Nokea
What causes osteoporosis?
- A. An increase in osteocyte activity while osteoclast activity continues at expected levels
- B. A decline in osteoblast activity while osteoclast activity continues at expected levels
- C. An increase in osteocyte activity while osteoblast activity continues at expected levels
- D. A decline in osteoclast activity while osteoblast activity continues at expected levels
Correct Answer: B
Rationale: Osteoporosis is a condition characterized by reduced bone density and mass, leading to brittle bones. Osteoblasts are cells responsible for forming new bone tissue, while osteoclasts break down old or damaged bone. In osteoporosis, there is a decrease in osteoblast activity, causing a net loss of bone as the breakdown surpasses formation. Meanwhile, osteoclast activity remains relatively stable. This imbalance between bone formation (osteoblast activity) and bone resorption (osteoclast activity) contributes to the development of osteoporosis by reducing bone strength and increasing susceptibility to fractures.
You may also like to solve these questions
Which class of biological molecules includes enzymes?
- A. Carbohydrates
- B. Vitamins
- C. Lipids
- D. Proteins
Correct Answer: D
Rationale: Enzymes are proteins that serve as biological catalysts, accelerating chemical reactions in living organisms. Proteins, a class of biological molecules crucial for the structure and function of cells, tissues, and organs, include enzymes. While carbohydrates, vitamins, and lipids are essential biomolecules, they do not encompass enzymes. Therefore, the correct answer is Proteins (Choice D).
Where does fertilization of an egg cell typically occur?
- A. Cervical canal
- B. Ovary
- C. Uterus
- D. Fallopian tube
Correct Answer: D
Rationale: Fertilization of an egg cell typically occurs in the fallopian tube. After ovulation, the egg is released from the ovary and travels through the fallopian tube, where it may encounter sperm for fertilization. The fertilized egg, known as a zygote, then moves into the uterus for implantation and further development into an embryo.
Which of the following organelles is the site of intracellular digestion?
- A. Ribosomes
- B. Lysosomes
- C. Centrosomes
- D. Mitochondria
Correct Answer: B
Rationale: Lysosomes are the organelles responsible for intracellular digestion within the cell. These specialized vesicles contain various enzymes that break down different molecules, such as old cell components or foreign substances. This breakdown process aids in cellular maintenance, recycling of materials, and waste elimination. Ribosomes are primarily involved in protein synthesis, centrosomes are essential for cell division processes, and mitochondria are the powerhouses of the cell, producing energy in the form of ATP. Therefore, the correct answer is B, Lysosomes, as they are specifically designed for intracellular digestion.
Which of the following is classified as a noninfectious disease?
- A. Dengue
- B. Psoriasis
- C. Chikungunya
- D. Brucellosis
Correct Answer: B
Rationale: Psoriasis is classified as a noninfectious disease because it is linked to an overactive immune system that leads to skin inflammation and rapid skin cell growth. Unlike infectious diseases such as Dengue, Chikungunya, and Brucellosis, which are caused by bacteria, viruses, or other pathogens, Psoriasis does not spread through pathogens. Therefore, Psoriasis is the correct choice for a noninfectious disease.
In a phase diagram, what term is used for a substance held at a temperature and pressure where solid, liquid, and gaseous states of a substance exist simultaneously?
- A. critical temperature
- B. triple point
- C. absolute zero
- D. critical point
Correct Answer: B
Rationale: The point described in the question is called the triple point. At the triple point, all three phases of a substance (solid, liquid, and gas) coexist in equilibrium. The critical temperature is the highest temperature at which a distinct liquid phase can form, while absolute zero is the lowest possible temperature. The critical point is the point on a phase diagram that represents the highest temperature and pressure at which a distinct liquid and gas phase can coexist. Therefore, the correct answer is the triple point, where all three phases coexist.