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 type of epithelium lines the inner surface of blood vessels?

A. Simple squamous epithelium
B. Simple columnar epithelium
C. Stratified squamous epithelium
D. Stratified columnar epithelium

Correct answer: A

Rationale: The correct answer is simple squamous epithelium (Choice A). The inner surface of blood vessels is lined by a single layer of flattened cells, known as simple squamous epithelium. This epithelium type is thin and allows for efficient diffusion and filtration, which is essential for the exchange of gases and nutrients across blood vessel walls. Simple columnar epithelium (Choice B) is typically found in the lining of the gastrointestinal tract and is responsible for absorption and secretion. Stratified squamous epithelium (Choice C) is commonly found in the skin, providing protection against mechanical stress. Stratified columnar epithelium (Choice D) is not a characteristic epithelium type found in the lining of blood vessels, as it is more commonly present in specific regions of the body like parts of the male urethra and the conjunctiva of the eye.

3. Which of the following is NOT a method of sterilization?

A. Autoclave
B. UV light
C. Chemical disinfectants
D. Boiling water

Correct answer: D

Rationale: A) Autoclave: An autoclave is a method of sterilization that uses high pressure and steam to kill microorganisms, making it an effective way to sterilize equipment and materials.\nB) UV light: UV light is a method of sterilization that damages the DNA of microorganisms, preventing them from reproducing and causing infections.\nC) Chemical disinfectants: Chemical disinfectants are used to kill or inactivate microorganisms on surfaces, but they may not always achieve sterilization, which is the complete destruction of all microorganisms.\nD) Boiling water: Boiling water is a method of disinfection rather than sterilization. While boiling water can kill many microorganisms, it may not be effective against all types of bacteria, viruses, and spores, making it unsuitable for achieving sterilization.\n\nTherefore, the correct answer is D) Boiling water, as it is not a method of sterilization.

4. Which of the following units is equivalent to a joule?

A. Newton-meter (N·m)
B. Watt (W)
C. Kilogram (kg)
D. Ampere (A)

Correct answer: A

Rationale: A joule is the SI unit of energy and work, defined as the work done by a force of one newton acting over a distance of one meter. Therefore, a joule is equivalent to a newton-meter (N·m), which represents the product of force (newton) and distance (meter). This unit reflects the energy transferred when a force of one newton moves an object one meter. Choice B, Watt (W), is the unit of power and is not equivalent to a joule. Choice C, Kilogram (kg), is a unit of mass. Choice D, Ampere (A), is the unit of electric current.

5. Which of the following meninges is a thin membrane containing numerous nerves and blood vessels that supply nourishment to the underlying brain cells and spinal cord?

A. Arachnoid mater
B. Dura mater
C. Periosteum
D. Pia mater

Correct answer: D

Rationale: The pia mater is the correct answer. It is a thin, innermost layer of the meninges that contains numerous nerves and blood vessels, providing nourishment to the underlying brain cells and spinal cord. The arachnoid mater (Choice A) is the middle layer of the meninges and does not contain as many nerves and blood vessels as the pia mater. The dura mater (Choice B) is the tough, outermost layer of the meninges and is not responsible for supplying nourishment. The periosteum (Choice C) is a connective tissue membrane covering bones, not part of the meninges.