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Beta waves, associated with alertness and focused attention, typically fall within the range of:
- A. 0.5-4 Hz
- B. 4-8 Hz
- C. 8-13 Hz
- D. 13-30 Hz
Correct Answer: D
Rationale: Beta waves, associated with alertness and focused attention, typically fall within the range of 13-30 Hz. These waves are present when individuals are engaged in cognitive tasks, problem-solving, or focused mental activities. Options A, B, and C are incorrect because these frequency ranges are not characteristic of beta waves. Beta waves are higher in frequency and are associated with more active mental states compared to the ranges mentioned in options A, B, and C. Therefore, the correct answer is 13-30 Hz (Choice D).
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What generates action potentials, the all-or-nothing electrical signals traveling along neurons?
- A. Glucose
- B. Sodium and potassium ions
- C. Neurotransmitters
- D. Myelin
Correct Answer: B
Rationale: Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of sodium and potassium ions across the neuronal membrane. This movement creates changes in the membrane potential, leading to the propagation of the electrical signal along the neuron. Glucose is a source of energy for neurons but is not directly involved in generating action potentials. Neurotransmitters are involved in communication between neurons but do not directly generate action potentials. Myelin is a fatty substance that insulates and speeds up the conduction of action potentials but does not generate them.
What is the name for the hard, protective protein that makes up hair and nails?
- A. Collagen
- B. Keratin
- C. Elastin
- D. Fibrin
Correct Answer: B
Rationale: Keratin is the correct answer as it is the hard, protective protein that comprises hair and nails. Collagen is a different type of protein found in connective tissues, providing structure and support. Elastin imparts elasticity to tissues, allowing them to stretch and recoil. Fibrin is a protein involved in the blood clotting process and is not related to the structure of hair and nails. Therefore, choices A, C, and D are incorrect in the context of the question.
The Hardy-Weinberg equilibrium describes a population that is:
- A. Undergoing rapid evolution due to strong directional selection.
- B. Not evolving and at genetic equilibrium with stable allele frequencies.
- C. Experiencing a founder effect leading to a reduction in genetic diversity.
- D. Dominated by a single homozygous genotype that eliminates all variation.
Correct Answer: B
Rationale: The Hardy-Weinberg equilibrium describes a theoretical population in which allele frequencies remain constant from generation to generation, indicating that the population is not evolving. This equilibrium occurs under specific conditions: no mutation, no gene flow, random mating, a large population size, and no natural selection. In this scenario, all genotypes are in proportion to the allele frequencies, and genetic diversity is maintained. Options A, C, and D do not accurately describe a population in Hardy-Weinberg equilibrium. Option A suggests rapid evolution due to strong directional selection, which would disrupt the equilibrium. Option C mentions a founder effect, which can reduce genetic diversity but is not a characteristic of a population in Hardy-Weinberg equilibrium. Option D describes a population dominated by a single homozygous genotype, which also does not align with the genetic diversity seen in a population at Hardy-Weinberg equilibrium.
What is the main component that gives bones their rigidity and hardness?
- A. Collagen
- B. Calcium phosphate
- C. Cartilage
- D. Ligaments
Correct Answer: B
Rationale: Calcium phosphate is the main component that gives bones their rigidity and hardness. It combines with calcium hydroxide to form hydroxyapatite crystals, which provide strength and structure to bones. Collagen, on the other hand, provides flexibility and tensile strength. Cartilage is a type of connective tissue found in joints, and ligaments are fibrous tissues that connect bones to other bones, but they do not contribute to the rigidity and hardness of bones.
How can bacteria acquire new genetic material from their environment?
- A. Transformation
- B. Transduction
- C. Conjugation
- D. All of the above
Correct Answer: D
Rationale: A) Transformation: Transformation is the process by which bacteria can take up free DNA from their environment and incorporate it into their own genome, leading to the acquisition of new genetic material and traits.
B) Transduction: Transduction involves the transfer of genetic material from one bacterium to another by a bacteriophage, a virus that infects bacteria. The bacteriophage carries bacterial DNA from one host cell to another, facilitating the transfer of genetic material.
C) Conjugation: Conjugation is a mechanism of horizontal gene transfer in bacteria where genetic material is transferred between two bacterial cells in direct contact. This transfer is facilitated by a conjugative plasmid carrying the genetic information.
Therefore, all the processes mentioned (transformation, transduction, and conjugation) are ways in which bacteria can acquire new genetic material from their environment.