Nokea
Which type of muscle tissue contracts involuntarily and is found in organs like the heart and intestines?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. All of the above
Correct Answer: C
Rationale: Smooth muscle is the type of muscle tissue that contracts involuntarily and is found in organs like the heart and intestines. Skeletal muscle is responsible for voluntary movements, like those involved in skeletal system actions. Cardiac muscle is found in the heart and contracts involuntarily, but it is distinct from smooth muscle. The heart's muscle is specialized and forms the myocardium, which is not the same as the smooth muscle found in organs like the intestines. Therefore, the correct answer is C) Smooth muscle.
You may also like to solve these questions
Where is the heart located within the human body cavities?
- A. Dorsal cavity
- B. Ventral cavity
- C. Thoracic cavity
- D. Abdominal cavity
Correct Answer: C
Rationale: The heart is located within the thoracic cavity, specifically in the mediastinum, which is the central compartment of the thoracic cavity. The thoracic cavity is part of the ventral cavity, which also includes the abdominal cavity. The dorsal cavity refers to the posterior side of the body and does not contain the heart. The heart is situated in the thoracic cavity between the lungs and above the diaphragm, making option C the correct choice. Therefore, the correct answer is the thoracic cavity (option C). The ventral cavity (option B) includes the thoracic and abdominal cavities, but the heart is specifically situated in the thoracic cavity. The dorsal cavity (option A) is located on the posterior side of the body, not where the heart is positioned. The abdominal cavity (option D) is below the thoracic cavity and houses organs such as the stomach, liver, and intestines, but it does not contain the heart.
The Becquerel (Bq) is the designated unit for quantifying:
- A. Electron volt (eV) measurements of energy
- B. Radioactivity
- C. Electric charge (Coulombs)
- D. Force (Newtons)
Correct Answer: B
Rationale: The Becquerel (Bq) is the unit used to measure radioactivity, specifically the activity of a quantity of radioactive material. It represents the number of radioactive disintegrations or transformations per unit of time. Choice A, electron volt (eV), is a unit of energy, not radioactivity. Choice C, electric charge (Coulombs), is measured in Coulombs, not Becquerels. Choice D, force (Newtons), is a unit of force, not radioactivity. Therefore, the correct answer is B.
What is the outermost protective layer of the kidney?
- A. Renal cortex
- B. Renal medulla
- C. Renal capsule
- D. Renal pelvis
Correct Answer: C
Rationale: The correct answer is C, Renal capsule. The renal capsule is the outermost protective layer of the kidney. It is a tough fibrous layer that surrounds the kidney and helps protect it from injury and maintain its shape. Choice A, Renal cortex, is the outer region of the kidney where filtration occurs. Choice B, Renal medulla, is the inner region of the kidney where urine is formed. Choice D, Renal pelvis, is the funnel-shaped structure that collects urine from the kidney and funnels it into the ureter. Therefore, the renal capsule is specifically designated as the outermost protective layer of the kidney.
What is the importance of RNA splicing?
- A. Removes introns from the mRNA molecule
- B. Adds the poly-A tail to the mRNA molecule
- C. Activates the mRNA molecule for translation
- D. Modifies the structure of the protein
Correct Answer: A
Rationale: RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis.
B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns.
C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing.
D) Modifying the structure of the protein is not directly related to the process of RNA splicing, which primarily focuses on mRNA maturation by removing non-coding introns.
Memory B cells and memory T cells are crucial for immunological memory. How does immunological memory enhance the immune response upon re-exposure to a pathogen?
- A. It increases the production of the same ineffective antibodies.
- B. It allows for a quicker and more robust immune response.
- C. It suppresses the immune system to prevent overreaction.
- D. It triggers a completely different immune response.
Correct Answer: B
Rationale: Immunological memory enhances the immune response upon re-exposure to a pathogen by allowing for a quicker and more robust immune response. Memory B cells and memory T cells are primed to recognize the pathogen quickly and mount a faster and more effective response, leading to a more efficient clearance of the pathogen. Choice A is incorrect because immunological memory does not increase the production of ineffective antibodies but rather promotes the production of specific antibodies that are effective against the pathogen. Choice C is incorrect as immunological memory does not suppress the immune system; instead, it enhances the response. Choice D is incorrect because immunological memory leads to a recall of the specific immune response mounted during the initial exposure, not a completely different response.