how are lipids different than other organic molecules

HESI A2

HESI A2 Practice Test Biology

1. How are lipids different from other organic molecules?

A. They are indivisible.
B. They are not water soluble.
C. They contain zinc.
D. They form long proteins.

Correct answer: B

Rationale: The correct answer is B: 'They are not water soluble.' Lipids are not water-soluble, which distinguishes them from other organic molecules. Choice A is incorrect because lipids are not indivisible; they can be broken down into fatty acids and glycerol. Choice C is incorrect as lipids do not necessarily contain zinc; they are a diverse group of molecules. Choice D is incorrect because lipids do not form long proteins; proteins are made up of amino acids, not lipids.

2. From which component do RNA and DNA derive their names?

A. From the sugar each contains
B. From the structure of their nucleotides
C. From the information they transfer
D. From their formative processes

Correct answer: A

Rationale: RNA and DNA derive their names from the sugar each contains. RNA stands for Ribonucleic Acid, with 'ribo' indicating the ribose sugar in its structure. DNA stands for Deoxyribonucleic Acid, with 'deoxyribo' referring to the deoxyribose sugar in its structure. The sugars in RNA and DNA molecules distinguish them and are the basis for their names. Choices B, C, and D are incorrect as they do not accurately explain how RNA and DNA derive their names.

3. In order, from lower to upper, the layers of the atmosphere are:

A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere

Correct answer: B

Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.

4. Which is not one of the raw materials needed for cellular respiration?

A. ADP
B. Phosphate
C. Water
D. Glucose

Correct answer: C

Rationale: Water is not one of the raw materials needed for cellular respiration. The essential raw materials for cellular respiration include glucose (which is broken down to produce energy), oxygen, and ADP (adenosine diphosphate) and phosphate (which are necessary for the formation of ATP, the energy currency of cells). While water is crucial for many cellular processes and makes up a significant portion of cells, it is not directly involved as a raw material in the cellular respiration process.

5. Which bacteria are spherical in shape?

A. Clostridia
B. Bacilli
C. Spirilla
D. Cocci

Correct answer: D

Rationale: The correct answer is D, Cocci. Bacteria that are spherical in shape are known as cocci. They can be found in various arrangements such as clusters, chains, or pairs. Examples of cocci bacteria include Staphylococcus aureus and Streptococcus pneumoniae. Choice A, Clostridia, consists of rod-shaped bacteria. Choice B, Bacilli, refers to rod-shaped bacteria as well. Choice C, Spirilla, are spiral-shaped bacteria, not spherical.