Nokea
What is the scientific unit used to measure the radioactivity of a substance?
- A. Becquerel (Bq)
- B. Joule (J)
- C. Newton (N)
- D. Kelvin (K)
Correct Answer: A
Rationale: The correct answer is A: Becquerel (Bq). The Becquerel (Bq) is the scientific unit used to measure the radioactivity of a substance. It is named after Henri Becquerel, who discovered radioactivity. The Joule (J) is the unit of energy, Newton (N) is the unit of force, and Kelvin (K) is the unit of temperature. When measuring radioactivity, the Becquerel is used to quantify the rate of radioactive decay in a substance. Choices B, C, and D are incorrect as they represent units for energy, force, and temperature, respectively, not radioactivity.
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Identify the function NOT attributed to the lymphatic system.
- A. Fluid drainage from tissues
- B. Immune response via white blood cell production
- C. Nutrient transport throughout the body
- D. Waste removal through lymph nodes
Correct Answer: C
Rationale: A) Fluid drainage from tissues: This function is attributed to the lymphatic system. Lymphatic vessels collect excess fluid from tissues and return it to the bloodstream.
B) Immune response via white blood cell production: The lymphatic system plays a crucial role in the body's immune response by producing and transporting white blood cells, such as lymphocytes, which help fight infections.
C) Nutrient transport throughout the body: Nutrient transport is primarily carried out by the circulatory system (blood vessels), not the lymphatic system. The circulatory system transports nutrients, oxygen, and hormones to cells and removes waste products.
D) Waste removal through lymph nodes: The lymphatic system helps remove waste and toxins from the body by filtering lymph through lymph nodes, where harmful substances are trapped and destroyed by immune cells.
Therefore, the function NOT attributed to the lymphatic system is C) Nutrient transport throughout the body.
Fluorescent microscopy utilizes which property of certain molecules to create a visible image?
- A. Staining properties
- B. Light absorption
- C. Fluorescence emission
- D. Refraction
Correct Answer: C
Rationale: Fluorescent microscopy relies on the property of certain molecules to fluoresce when exposed to specific wavelengths of light. When these molecules absorb light energy, they become excited and then emit light at a longer wavelength, producing a visible image. This emitted light is what is used to create the image in fluorescent microscopy, making option C, fluorescence emission, the correct answer. Staining properties (option A) are used to enhance contrast in microscopy but are not the primary mechanism in fluorescent microscopy. Light absorption (option B) is involved in the excitation of fluorescent molecules but is not the property used to create the visible image. Refraction (option D) is the bending of light as it passes through different mediums and is not the property utilized in fluorescent microscopy.
What is the building block of RNA?
- A. Amino acid
- B. Nucleotide
- C. Protein
- D. Fatty acid
Correct Answer: B
Rationale: Nucleotide: Nucleotides are the building blocks of RNA. A nucleotide consists of a nitrogenous base (adenine, guanine, cytosine, or uracil in RNA), a sugar (ribose in RNA), and a phosphate group. A) Amino acid: Amino acids are the building blocks of proteins, not RNA. C) Protein: Proteins are made up of amino acids, not nucleotides. D) Fatty acid: Fatty acids are components of lipids, not RNA.
Which part of the brain is responsible for coordinating muscle movements, maintaining balance, and posture?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Thalamus
Correct Answer: B
Rationale: The correct answer is B, the cerebellum. The cerebellum plays a crucial role in coordinating muscle movements, maintaining balance, and posture. It receives inputs from sensory systems, the spinal cord, and other brain regions to fine-tune motor movements. The cerebrum, choice A, is primarily involved in higher brain functions like thinking and decision-making. The medulla oblongata, choice C, controls essential functions such as breathing and heart rate. The thalamus, choice D, serves as a relay center for sensory information but is not directly responsible for coordinating muscle movements, balance, or posture.
How can the peripheral nervous system be further divided?
- A. Sensory and motor
- B. Sympathetic and parasympathetic
- C. Myelinated and unmyelinated
- D. Central and peripheral
Correct Answer: A
Rationale: The peripheral nervous system can be further divided into sensory (afferent) neurons that carry information from sensory receptors to the central nervous system and motor (efferent) neurons that carry information from the central nervous system to muscles and glands. Choice A, 'Sensory and motor,' is the correct answer as it accurately identifies the two main functional divisions of the peripheral nervous system. Choices B, 'Sympathetic and parasympathetic,' are divisions of the autonomic nervous system, not the peripheral nervous system. Choice C, 'Myelinated and unmyelinated,' refers to the structural classification of nerve fibers rather than functional divisions. Choice D, 'Central and peripheral,' contrasts the central nervous system with the peripheral nervous system, not further dividing the peripheral nervous system itself.