Multiple Choice Question Test - IX (Basic Periodontology).

This is a self assessment test consisting of ten questions. Click evaluate to get result.

1. C reactive proteins (CRP) are produced by,

C-reactive proteins (CRP), composed of 5 23-kDa subunits, are acute phase reactants. They are found in the blood, the levels of which rise in response to inflammation. CRP’s are synthesized by the liver in response to factors released by macrophages and adipocytes. They were named so because they were first discovered as a substance in the serum of patients with acute inflammation that reacted with the C-polysaccharide of pneumococcus.

Correct Answer - option 3

2. Platelet derived growth factor (PDGF) exists in,

Platelet derived growth factor (PDGF) is a polypeptide dimer coperising either of PDGF-A or PDGF-B subunit and is produced in a variety of tissues where it acts as a local mitogen. These dimmers lead to formation of three isoforme of PDGF namely: PDGF-AA, PDGF-AB, PDGF-BB.

Reference: M Centrella et al. Isoform-specific regulation of platelet-derived growth factor activity and binding in osteoblast-enriched cultures from fetal rat bone. J Clin Invest. 1992 April; 89(4): 1076–1084.

2 isoforms.
3 isoforms.
4 isoforms.
5 isoforms.
Correct Answer - option 2

3. Which of the following has cell binding and Osteoclast anchoring activity,

Osteopontin (OPN), meaning "bone bridging", is highly expressed in mineralized tissues. It is also expressed in other tissues including cartilage, kidney, vascular tissues, activated macrophages, lymphocytes, and epithelia. In addition to being incorporated in the matrix of mineralized connective tissues, secreted OPN is found in various biological fluids including blood, milk, urine, and seminal fluid. A portion of cell expressed OPN is also retained intracellularly. In vitro, OPN stimulates the adhesion of osteoclasts to bone, and bone resorption is blocked by inhibition of this interaction.

References: Reinholt, F.P. et al. (1990) Proc. Natl. Acad. Sci. USA 87:4473.

Ross, F.P. et al. (1993) J. Biol. Chem. 268:9901.

Matrix-gla protein.
Correct Answer - option 3

4. Which of the following is not true about laminin,

The laminins are a family of glycoproteins that provide an integral part of the structural scaffolding of basement membranes in almost every animal tissue. Each laminin is a heterotrimer assembled from alpha, beta, and gamma chain subunits, secreted and incorporated into cell-associated extracellular matrices. Laminins are composed of a central ~400 kDa alpha chain (heavy chain) with a varying number of globular regions and two ~200 kDa chains (beta and gamma)(light chains) with helical α-helical and globular regions. Cysteine-rich repeats are prevalent in all the laminin chains.  They have binding regions for collagen, integrins, cellular domains, and proteoglycans such as dystroglycan.

Reference: Colognato H et al. Form and function: the laminin family of heterotrimers. Dev Dyn. 2000 Jun;218(2):213-34.

It is a glycoprotein.
It is composed of one heavy and 2 light chains.
It has got a linear structure.
Its functions include cell attachment, migration and differentiation.
Correct Answer - option 3

5. Major surface protein (MSP) is associated with,

T. Denticola has many bacterial virulent factors, manifesting specific cytotoxic effects. One of these components, the 53-kDa major surface protein (Msp), was extensively studied in terms of its chemical and molecular structure and biological activities.

Reference: Sela MN. Role of Treponema denticola in periodontal diseases. Crit Rev Oral Biol Med. 2001;12(5):399-413.

P. Gingivalis.
P. Intermedia.
T. Denticola.
T. Forsythia.
Correct Answer - option 3

6. Which of the following is not accurate about refractory periodontitis,

Refractory periodontal disease is characterized by low plaque scores and low responsiveness to periodontal therapy. The subgingival microflora of refractory disease may be either predominantly gram-positive with elevated levels of Streptococcus intermedius or may be gram negative and contain elevated levels of the classical periodontal pathogens. Plaque samples are dominated by Capnocytophaga species, E corrodens and C rectus.

