BIO 250 Final Exam 3 Questions With
Complete Solutions.
1. Which of the following genes are regulated by the presence of sugars? (Select all that apply.)
a. LacA, which codes for transaminase
b. LacI, which codes for the lac repressor
c. LacY, which codes for permease
d. LacZ, which codes for beta-galactosidase - Answer a. LacA, which codes for transaminase, c. LacY,
which codes for permease, and d. LacZ, which codes for beta-galactosidase
1. In normal bacteria, when is the lac operon repressed? (Select all that apply.)
a. In the presence of glucose and absence of lactose
b. In the absence of glucose and lactose
c. In the presence of glucose and lactose
d. In the absence of glucose and the presence of lactose - Answer a. in the presence of glucose and
absence of lactose
b. in the absence of glucose and lactose
What is a housekeeping protein in eukaryotic cells? Provide one example. - Answer A housekeeping
protein is one which the cell needs to maintain basic cellular processes. These proteins are expressed in
all cells of an organism under normal and most pathological conditions. For example, proteins involved in
processes such as transcription and translation. Examples may vary, but can include: RNA polymerase,
Ribosomes, Splicing factors, general transcription factors, general translation factors, capping enzyme,
histones, polyadenylase, enzymes involved in cellular respiration, etc.
1. You are interested in studying the role of a regulatory element proximal to the promoter region of a
gene expressed in cardiac smooth muscle cells. In normal cardiac smooth muscle cells, the gene is
expressed at high levels. However, in kidney cells, the gene is not expressed at all. You make a luciferase
construct to study the function of this regulatory element in each of these two cell types. The construct
contains the full promoter along with this element driving expression of the luciferase gene. You mutate
this element in that construct and observe the effect it has on expression from that promoter. The
normal, non-mutated construct has high luciferase expression in the cardiac smooth muscle cells, but no
luciferase expression in the kidney cells. The mutated construct has high luciferase expression in the
, cardiac smooth muscle cells and high luciferase expression in the kidney cells. From this data, you con -
Answer d. the regulatory element binds a repressor protein in the kidney cells
True or false: histone deacetylases remove lysines from histone tails - Answer False
1. Acetylcholine is released from pre-synaptic cells to initiate muscle cell contraction at neuromuscular
junctions. What kind of signaling is this?
a. Endocrine
b. Autocrine
c. Paracrine
d. Neuronal
e. Contact-dependent - Answer neuronal
1. Which of the following represents the initial step in a cell signaling pathway?
a. Gene expression changes
b. Phosphorylation of signaling molecules in a kinase cascade
c. Activation of effector molecules
d. Binding of a ligand to its receptor
e. Exchange of GTP for GDP in a small-GTPase - Answer d. binding ofa ligand to its receptor
1. Which of the following is true about protein kinases? (Select all that apply.)
a. Protein kinases act as transcription factors to regulate gene expression
b. Protein kinases add phosphate groups to serine, threonine, and/or tyrosine residues on target
proteins
c. Protein kinases remove phosphate groups from serine, threonine, and/or tyrosine residues on target
proteins
d. Protein kinases can amplify signals by rapidly phosphorylating many target proteins - Answer b.
protein kinases add phosphate groups to serine, threonine, and/or tyrosine residues on target proteins
d. protein kinases can amplify signals by rapidly phosphorylating many target proteins
Complete Solutions.
1. Which of the following genes are regulated by the presence of sugars? (Select all that apply.)
a. LacA, which codes for transaminase
b. LacI, which codes for the lac repressor
c. LacY, which codes for permease
d. LacZ, which codes for beta-galactosidase - Answer a. LacA, which codes for transaminase, c. LacY,
which codes for permease, and d. LacZ, which codes for beta-galactosidase
1. In normal bacteria, when is the lac operon repressed? (Select all that apply.)
a. In the presence of glucose and absence of lactose
b. In the absence of glucose and lactose
c. In the presence of glucose and lactose
d. In the absence of glucose and the presence of lactose - Answer a. in the presence of glucose and
absence of lactose
b. in the absence of glucose and lactose
What is a housekeeping protein in eukaryotic cells? Provide one example. - Answer A housekeeping
protein is one which the cell needs to maintain basic cellular processes. These proteins are expressed in
all cells of an organism under normal and most pathological conditions. For example, proteins involved in
processes such as transcription and translation. Examples may vary, but can include: RNA polymerase,
Ribosomes, Splicing factors, general transcription factors, general translation factors, capping enzyme,
histones, polyadenylase, enzymes involved in cellular respiration, etc.
1. You are interested in studying the role of a regulatory element proximal to the promoter region of a
gene expressed in cardiac smooth muscle cells. In normal cardiac smooth muscle cells, the gene is
expressed at high levels. However, in kidney cells, the gene is not expressed at all. You make a luciferase
construct to study the function of this regulatory element in each of these two cell types. The construct
contains the full promoter along with this element driving expression of the luciferase gene. You mutate
this element in that construct and observe the effect it has on expression from that promoter. The
normal, non-mutated construct has high luciferase expression in the cardiac smooth muscle cells, but no
luciferase expression in the kidney cells. The mutated construct has high luciferase expression in the
, cardiac smooth muscle cells and high luciferase expression in the kidney cells. From this data, you con -
Answer d. the regulatory element binds a repressor protein in the kidney cells
True or false: histone deacetylases remove lysines from histone tails - Answer False
1. Acetylcholine is released from pre-synaptic cells to initiate muscle cell contraction at neuromuscular
junctions. What kind of signaling is this?
a. Endocrine
b. Autocrine
c. Paracrine
d. Neuronal
e. Contact-dependent - Answer neuronal
1. Which of the following represents the initial step in a cell signaling pathway?
a. Gene expression changes
b. Phosphorylation of signaling molecules in a kinase cascade
c. Activation of effector molecules
d. Binding of a ligand to its receptor
e. Exchange of GTP for GDP in a small-GTPase - Answer d. binding ofa ligand to its receptor
1. Which of the following is true about protein kinases? (Select all that apply.)
a. Protein kinases act as transcription factors to regulate gene expression
b. Protein kinases add phosphate groups to serine, threonine, and/or tyrosine residues on target
proteins
c. Protein kinases remove phosphate groups from serine, threonine, and/or tyrosine residues on target
proteins
d. Protein kinases can amplify signals by rapidly phosphorylating many target proteins - Answer b.
protein kinases add phosphate groups to serine, threonine, and/or tyrosine residues on target proteins
d. protein kinases can amplify signals by rapidly phosphorylating many target proteins
