Nokea
What is the main function of lysosomes?
- A. Breaking down and recycling cellular waste
- B. Storing carbohydrates
- C. Synthesizing lipids
- D. Transcribing DNA into mRNA
Correct Answer: A
Rationale: The main function of lysosomes is to break down and recycle cellular waste materials, such as old organelles, foreign substances, and cellular debris. This process is crucial for maintaining cellular homeostasis and proper functioning. Storing carbohydrates (B), synthesizing lipids (C), and transcribing DNA into mRNA (D) are not functions typically associated with lysosomes. Storing carbohydrates is primarily done by other organelles like vacuoles. Synthesizing lipids is a function usually associated with the endoplasmic reticulum and transcribing DNA into mRNA occurs in the nucleus by the process of transcription.
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Which type of joint allows for the greatest range of motion?
- A. Hinge joint
- B. Ball-and-socket joint
- C. Pivot joint
- D. Saddle joint
Correct Answer: B
Rationale: The correct answer is B: Ball-and-socket joint. The ball-and-socket joint, like the shoulder joint, allows for the greatest range of motion due to its structure, enabling movement in multiple directions. In contrast, hinge joints, pivot joints, and saddle joints have more restricted ranges of motion compared to ball-and-socket joints. Hinge joints primarily allow movement in one plane, pivot joints allow rotation around a central axis, and saddle joints have limited movement compared to ball-and-socket joints.
What is the scientific term for inflammation of the bronchi, often associated with a cough and mucus production?
- A. Pneumonia
- B. Bronchitis
- C. Emphysema
- D. Pleurisy
Correct Answer: B
Rationale: Bronchitis is the correct answer. It is the inflammation of the bronchi, which are the air passages in the lungs. Bronchitis typically presents with symptoms such as a persistent cough, mucus production, and sometimes difficulty breathing. Pneumonia, on the other hand, is an infection that causes inflammation in the air sacs of the lungs, not specifically the bronchi. Emphysema is a chronic lung condition characterized by the gradual destruction of the air sacs in the lungs, resulting in breathing difficulties. Pleurisy refers to inflammation of the pleura, the lining around the lungs and chest cavity, causing chest pain when breathing or coughing.
Which of the following vessels is responsible for transporting blood from the heart to the lungs?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Superior vena cava
Correct Answer: B
Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.
DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?
- A. It runs 5' to 3'.
- B. It runs 3' to 5'.
- C. It is used in replication.
- D. It is the direction in which DNA is stored.
Correct Answer: B
Rationale: The correct answer is B. The antisense strand runs 3' to 5', which is opposite to the direction of the sense strand. It serves as the template strand for transcription, where an RNA molecule is synthesized complementary to the antisense strand. Choice A is incorrect because the antisense strand runs in the opposite direction. Choice C is incorrect as the antisense strand is primarily involved in transcription, not replication. Choice D is incorrect as the direction of DNA storage is not determined by the antisense strand.
What step of the scientific method must come before generating a hypothesis?
- A. Collecting and organizing data.
- B. Communicating the results in a scientific journal.
- C. Conducting an experiment.
- D. Researching previous studies for background.
Correct Answer: D
Rationale: The correct answer is D, 'Researching previous studies for background.' Before formulating a hypothesis, it is essential to review existing literature, studies, and information related to the topic to understand the context and identify gaps in knowledge. This step helps researchers build on existing knowledge and formulate a clear hypothesis based on the information gathered. Choices A, B, and C are incorrect because they come after the step of researching previous studies and developing a hypothesis. Collecting and organizing data, conducting an experiment, and communicating results typically follow the hypothesis generation step in the scientific method.