Nokea
What is the formula to calculate work?
- A. Work = Force Distance
- B. Work = Mass Velocity
- C. Work = Power Time
- D. Work = Energy · Time
Correct Answer: A
Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. The formula to calculate work is represented by Work = Force Distance, where force is the applied force on an object and distance is the displacement over which the force is applied. Therefore, the correct formula to calculate work is Work = Force Distance.
Choice B, 'Work = Mass Velocity,' is incorrect because work involves force and distance, not mass and velocity. Choice C, 'Work = Power Time,' is incorrect because work is not directly calculated using power and time. Choice D, 'Work = Energy · Time,' is incorrect because work is not typically calculated by dividing energy by time; rather, it involves the product of force and distance.
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Differentiate between genotype and phenotype in the context of gene expression.
- A. Genotype refers to the physical manifestation of a trait, while phenotype represents its underlying genetic makeup.
- B. Genotype encompasses the spectrum of possible traits encoded by an organism's genes, while phenotype signifies the specific trait observed.
- C. Genotype denotes the presence of dominant alleles, while phenotype reflects the influence of recessive alleles.
- D. There is no distinction; both terms are interchangeable.
Correct Answer: B
Rationale: - Genotype refers to the genetic makeup of an organism, including all the genes and alleles it possesses.
- Phenotype, on the other hand, refers to the observable physical characteristics or traits of an organism, which result from the interaction between its genotype and the environment.
- While genotype represents the genetic potential or range of traits that an organism can express, phenotype reflects the actual expression of specific traits.
- Therefore, option B correctly captures the distinction between genotype and phenotype in the context of gene expression.
Chyle, a milky white fluid, is transported by lymphatic vessels from the:
- A. Lungs
- B. Intestines
- C. Kidneys
- D. Skin
Correct Answer: B
Rationale: Chyle, a milky white fluid, is formed in the small intestine during digestion. It is composed of lymph and emulsified fats. Lymphatic vessels in the intestines, specifically lacteals, transport chyle from the intestines to the bloodstream for the distribution of nutrients throughout the body. The transport of chyle from the lungs, kidneys, or skin is not correct as these organs are not primarily involved in the production or transportation of chyle.
Elements tend to gain or lose electrons to achieve stable electron configurations like those of noble gases. Their group number often indicates the number of electrons gained/lost and the resulting ionic charge, providing a good starting point for prediction.
- A. Ionic bonds involve electron sharing, while metallic bonds involve electron transfer.
- B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
- C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
- D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.
Correct Answer: C
Rationale: Ionic bonds typically form between metals and non-metals, where one atom donates electrons (cation) and the other accepts electrons (anion). This results in the transfer of electrons. Metallic bonds, on the other hand, occur between metal atoms where electrons are shared among a sea of delocalized electrons, leading to the characteristic properties of metals like malleability and conductivity. Choice A is incorrect because ionic bonds involve electron transfer, not sharing. Choice B is incorrect as ionic bonds are strong, not weak, and are non-directional, while metallic bonds are strong and non-directional. Choice D is incorrect as ionic bonds do not form discrete molecules but rather a lattice structure, whereas metallic bonds form extended structures.
How does the structure of centromeres contribute to chromosome movement during mitosis?
- A. The centromere provides a binding site for spindle fibers, allowing chromosomes to be attached and manipulated.
- B. The centromere serves as a dividing point between sister chromatids, ensuring their separation during anaphase.
- C. The centromere maintains chromosome stability by preventing chromosomal breaks and rearrangements.
- D. The centromere plays a role in DNA replication, ensuring accurate copying of the genetic material.
Correct Answer: A
Rationale: A) The centromere provides a binding site for spindle fibers, which are microtubules that help move chromosomes during cell division. This attachment allows the chromosomes to be pulled towards opposite poles of the cell during mitosis. Therefore, the structure of centromeres directly contributes to chromosome movement during mitosis by facilitating the attachment and manipulation of chromosomes by the spindle fibers.
B) While the centromere does serve as a dividing point between sister chromatids, ensuring their separation during anaphase, this function is more related to the segregation of chromosomes rather than their movement.
C) The centromere does play a role in maintaining chromosome stability by ensuring proper chromosome segregation, but it is not primarily responsible for preventing chromosomal breaks and rearrangements.
D) The centromere is not directly involved in DNA replication. Its main function is
Which term refers to the resistance of a liquid to flow?
- A. Density
- B. Viscosity
- C. Surface tension
- D. Boiling point
Correct Answer: B
Rationale: Viscosity is the term that refers to the resistance of a liquid to flow. It is a measure of how thick or sticky a fluid is and determines how easily a liquid can flow. Density (A) is a measure of how much mass is contained in a given volume and is not related to the resistance of a liquid to flow. Surface tension (C) is the property of a liquid that allows it to resist an external force due to the cohesive nature of its molecules, but it is not directly related to the resistance of a liquid to flow. Boiling point (D) is the temperature at which a liquid changes to a vapor and is not a measure of the resistance of a liquid to flow.