the three main types of muscle tissue in the human body are

ATI TEAS 7

TEAS 7 practice test free science

1. What are the three main types of muscle tissue in the human body?

A. Smooth, cardiac, and voluntary skeletal
B. Smooth, skeletal, and involuntary cardiac
C. Voluntary smooth, cardiac, and skeletal
D. Striated, non-striated, and epithelial

Correct answer: A

Rationale: The three main types of muscle tissue in the human body are smooth muscle (involuntary), cardiac muscle (involuntary), and voluntary skeletal muscle. Smooth muscle is found in the walls of hollow organs, cardiac muscle is found in the heart, and skeletal muscle is attached to bones and is under voluntary control. Option A correctly identifies these three main types of muscle tissue in the human body. Choice B is incorrect because it lists skeletal muscle as involuntary, which is not accurate. Choice C is incorrect because it lists voluntary smooth muscle, which does not exist as smooth muscle is involuntary. Choice D is incorrect because it uses terms like striated, non-striated, and epithelial, which are not the main types of muscle tissue but rather descriptions related to muscle characteristics and location.

2. How does AIDS impair the immune system?

A. AIDS targets and destroys Helper T-Cells, preventing the activation of Cytotoxic T-Cells or B-Cells.
B. IgE stimulates mast cells to release excessive histamine.
C. IgE inhibits mast cells from releasing sufficient histamine.
D. Helper T-Cells deceive the body into attacking itself.

Correct answer: A

Rationale: AIDS targets and destroys Helper T-Cells, which play a crucial role in coordinating the immune response. By affecting these cells, AIDS prevents the activation of other important immune cells like Cytotoxic T-Cells or B-Cells. This disruption in the immune system's communication and response mechanisms leads to immune system failure and increased vulnerability to infections. Choices B and C are incorrect because they refer to the role of IgE in allergic reactions, which is not directly related to how AIDS impairs the immune system. Choice D is also incorrect as Helper T-Cells being destroyed in AIDS is not about deceiving the body into attacking itself, but rather the direct impact on immune system function.

3. What is the molar mass of Ca(NO3)2?

A. 74.1 g/mol
B. 132.1 g/mol
C. 164.1 g/mol
D. 78.1 g/mol

Correct answer: B

Rationale: To calculate the molar mass of Ca(NO3)2, we add up the individual atomic masses of its elements: Ca (40.08) + 2N (2 * 14.01) + 6O (6 * 16.00) = 40.08 + 28.02 + 96.00 = 164.1 g/mol. Therefore, the correct answer is 164.1 g/mol (Choice C). Choice A (74.1 g/mol) is incorrect as it does not account for the correct sum of atomic masses. Choice B (132.1 g/mol) is the correct molar mass calculation for Ca(NO3)2. Choice D (78.1 g/mol) is incorrect and does not reflect the accurate molar mass of the compound.

4. DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?

A. It runs 5' to 3'.
B. It runs 3' to 5'.
C. It is used in replication.
D. It is the direction DNA is stored.

Correct answer: B

Rationale: The correct answer is B: 'It runs 3' to 5'. The antisense strand runs in the 3' to 5' direction, complementing the sense strand. Choice A is incorrect as the antisense strand runs in the opposite direction, which is 3' to 5'. Choice C is incorrect because the antisense strand is not directly involved in replication. Choice D is incorrect as the direction DNA is stored is not determined by the antisense strand.

5. Which of the following enzymes unwinds the double-stranded DNA during replication?

A. Helicase
B. Ligase
C. Nuclease
D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.