ATDH - Admission Test for Dental Hygiene General Biology Concepts Questions and Answers — Questions and Answers
Question 1: In eukaryotic cells, which organelle is primarily responsible for generating the majority of the cell's supply of adenosine triphosphate (ATP) through aerobic respiration?
- Ribosome
- Nucleus
- Mitochondrion (Correct answer)
- Golgi apparatus
Correct answer: Mitochondrion
The mitochondrion is known as the 'powerhouse' of the cell because it is the site of the Krebs cycle and oxidative phosphorylation, which together produce the vast majority of cellular ATP.
Question 2: A patient uses a highly concentrated saline (saltwater) rinse, creating a hypertonic environment in the oral cavity. What is the most likely effect on bacterial cells present on the mucosal surfaces?
- The cells will swell and may burst.
- The cells will lose water and shrink. (Correct answer)
- The cells will rapidly divide.
- The cells will remain unaffected by the rinse.
Correct answer: The cells will lose water and shrink.
In a hypertonic solution, the solute concentration outside the cell is higher than inside. Due to osmosis, water moves from an area of higher water concentration (inside the cell) to an area of lower water concentration (outside the cell), causing the cell to lose water and shrink, a process called plasmolysis.
Question 3: Which of the following best describes the primary role of enzymes in biological reactions?
- To store and transmit genetic information.
- To act as catalysts that increase the rate of reactions. (Correct answer)
- To serve as the primary source of cellular energy.
- To provide structural support to cell membranes.
Correct answer: To act as catalysts that increase the rate of reactions.
Enzymes are biological catalysts that lower the activation energy required for a chemical reaction to proceed. This significantly speeds up the rate at which the reaction occurs without the enzyme being consumed in the process.
Question 4: A key structural difference between deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) is the type of sugar present in their nucleotide backbones. What are the respective sugars found in DNA and RNA?
- Ribose in DNA, Deoxyribose in RNA
- Glucose in DNA, Fructose in RNA
- Sucrose in both DNA and RNA
- Deoxyribose in DNA, Ribose in RNA (Correct answer)
Correct answer: Deoxyribose in DNA, Ribose in RNA
The names of the nucleic acids themselves indicate their sugar components. DNA contains the pentose sugar deoxyribose, while RNA contains the pentose sugar ribose. The key difference is that deoxyribose lacks an oxygen atom at the 2' carbon position that is present in ribose.
Question 5: Many pathogenic bacteria that contribute to periodontal disease thrive in the low-oxygen environment of subgingival pockets. These bacteria primarily generate energy through which metabolic process?
- Anaerobic respiration (Correct answer)
- Photosynthesis
- Aerobic respiration
- Chemosynthesis
Correct answer: Anaerobic respiration
Anaerobic respiration is a form of cellular respiration that generates energy in the absence of oxygen. This process is characteristic of obligate and facultative anaerobes that colonize deep periodontal pockets where oxygen is scarce.
Question 6: Saliva contains bicarbonate and phosphate ions that help maintain a relatively stable pH in the oral cavity, even after a person consumes acidic foods. This system is an example of a biological:
- Catalyst
- Solvent
- Isotope
- Buffer (Correct answer)
Correct answer: Buffer
A buffer system is a solution that can resist pH change upon the addition of an acidic or basic component. The bicarbonate and phosphate systems in saliva are crucial for neutralizing acids, thereby protecting tooth enamel from demineralization.
ATDH - Admission Test for Dental Hygiene General Biology Concepts Questions and Answers
In eukaryotic cells, which organelle is primarily responsible for generating the majority of the cell's supply of adenosine triphosphate (ATP) through aerobic respiration?