Nokea
What is the major difference between somatic and germline mutations?
- A. Somatic mutations usually benefit the individual while germline mutations usually harm them.
- B. Since germline mutations only affect one cell, they are less noticeable than the rapidly dividing somatic cells.
- C. Somatic mutations are not expressed for several generations, but germline mutations are expressed immediately.
- D. Germline mutations are usually inherited while somatic mutations will affect only the individual.
Correct Answer: D
Rationale: The major difference between somatic and germline mutations is that germline mutations are usually inherited and can be passed on to offspring, while somatic mutations occur in non-reproductive cells and only affect the individual in which they occur. This means that germline mutations have the potential to be present in future generations, while somatic mutations do not.
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What is a monohybrid cross, and what is the ratio of dominant to recessive gene manifestation?
- A. A cross involving two traits, 9:3:3:1
- B. A cross involving one trait, 3:1
- C. A cross involving two traits, 1:2:1
- D. A cross involving one trait, 1:1
Correct Answer: B
Rationale: A monohybrid cross is a genetic cross involving one trait. The ratio of dominant to recessive gene manifestation in the offspring is typically 3:1 when both parents are heterozygous. This ratio is the genotypic ratio, not just the phenotype ratio, where the dominant allele is present in 3 out of 4 offspring, and the recessive allele is present in 1 out of 4 offspring. Choice A is incorrect because it describes a dihybrid cross ratio. Choice C is incorrect as it represents the genotypic ratio for a monohybrid cross involving incomplete dominance. Choice D is incorrect as it does not reflect the typical ratio for a monohybrid cross.
Which of the following structures in the body is responsible for protecting the lungs and heart?
- A. Rib cage
- B. Pelvis
- C. Femur
- D. Vertebral column
Correct Answer: A
Rationale: The rib cage is the correct answer. It plays a crucial role in protecting vital organs like the lungs and heart. The rib cage forms a protective barrier around these organs, shielding them from external trauma or injuries. It acts as a sturdy cage, offering structural support and safeguarding the delicate tissues and structures of the lungs and heart. The pelvis, femur, and vertebral column do not directly protect the lungs and heart; instead, they have other important functions in the body, such as supporting the body's weight, enabling movement, and protecting the spinal cord.
Which types of glial cells are in the PNS?
- A. Schwann cells, satellite cells
- B. Astrocytes, oligodendrocytes
- C. Microglia, ependymal cells
- D. Satellite cells, oligodendrocytes
Correct Answer: A
Rationale: The correct answer is A, which includes Schwann cells and satellite cells as the types of glial cells found in the peripheral nervous system. Schwann cells support neurons and myelinate axons, while satellite cells provide structural support and regulate the microenvironment around neurons in the PNS. Options B, C, and D are incorrect as they refer to glial cell types that are typically found in the central nervous system, not the peripheral nervous system. Astrocytes and oligodendrocytes are primarily located in the CNS, where they perform functions such as providing structural support and forming the blood-brain barrier. Microglia are immune cells found in the CNS responsible for immune defense and maintenance of neural environment, while ependymal cells line the cerebral ventricles and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid.
Which structure in the digestive system absorbs the most nutrients?
- A. Stomach
- B. Small intestine
- C. Large intestine
- D. Esophagus
Correct Answer: B
Rationale: The small intestine is the primary site where the absorption of nutrients from digested food occurs. Its large surface area, specialized cells, and villi play key roles in maximizing nutrient absorption, making it the structure in the digestive system that absorbs the most nutrients. The stomach's main function is to break down food with acid and enzymes, not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients. The esophagus is a muscular tube that connects the throat with the stomach and does not play a role in nutrient absorption.
Which term describes a position closer to the midline of the body? Example: The chest is medial to the arm.
- A. Lateral
- B. Medial
- C. Proximal
- D. Distal
Correct Answer: B
Rationale: The correct answer is 'B: Medial.' 'Medial' refers to a position closer to the midline of the body, while 'lateral' refers to a position further from the midline. 'Proximal' describes a position closer to the point of attachment or trunk of the body, while 'distal' refers to a position further away from the point of attachment or trunk.