A)y gene of the lac operon
B)z gene of the lac operon
C)a gene of the lac operon
D)y gene of the trp operon
E)z gene of the trp operon

Accepted Answer

β-galactosidase is encoded by the z gene of the lac operon, which is involved in lactose metabolism in bacteria.

Question 2

Which of the traits below is characteristic of the classical nuclear localization signals?
A)possession of large numbers of hydrophobic amino acids
B)possession of one or two short stretches of negatively charged amino acids
C)possession of one or two short stretches of positively charged amino acids
D)twisted backbones
E)double helical regions

Accepted Answer

Classical nuclear localization signals possess one or two short stretches of positively charged amino acids, typically lysine or arginine residues.

Question 3

What is the name of the regulatory protein which binds to specific DNA sequences with high affinity and plays an important role in determining whether a genome segment is transcribed or not?
A)the operator
B)the terminator
C)the promoter
D)the repressor
E)the structural genes

Accepted Answer

The repressor protein binds to specific DNA sequences with high affinity and prevents transcription of certain genes by blocking RNA polymerase from binding to the promoter region. It plays an important role in regulating gene expression in prokaryotes.

Question 4

The operator is the site on the __________.
A)DNA where the repressor binds
B)DNA where DNA polymerase binds
C)DNA where reverse transcriptase binds
D)RNA where the repressor binds
E)ribosome where the polymerase binds

Accepted Answer

The operator is the specific DNA sequence where the repressor protein can bind to prevent RNA polymerase from transcribing downstream genes.

Question 5

What is the name of the proteins that make up the nuclear lamina and of what protein superfamily are they a member?
A)lamins, laminins
B)lamins, intermediate filaments
C)keratin, intermediate filaments
D)keratin, laminins
E)actin, microfilaments

Accepted Answer

The nuclear lamina is made up of proteins called lamins, which are members of the intermediate filament protein superfamily.

Question 6

When a regulatory protein inhibits transcription, this is known as _________________.
A)positive control
B)negative control
C)averaged control
D)circumspect control
E)neutral control

Accepted Answer

When a regulatory protein inhibits transcription, it is known as negative control. Positive control would be when a regulatory protein enhances transcription. Averaged control, circumspect control, and neutral control are not recognized terms in this context.

Question 7

Which of the following does NOT accurately describe the contents of the nucleus?
A)viscous
B)amorphous
C)undistinguished morphology
D)crystalline
E)highly extended nucleoprotein

Accepted Answer

The nucleus is not crystalline; it is a structure containing a viscous fluid, chromatin (a complex of DNA and proteins), and various other components, but it does not have a crystalline structure.

Question 8

What is the name of the site where RNA polymerase binds to the DNA prior to the beginning of transcription?
A)the operator
B)the terminator
C)the promoter
D)the repressor
E)the structural genes

Accepted Answer

The promoter is the specific DNA sequence where RNA polymerase binds to initiate transcription.

Question 9

Which two monosaccharides combine to form lactose?
A)2 glucose molecules
B)glucose and galactose
C)galactose and fructose
D)2 galactose molecules
E)glucose and fructose

Accepted Answer

Lactose is a disaccharide composed of glucose and galactose.

Question 10

The lac operon is an example of _______ operon.
A)a noninducible
B)a constitutive
C)an inducible
D)a repressible
E)an irrepressible

Accepted Answer

The lac operon is a classic example of an inducible operon, which means that the expression of genes is turned on by the presence of an inducer molecule. In the case of the lac operon, the inducer molecule is lactose. When lactose is present, it binds to the repressor protein and changes its shape, preventing it from binding to the operator site. This allows RNA polymerase to transcribe the genes needed to break down lactose.

Question 11

According to the text, what is the single most important distinction between prokaryotes and eukaryotes?
A)the existence of the Golgi complex
B)the separation of the cell's genetic material from the surrounding cytoplasm
C)the existence of ribosomes
D)the centrioles
E)the lysosomes and peroxisomes

Accepted Answer

The separation of the cell's genetic material from the surrounding cytoplasm is the key difference between prokaryotes (which have their DNA in a single circular chromosome in the cytoplasm) and eukaryotes (which have their DNA contained in a membrane-bound nucleus). While all the other structures listed may be present in one type of cell or the other, they do not serve as a definitive distinguishing feature.

Question 12

A transport receptor that moves macromolecules from the cytoplasm to the nucleus is called _______.
A)an exhalin
B)an exportin
C)an importin
D)a transportin
E)a receptin

Accepted Answer

Importins are transport receptors that specifically move macromolecules such as proteins and RNA into the nucleus. They recognize nuclear localization signals present on these molecules, bind to them, and then transport them through the nuclear pore complex into the nucleus. Exportins, on the other hand, move macromolecules from the nucleus to the cytoplasm. The other answer choices (exhalin, transportin, and receptin) are not real transport receptors.

Question 13

Which site in a bacterial operon is adjacent to or overlaps with a promoter?
A)operator
B)terminator
C)activator
D)repressor
E)structural genes

Accepted Answer

The operator site is located adjacent to or overlaps with the promoter in a bacterial operon. The promoter is the site where RNA polymerase binds to initiate transcription, and the operator site is located upstream of the structural genes, where it acts as a binding site for regulatory proteins such as repressors and activators to control transcription of the genes.

