which of these is not an example of a lipid

HESI A2

Biology HESI A2 Practice Exam

1. Which of these is not an example of a lipid?

A. Butter
B. Wax
C. Canola oil
D. Honey

Correct answer: D

Rationale: Honey is not an example of a lipid because lipids are fat-related molecules that are insoluble in water, while honey is a natural sweet substance made by bees and primarily consists of sugars such as glucose and fructose. Butter, wax, and canola oil are examples of lipids as they are all composed of fat-related molecules that do not dissolve in water.

2. What is the correct order of the hierarchy of levels in the biological classification of organisms?

A. Kingdom, phylum, class, order, family, genus, and species
B. Phylum, kingdom, class, order, family, genus, and species
C. Order, phylum, class, kingdom, family, genus, and species
D. Kingdom, phylum, order, class, family, genus, and species

Correct answer: A

Rationale: The correct order of the hierarchy of levels in the biological classification of organisms is Kingdom, Phylum, Class, Order, Family, Genus, and Species. This order is based on the Linnaean system of classification, with each level representing a progressively more specific grouping of organisms. Choice B is incorrect because it starts with Phylum instead of Kingdom. Choice C is incorrect as it places Order before Phylum. Choice D is incorrect because it does not follow the correct order of the biological classification hierarchy.

3. How should a researcher test the hypothesis that radiation from cell phones is significant enough to raise the temperature of water in a test tube?

A. Dial a cell phone that rests beside a test tube of water, let it ring for two minutes, and record the temperature of the water before and after the two-minute interval.
B. Dial a cell phone that rests beside a test tube of water; let it ring for two, three, and four minutes; and record the temperature of the water before and after each interval.
C. Use three different brands of cell phone; dial each as it rests beside its own test tube of water, let it ring for two minutes, and record the temperature of the water before and after the two-minute interval.
D. Use three different brands of cell phone, dial each and let one ring for two minutes, one for three minutes, and one for four minutes; record the temperature of the water before and after each interval.

Correct answer: A

Rationale: To test the hypothesis that radiation from cell phones raises the temperature of water in a test tube, the most appropriate method is to dial a cell phone next to a test tube of water, let it ring for a consistent two-minute interval, and record the temperature before and after. Choice A is correct because it provides a controlled approach to isolate the impact of the phone's radiation on the water temperature. Choices B, C, and D introduce additional variables that could confound the results. Choice B varies the duration of exposure, making it difficult to attribute temperature changes specifically to the radiation. Choice C introduces the factor of different cell phone brands, which could introduce variability not related to radiation. Choice D also varies exposure times and introduces the factor of multiple phone brands, making it harder to determine the direct impact of cell phone radiation on water temperature. Therefore, choice A is the most suitable option for this experiment.

4. Huntington’s disease is carried on the dominant allele. In a situation where two heterozygous parents have the disease, what percentage of their offspring are predicted to be disease-free?

A. 0%
B. 25%
C. 50%
D. 100%

Correct answer: B

Rationale: In this scenario, both parents are heterozygous for Huntington's disease, meaning each carries one dominant allele (representing the disease) and one recessive allele (representing no disease). When they have offspring, there is a 25% chance that each child will inherit two recessive alleles, making them disease-free. The Punnett square for two heterozygous parents (Hh x Hh) yields a 25% probability of offspring being homozygous recessive (hh) and therefore disease-free. Choice A (0%) is incorrect because there is a possibility of disease-free offspring. Choice C (50%) is incorrect as it represents the likelihood of being a carrier. Choice D (100%) is incorrect as all offspring will not be disease-free in this scenario.

5. How many chromosomes do sperm and egg produce in meiosis?

A. 23
B. 46
C. 25
D. 50

Correct answer: A

Rationale: During meiosis, sperm and egg cells produce half the number of chromosomes found in somatic cells. Each contributes 23 chromosomes, which combine to form a zygote with a total of 46 chromosomes. Choice B (46) is incorrect because this is the number of chromosomes produced in mitosis, not meiosis. Choices C (25) and D (50) are also incorrect as they do not align with the chromosome count in sex cells during meiosis.