Pathophysiology and Drug Action Exam 5

Question 1

Nonsense Mutation Refers to:
A. A single base substitution that changes an amino acid to another amino acid in the same category in terms of charge, hydrophobicity, and polarity
B. A single base substitution that does not change the coded amino acid
C. A single base substitution that causes termination of protein translation
D. Insertion of a single nucleotide that causes a stop codon
E. Deletion of a single nucleotide that causes a stop codon

Answer 1

C. A single base substitution that causes termination of protein translation

Question 2

Which of the following mutations may lead to a frameshift?
A. A single base substitution that changes an amino acid to another amino acid in the same category in terms of charge, hydrophobicity, and polarity
B. A single base substitution that changes an amino acid to another amino acid in terms of charge, hydrophobicity, and polarity
C. Insertion of two nucleotides
D. Trinucleotide repeat mutations
E. All of the above

Answer 2

C. Insertion of two nucleotides

Question 3

The major cause of aneuploidy is:
A. Amplification of one or more chromosomes
B. Defect in cell mitosis
C. Fragmentation of chromosomes
D. Nondisjunction of a homologous pair of chromosomes at the first or second meiotic division
E. All of the above

Answer 3

D. Nondisjunction of a homologous pair of chromosomes at the first or second meiotic division

Question 4

Huntington Disease is a genetically inherited neurodegenerative disease. Patients often have more than 40 CAG repeats in one of the exons in the huntington gene. These CAG repeats likely cause:
A. An increase in the huntington gene transcription
B. An increase in the huntington gene translation
C. Alteration of the Huntington protein structure and function
D. An increase in the huntington mRNA degradation
E. An increase in the huntington mRNA stability

Answer 4

C. Alteration of the Huntington protein structure and function

Question 5

Inheritance type:
1. Patient with a gain-of-function mutation in one copy of the gene

Answer 5

A. Autosome dominant disorder

Question 6

Inheritance type:
2. Patient with a three-fold more protein product caused by a mutation in one copy of the gene

Answer 6

A. Autosome dominant disorder

Question 7

Inheritance type:
3. Both sons and daughter may be affected

Answer 7

D. Autosome dominant disorder and Autosome recessive disorder

Question 8

Inheritance type:
4. All children (100%) of an affected parent are carriers

Answer 8

B. Autosome recessive disorder

Question 9

Inheritance type:
5. The altered gene product (protein) can antagonize the function of the wild-type proteins

Answer 9

A. Autosome dominant disorder

Question 10

Inheritance type:
6. one of the patient’s parents must also be a patient

Answer 10

A. Autosome dominant disorder

Question 11

Inheritance type:
7. mutations that often affect structural proteins

Answer 11

A. Autosomal dominant disorder

Question 12

Inheritance type:
8. mutations that often affect enzymes

Answer 12

B. Autosomal recessive disorder

Question 13

Inheritance type:
9. Daughters are rarely affected

Answer 13

C. X-linked recessive disorder

Question 14

Inheritance type:
10. Female carriers have a 50% chance of passing the gene to their sons and daughters

Answer 14

C. X-linked recessive disorder

Question 15

Genomic Imprinting defects refers to:
A. Epigenetic inactivation of a maternal or paternal homologous gene
B. Epigenetic inactivation of a pair of homologous genes
C. Deletion of a pair of homologous genes
D. B and C
E. A, B and C

Answer 15

A. Epigenetic inactivation of a maternal or paternal homologous gene

Question 16

Compared with benign tumors, which of the following is NOT the characteristic of malignant tumors?
A. Malignant tumors grow more rapidly
B. Malignant tumors are more invasive
C. Malignant tumors are poorly differentiated
D. Malignant tumors tend to metastasize to distant organs
E. Malignant tumors are bigger

