Nokea
In an oxidation reaction,
- A. an oxidizing agent gains electrons.
- B. an oxidizing agent loses electrons.
- C. a reducing agent gains electrons.
- D. a reducing agent loses electrons.
Correct Answer: B
Rationale: In an oxidation reaction, the substance being oxidized loses electrons, not gains them. An oxidizing agent is responsible for causing oxidation in another substance by accepting electrons, hence it undergoes reduction and loses electrons. Therefore, the correct statement is 'an oxidizing agent loses electrons,' making choice B the correct answer. Choices A, C, and D are incorrect because in an oxidation reaction, the oxidizing agent does not gain electrons, a reducing agent does not gain electrons, and a reducing agent does not lose electrons.
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In the human skeleton, which of the following lists some of the vertebrae in descending order?
- A. Atlas, axis, thoracic, lumbar, sacral, coccyx.
- B. Axis, sacral, coccyx, atlas, lumbar, thoracic.
- C. Thoracic, sacral, lumbar, axis, coccyx, atlas.
- D. Coccyx, lumbar, axis, sacral, thoracic, atlas.
Correct Answer: A
Rationale: The correct order of some of the vertebrae in the human skeleton in descending order is Atlas, Axis, Thoracic, Lumbar, Sacral, Coccyx. This sequence follows the typical arrangement from the top of the spine down towards the pelvis. Choice B is incorrect as it does not follow the descending order of vertebrae. Choice C is incorrect as it starts with Thoracic which is not the first vertebra in the descending order. Choice D is incorrect as it starts with Coccyx which is the last vertebra in the descending order.
Which of the following functions is not controlled by the autonomic nervous system?
- A. Digestion
- B. Walking
- C. Heartbeat
- D. Temperature regulation
Correct Answer: B
Rationale: The correct answer is B: Walking. Walking is not directly controlled by the autonomic nervous system. Walking is a voluntary action governed by the somatic nervous system, which controls voluntary skeletal muscle movement. The autonomic nervous system, on the other hand, regulates functions that are involuntary, such as digestion, heartbeat, and temperature regulation. Choices A, C, and D are all functions controlled by the autonomic nervous system. Digestion involves processes like peristalsis and secretion of digestive enzymes, heartbeat is regulated by the autonomic nervous system to maintain blood pressure and circulation, and temperature regulation includes responses like sweating or shivering to maintain body temperature within a narrow range.
Which of the following organs does not belong with the others?
- A. Thyroid gland
- B. Stomach
- C. Intestines
- D. Pancreas
Correct Answer: B
Rationale: The correct answer is B - Stomach. The stomach is primarily involved in the digestive system, breaking down food through digestion. In contrast, the thyroid gland, intestines, and pancreas are part of the endocrine system or digestive system, involved in hormone production, nutrient absorption, and digestion. Therefore, the stomach stands out as the odd one in this group as it is the only organ specifically dedicated to digestion, while the others have dual roles or different primary functions.
What are substances that stimulate adaptive immunity called?
- A. Peptides
- B. Phagocytes
- C. Prions
- D. Platelets
Correct Answer: A
Rationale: Substances that stimulate adaptive immunity are called peptides. Peptides are short chains of amino acids that play a crucial role in activating the immune response by interacting with immune cells such as T cells and B cells. Peptides are important in antigen presentation and recognition, leading to the development of specific immune responses against pathogens. Choice B, phagocytes, are cells that engulf and digest pathogens but are not substances that stimulate adaptive immunity. Choice C, prions, are infectious agents made of misfolded proteins and are not related to stimulating adaptive immunity. Choice D, platelets, are cell fragments involved in blood clotting and have no direct role in stimulating adaptive immunity.
What is hemoglobin?
- A. an enzyme
- B. a protein
- C. a lipid
- D. an acid
Correct Answer: B
Rationale: Hemoglobin is a protein found in red blood cells that plays a crucial role in transporting oxygen from the lungs to the tissues and organs in the body. It is composed of four protein subunits, each containing a heme group that binds to oxygen molecules. Choice A is incorrect as hemoglobin is not an enzyme, but rather a protein. Choice C is incorrect as hemoglobin is not a lipid, but a protein. Choice D is incorrect as hemoglobin is not an acid, but a protein.