which valve prevents the return of blood into the right ventricle

ATI TEAS 7

ATI TEAS Science Questions

1. Which valve prevents the return of blood into the right ventricle?

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

Correct answer: A

Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.

2. What is the name for the process by which a cell divides into two daughter cells?

A. Meiosis
B. Mitosis
C. Fission
D. Binary fission

Correct answer: B

Rationale: Mitosis is the correct process by which a cell divides into two genetically identical daughter cells. Meiosis involves two rounds of cell division resulting in four daughter cells with half the number of chromosomes as the parent cell. Fission refers to the division of a single-celled organism into two separate organisms, while binary fission specifically describes the division of prokaryotic cells. Therefore, the correct answer is Mitosis as it accurately represents the process of a cell dividing into two daughter cells.

3. How are genetic markers utilized in paternity testing?

A. They identify unique sequences in the father's DNA present in the child.
B. They analyze the presence or absence of specific alleles for certain genes.
C. They compare the child's blood type to the parents' blood types.
D. They measure the child's physical resemblance to the father.

Correct answer: B

Rationale: Genetic markers are specific DNA sequences that can vary among individuals. In paternity testing, genetic markers are used to compare the DNA of the child with that of the alleged father. By analyzing the presence or absence of specific alleles (different forms of a gene) at these genetic markers, scientists can determine the likelihood of paternity. This method is more accurate and reliable than comparing blood types (choice C) or physical resemblance (choice D) as genetic markers provide a direct comparison of DNA sequences between individuals. Therefore, option B is the correct choice as it accurately describes the use of genetic markers in paternity testing.

4. Melatonin is a hormone produced by the pineal gland. What is its primary function?

A. Regulate blood pressure
B. Stimulate the digestive system
C. Control sleep-wake cycles
D. Maintain bone density

Correct answer: C

Rationale: Melatonin is primarily known for its role in controlling sleep-wake cycles. It is produced by the pineal gland in response to darkness, helping signal the body that it is time to sleep. Melatonin levels typically rise in the evening and stay elevated throughout the night, promoting sleep. Choices A, B, and D are incorrect as melatonin's primary function is not to regulate blood pressure, stimulate the digestive system, or maintain bone density. While melatonin may have some indirect effects on these functions, its main role lies in regulating the circadian rhythm and promoting a restful sleep cycle.

5. What is the process by which a cell divides into two or more new cells?

A. Mitosis
B. Meiosis
C. Both mitosis and meiosis
D. None of the above

Correct answer: A

Rationale: Mitosis is the process by which a cell divides into two identical daughter cells. This type of cell division is essential for growth, repair, and maintenance of multicellular organisms. Meiosis, on the other hand, is a type of cell division that produces gametes (sperm and egg cells) with half the number of chromosomes as the parent cell. Meiosis does not directly result in the formation of new cells, as it is specifically geared towards the production of reproductive cells. Therefore, the correct answer is A. Option C, stating both mitosis and meiosis, is incorrect because meiosis is not involved in the general process of cell division to produce new cells; it is specialized for gamete formation. Option D is incorrect because mitosis is indeed the process responsible for cell division in which one cell divides into two daughter cells, making it the accurate choice for this question.