how do isotopes affect the atomic mass of an element

ATI TEAS 7

TEAS 7 science practice

1. How do isotopes affect the atomic mass of an element?

A. Isotopes have no effect on the atomic mass of an element.
B. Isotopes cause the atomic mass of an element to vary slightly.
C. Isotopes cause the atomic mass of an element to be exactly the same for all isotopes of that element.
D. Isotopes cause the atomic mass of an element to vary greatly.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Since the atomic mass of an element is the weighted average of the masses of its isotopes, the presence of isotopes causes the atomic mass of an element to vary slightly. This variation occurs because different isotopes have different masses due to their varying numbers of neutrons. The atomic mass is affected by the abundance of each isotope, leading to a slight fluctuation in the overall atomic mass of the element. Choice A is incorrect because isotopes do influence the atomic mass. Choice C is incorrect because isotopes have different masses, affecting the overall atomic mass. Choice D is incorrect as isotopes typically do not cause a significant variation in atomic mass, but rather a slight fluctuation.

2. Which of the following is NOT a major component of a healthy blood pressure reading?

A. Systolic pressure (peak pressure during ventricular contraction)
B. Diastolic pressure (pressure within arteries during ventricular relaxation)
C. Pulse pressure (difference between systolic and diastolic pressure)
D. Blood oxygen saturation levels. While blood oxygen levels are crucial for overall health, they are not directly reflected in a blood pressure reading.

Correct answer: D

Rationale: Blood oxygen saturation levels are essential for overall health but are not directly part of a blood pressure reading. A healthy blood pressure reading consists of systolic pressure, diastolic pressure, and pulse pressure. Systolic pressure represents the peak pressure during ventricular contraction, diastolic pressure reflects the pressure within arteries during ventricular relaxation, and pulse pressure is the difference between systolic and diastolic pressure. These components collectively provide information about the pressure variations within the arteries throughout the cardiac cycle phases, contributing to the assessment of cardiovascular health. Therefore, choice D, blood oxygen saturation levels, is not a major component of a healthy blood pressure reading and is the correct answer. Choices A, B, and C are major components of a healthy blood pressure reading and directly relate to the pressure variations within the arteries during different phases of the cardiac cycle.

3. Which of the following bones is part of the axial skeleton?

A. Femur
B. Humerus
C. Skull
D. Pelvis

Correct answer: C

Rationale: The correct answer is C: Skull. The axial skeleton consists of bones along the body's central axis, including the skull, vertebral column, ribs, and sternum. Choices A, B, and D are incorrect because the femur, humerus, and pelvis are part of the appendicular skeleton, which comprises the bones of the limbs and girdles.

4. What term refers to the mechanical act of breathing?

A. Diffusion
B. Perfusion
C. Respiration
D. Ventilation

Correct answer: D

Rationale: Ventilation is the correct answer as it specifically refers to the mechanical process of breathing air in and out of the lungs. Diffusion (choice A) is the movement of molecules from an area of high concentration to low concentration, not related to the mechanical act of breathing. Perfusion (choice B) is the process of blood flow through the tissues and organs, not directly related to breathing mechanically. Respiration (choice C) involves the exchange of oxygen and carbon dioxide at the cellular level, different from the mechanical act of breathing.

5. If an organism is AB, which of the following combinations in the gametes is NOT possible?

A. AB
B. AA
C. BB
D. AB

Correct answer: B

Rationale: The correct answer is B. If an organism is AB, it indicates that it carries two different alleles. During gamete formation, each gamete receives only one allele from the pair present in the organism. Therefore, in this case, the possible gametes would be 'A' and 'B,' making 'AA' impossible. Choice A, 'AB,' is possible as each gamete can carry one of the alleles from the genotype. Similarly, 'BB' is also possible if one of the alleles separates into a gamete. Choice D, 'AB,' is essentially the same genotype as the organism and is a possible combination in the gametes.