Nokea
Which part of the cell serves as the control center for all cell activity?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct Answer: A
Rationale: The corrected question and answer are accurate. The correct answer is A: Nucleus. The nucleus is known as the control center of the cell as it contains the cell's genetic material (DNA) and directs all cell activities including growth, metabolism, and reproduction. The other organelles listed in the choices, while important for various cellular functions, do not serve as the central control center for overall cell activity.
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Which of the following is an example of the location and function of cartilage in the body?
- A. The dense connective tissue that makes up the majority of the structural skeleton
- B. The supportive pads that provide cushioning at joints, such as between the vertebrae of the spinal cord
- C. The connective structure made of fibrous collagen that connects muscles and bones
- D. The layer beneath the skin and on the outside of internal organs that provides cushioning and protection
Correct Answer: B
Rationale: Cartilage is a type of flexible connective tissue that acts as supportive pads providing cushioning at joints, like those found between the vertebrae of the spine. This specific function of cartilage helps in reducing friction and absorbing shock in these areas, contributing to joint flexibility and protection. Choices A, C, and D do not accurately describe the function and location of cartilage in the body. Option A incorrectly refers to dense connective tissue, which is different from cartilage. Option C describes tendons or ligaments, which are not cartilage. Option D refers to adipose tissue, which is a type of connective tissue that stores fat and provides insulation, but it is not cartilage.
Which of the following describes a responsibility of the integumentary system?
- A. Distributing vital substances, such as nutrients, throughout the body.
- B. Blocking pathogens that cause disease.
- C. Sending leaked fluids from the cardiovascular system back to the blood vessels.
- D. Storing bodily hormones that influence gender traits.
Correct Answer: B
Rationale: The correct responsibility of the integumentary system is to act as a barrier that blocks pathogens from entering the body, thus helping to prevent diseases and infections. This function serves as the first line of defense for the body against external threats. Choices A, C, and D are incorrect. Choice A is a function of the circulatory system, not the integumentary system. Choice C relates to the lymphatic system, not the integumentary system. Choice D involves the endocrine system, not the integumentary system.
Which statement most accurately compares and contrasts the structures of DNA and RNA?
- A. Both DNA and RNA have 4 nucleotide bases. Three of the bases are the same, but the fourth base is thymine in DNA and uracil in RNA.
- B. Both DNA and RNA have the same 4 nucleotide bases. However, the nucleotides bond differently in DNA compared to RNA.
- C. Both DNA and RNA have different numbers of nucleotide bases. DNA is a double helix while RNA is a single strand.
- D. Both DNA and RNA have a double helix structure. However, DNA contains 6 nucleotide bases and RNA contains 4 nucleotide bases.
Correct Answer: A
Rationale: The correct answer is A because DNA and RNA both consist of 4 nucleotide bases, namely adenine, cytosine, and guanine, which are common in both. The key difference lies in the fourth base, which is thymine in DNA and uracil in RNA. This distinction is fundamental in understanding the structural variances between DNA and RNA. Choice B is incorrect as it incorrectly states that the nucleotides bond differently in DNA compared to RNA without specifying the crucial base differences. Choice C is inaccurate as it misrepresents the numbers of nucleotide bases in DNA and RNA, and incorrectly describes DNA as a double helix and RNA as a single strand, which is not related to the difference in bases. Choice D is incorrect as it inaccurately portrays DNA with 6 nucleotide bases and RNA with 4, which is not true; both DNA and RNA have 4 nucleotide bases, but with differences in one of the bases.
In the suburban neighborhood of Northwoods, there has been a large population of deer, and residents have complained about them eating flowers and garden plants. What would be a logical explanation for the large increase in the deer population over the last two seasons?
- A. There has been an increase in the quantity of food sources in surrounding areas.
- B. The population of natural predators in Northwoods has decreased.
- C. Deer have migrated from surrounding areas.
- D. There has been a recent increase in hunting licenses sold.
Correct Answer: B
Rationale: The correct answer is B because a decrease in natural predators can lead to an increase in the deer population as there are fewer predators to control their numbers. This explanation aligns with the situation described in the question, where the deer population has increased, causing issues for residents. Choice A is incorrect because an increase in food sources would not directly explain the increase in the deer population. Choice C is incorrect as it introduces a new factor of migration which is not mentioned in the question. Choice D is incorrect as an increase in hunting licenses sold would likely have the opposite effect on the deer population.
Fill in the blanks in the following sentence: Enzymes are ________ molecules that serve as _______ for certain biological reactions.
- A. complex; suppressors
- B. acidic; triggers
- C. small; targets
- D. large; catalysts
Correct Answer: D
Rationale: Enzymes are large molecules that act as catalysts, accelerating chemical reactions by lowering the activation energy required for the reactions to occur. In the context of biological reactions, enzymes function as catalysts, not suppressors, triggers, or targets. The use of 'large' and 'catalysts' accurately describes the nature and role of enzymes in facilitating biological processes.