Free HESI A2 Biology practice for HESI A2 Biology Version 1 (HESI A2). Answer 24 nursing exam-style questions with rationales, exam mode, and progress tracking
How is the aerodynamic nature of a bird's wing best categorized in biology?
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Explanation:
The aerodynamic nature of a bird's wing exemplifies the relationship between its structure and its function, showcasing how its form is intricately adapted for its function of flight. This concept of the interdependence of structure and function is a fundamental theme in biology. It emphasizes how the structures of living organisms are precisely designed to carry out specific functions, thereby influencing their survival and success in their respective environments.
What structure in a plant cell acts as a barrier and provides support to the cell?
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Explanation:
The cell wall is the correct answer. It acts as a rigid barrier that surrounds the plant cell membrane, providing structural support and protection. Plant cells have cell walls, unlike animal cells, which give them their shape and rigidity.
Which vitamin is recognized for its healing antioxidant properties?
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Explanation:
Vitamin A is well-known for its antioxidant properties, essential for healing, maintaining healthy skin and tissues, and supporting the immune system. It plays a vital role in repairing damaged tissues, making it crucial for overall health and facilitating healing processes.
Which is an example of the correct organizational hierarchy for a wolf?
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Explanation:
The correct organizational hierarchy in biology follows a specific order from smallest to largest. It starts with DNA (genetic material), followed by blood cells (basic units of life), then muscle tissue (a collection of cells), followed by the heart (an organ), then the circulatory system (a system of organs), and finally the whole organism, the wolf. Therefore, the correct sequence for the organizational hierarchy for a wolf is DNA, blood cell, muscle tissue, heart, circulatory system, and wolf.
Which method of glucose conversion generates the most usable and efficient form of ATP within the human body?
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Explanation:
Aerobic respiration generates the most ATP (around 36-38 ATP molecules per glucose molecule). It uses oxygen and occurs in the mitochondria, making it the most efficient way for the body to produce energy. In contrast, anaerobic respiration and fermentation produce significantly less ATP and are less efficient processes. Lactic acidosis is a medical condition involving the buildup of lactic acid in the body and is not a method of glucose conversion for energy production.
What structure enables sperm cells to move effectively?
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Explanation:
The flagellum is a whip-like structure that is crucial for sperm cells to swim and move effectively. It provides the necessary motility for sperm, allowing them to navigate through the female reproductive tract to reach the egg for fertilization. In contrast, structures like centriole, cilium, and centrosome do not have the propelling ability required for sperm cell movement.
What is the first step in the process of respiration?
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Explanation:
The correct answer is Glycolysis. Glycolysis is the initial step in cellular respiration where glucose is broken down into pyruvate, producing a small amount of ATP and NADH in the cytoplasm. This step is crucial as it initiates the breakdown of glucose, setting the stage for further energy production in subsequent stages like the Krebs cycle and electron transport chain.
Which cell organelle can be functionally compared to a door of a house?
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Explanation:
The cell membrane can be likened to a door of a house because it functions to regulate what enters and exits the cell, maintaining internal balance (homeostasis) and safeguarding the cell's interior. Just as a door controls access to a house, the cell membrane controls the passage of substances into and out of the cell, thereby playing a crucial role in maintaining the cell's integrity and functionality.
If the zygomatic arch is broken, where is the fracture located?
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Explanation:
The zygomatic arch, also known as the cheekbone, is a bony structure on the side of the face. A fracture in this area is classified as a facial fracture, making the correct location for the fracture in the face.
What part of a light microscope is used to hold the slide in place?
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Explanation:
The correct answer is 'Stage clips.' Stage clips are utilized to secure the slide on the stage of a light microscope, ensuring it remains in position while examining the specimen. The base of the microscope provides stability, the arm supports the upper part of the microscope, and the rack stop restricts the movement of the stage. However, specifically, it is the stage clips that hold the slide in place during observations.
Which term means a group of similar cells combined to perform a common function?
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Explanation:
The correct answer is 'Tissue.' Tissue is a group of similar cells that work collectively to carry out a specific function. These specialized cells combine to form tissues, which further combine to create organs. Organs then collaborate within systems in the body to maintain balance (homeostasis) and perform various functions such as digestion, circulation, and respiration.
Which term means alternate forms of a gene for the same trait?
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Explanation:
Alleles are different versions of a gene that can exist for a given trait. For example, a gene for flower color may have a red allele and a white allele, representing the alternate forms of that gene. Genotypes refer to the genetic makeup, while phenotypes refer to the observable traits.
What does the mitochondrion produce that causes it to often be called the powerhouse of the cell?