Answer 16

E. Malignant tumors are bigger

Question 17

In order to metastasize to different organs, cancer cells must express:
A. Enzymes must break down the surrounding ECM and gain access to blood circulation
B. Proteins that can kill immune cells
C. p53 that can induce apoptosis of fibroblasts in ECM
D. VEGF to form new blood vessels to deliver cancer cells to blood circulation
E. ligand that bind to kinase receptors

Answer 17

A. Enzymes must break down the surrounding ECM and gain access to blood circulation

Question 18

Which of the following may NOT lead to cancer development?
A. Gain-of-function mutations in Ras
B. Amplification of the EGFR gene
C. Gain-of-function mutations in Raf
D. Gain-of-function mutations in p53
E. Overexpression of MEK

Answer 18

D. Gain-of-function mutations in p53

Question 19

The loss of p53 could potentially lead to the following defects EXCEPT:
A. Inability to induce cell cycle arrest
B. Inability to repair DNA damages
C. Inability to induce apoptosis
D. Inability to induce necrosis

Answer 19

D. inability to induce necrosis

Question 20

The “Two-hit” Hypothesis for tumor suppressors refers to:
A. That an oncogenic activation occurs first before the loss of a tumor suppressor
B. That two tumor suppressor genes must be inactivated for tumor development
C. That two mutant alleles for a tumor suppressor must be inherited from father and mother
D. That two alleles for a tumor suppressor must be inactivated in order to show effect
E. That one mutant allele must be inherited and another allele must be inactivated in somatic cells

Answer 20

D. That two alleles for a tumor suppressor must be inactivated in order to show effect

Question 21

Loss-of-function mutations in DNA repair genes often lead to cancer development. This is because:
A. DNA damages cannot be properly repaired and mutations are accumulated with cell divisions
B. These DNA repair genes are also involved in apoptosis
C. All DNA repair genes are also tumor suppressors
D. DNA repair genes are on the same chromosomes with tumor suppressor genes
E. All of the above

Answer 21

A. DNA damages cannot be properly repaired and mutations are accumulated with cell divisions

Question 22

Targeted therapy is an important treatment strategy for cancer patients. Herceptin is a monoclonal antibody that can bind HER2 and is clinically used to treat breast cancer patients. Which of the following patients may benefit MOST from the use of Herceptin?
A. Patients with HER2 overexpression
B. Patients with HER2 expression negative
C. Triple negative patients
D. Patients with HER1 overexpression
E. Triple postive patients

Answer 22

A. Patients with HER2 overexpression

Question 23

Susan is diagnosed with breast cancer, and she has amplification of the EGFR gene. She could benefit from the following treatments EXCEPT
A. EGFR inhibitors
B. Ras inhibitors
C. ER targeted anti-hormone therapy
D. Raf inhibitors
E. MEK inhibitors

Answer 23

C. ER targeted anti-hormone therapy

Question 24

Chronic viral infections could potentially lead to cancer development by the following mechanisms:
A. Some viral proteins may induce chronic inflammatory response
B. Some viral DNA may integrate into human genome and activate proto-oncogenes
C. Some viral proteins may suppress the function of tumor suppressors such as p53 and Rb
D. Some viral proteins may disrupt normal cell cycle control
E. All of the above

Answer 24

E. All of the above

Question 25

Some viruses such as HTLV-1, HPV and EBV can cause cancer development. Which of the following statements about the mechanisms by which these viruses cause cancer development is FALSE?
A. HTLV-1 TAX protein can induce chronic inflammatory response
B. HTLV-1 TAX and HPV E6 can inactivate p53
C. HPV E7 can dissociate E7 Rb from E2F
D. LMP proteins from EBV can activate mitogenic pathways
E. Viral proteins are tumor suppressors

Answer 25

E. Viral proteins are tumor suppressors

Question 26

Cancer cells have limitless replicative potential. This is usually due to:
A. Oncogenic activation of the Ras proto-oncogene
B. deletion of the Rb alleles
C. Overexpression of telomerase
D. Amplification of c-Myc oncogene
E. All of the above

Answer 26

C. Overexpression of telomerase