which valve prevents backflow into the atrium when ventricles contract

ATI TEAS 7

ATI TEAS Science Practice Test

1. Which valve prevents backflow into the atrium when the ventricles contract?

A. Pulmonary valve
B. Tricuspid valve
C. Mitral valve
D. Aortic valve

Correct answer: B

Rationale: The tricuspid valve (right atrioventricular valve) prevents backflow into the right atrium when the right ventricle contracts. This valve ensures that blood flows in the correct direction, preventing regurgitation into the atrium. The pulmonary valve is responsible for preventing backflow into the right ventricle from the pulmonary artery. The mitral valve prevents backflow into the left atrium, and the aortic valve prevents backflow into the left ventricle from the aorta. Therefore, the correct answer is the tricuspid valve as it specifically addresses the scenario of backflow into the atrium during ventricular contraction.

2. In the body, muscle tissue is involved in which of the following functions?

A. Generation of body heat
B. Joint stabilization
C. Maintenance of posture
D. All of the above

Correct answer: D

Rationale: Muscle tissue serves multiple functions in the body, including the generation of body heat, joint stabilization, and maintenance of posture. These functions are essential for movement, stability, and overall bodily functions. The correct answer is 'All of the above' because muscle tissue plays a key role in each of these vital functions. The generation of body heat occurs through muscle activity, joint stabilization is achieved by muscles surrounding joints, and maintaining posture involves muscle contraction to support the body's position. Therefore, all the listed functions are interconnected and rely on the proper functioning of muscle tissue.

3. What is the process of making copies of DNA called?

A. Transcription
B. Translation
C. Replication
D. DNA repair

Correct answer: C

Rationale: A) Transcription is the process of synthesizing RNA from a DNA template. It involves the creation of mRNA molecules from a DNA template. B) Translation is the process of synthesizing proteins from mRNA. During translation, the genetic code carried by mRNA is decoded to produce a specific sequence of amino acids, forming a protein. C) Replication is the process of making copies of DNA. This process occurs before cell division and ensures that each daughter cell receives an identical copy of the genetic material. D) DNA repair is a cellular mechanism that corrects errors in DNA that arise due to various factors such as exposure to mutagens or mistakes during DNA replication. It is essential for maintaining the integrity of the genetic material.

4. What are energy levels and orbitals?

A. Energy levels are the paths that electrons travel around the nucleus of an atom, and orbitals are the regions where electrons are most likely to be found.
B. Energy levels are the regions where electrons are most likely to be found, and orbitals are the paths that electrons travel around the nucleus of an atom.
C. Energy levels are the same as orbitals.
D. Energy levels and orbitals do not exist.

Correct answer: A

Rationale: Energy levels refer to the specific energies that electrons in an atom can have, while orbitals are the regions within an atom where electrons are most likely to be found. Electrons do not travel in fixed paths around the nucleus like planets around the sun, as suggested in option B. Option C is incorrect because energy levels and orbitals are distinct concepts in atomic structure. Option D is incorrect as energy levels and orbitals are fundamental concepts in understanding the behavior of electrons in atoms.

5. Which of the following is NOT a function of the liver?

A. nutrient processing
B. blood filtration and detoxification
C. cholesterol and lipoprotein production
D. insulin production and blood sugar regulation

Correct answer: D

Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.