TEAS 7 Chemistry: Essential Practice for Success

ATI TEAS 7

Chemistry

1. What is the formula for calculating molarity?

A. M = n/V
B. M = n/L
C. M = mol/L
D. M = mol/dmÂ³

Correct answer: a

Rationale: All of these choices are equivalent to the original formula. The symbol "n" represents the number of moles of solute, and the symbol "V" represents the volume of the solution in liters. The symbol "L" is an abbreviation for "liters," and "dmÂ³" is an alternative way to represent liters.

2. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

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

Correct answer: D

Rationale: The correct answer is D, the mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its main function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) is responsible for preventing the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents backflow from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents backflow from the right ventricle into the right atrium. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer in this case.

3. Insulin, a hormone responsible for regulating blood sugar levels, is produced by the:

A. Parathyroid gland
B. Pancreas
C. Thymus gland
D. Ovaries

Correct answer: B

Rationale: The correct answer is B: Pancreas. Insulin is a hormone that plays a crucial role in regulating blood sugar levels by allowing cells to take in glucose from the bloodstream. The pancreas is an organ located near the stomach that contains clusters of cells called islets of Langerhans, which are responsible for producing insulin. The parathyroid gland, option A, regulates calcium levels in the blood. The thymus gland, option C, is involved in the development of the immune system. The ovaries, option D, produce hormones like estrogen and progesterone but not insulin. Therefore, the pancreas is the correct gland responsible for producing insulin.

4. What term describes the point where parallel rays of light converge or appear to diverge from after passing through a lens or reflecting off a mirror?

A. Aperture
B. Focal length
C. Refractive index
D. Lens thickness

Correct answer: B

Rationale: The focal length is the term that describes the point where parallel rays of light converge or appear to diverge from after passing through a lens or reflecting off a mirror. It is a crucial parameter in optics and is used to determine the magnification and image formation in optical systems. The other options (A) Aperture, (C) Refractive index, and (D) Lens thickness are not directly related to the point where parallel rays of light converge or appear to diverge.

5. Which blood type is a universal donor?

A. A
B. B
C. AB
D. O

Correct answer: D

Rationale: Rationale: Blood type O is considered the universal donor because individuals with type O blood can donate red blood cells to individuals with any ABO blood type (A, B, AB, or O) without causing an adverse reaction. This is because type O blood lacks A or B antigens on the surface of red blood cells, which helps minimize the risk of an immune response when transfused into individuals with different blood types. Therefore, type O blood is in high demand for blood transfusions in emergency situations when the recipient's blood type is unknown or when there is a shortage of specific blood types.