Reference: Magnusson I, Walker CB. Refractory periodontitis or recurrence of disease.  J Clin Periodontol. 1996 Mar;23(3 Pt 2):289-92.

Plaque microflora has complex ecosystem.
AAC is a prominent component of microflora.
Plaque samples are dominated by P. Gingivalis, P. Intermedia and B forsythus.
Plaque samples are dominated by Capnocytophaga species, E corrodens and C rectus.
Correct Answer - option 3

7. Receptor for Epstein-Barr virus on B-cell surface is,

The human complement receptor type 2 (CR2), designed as CD21, is a membrane glycoprotein and serves as a receptor for the C3d, C3dg, and iC3b proteins of complement. Structurally, it consists of 15 or 16 extracellular short consensus repeats (SCR) followed by a trans-membrane domain and an intra-cytoplasmic region. CD21 was described as a receptor for the envelope glycoprotein gp350/220 of the EBV and also as a receptor for interferon-alpha (IFN-α). It is found on mature B lymphocytes and follicular dendritic cells. The CD21 molecule is a functional ligand for CD23 and is involved in IgE and IgG4 production of human B lymphocytes. Binding of the EBV antigen gp350/220 leads to capping of EBV–receptor complexes on the surface of B cells and mediates subsequent internalization of EBV into the cell.

Reference: W J Jabs et al. Analysis of Epstein–Barr virus (EBV) receptor CD21 on peripheral B lymphocytes of long-term EBV adults. Clin Exp Immunol. 1999 June; 116(3): 468–473.

Correct Answer - option 1

8. One of the important virulence factors produced by spichetes is dentilisin which is encoded by,

Treponema denticola is the most frequently cultivated oral spirochete. Clinical micriobiology studies associate it among a few other oral anaerobes in the mixed gingival sulcus microbiota that contribute to the etiology of periodontitis in adults. The outer sheath of Treponema denticola contains a few proteins that have been investigated for their cytopathogenicity in human cell culture systems. Most prominent among these are the major surface protein, Msp, and a cell-associated serine protease, dentilisin or PrtP.

Reference: Richard P. Ellen. Insertional Inactivation of the prtP Gene of Treponema denticola Confirms Dentilisin’s Disruption of Epithelial Junctions. J. Mol. Microbiol. Biotechnol. (2000) 2(4): 581-586.

prtP gene.
prtQ gene.
prtR gene.
prtT gene.
Correct Answer - option 1

9. Lower gingipain (proteolytic) activity of P. Gingivalis has been observed in,

P. gingivalis becomes more proteolytic (e.g. higher gingipain activity) in response to an increase in haemin availability, and an increase in environmental pH results in further upregulation of gingipain activity. In contrast, a high temperature results in P. Gingivalis down regulating protease activity.

Reference: Philip D. Marsh, Annette Moter & Deirdre A. Devine Dental plaque biofilms: communities, conflict and control. Periodontology 2000, Vol. 55, 2011, 16–35.

Increased haemin availability.
Increased temperature.
Increased environmental pH.
None of above.
Correct Answer - option 2

10. Co- adhesion is,

During co-adhesion, secondary and late colonizers adhere via cell-surface adhesins to receptors on already attached bacteria, leading to an increase in microbial diversity within the developing biofilm (microbial succession).

Reference: Philip D. Marsh, Annette Moter & Deirdre A. Devine Dental plaque biofilms: communities, conflict and control. Periodontology 2000, Vol. 55, 2011, 16–35.

Initial colonisation of microorganisms on tooth surface.
Reversible adhesion involves weak, long-range, physico-chemical interactions.
Secondary and late colonizers adhering via cell-surface adhesins to receptors on already attached bacteria.
Irreversible adhesion of specific molecules on the microbial cell surface and the acquired pellicle.
Correct Answer - option 3

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