Nokea
Delta waves, associated with deep sleep, exhibit what frequency range?
- A. 0.5-4 Hz
- B. 4-8 Hz
- C. 8-13 Hz
- D. 13-30 Hz
Correct Answer: A
Rationale: Delta waves are slow brain waves associated with deep sleep stages, specifically stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz. Choice B (4-8 Hz) refers to theta waves, which are associated with light sleep and relaxation. Choice C (8-13 Hz) corresponds to alpha waves, present during wakeful relaxation. Choice D (13-30 Hz) represents beta waves, seen in active thinking and concentration. Therefore, the correct answer is A because it aligns with the frequency range characteristic of delta waves during deep sleep.
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What checkpoint mechanism ensures all chromosomes are attached to the spindle fibers before anaphase begins?
- A. Prometaphase
- B. Metaphase
- C. Cyclin degradation
- D. Sister chromatid cohesion
Correct Answer: A
Rationale: A) Prometaphase is the correct answer because it is the stage of mitosis where all chromosomes are attached to the spindle fibers before anaphase begins. During prometaphase, the nuclear envelope breaks down, allowing the spindle fibers to attach to the kinetochores of the chromosomes. This attachment is necessary for proper chromosome alignment and segregation during anaphase.
B) Metaphase is incorrect because it is the stage where chromosomes are aligned at the metaphase plate but do not necessarily have all spindle fibers attached.
C) Cyclin degradation is incorrect because it is a regulatory mechanism that controls the progression of the cell cycle but is not specifically related to ensuring all chromosomes are attached to spindle fibers.
D) Sister chromatid cohesion is incorrect because it refers to the physical connection between sister chromatids that is maintained until anaphase, but it does not ensure that all chromosomes are attached to spindle fibers.
What type of molecule forms the cell membrane and controls what enters and exits the cell?
- A. Proteins
- B. Carbohydrates
- C. Lipids
- D. Nucleic acids
Correct Answer: C
Rationale: The cell membrane is primarily composed of lipids, specifically phospholipids, which form a lipid bilayer. This lipid bilayer controls what enters and exits the cell, providing a barrier that is selectively permeable. While proteins are also important components of the cell membrane and play various roles, lipids are the main structural component responsible for the membrane's permeability and function. Carbohydrates and nucleic acids are not the primary components of the cell membrane and do not have the same structural role as lipids.
What term describes the functional unit of a skeletal muscle responsible for muscle contraction?
- A. Myofibril
- B. Sarcomere
- C. Tendon
- D. Myoglobin
Correct Answer: B
Rationale: The correct answer is B, 'Sarcomere.' The sarcomere is indeed the functional unit of a skeletal muscle responsible for muscle contraction. It is composed of actin and myosin filaments that interact to generate muscle contraction. Choice A, 'Myofibril,' is incorrect as myofibrils are composed of sarcomeres, not the functional units themselves. Choice C, 'Tendon,' is incorrect as tendons connect muscles to bones and do not directly participate in muscle contraction. Choice D, 'Myoglobin,' is incorrect as myoglobin is a protein that stores oxygen in muscle cells and is not directly involved in muscle contraction.
Which nervous system controls the involuntary 'fight-or-flight' response?
- A. Sympathetic nervous system
- B. Parasympathetic nervous system
- C. Enteric nervous system
- D. Sensory nervous system
Correct Answer: A
Rationale: The correct answer is the sympathetic nervous system. The sympathetic nervous system is responsible for activating the body's response to stress or danger, leading to the 'fight-or-flight' response. It prepares the body for action by increasing heart rate, dilating pupils, and redirecting blood flow to muscles. Choice B, the parasympathetic nervous system, is responsible for the body's 'rest-and-digest' activities, which are opposite to the 'fight-or-flight' response. Choice C, the enteric nervous system, primarily regulates the gastrointestinal system and is not directly involved in the 'fight-or-flight' response. Choice D, the sensory nervous system, transmits sensory information from the body to the central nervous system and is not responsible for the physiological changes associated with the 'fight-or-flight' response.
What is a reaction between an acid and a base known as?
- A. Precipitation
- B. Neutralization
- C. Oxidation-reduction
- D. Photolysis
Correct Answer: B
Rationale: The correct answer is B: Neutralization. When an acid and a base react, they neutralize each other's properties, resulting in the formation of water and a salt. Choice A, 'Precipitation,' refers to the formation of a solid from a solution during a chemical reaction. Choice C, 'Oxidation-reduction,' involves the transfer of electrons between reactants. Choice D, 'Photolysis,' is a reaction where a compound is broken down into smaller components by light energy. Therefore, the most appropriate term for a reaction between an acid and a base is neutralization.