Nokea
Which of the following structures has the lowest blood pressure?
- A. Arteries
- B. Arterioles
- C. Venules
- D. Veins
Correct Answer: D
Rationale: Veins have the lowest blood pressure among the listed structures. Blood pressure decreases as blood flows from arteries to arterioles, then to venules, and finally to veins. Veins return blood to the heart under low pressure because they have thinner walls and larger lumens compared to arteries and arterioles. This anatomical difference allows veins to accommodate a greater volume of blood without a significant rise in pressure. Arteries have the highest blood pressure to propel blood away from the heart, followed by arterioles which regulate blood flow to capillaries. Venules collect blood from capillaries and connect to veins, which then carry blood back to the heart at a lower pressure.
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Which of the following is not a type of muscle tissue?
- A. Skeletal
- B. Smooth
- C. Cardiac
- D. Adipose
Correct Answer: D
Rationale: The correct answer is D, Adipose. Adipose tissue is a type of connective tissue that stores fat, not muscle tissue. Skeletal, smooth, and cardiac are all types of muscle tissues found in the body. Skeletal muscle tissue is responsible for voluntary movements and is attached to bones. Smooth muscle tissue is found in the walls of hollow organs and blood vessels, responsible for involuntary movements. Cardiac muscle tissue is found in the heart and is responsible for pumping blood throughout the body. Adipose tissue, on the other hand, primarily functions as a storage site for energy in the form of fat.
When a biologist describes the physical and visible expression of a genetic trait, which of the following is being referred to?
- A. Phenotype
- B. Allele
- C. Gamete
- D. Genotype
Correct Answer: A
Rationale: The correct answer is A: Phenotype. Phenotype specifically refers to the observable physical characteristics resulting from the interaction of an individual's genetic makeup (genotype) with environmental influences. It represents the outward expression of an organism's genetic makeup. Allele, represented by choice B, refers to different forms of a gene and is not the visible expression of a trait. Gamete, represented by choice C, is a reproductive cell and not directly related to the physical expression of traits. Genotype, represented by choice D, refers to the genetic makeup of an organism and is distinct from the observable physical characteristics denoted by phenotype.
What is the pathway of oxygenated blood from the lungs?
- A. Lungs to the left atrium, through the mitral valve into the left ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and capillaries
- B. Lungs to the right atrium, through the mitral valve into the right ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and veins
- C. Lungs to the left atrium, directly to the right aorta, then dispersed to tissues via a network of arteries and capillaries
- D. Lungs to the left atrium, through the septal valve, stored in the left ventricles, then dispersed to tissues via a network of arteries and capillaries
Correct Answer: A
Rationale: The correct pathway of oxygenated blood from the lungs is as follows: Oxygenated blood travels from the lungs to the left atrium, then passes through the mitral valve into the left ventricle. From there, it is pumped into the aorta upon contraction of the heart and is then dispersed to various tissues throughout the body via a network of arteries and capillaries. Choice B is incorrect as it incorrectly mentions the right atrium and ventricle, which are associated with deoxygenated blood. Choice C is incorrect as it mentions a direct connection to the right aorta, which does not exist in the circulatory system. Choice D is incorrect as it refers to the septal valve (which is not anatomically correct) and storing blood in the left ventricle, which does not occur in the normal circulation of blood.
When human cells divide by meiosis, how many chromosomes do the resulting cells contain?
- A. 96
- B. 54
- C. 46
- D. 23
Correct Answer: D
Rationale: When human cells divide by meiosis, the resulting cells contain 23 chromosomes. This is because meiosis is a cell division process that reduces the chromosome number by half, resulting in cells with a haploid number of chromosomes. In humans, the diploid number of chromosomes is 46. Therefore, after meiosis, the resulting cells have 23 chromosomes, ensuring the correct chromosome number is restored upon fertilization. Choices A, B, and C are incorrect as they do not represent the correct chromosome number resulting from meiosis in human cells.
What type of bond connects sugar and phosphate in DNA?
- A. Hydrogen
- B. Ionic
- C. Covalent
- D. Overt
Correct Answer: C
Rationale: The correct answer is Covalent (C). In DNA, a covalent bond connects sugar and phosphate molecules. This bond involves the sharing of electron pairs between the atoms, providing stability to the DNA structure. Hydrogen bonds are important in DNA structure but are not the primary bond connecting sugar and phosphate. Ionic bonds involve the transfer of electrons, and 'overt' is not a term related to the bond connecting sugar and phosphate in DNA.