Bio 151 Exam 3 Questions with
Verified Solutions
A double-stranded DNA molecule can be separated into single strands by heating it to
90 degrees C because ________. - ANSWER-heat disrupts hydrogen bonding between
complementary nucleotides
Each unique DNA molecule melts at a different temperature. In this context, melting
temperature is at the point which two strands separate or become denatured. Which
DNA sequence listed below would have the highest Tm? - ANSWER-GGCGCACC
All steroid hormones - ANSWER-bind intracellular receptors to form complexes that
migrate to the nucleus
Which type of cell signaling involves transport of hormones through the bloodstream? -
ANSWER-Endocrine
A cellular response to a signal can be terminated by
A. Depletion of the single that actives the receptor
B. inactivation of intracellular signal-transduction proteins
C. Automatic inactivation of proteins in the signal pathway over time
D. Depletion of a second messenger
E. All of the above - ANSWER-The answer: E
Processes that regulate cell division in mammals include all of the following except:
A. rapid production of cyclin proteins that activate CDK enzymes
B. Activated cyclin-CDK complexes trigger cell cycle events
C. Different cyclins and CKDs act at different stages of the cell cycle to promote cell
division
D. Rapid degradation of cyclins after CDK activation
E. rapid production of CDK enzymes that activate cyclin proteins - ANSWER-The
answer: E
Defects in cell signaling can lead to a cancerous cell due to all of the following except: -
ANSWER-a defective signal-transduction protein that stays in the inactivated state and
fails to trigger cell division
, Phosphatase are a family of enzymes that specifically removed phosphate groups from
proteins that were added by protein kinases. Vanadate is an inhibitor of phosphatase in
eukaryotic cells. What effect would vanadate have on the response of cells to signals
received by receptor kinases? - ANSWER-The reponse of the cell would last longer
than it normally would
Continual activation of the MAP kinase pathway even in the absence of signaling
molecule - ANSWER-Hydrolysis-deficient RAS mutant
Failure to activate MAP kinase pathway following ligand binding to receptor kinase -
ANSWER-High GDP affinity RAS mutant
Failure of receptor kinase to dimerize in the presence of ligand - ANSWER-Hydrolysis-
deficient RAS mutant
Change in the expression of genes in the absence of the appropriate signaling molecule
- ANSWER-High GDP affinity RAS mutant
Target genes are not expressed even in the presence of signaling molecule - ANSWER-
High GDP affinity RAS mutant
A continuously activated receptor in the absence of ligand - ANSWER-Neither
Hydrolysis deficient RAS mutant or High GDP affinity RAS mutant
Which of the following is not a hallmark of cancer - ANSWER-Ability of cells to inhibit
cell division when conditions are not optimal
Place the following events of mitosis in the correct order:
I. Sister chromatids align on the metaphase plate
II. The cleavage furrow forms
III. The nuclear membrane breaks up
IV. chromosomes condense
V. Sister chromatids separate - ANSWER-IV, III, I, V, II
A homologous chromosome pair is best described as two chromosomes that have
________ - ANSWER-the same genes in the same order but possibly with different
versions of some of the genes
Consider a diploid organism (2n) with a haploid complement (n) of four chromosomes.
At Prophase I, how many total chromosomes will be present in a cell? - ANSWER-eight,
four pairs of homologous chromosomes
How many copies of each gene are present in skin ells at G1 of interphase? -
ANSWER-2
Verified Solutions
A double-stranded DNA molecule can be separated into single strands by heating it to
90 degrees C because ________. - ANSWER-heat disrupts hydrogen bonding between
complementary nucleotides
Each unique DNA molecule melts at a different temperature. In this context, melting
temperature is at the point which two strands separate or become denatured. Which
DNA sequence listed below would have the highest Tm? - ANSWER-GGCGCACC
All steroid hormones - ANSWER-bind intracellular receptors to form complexes that
migrate to the nucleus
Which type of cell signaling involves transport of hormones through the bloodstream? -
ANSWER-Endocrine
A cellular response to a signal can be terminated by
A. Depletion of the single that actives the receptor
B. inactivation of intracellular signal-transduction proteins
C. Automatic inactivation of proteins in the signal pathway over time
D. Depletion of a second messenger
E. All of the above - ANSWER-The answer: E
Processes that regulate cell division in mammals include all of the following except:
A. rapid production of cyclin proteins that activate CDK enzymes
B. Activated cyclin-CDK complexes trigger cell cycle events
C. Different cyclins and CKDs act at different stages of the cell cycle to promote cell
division
D. Rapid degradation of cyclins after CDK activation
E. rapid production of CDK enzymes that activate cyclin proteins - ANSWER-The
answer: E
Defects in cell signaling can lead to a cancerous cell due to all of the following except: -
ANSWER-a defective signal-transduction protein that stays in the inactivated state and
fails to trigger cell division
, Phosphatase are a family of enzymes that specifically removed phosphate groups from
proteins that were added by protein kinases. Vanadate is an inhibitor of phosphatase in
eukaryotic cells. What effect would vanadate have on the response of cells to signals
received by receptor kinases? - ANSWER-The reponse of the cell would last longer
than it normally would
Continual activation of the MAP kinase pathway even in the absence of signaling
molecule - ANSWER-Hydrolysis-deficient RAS mutant
Failure to activate MAP kinase pathway following ligand binding to receptor kinase -
ANSWER-High GDP affinity RAS mutant
Failure of receptor kinase to dimerize in the presence of ligand - ANSWER-Hydrolysis-
deficient RAS mutant
Change in the expression of genes in the absence of the appropriate signaling molecule
- ANSWER-High GDP affinity RAS mutant
Target genes are not expressed even in the presence of signaling molecule - ANSWER-
High GDP affinity RAS mutant
A continuously activated receptor in the absence of ligand - ANSWER-Neither
Hydrolysis deficient RAS mutant or High GDP affinity RAS mutant
Which of the following is not a hallmark of cancer - ANSWER-Ability of cells to inhibit
cell division when conditions are not optimal
Place the following events of mitosis in the correct order:
I. Sister chromatids align on the metaphase plate
II. The cleavage furrow forms
III. The nuclear membrane breaks up
IV. chromosomes condense
V. Sister chromatids separate - ANSWER-IV, III, I, V, II
A homologous chromosome pair is best described as two chromosomes that have
________ - ANSWER-the same genes in the same order but possibly with different
versions of some of the genes
Consider a diploid organism (2n) with a haploid complement (n) of four chromosomes.
At Prophase I, how many total chromosomes will be present in a cell? - ANSWER-eight,
four pairs of homologous chromosomes
How many copies of each gene are present in skin ells at G1 of interphase? -
ANSWER-2
