Nokea
What is the 3D structure of a protein called?
- A. Tertiary structure
- B. Secondary structure
- C. Primary structure
- D. Quaternary structure
Correct Answer: A
Rationale: - Primary structure refers to the linear sequence of amino acids in a protein.
- Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets.
- Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment.
- Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex.
Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.
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Which element shares the same group (family) on the periodic table with helium (He)?
- A. Neon (Ne)
- B. Boron (B)
- C. Carbon (C)
- D. Oxygen (O)
Correct Answer: A
Rationale: Neon (Ne) shares the same group (family) on the periodic table with helium (He). Both helium and neon belong to Group 18 (Noble Gases) due to their complete and stable outer electron shells, making them chemically inert. Boron (B), Carbon (C), and Oxygen (O) are not in the same group as helium. Boron is in Group 13, Carbon is in Group 14, and Oxygen is in Group 16 on the periodic table.
Which bone is the longest in the human body?
- A. Femur (Thigh bone)
- B. Humerus (Upper arm bone)
- C. Tibia (Shin bone)
- D. Scapula (Shoulder blade)
Correct Answer: A
Rationale: The correct answer is the femur (thigh bone) as it is the longest bone in the human body, extending from the hip to the knee. It plays a vital role in supporting the body's weight and enabling movement. The humerus is located in the upper arm and is not as long as the femur. The tibia is the shin bone and is shorter than the femur. The scapula is the shoulder blade and is not the longest bone in the body, making it an incorrect choice.
What is the primary function of the respiratory system?
- A. Maintain body temperature
- B. Deliver oxygen to the bloodstream and remove carbon dioxide
- C. Produce antibodies for the immune system
- D. Break down food molecules for energy
Correct Answer: B
Rationale: The primary function of the respiratory system is to deliver oxygen to the bloodstream and remove carbon dioxide. This process occurs through breathing, where oxygen is inhaled into the lungs and then transferred to the bloodstream, while carbon dioxide is removed from the bloodstream and exhaled out of the body. Maintaining body temperature (A), producing antibodies for the immune system (C), and breaking down food molecules for energy (D) are functions of other systems in the body, not the respiratory system. Therefore, the correct answer is B.
Which of the following is a common property of both acids and bases?
- A. React with metals to produce hydrogen gas
- B. Taste sour
- C. Turn blue litmus paper red
- D. Conduct electricity when dissolved in water
Correct Answer: D
Rationale: The correct answer is D. Both acids and bases can conduct electricity when dissolved in water. Acids ionize in water to produce H+ ions, which can carry an electric current, while bases ionize to produce OH- ions, which also conduct electricity. The other options are not common properties of both acids and bases. Reacting with metals to produce hydrogen gas is characteristic of acids, tasting sour is a property of acids, and turning blue litmus paper red is a property of bases, not a common property shared by both.
What determines the final velocity of a block sliding down a frictionless inclined plane?
- A. The length of the incline
- B. The angle of the incline
- C. The mass of the block
- D. All of the above
Correct Answer: B
Rationale: The final velocity of a block sliding down a frictionless inclined plane is determined by the angle of the incline. The angle directly impacts the acceleration of the block, affecting the final velocity it attains at the bottom. The length of the incline and the mass of the block do not play a direct role in determining the final velocity. Therefore, the correct answer is the angle of the incline (Choice B). Choices A and C are incorrect because the length of the incline and the mass of the block do not have a direct influence on the final velocity of the block in this scenario.