This set of Cytogenetics Multiple Choice Questions & Answers (MCQs) focuses on “Apoptosis and Cancer -1”.
1. Which of the following is an active cell death process?
Explanation: Apoptosis is an active and regulated cell death process that occurs in the body. In necrosis the cell membrane is ruptured and so is the case in option c and d.
2. Apoptosis can’t kill which of the following?
a) Cell infected with viruses
b) Cell with DNA damage
c) Cancer cells
d) Immune cells
Explanation: Improper regulation of apoptosis is the main cause of proliferative cell growth like cancer. Thus apoptosis can’t actually occur in cancer cells. Other options are types of cells where apoptosis occurs.
3. Which of the following is an anti apoptotic protein?
b) Bfl 1
Explanation: Bcl-Xs is a Bcl-2 family protein which is pro-apototic, also bim and NOXA are proapoptotic factors. Bfl 1 is an anti apoptotic member of Bcl- 2 family.
4. Which of the following cell organelle actively participates in animal apoptosis?
Explanation: Mitochondria in animals is an important member regulating the intrinsic pathway of apoptosis, it releases cytochrome which triggers the process.
5. Which of the following can trigger cytochrome release from mitochondria?
Explanation: Among the following options bid, bad and Smac are pro-apoptotic and Akt is anti apoptotic. But only Bid among the options directly helps in release of cytochrme c from the mitochondria as tBid.
6. Which of the following is an inhibitor of apoptosis?
Explanation: Caspases are the effectors of apoptosis. IAP binds to the caspases thus preventing apoptosis from taking place. Smac and Diablo binds to IAP thus inhibiting it so they are also pro-apoptotic.
7. Caspases belong to the class of _________________
a) Serine proteases
b) Cystine proteases
c) Aspertate proteases
Explanation: Caspases are cystine proteases which cleaves the peptide using an activated cystine animo acid in the catalytic site.
8. Caspases can be activated by______________
Explanation: The caspases are activated by cytochromes which are released from the mitochondria. This interacts wth Apaf1 adapter protein which in turn activated the caspases by aggregation.
9. Caspase 8 is an effector caspase.
Explanation: Caspase 8 is an initiator caspase that is activated downstream of FAS receptor complex, it activates the other effector caspases like caspase 3.
10. Which of the following is not a characteristic of apoptotic animal cell?
a) Trasglutaminase forms a net like structure
b) Cell membrane blebbing
c) Mitochondria swollen
d) DNA marginization and fragmentation
Explanation: In apoptotic cells the mitochondria are either shrunken or remains of the same size. The ER on the other hand may be swollen. Remaining options are correct events happening during apoptosis.
11. What is the unusual characteristic of cell membrane seen in apoptotic cell?
a) Cell membrane ruptures
b) Cell membrane channels stop working
c) Cell membrane exposes phosphatidyl serine on the outer side
d) Cell membrane exposes the cholesterol and lipid rafts on the outer side
Explanation: Phosphatidyl serine is mainly present on the inner side of the cell membrane, this is seen in the outer side of the apoptotic cell membrane that encourages phagocytosis.
12. Akt doesn’t phosphorylate ________________
c) Gsk -3
Explanation: Akt is an inhibitory src kinase that is activated downstream of anti- apoptotic pathway. This phosphorylates bad and FOXO generating 14-3-3 protein binding site, and also phosphorylates Gsk-3. But it doesn’t phosphorylate caspases.
13. TRAIL interacts with ___________ receptor.
Explanation: DR4 is another receptor on the cell surface like Fas which consists of death domains. This accepts TRAIL or TNF receptor related apoptosis inducing ligand.
14. Which of the following is not an RHG family protein?
Explanation: Rad51 is the human homologue of Rec that helps in DSB repair. RHG is a group of drosophila pro- apoptotic proteins which consists of Hid, Reaper, Sickel and grim.
15. If you inject Bcl-2 within a cell it will not undergo apoptosis.
Explanation: Bcl-2 is an anti apoptotic protein. The proper balance of the pro apoptotic and anti apoptotic proteins maintains the apoptosis. In this case the apoptosis will be prevented.
Sanfoundry Global Education & Learning Series – Cytogenetics.
To practice all areas of Cytogenetics, here is complete set of 1000+ Multiple Choice Questions and Answers.