what characteristic of water allows for hydrogen bonding between molecules

HESI RN

Biology Practice Test

1. What characteristic of water allows for hydrogen bonding between molecules?

A. Its covalent bonds
B. Its cohesive properties
C. Its high specific heat
D. Its polar nature

Correct answer: D

Rationale: The correct answer is D: Its polar nature. Water is a polar molecule with a partial positive charge on hydrogen atoms and a partial negative charge on oxygen atoms. This polarity allows water molecules to form hydrogen bonds with each other. Choice A, covalent bonds, is incorrect because while water indeed has covalent bonds, they do not directly enable hydrogen bonding. Choice B, cohesive properties, is incorrect as cohesion refers to water's ability to stick to other substances, not the specific characteristic that allows for hydrogen bonding. Choice C, high specific heat, is also incorrect as it refers to water's ability to resist changes in temperature, not its property that leads to hydrogen bonding.

2. Protein synthesis begins with a process known as transcription. Where does this process occur?

A. In the cytoplasm
B. In the nuclear envelope
C. In the ribosome unit
D. In the nucleus

Correct answer: D

Rationale: The correct answer is D: In the nucleus. Transcription, the initial step of protein synthesis, takes place in the nucleus where DNA is transcribed into mRNA. This mRNA then leaves the nucleus and enters the cytoplasm where translation occurs on the ribosomes. Choices A, B, and C are incorrect because transcription specifically occurs in the nucleus, not in the cytoplasm, nuclear envelope, or ribosome unit.

3. What do prokaryotic cells lack in comparison to eukaryotic cells?

A. A defined nucleus and a series of membrane-bound organelles
B. A defined nucleus and no membrane-bound organelles
C. No defined nucleus and a series of membrane-bound organelles
D. No defined nucleus and no membrane-bound organelles

Correct answer: D

Rationale: Prokaryotic cells are characterized by the absence of a defined nucleus and membrane-bound organelles. Choice A is incorrect because prokaryotic cells lack membrane-bound organelles. Choice B is incorrect because prokaryotic cells lack both a defined nucleus and membrane-bound organelles. Choice C is incorrect as prokaryotic cells have no defined nucleus. Therefore, the correct answer is D.

4. Which of the following serves as the information processing and administrative center of the cell?

A. Golgi apparatus
B. Cytoplasm
C. Nucleus
D. Lysosomes

Correct answer: C

Rationale: The correct answer is C, the nucleus. The nucleus is indeed the information processing and administrative center of the cell as it contains the genetic material (DNA) and is responsible for controlling cellular activities. The Golgi apparatus (Choice A) is involved in processing and packaging proteins, the cytoplasm (Choice B) is the fluid that fills the cell and provides a medium for organelles to be suspended, and lysosomes (Choice D) are responsible for digesting waste materials and foreign invaders. Therefore, the nucleus is the most appropriate choice for the given function.

5. Which of the following terms is used to represent two alleles that are the same type?

A. Homosynchronous
B. Hypersynchronous
C. Heterozygous
D. Homozygous

Correct answer: D

Rationale: The correct answer is D, 'Homozygous.' Homozygous refers to having two identical alleles for a particular gene. In this context, 'Homosynchronous' (choice A) is not a recognized genetic term. 'Hypersynchronous' (choice B) is not a term used in genetics. 'Heterozygous' (choice C) refers to having two different alleles for a particular gene, which is the opposite of homozygous.