Nursing Elites

1. Enzymes are ________ molecules that serve as _______ for certain biological reactions.

• A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
• B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
• C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
• D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.

Correct answer: D

Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.

2. What is the primary function of tight junctions, specialized regions between animal cells?

• A. Communication between cells
• B. Anchorage between cells
• C. Selective passage of materials
• D. All of the above

Correct answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

3. Which of the following statements describes a chemical property of water?

• A. Water has a pH of 1.
• B. A water molecule contains 2 hydrogen atoms and 1 oxygen atom.
• C. A water molecule contains 2 oxygen atoms and 1 hydrogen atom.
• D. The chemical formula for water is HO.

Correct answer: B

Rationale: The correct answer is B because a water molecule consists of two hydrogen atoms and one oxygen atom, which is a fundamental chemical property of water. The pH of water is not a property of the water molecule itself but rather a measure of its acidity or alkalinity. Choice C is incorrect as it describes a different molecule, not water. Choice D provides an incorrect chemical formula for water, which is H2O.

4. Why can optical fibers transmit light signals around bends?

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Polarization

Correct answer: B

Rationale: Optical fibers can transmit light signals around bends primarily due to refraction. Refraction is the bending of light as it passes from one medium to another, such as from air to glass in an optical fiber. This bending allows the light signals to travel through the fiber even around bends, making optical fibers an efficient means of transmitting light signals over long distances. Reflection (Choice A) occurs when light bounces off a surface, which is not the primary mechanism allowing light to travel around bends in optical fibers. Diffraction (Choice C) refers to the bending of light waves around obstacles or openings, but it is not the main reason light signals can traverse bends in optical fibers. Polarization (Choice D) is the orientation of light waves in a specific plane, but it does not play a significant role in enabling light to navigate bends in optical fibers.

5. Which state of matter has both a definite volume and a definite shape?

• A. Solid
• B. Liquid
• C. Gas
• D. Plasma

Correct answer: A

Rationale: The correct answer is 'Solid.' Solids have both a definite volume and a definite shape because the particles are closely packed together and vibrate in fixed positions. This close arrangement of particles allows solids to maintain their shape and volume, unlike liquids and gases which do not have a definite shape. Liquids take the shape of their container but have a definite volume. Gases, on the other hand, do not have a definite shape or volume as they expand to fill the space available to them. Plasma is a high-energy state of matter where atoms are stripped of their electrons and is not characterized by definite shape or volume.

Similar Questions