Question 14

With what structure is the outer membrane of the nuclear envelope continuous?
A)Rough endoplasmic reticulum
B)Smooth endoplasmic reticulum
C)Golgi complex
D)the spindle
E)the plasma membrane

Accepted Answer

The rough endoplasmic reticulum is continuous with the outer membrane of the nuclear envelope, as they are both involved in protein synthesis and transport. The smooth endoplasmic reticulum, Golgi complex, spindle, and plasma membrane are not directly connected to the nuclear envelope.

Question 15

How do allolactose and lactose differ?
A)They are composed of different sugars.
B)Allolactose has a negative charge, while lactose has a positive charge.
C)The type of linkage holding the two constituent sugars together differs between lactose and allolactose.
D)The order of the sugars is reversed in the two molecules.
E)The constituent sugars are both upside down in lactose and right-side-up in allolactose.

Accepted Answer

Allolactose and lactose differ in the type of glycosidic linkage between the glucose and galactose units. In lactose, the linkage is β-1,4-glycosidic, while in allolactose, which is an isomer of lactose, the linkage is β-1,6-glycosidic. This difference in linkage is crucial for the function of allolactose as an inducer of the lac operon in bacteria.

Question 16

A section of a bacterial chromosome in which genes for the enzymes of a particular metabolic pathway are clustered together in a functional complex under coordinate control is called ______.
A)an operator
B)an operon
C)a promoter
D)a repressor
E)an activator

Accepted Answer

An operon is a section of a bacterial chromosome in which genes for the enzymes of a particular metabolic pathway are clustered together in a functional complex under coordinate control. The other options are not directly related to this definition.

Question 17

What is the name of the linkage than holds the lactose disaccharide together?
A)β-galactoside linkage
B)α-lipophilic linkage
C)β-glycosidic linkage
D)α-galactoside linkage
E)ester linkage

Accepted Answer

The answer of What is the name of the linkage...

Question 18

What future goals are being considered for cellular engineering attempts to reprogram cellular behavior?
A)reprogramming developmental events so that all humans will reach a standardized height
B)reprogramming metabolism to eliminate obesity and diabetes
C)reprogramming surface receptor responses so that receptor binding might cause tumor cell destruction
D)reprogramming cellular receptors to eliminate infectious disease
E)all these options are actively being pursued and researched

Accepted Answer

While all of the options listed have been studied to some extent, reprogramming surface receptor responses to cause tumor cell destruction is currently the most practical and promising approach to cellular engineering. The other options listed largely involve attempting to influence complex developmental or metabolic processes that are influenced by multiple genetic and environmental factors, whereas altering cell receptors is a more specific and targeted strategy that has already been used successfully in some clinical trials.

Question 19

Digital logic relies on all of the following EXCEPT:
A)0,1 binary values
B)electronic circuits where voltage switches are ON or OFF
C)circuit output regulating input
D)AND gates where two input circuits must be active to generate activity past the logic gate
E)OR gates where either of two input circuits must be active to generate activity past the logic gate

Accepted Answer

Digital logic actually relies on circuit input regulating output, not output regulating input.

Question 20

The thin filamentous meshwork that is bound by integral membrane proteins of the inner surface of the nuclear envelope in animal cells is called the _________.
A)basement lamina
B)basal lamina
C)nuclear lamina
D)nucleon
E)nuclear limulus

Accepted Answer

The nuclear lamina is a thin filamentous meshwork that is bound by integral membrane proteins of the inner surface of the nuclear envelope in animal cells. The basement lamina and basal lamina are extracellular matrices that are found outside of cells. Nucleon and nuclear limulus are not accurate terms.

Quiz 12: Control of Gene Expression

β-galactosidase is encoded by the ___________.

Which of the traits below is characteristic of the classical nuclear localization signals?

What is the name of the regulatory protein which binds to specific DNA sequences with high affinity and plays an important role in determining whether a genome segment is transcribed or not?

The operator is the site on the __________.

What is the name of the proteins that make up the nuclear lamina and of what protein superfamily are they a member?

When a regulatory protein inhibits transcription, this is known as _________________.

Which of the following does NOT accurately describe the contents of the nucleus?

What is the name of the site where RNA polymerase binds to the DNA prior to the beginning of transcription?

Which two monosaccharides combine to form lactose?

The lac operon is an example of _______ operon.

According to the text, what is the single most important distinction between prokaryotes and eukaryotes?

A transport receptor that moves macromolecules from the cytoplasm to the nucleus is called _______.

Which site in a bacterial operon is adjacent to or overlaps with a promoter?

With what structure is the outer membrane of the nuclear envelope continuous?

How do allolactose and lactose differ?

A section of a bacterial chromosome in which genes for the enzymes of a particular metabolic pathway are clustered together in a functional complex under coordinate control is called ______.

What is the name of the linkage than holds the lactose disaccharide together?

What future goals are being considered for cellular engineering attempts to reprogram cellular behavior?

Digital logic relies on all of the following EXCEPT:

The thin filamentous meshwork that is bound by integral membrane proteins of the inner surface of the nuclear envelope in animal cells is called the _________.