Nokea
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.
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Which of the following cells transfers pigment granules to adjust epidermal cells?
- A. Merkel Cells
- B. Keratinocytes
- C. Langerhans cells
- D. Melanocytes
Correct Answer: D
Rationale: Melanocytes are the cells responsible for transferring pigment granules to adjust epidermal cells. Melanocytes produce melanin, the pigment that gives skin its color and provides protection against UV radiation. Once produced, melanin is transferred to neighboring skin cells, primarily keratinocytes, to distribute the pigment throughout the epidermis. Merkel cells are associated with the sense of touch, not pigment transfer. Keratinocytes are the predominant cells in the epidermis that produce keratin, a structural protein for skin, nails, and hair. Langerhans cells are part of the immune system in the skin, helping to recognize and respond to foreign invaders.
Which of the following immune system molecules creates pores in the cell membrane of their target cells to destroy the cell?
- A. Lymphotoxins
- B. Perforins
- C. Interferons
- D. Cytokines
Correct Answer: B
Rationale: Perforins are immune system molecules that function by creating pores in the cell membrane of target cells. These pores compromise the cell's integrity, ultimately leading to cell destruction. Lymphotoxins induce cell death, but they do not create pores in the cell membrane like perforins. Interferons are signaling proteins that regulate the immune response, while cytokines are a diverse group of proteins involved in cell signaling during immune reactions. Perforins specifically target cell membranes, disrupting their integrity and leading to cell destruction, making them the correct answer in this context.
A student makes a solution that simulates stomach acid. Which of the following would be true of this solution, compared to distilled water?
- A. It has a higher pH.
- B. It has more hydrogen ions.
- C. It contains more hydroxyl ions.
- D. It has more hydroxyl ions.
Correct Answer: B
Rationale: The correct answer is B. A solution that simulates stomach acid is acidic, which means it has a higher concentration of hydrogen ions compared to distilled water, which is neutral. Stomach acid is characterized by its high hydrogen ion concentration, which is responsible for its acidic nature. Hydroxyl ions are associated with bases, not acids, so options C and D are incorrect. Option A is incorrect as well because stomach acid would have a lower pH compared to distilled water due to its high acidity.
Which of the following allows the skull to rotate on the neck?
- A. Vertebral foramen
- B. Spinous process
- C. Atlas
- D. Sacrum
Correct Answer: C
Rationale: The atlas is the first cervical vertebra that supports the skull and allows it to rotate on the neck. The vertebral foramen is an opening in the vertebra for the spinal cord, and the spinous process is a bony projection, not involved in rotation.
What is the function of sodium bicarbonate released by the pancreas?
- A. Sodium bicarbonate neutralizes the acidity of chyme.
- B. Sodium bicarbonate stimulates the protease that digests carbonates.
- C. Sodium bicarbonate inhibits peristalsis.
- D. Sodium bicarbonate stimulates the protease.
Correct Answer: A
Rationale: The correct answer is A because sodium bicarbonate released by the pancreas functions by neutralizing the acidity of chyme in the small intestine. This action helps to create a more alkaline environment, which is crucial for the activity of pancreatic enzymes and the absorption of nutrients. Option B is incorrect as sodium bicarbonate itself does not stimulate a protease to digest carbonates. Option C is incorrect as sodium bicarbonate does not inhibit peristalsis; instead, it aids in digestion. Option D is incorrect as sodium bicarbonate does not directly stimulate the protease but rather helps in maintaining the optimal pH for enzyme activity.