which organelle is responsible for controlling the activities of the cell

ATI TEAS 7

ati teas 7 science

1. Which organelle is responsible for controlling the activities of the cell?

A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: The nucleus is the organelle responsible for controlling the activities of the cell. It contains the cell's genetic material (DNA) and serves as the command center of the cell, regulating gene expression and directing cellular activities. The nucleus plays a crucial role in cell growth, metabolism, and reproduction. While the Golgi apparatus is involved in processing and packaging proteins, the mitochondria are responsible for producing energy in the form of ATP, and ribosomes are involved in protein synthesis, none of these organelles have the primary function of controlling the activities of the cell like the nucleus does. Therefore, the correct answer is the nucleus.

2. Which organ system is most responsible for maintaining control of body temperature?

A. The skeletal system.
B. The circulatory system.
C. The immune system.
D. The muscular system.

Correct answer: B

Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.

3. The acceleration of a falling object due to gravity has been proven to be 9.8 m/s^2. A scientist drops a cactus four times and measures the acceleration with an accelerometer and gets the following results: 9.79 m/s^2, 9.81 m/s^2, 9.80 m/s^2, and 9.78 m/s^2. Which of the following accurately describes the measurements?

A. They're both accurate and precise.
B. They're accurate but not precise.
C. They're precise but not accurate.
D. They're neither accurate nor precise.

Correct answer: A

Rationale: The measurements are close to the true value of 9.8 m/s^2 and are also close to each other, indicating both accuracy and precision. Accuracy refers to how close a measurement is to the true value, while precision refers to how close repeated measurements are to each other. In this case, the measurements are accurate because they are close to the accepted value of 9.8 m/s^2, and they are precise because they are clustered closely around each other. Therefore, choice A, 'They're both accurate and precise,' is the correct answer. Choice B is incorrect because the measurements are precise as they are close to each other, but they are also accurate as they are close to the true value. Choice C is incorrect because the measurements are accurate as they are close to the true value, and choice D is incorrect because the measurements exhibit both accuracy and precision in this scenario.

4. Which enzyme found in saliva is responsible for breaking down carbohydrates into smaller molecules like sugars?

A. Pepsin
B. Amylase
C. Lipase
D. Trypsin

Correct answer: B

Rationale: The correct answer is B. Saliva contains an enzyme called amylase, which specifically targets carbohydrates and breaks them down into smaller molecules like sugars. Pepsin, choice A, is an enzyme found in the stomach that breaks down proteins, not carbohydrates. Lipase, choice C, is responsible for breaking down fats, not carbohydrates. Trypsin, choice D, is an enzyme that breaks down proteins in the small intestine, not carbohydrates. Therefore, choices A, C, and D are incorrect for this question.

5. What is the significance of the nuclear envelope breaking down during mitosis?

A. It allows the chromosomes to condense and become visible.
B. It allows the spindle apparatus to form and attach to the chromosomes.
C. It allows the sister chromatids to separate.
D. It allows the nuclear material to be evenly distributed to the daughter cells.

Correct answer: B

Rationale: A) The breakdown of the nuclear envelope does not directly cause the chromosomes to condense and become visible. Chromosome condensation is a separate process that occurs before mitosis begins. B) The breakdown of the nuclear envelope is crucial for the formation of the spindle apparatus, a structure made of microtubules that helps separate the chromosomes during cell division. The spindle apparatus attaches to the chromosomes and helps move them to opposite poles of the cell. C) The separation of sister chromatids occurs during anaphase, which is facilitated by the spindle apparatus. The breakdown of the nuclear envelope is not directly involved in this process. D) The even distribution of nuclear material to daughter cells is achieved through the movement of chromosomes by the spindle apparatus, which is made possible by the breakdown of the nuclear envelope.