Cell Structures and Biofilms Flashcards
(25 cards)
What are prokaryotes?
organisms that do not have a distinct nuclear compartment to house their DNA. Bacteria (eubacteria) and archaea are the two major classes of prokaryotic organisms.
Which of these structures would not be in a Prokaryotic Cell? A. Cell Membrane B. Nucleus C. Mitochondria D. Both B and C
D. Both B and C
The organelles within a Prokaryotic Cell are:
Cell membrane, vesicles, ribosomes, fimbriae (pili), flagella, lipopolysaccharides (LPS), Capsule
What are eukaryotes?
organisms that house their DNA in a distinct, subcellular compartment (nucleus).
Which of these structures would be in a eukaryotic cell? A. Fibriae B. Flagella C. Nucleus D. None of the above
C. Nucleus
Key Stuctures of the Eukaryotic Cells: Plasma membrane, nucleus, endoplasmic reticulum, rough ER, smooth ER, Golgi, Mitochondria, Lysosomes
A key structure of gram positive bacteria is: A. A thick peptidoglycan layer B. LPS C. A thin peptidoglycan layer D. None of the above
A. A thick peptidogyclan layer
Gram positive bacteria: thick pepditoglycan layer
Gram negative bacteria: LPS
What is peptidoglycan comprised of?
Chains of alternating NAM and NAG sugars cross linked by oligopeptides
What enzyme is responsible for cross linking peptidoglycan? A. Lipase B. Transpeptidase C. Phospholipase C D. Glycogen synthase
B. Transpeptidase
Transpeptidase is responsible for crosslinking and is inhibited by the antibiotic, AMPICILLIN
What are biofilms?
Biofilms are a cooperating community of microorganisms within a matrix that is attached to a surface
Where do dental biofilms exist?
Tooth surfaces and mucosal surfaces of the oral cavity
When do gram-negative bacteria develop in dental biofilms? A. Seconds B. Minutes C. Hours D. Days
C. Hours
Gram-negative bacteria develop in the STATIONARY III phase of the Microbial Cycle. Gram-negative bacteria develop after gram-positive bacteria
How does the pellicle form?
The pellicle forms from proteins in the saliva or GCF. It serves as a conditioning film for attachment of the initial colonizing bacteria
What is the is the initial colonizing bacteria on the pellicle of a tooth surface?
A. Gram-negative bacteria
B. Bacteria with a thin peptidoglycan layer
C. Bacteria with an LPS layer
D. Gram postive bacteria
D. Gram positive bacteria
Which of these is not present in the structural complex of a dental biofilm? A. Fluid Channels B. Pellicle C. mitochondria D. Chemical signals
C. Mitochondria
The mitochondria is not present in bacterial cells
True or False: Even in healthy individuals the bacteria in oral biofilms have a relative abundance?
True
Which of the following is true about cariogenic bacteria?
A. Cariogenic bacteria produce extracellular polysaccharides from sucrose
B. Cariogenic Bacteria are gram-negative
C. Cariogenic Bacteria prefer high pH environments
D. Cariogenic bacteria are found in the GCF
A. Cariogenic bacteria produce extracellular polysaccharides from sucrose
Cariogenic bacteria are gram-positive bacteria that prefer acidic environments. Sucrose, broken down into glucans and fructans serves as their nutritional source, which supports further adhesion and subsequent accumulation of plaque
What is the role of sucrose in dental biofilms and caries?
Sucrose is highly soluble and diffuses rapidly into the plaque biofilm where is serves as a substrate for production of extracellular Polysaccharides and acids
FOR EXTRACELLULAR POLYSACCARIDES
A. Sucrose is split into glucose and fructose
B. Glucose and fructose can be built into homopolymers glucans and fructans
C. Glucans and Fructans (extracellular polysaccharides) serve as a nutritional source for bacteria, which supports further adhesion and subsequent accumulation of plaque
FOR LACTIC ACID
A. Sucrose is split into glucose and fructose
B. The gram-positive cariogenic bacteria (Streptococcus mutans, Lactobacillus casei, and Lactobacillus fermentum) ferment the sugars (glucose and fructose) into lactic acid
C. Lactic acid results in low pH, which can result in demineralization of the enamel and dentin, resulting in caries
How do saccharolytic bacteria derive energy? A. Glycolysis B. Krebs cycle C. Amino Acids D. Anaerobic energy pathways
A. Glycolysis
What is the difference between plaque and calculus?
Calculus can form from plaque, but plaque cannot form from calculus. Plaque will break down the mineral components of a tooth and will eventually lead to caries. Calculus is extremely hard and can only be removed by a dental professional.
What is the end product of cariogenic bacteria fermentation? A. Pyruvate B. Lactic Acid C. Ammonium Acetate D. None of the above
B. Lactic Acid
Although pyruvate is a part of the fermentation process, it is ultimately turned into lactate. The production of lactic acid results in a low pH, which can result in demineralization of the tooth enamel and dentin resulting in a carie
Asaccharolytic bacteria A. Derive their energy from amino acids B. Form in the gingival sulcus area C. Raise the pH of the environment D. All of the above
D. All of the above
Serous Saliva is the main product of which gland? A. Parotid glands B. Minor glands C. Sublingual glands D. Submandibular glands
A. Parotid glands
Serous - Parotid glands
Mucos - Minor glands
Mixed Serous and Mucas - Sublingual and submandibular glands
Which of these is not a function of saliva in the body? A. Lubrication and protection B. Buffering action and clearance C. Maintenance of tooth integrity D. All of these are functions of saliva
D. All of these are functions of saliva
The functions of saliva are:
Lubrication and protection Buffering action and clearance Maintenance of tooth integrity Antibacterial activity Taste and digestion
Where is the gingival crevicular fluid located?
Secreted into the space (gingival sulcus) between the surface of the tooth and the free margin of the epithelium lining of the gingiva
Which of these is not a function of the gingival crevicular fluid?
A. Maintenance of tooth integrity
B. Cleansing the sulcus
C. Improve adhesion of the epithelium to the tooth
D. Antimicrobial properties
A. Maintenance of tooth integrity
The functions of the GCF include:
- Cleansing the sulcus
- Improve adhesion of the epithelium to the tooth
- Antimicrobial properties
- Antibody defense of the gingiva
