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As a car accelerates from rest, what happens to its kinetic energy and the work done on it?
- A. Both kinetic energy and work done increase.
- B. Kinetic energy increases, but work done remains constant.
- C. Work done increases, but kinetic energy remains constant.
- D. Both kinetic energy and work done remain constant.
Correct Answer: A
Rationale: When a car accelerates from rest, its speed and kinetic energy increase. The work done on the car is what increases its kinetic energy, so both kinetic energy and work done increase simultaneously. Option A is correct because acceleration results in an increase in both kinetic energy and the work done on the car. Option B is incorrect because work done is required to increase kinetic energy during acceleration. Option C is incorrect as work done is directly related to the change in kinetic energy. Option D is incorrect as both kinetic energy and work done increase when the car accelerates.
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What is the process of breaking down lipids into fatty acids and glycerol called?
- A. Lipolysis
- B. Gluconeogenesis
- C. Krebs cycle
- D. Oxidative phosphorylation
Correct Answer: A
Rationale: - Lipolysis is indeed the correct answer. It is the process of breaking down lipids (fats) into fatty acids and glycerol. This process occurs in adipose tissue and is important for releasing stored energy in the form of fatty acids.
- Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources like amino acids and glycerol, not breaking down lipids.
- The Krebs cycle (also known as the citric acid cycle) is a series of chemical reactions that occur in the mitochondria to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.
- Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced through the transfer of electrons in the electron transport chain. It is not specifically related to the breakdown of lipids into fatty acids and glycerol.
Why do emerging infectious diseases (EIDs) pose a significant public health threat?
- A. Because they are well-understood by medical professionals
- B. Because they are easily treatable with existing antibiotics
- C. Because they are new, rapidly evolving, and can spread quickly
- D. Because they primarily affect animals and not humans
Correct Answer: C
Rationale: Emerging infectious diseases (EIDs) are a significant public health threat because they are characterized by being new or newly identified diseases that are rapidly evolving. These diseases can spread quickly within populations due to factors such as globalization, travel, urbanization, and changes in climate. EIDs often present challenges to medical professionals as they may not be well-understood initially, making it difficult to develop effective treatments or preventive measures. While some EIDs can be treatable with existing antibiotics, the rapid evolution of these diseases can lead to the development of drug resistance, further complicating treatment efforts. Additionally, EIDs are not limited to affecting animals; they can also have serious implications for human health and well-being. Therefore, the correct answer is that EIDs pose a threat because they are new, rapidly evolving, and can spread quickly. Choices A, B, and D are incorrect because EIDs are not well-understood initially, may develop drug resistance, and can affect humans significantly, not just animals.
Which vitamin deficiency can lead to kidney stones?
- A. Vitamin A
- B. Vitamin B12
- C. Vitamin D
- D. Vitamin K
Correct Answer: C
Rationale: The correct answer is Vitamin D. Vitamin D deficiency can lead to kidney stones because Vitamin D helps regulate calcium levels in the body. Low levels of Vitamin D can result in increased calcium absorption from the intestines, leading to higher levels of calcium in the urine, which can form kidney stones. Choices A, B, and D are incorrect as deficiencies in these vitamins are not directly associated with kidney stone formation.
What is the myelin sheath and what does it do?
- A. A group of nerve cells that perform a specific function.
- B. A fatty substance that insulates some nerve fibers.
- C. A fluid-filled cavity within the brain.
- D. The junction between two neurons.
Correct Answer: B
Rationale: The myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.
What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?
- A. Both have the same phenotype, but different genotypes.
- B. Both have the same genotype, but different phenotypes.
- C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
- D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.
Correct Answer: D
Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele).
- Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele).
- The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles.
- This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.