HESI A2 biology practice questions set 8

Correct answer:

Cows are ruminant animals that have multiple stomachs and require large amounts of food to digest and convert into energy. They have lower energy efficiency compared to insects like caterpillars, coyotes, and crickets, which have more efficient nutrient consumption processes. The digestive system and metabolic functions of cows result in them having the least energy efficiency in nutrient consumption among the given choices. Caterpillars, coyotes, and crickets have more efficient nutrient consumption processes, making them more energy-efficient than cows.

Correct answer:

Sugar and phosphate are indeed connected by covalent bonds in DNA. Covalent bonds involve the sharing of electrons between atoms, which is essential for forming the backbone of the DNA molecule. Hydrogen bonds (Choice A) are important in holding the nitrogenous bases together in the DNA double helix but do not connect sugar and phosphate. Ionic bonds (Choice B) involve the transfer of electrons between atoms and are not the primary bond connecting sugar and phosphate in DNA. 'Overt' (Choice D) is not a type of chemical bond and is an incorrect distractor.

Correct answer:

The correct answer is A: Mitochondrion. The mitochondrion is the site of energy production in a cell. It is often referred to as the powerhouse of the cell because it is where cellular respiration occurs, generating energy in the form of adenosine triphosphate (ATP) through processes like the citric acid cycle and oxidative phosphorylation. The other organelles listed play different roles in the cell - vacuoles store materials, the cell membrane regulates the movement of substances in and out of the cell, and ribosomes are involved in protein synthesis.

Correct answer:

Lactic acid is a byproduct of fermentation in muscle cells. During intense exercise or when oxygen is limited, muscle cells use anaerobic respiration to generate energy. This process breaks down glucose into lactic acid, which can cause muscle fatigue and soreness. Choice A, Ethanol, is not produced in muscle cells during fermentation. Choice B, Pyruvic acid, is an intermediate product in glucose metabolism but is not a byproduct of fermentation in muscle cells. Choice D, Oxygen, is not a byproduct of fermentation but a reactant in aerobic respiration.

Correct answer:

Ribosomes are the organelles involved in the synthesis of proteins. They are the cellular machinery responsible for translating mRNA into proteins, making them essential for cell function and structure. The other organelles listed, such as the Endoplasmic Reticulum, Lysosomes, and Vacuoles, have different functions unrelated to protein synthesis. The Endoplasmic Reticulum plays a role in protein processing and transport, Lysosomes are involved in digestion and waste removal, and Vacuoles are responsible for storage and maintaining cell turgor pressure.

Correct answer:

The correct answer is B: 'It is reliable, but not valid.' The measurement is reliable because it consistently provides the same result (75 kg). However, it is not valid because it does not accurately reflect the true weight of Patient A (68 kg). Choice A is incorrect because if the scale consistently shows the same weight (75 kg), it is reliable. Choice C is incorrect because although the scale is consistent, the measurement does not reflect the true weight, making it not valid. Choice D is incorrect as the measurement is reliable but lacks validity.

Correct answer:

The correct answer is A: mitochondria. Mitochondria are not found in bacterial cells. Bacterial cells lack membrane-bound organelles like mitochondria, which are commonly found in eukaryotic cells. Choices B, C, and D are all components that can be found within a bacterial cell. Bacterial cells contain DNA as their genetic material, vesicles for various cellular functions, and ribosomes for protein synthesis. Therefore, the presence of mitochondria is the distinguishing factor that is not found in bacterial cells, making option A the correct answer.

Correct answer:

The correct answer is A: Carbohydrates, lipids, protein, and nucleic acids are considered the most important molecules in biology. Carbohydrates are essential for providing energy, lipids for storing energy and forming cell membranes, proteins for various structural and functional roles, and nucleic acids (DNA and RNA) for storing genetic information. Choices B, C, and D are incorrect because while carbohydrates, lipids, and proteins are crucial biomolecules, calcium, sulfur, and iron are not considered among the most important molecules in biology.

Correct answer:

Blue light is the most effective color for growing green plants indoors. Blue light has a higher energy level compared to other colors, which is crucial for promoting vegetative growth, strong stems, and lush foliage in plants. Additionally, blue light helps regulate plant growth hormones, making it essential for the overall health and development of green plants. Yellow, green, and orange light do not provide the necessary energy levels or spectrum needed for optimal plant growth, making them less effective choices for growing green plants indoors.

Correct answer:

The classification 'Carnivora' refers to an order in the taxonomic hierarchy. In the Linnaean classification system, the order comes below the class but above the family level. Therefore, Carnivora is a higher classification that includes dog species as well as other carnivorous mammals like cats, bears, and weasels. Option A (Kingdom) is too broad and refers to the highest taxonomic rank. Option B (Class) is a lower taxonomic rank than order. Option D (Genus) is a much more specific rank that comes below the family level in the Linnaean hierarchy.