what of the following cations is found at the center of a heme

ATI TEAS 7

Practice Science TEAS Test

1. Which of the following cations is found at the center of a heme?

A. Cr (III)
B. Cu (II)
C. Iron (II)
D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

2. What is the relationship between the Pauli exclusion principle and the structure of the atom?

A. It defines the maximum number of electrons allowed in each energy level.
B. It explains why oppositely charged particles attract each other.
C. It describes the wave-particle duality of electrons.
D. It determines the arrangement of protons and neutrons in the nucleus.

Correct answer: A

Rationale: The Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers. This principle defines the maximum number of electrons allowed in each energy level, influencing the structure of the atom. Choice B is incorrect as it refers to the concept of electrostatic attraction, not directly related to the Pauli exclusion principle. Choice C is incorrect as it pertains to the wave-particle duality, a different aspect of quantum mechanics. Choice D is incorrect as it relates to the arrangement of protons and neutrons in the nucleus, not governed by the Pauli exclusion principle.

3. Which structure in the heart is responsible for pumping oxygenated blood to the body?

A. Right ventricle
B. Left ventricle
C. Left atrium
D. Right atrium

Correct answer: B

Rationale: The left ventricle is the chamber responsible for pumping oxygenated blood from the heart to the body. It receives oxygen-rich blood from the left atrium and contracts to push this blood out to the rest of the body through the aorta. The right ventricle pumps deoxygenated blood to the lungs for oxygenation, making choices A, C, and D incorrect for this function. Therefore, the correct answer is B, the Left ventricle.

4. What is the acceleration due to gravity near the Earth's surface?

A. 9.8 meters per second squared (m/s²)
B. 6.3 meters per second squared (m/s²)
C. 5.0 meters per second squared (m/s²)
D. 12.5 meters per second squared (m/s²)

Correct answer: A

Rationale: The acceleration due to gravity near the Earth's surface is approximately 9.8 m/s². This value is commonly used in physics calculations and represents the rate at which an object accelerates towards the Earth when in free fall. The acceleration due to gravity is a constant value near the Earth's surface and affects the motion of all objects. Choices B, C, and D are incorrect as they do not represent the standard value of 9.8 m/s². Understanding the correct value of acceleration due to gravity is fundamental in physics as it helps in solving various problems related to motion, forces, and energy.

5. What substance is required to drive the sliding filament process during muscle contraction?

A. ATP
B. Hormone
C. Potassium
D. Water

Correct answer: A

Rationale: The substance required to drive the sliding filament process during muscle contraction is ATP (adenosine triphosphate). ATP provides the energy needed for muscle contraction by enabling the myosin heads to bind to actin and generate force. This energy release drives the sliding of the filaments, causing muscle fibers to contract. Hormones, potassium, and water do not directly drive the sliding filament process in muscle contraction. Hormones are signaling molecules that regulate various physiological processes but do not directly provide energy for muscle contraction. Potassium is an electrolyte important for nerve and muscle function but is not the primary driver of the sliding filament process. Water is essential for overall hydration and bodily functions but does not directly participate in the muscle contraction process.