the involuntary rhythmic contractions of the heart muscle are controlled by a specialized group of cells located in the

ATI TEAS 7

Mometrix TEAS 7 science practice test

1. What controls the involuntary, rhythmic contractions of the heart muscle?

A. Lungs
B. Brain
C. Spinal cord
D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located within the heart called the sinoatrial node (SA node). The SA node acts as the heart's natural pacemaker, producing electrical impulses that regulate the heart rate and synchronize the contractions of the heart muscle. Choices A, B, and C (Lungs, Brain, Spinal cord) are not responsible for directly influencing the rhythmic contractions of the heart muscle.

2. What is the role of RNA interference in silencing genes?

A. Increases protein production
B. Promotes gene mutation
C. Inhibits the expression of specific genes
D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

3. Which mineral is essential for muscle function and nerve transmission?

A. Calcium
B. Iron
C. Sodium
D. Potassium

Correct answer: D

Rationale: Potassium is the correct answer as it is essential for muscle function and nerve transmission. Potassium plays a crucial role in regulating muscle contractions, including the heart's beating, and is vital for transmitting electrical signals within the nervous system. Calcium (Choice A) is important for muscle contraction but is not the primary mineral for nerve transmission. Iron (Choice B) is important for oxygen transport in the blood. Sodium (Choice C) is important for fluid balance but is not primarily responsible for muscle function and nerve transmission.

4. The ureters are paired tubes that transport urine from the:

A. Bladder to the urethra
B. Kidneys to the bladder
C. Urethra to the kidneys
D. Skin to the kidneys

Correct answer: B

Rationale: The ureters are responsible for carrying urine from the kidneys to the bladder. Once urine is produced in the kidneys, it travels down the ureters to be stored in the bladder until it is eliminated from the body through the urethra. Therefore, the correct answer is B, 'Kidneys to the bladder.' Choices A, C, and D are incorrect as they do not accurately describe the function of the ureters in the urinary system. Choice A, 'Bladder to the urethra,' is incorrect because the ureters carry urine from the kidneys to the bladder, not from the bladder to the urethra. Choice C, 'Urethra to the kidneys,' is incorrect as the flow of urine is from the kidneys to the bladder via the ureters, not in the reverse direction. Choice D, 'Skin to the kidneys,' is unrelated to the urinary system; the ureters are not involved in transporting substances from the skin to the kidneys.

5. Which form of energy is associated with the motion of an object?

A. Kinetic energy
B. Potential energy
C. Thermal energy
D. Electrical energy

Correct answer: A

Rationale: Kinetic energy is the form of energy associated with the motion of an object. When an object is in motion, it possesses kinetic energy due to its movement. Potential energy, on the other hand, is stored energy that an object has due to its position or condition. Thermal energy is related to heat, while electrical energy is associated with the flow of electric charge. In this case, the correct answer is kinetic energy as it directly correlates with the motion of an object.