1. Melatonin is a hormone produced by the pineal gland. What is its primary function?

A. Regulate blood pressure
B. Stimulate the digestive system
C. Control sleep-wake cycles
D. Maintain bone density

Correct answer: C

Rationale: The correct answer is C: 'Control sleep-wake cycles.' Melatonin is a hormone that plays a key role in regulating the body's sleep-wake cycle, also known as the circadian rhythm. The pineal gland releases melatonin in response to darkness, helping to signal to the body that it is time to sleep. By influencing the timing and quality of sleep, melatonin helps maintain a healthy sleep pattern and overall well-being. While blood pressure, digestive system stimulation, and bone density are important functions in the body, melatonin's primary function is to regulate the sleep-wake cycle.

2. Which part of the spinal cord is responsible for transmitting sensory information from the body to the brain?

A. Dorsal root
B. Ventral root
C. Gray matter
D. White matter

Correct answer: a

Rationale: The correct answer is A: Dorsal root. The dorsal root of the spinal cord is responsible for transmitting sensory information from the body to the brain. This root contains sensory nerve fibers that carry information such as touch, temperature, and pain signals from the peripheral nervous system to the central nervous system. Ventral roots, on the other hand, are responsible for transmitting motor information from the brain to the muscles. Gray matter is primarily composed of nerve cell bodies and is involved in processing information, while white matter consists of myelinated nerve fibers that facilitate communication between different parts of the nervous system. Therefore, in this context, the dorsal root is the specific structure that handles sensory information transmission.

3. What do isotopes of the same element have in common?

A. Identical number of protons and neutrons.
B. Identical chemical properties.
C. Identical number of electrons.
D. Identical mass number.

Correct answer: A

Rationale: Identical number of protons and neutrons - Isotopes have the same atomic number but different mass numbers due to varying neutron counts.

4. The axial skeleton consists of bones in the:

A. Head, neck, and trunk
B. Arms and legs
C. Hands and feet
D. All of the above

Correct answer: A

Rationale: The correct answer is A: 'Head, neck, and trunk.' The axial skeleton includes the bones along the body's central axis, comprising the skull, vertebral column, rib cage, and sternum. These bones provide structural support and protect vital organs. Choices B and C are incorrect as the arms, legs, hands, and feet are part of the appendicular skeleton. Therefore, the axial skeleton primarily encompasses the head, neck, and trunk, making option A the correct choice.

5. A pendulum swings back and forth. What type of energy conversion occurs during its motion?

A. Potential energy to kinetic energy and vice versa
B. Thermal energy to mechanical energy and vice versa
C. Chemical energy to electrical energy and vice versa
D. Nuclear energy to radiant energy and vice versa

Correct answer: A

Rationale: As the pendulum swings back and forth, it undergoes a continuous conversion between potential energy (at the highest point of the swing) and kinetic energy (at the lowest point of the swing). At the highest point, the pendulum has maximum potential energy due to its height above the ground. As it swings down, this potential energy is converted into kinetic energy, which is the energy of motion. At the lowest point of the swing, the pendulum has maximum kinetic energy and minimal potential energy. The process repeats as the pendulum swings back in the opposite direction, demonstrating the conversion between potential and kinetic energy.

6. 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: 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.