HESI A2 Practice Test Biology - Nurselytic

Correct Answer: B

Rationale: The correct answer is B: Ribosome. Ribosomes are responsible for organizing protein synthesis by assembling amino acids. They are the cellular machinery where proteins are synthesized. The other choices, such as the nucleus, lysosome, and vacuole, do not directly participate in protein synthesis. The nucleus contains DNA and controls cell activities, the lysosome is involved in digestion and waste removal, and the vacuole is responsible for storage and maintaining cell turgor pressure.

Correct Answer: C

Rationale: Water molecules are bonded to each other by 'hydrogen' bonds. These bonds are not as strong as covalent bonds, which hold the atoms within each water molecule together (
Choice
B). Ionic bonds (
Choice
A) involve the transfer of electrons between atoms, which is not the case in water molecules. The term 'molecular' (
Choice
D) is too general and doesn't specifically describe the type of bond between water molecules.

Correct Answer: B

Rationale: The correct answer is B, red blood cell. In humans, red blood cells do not have a nucleus. This unique feature allows them to have more space to carry oxygen efficiently. Platelets (choice
A), white blood cells (choice
C), and phagocytes (choice
D) all have nuclei. Platelets are cell fragments, while white blood cells and phagocytes are types of immune cells that contain a nucleus for DNA and cellular functions.

Correct Answer: D

Rationale: The correct answer is 'gradient.' In cell diffusion, substances move from an area of high concentration to an area of low concentration, driven by the concentration gradient. This process does not require water, membrane, or ATP specifically. Water can aid in the movement of substances, but it is not necessary for diffusion itself. The membrane is involved in regulating diffusion but is not a requirement for the process. ATP is not directly involved in simple diffusion processes; instead, it is more related to active transport mechanisms.
Therefore, the concentration gradient is essential for cell diffusion to occur.

Correct Answer: C

Rationale: The correct answer is 'Selectively permeable.' The cell membrane's bilayer structure allows it to be selectively permeable, meaning it can control the passage of substances. This property enables the membrane to regulate the entry and exit of specific molecules, ions, and other substances.
Choice A, 'Impermeable,' is incorrect as the cell membrane is not completely impermeable and does allow certain substances to pass through.
Choice B, 'Permeable,' is also incorrect as it does not address the selective nature of the membrane.
Choice D, 'Selectively impermeable,' is a contradictory term and does not accurately describe the cell membrane's function.