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Explanation:
The mitochondrion produces ATP (adenosine triphosphate), which is the primary energy currency of the cell. This energy production is why mitochondria are referred to as the powerhouse of the cell. ATP generated by mitochondria is essential for various cellular processes, such as muscle contraction, cell division, and macromolecule synthesis, making it a crucial organelle for cell function.
Human cells need oxygen for respiration. What system of the body is responsible for transporting an oxygen molecule to different locations throughout the body?
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Explanation:
The circulatory system is responsible for transporting oxygen throughout the body. It consists of the heart, blood vessels, and blood, which work together to deliver oxygen from the lungs to cells and tissues, facilitating cellular respiration. The skeletal system provides structural support and protection for the body but is not involved in oxygen transport. The lymphatic system helps maintain fluid balance and immune function, not oxygen transport. The respiratory system is responsible for gas exchange in the lungs but relies on the circulatory system to transport oxygen to cells and tissues.
In the human life cycle, only sperm and eggs have which number of chromosomes?
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Explanation:
In humans, sperm and egg cells are haploid, meaning they contain half the number of chromosomes (23) compared to diploid cells (46). This reduction in chromosome number is essential for sexual reproduction, allowing the formation of a diploid zygote upon fertilization. Haploid cells carry only one set of chromosomes, which is necessary for genetic diversity and the fusion of genetic material during fertilization.
Which set is correctly listed for characteristic chromosome number, and most of their cells have a complete set of these chromosomes?
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Explanation:
The correct order from largest to smallest is Phylum, Order, Genus, Species. In biological classification, the hierarchy of taxonomic ranks is structured such that phylum is the broadest category, followed by order, genus, and species, which is the most specific. When looking at the characteristic chromosome number, most cells have a complete set of chromosomes, and this order aligns with the genetic similarity and differences observed in organisms.
Where is the slide placed on a light microscope?
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Explanation:
In a light microscope, the slide is placed on the stage, which is a flat platform designed to hold the specimen being observed. The stage provides stability for the slide and allows for adjustments to focus the lens on the specimen. The arm, lens, and base have specific functions in the operation of the microscope but are not where the slide is placed.
What type of bond in the DNA nucleotide base holds the strands together?
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Explanation:
Hydrogen bonds are the type of bonds that hold the two strands of DNA together by connecting complementary nitrogenous bases (adenine with thymine and cytosine with guanine). These weak bonds allow the DNA strands to separate during replication and transcription while providing stability to the overall structure of the DNA molecule.
In the presence of which molecule does aerobic respiration occur?
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Explanation:
Aerobic respiration is a process that requires oxygen to efficiently convert glucose into carbon dioxide, water, and ATP. Oxygen plays a critical role in this metabolic pathway by acting as the final electron acceptor in the electron transport chain, allowing the production of ATP through oxidative phosphorylation. Therefore, oxygen is the essential molecule for aerobic respiration to take place.
What is the purpose of cellular respiration?
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Explanation:
The correct answer is D. The primary purpose of cellular respiration is to obtain energy in the form of ATP. During cellular respiration, glucose and other organic molecules are broken down to release energy in the form of ATP, which is crucial for various cellular functions and activities. This energy is used by cells to carry out processes such as growth, repair, movement, and maintaining homeostasis.
How are viruses categorized?
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Explanation:
Viruses are categorized based on several criteria, including size and shape, presence or absence of an outer envelope, and type of nucleic acid (DNA or RNA). Therefore, the most comprehensive answer is that all these factors are used for categorization.
What type of cell primarily makes up animals?
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Explanation:
Animals are composed primarily of eukaryotic cells, characterized by a defined nucleus and membrane-bound organelles. Eukaryotic cells are complex and serve as the basis for multicellular organisms such as animals, contrasting with prokaryotic cells that lack a defined nucleus and organelles.
Which genetic descriptor refers to an organism's actual appearance?
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Explanation:
Phenotype refers to the observable characteristics or traits of an organism, including physical appearance, behavior, and physiological properties. It is influenced by the organism's genotype and environmental factors. Genotype, on the other hand, represents the genetic makeup of an organism, while homozygote refers to an individual having two identical alleles for a particular gene. Karyotype, on the other hand, refers to the complete set of chromosomes in an individual.
What substances make up the bilayer of the cellular membrane?
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Explanation:
The cellular membrane consists of a bilayer of phospholipids. This phospholipid bilayer forms a flexible barrier around the cell, providing structural integrity and fluidity. While proteins and carbohydrates are also present in the cell membrane, the main component of the membrane's structure is the phospholipid bilayer, which plays a crucial role in maintaining the cell's functions.
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