Free HESI A2 Biology practice for HESI A2 Biology Version 4 (HESI A2). Answer 26 nursing exam-style questions with rationales, exam mode, and progress tracking
Where is DNA stored?
Select the best answer.
Explanation:
DNA, the genetic material of a cell, is stored within the nucleus. The nucleus serves as the control center of the cell and houses the DNA, which contains the instructions for building and maintaining the cell's structures and functions. Ribosomes are involved in protein synthesis, the endoplasmic reticulum plays a role in protein and lipid synthesis, while mitochondria are responsible for energy production through cellular respiration. Therefore, the correct answer is the nucleus where DNA is securely contained and regulated.
Why doesn't an antibiotic work for treating flu symptoms in a patient?
Select the best answer.
Explanation:
Antibiotics are designed to treat bacterial infections, not viral infections like the flu. The flu is caused by a virus, so antibiotics are ineffective in treating flu symptoms. To effectively manage and treat flu cases, antiviral medications specifically designed to target viral infections should be used.
What is the primary purpose of cellular respiration?
Select the best answer.
Explanation:
Cellular respiration is a fundamental metabolic process in cells where nutrients are broken down to produce energy in the form of ATP. This energy is essential for powering various cellular functions and activities. Therefore, the primary goal of cellular respiration is to convert nutrients into energy, providing the cell with the necessary fuel to efficiently carry out its functions.
Where does anaerobic respiration happen and why?
Select the best answer.
Explanation:
Anaerobic respiration occurs in bacteria as they live in environments with low oxygen levels. In the absence of oxygen, bacteria resort to anaerobic respiration to produce energy. In contrast, animals and plants predominantly rely on aerobic respiration, which necessitates oxygen. Therefore, option C is correct as it accurately identifies the primary environment where anaerobic respiration takes place.
Are all bacteria bad, and do they always cause infections?
Select the best answer.
Explanation:
The misconception that all bacteria are harmful and always cause infections is incorrect. Although some bacteria can lead to diseases, it is essential to note that not all bacteria are harmful. In reality, certain bacteria are beneficial and serve important functions in the body, such as aiding in digestion. Therefore, the correct answer is FALSE.
Which of the following statements about antibiotics is incorrect?
Select the best answer.
Explanation:
Antibiotics are medications designed to inhibit or kill bacteria. Options A and B are true statements about antibiotics, as they interfere with bacteria's ability to survive and affect their multiplication. However, antibiotics do not cause more bacteria to grow; instead, they aim to decrease bacterial growth by killing or inhibiting them. Therefore, the statement in option C is incorrect, making it the correct answer.
Which characteristic is typically found in prokaryotic cells?
Select the best answer.
Explanation:
Prokaryotic cells are characterized by the absence of a nucleus and membrane-bound organelles. One common feature of prokaryotic cells is the presence of a capsule, which is a protective layer outside the cell wall. This capsule helps protect the cell and can also assist in adherence to surfaces. Therefore, the correct characteristic typically found in prokaryotic cells is that they have a capsule.
Which of the following cell parts are present in plant cells but not animal cells (there may be more than one answer):
Select the best answer.
Explanation:
The correct answer is 'D - Chloroplast' because it is a unique cell part found only in plant cells and is responsible for photosynthesis. Animal cells do not possess chloroplasts. Both plant and animal cells have cell membranes, which are essential for cellular function. The cell wall is a structural component specific to plant cells, providing support and protection. Ribosomes, responsible for protein synthesis, are organelles present in both plant and animal cells.
What are the three types of muscle tissue?
Select the best answer.
Explanation:
The correct answer is B: Smooth, skeletal, cardiac. Muscle tissue in the body is classified into three main types: smooth muscle (found in hollow organs like the digestive tract), skeletal muscle (attached to bones, responsible for voluntary movement), and cardiac muscle (specific to the heart, responsible for its rhythmic contractions). Therefore, option B is the correct answer as it lists the three types of muscle tissue.
Which statement accurately describes the head of a phospholipid?
Select the best answer.
Explanation:
The head of a phospholipid is hydrophilic, meaning it is attracted to water. This property allows the head to interact with water molecules. Additionally, the head is positioned on the outer side of the lipid bilayer in cell membranes, facing the watery environments inside and outside the cell. As a result, the correct answer is 'Both A and C,' as the head of a phospholipid is both hydrophilic and located on the outer side of the layer.
Why does cytokinesis occur?
Select the best answer.
Explanation:
Cytokinesis is the process of separating daughter cells at the end of cell division. It ensures that the newly formed cells can function independently. Choice A is incorrect because DNA duplication occurs during the S phase of the cell cycle, not during cytokinesis. Choice B is incorrect as organelles converting energy is not the primary purpose of cytokinesis. Choice C is irrelevant as the elimination of bacteria is not related to cytokinesis.
Why can animal cells use a contractile ring but plant cells cannot?
Select the best answer.
Explanation:
Plant cells have a rigid cell wall surrounding their cell membrane, which prevents the formation of a contractile ring during cell division. The contractile ring is a structure composed of actin filaments responsible for pinching the cell in two during cytokinesis. Since plant cells cannot form a contractile ring due to the presence of the cell wall, they rely on other methods such as cell plate formation to complete cell division.
Which option demonstrates complementary base pairing in DNA?
Select the best answer.
Explanation:
In DNA, adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). This is known as complementary base pairing. Adenine always pairs with thymine via two hydrogen bonds, forming a strong bond essential for DNA structure and replication. Therefore, the correct option that demonstrates complementary base pairing in DNA is A and T (D). This pairing is crucial during DNA replication and ensures the accurate transmission of genetic information.
Which DNA strand would complement this segment: ACTTGCA?
Select the best answer.
Explanation:
To find the complementary DNA strand, you need to pair each nucleotide with its complementary base: A with T, C with G, T with A, and G with C. Therefore, the correct match for ACTTGCA is TGAACGT. Only Choice A follows this complementary base pairing rule, making it the correct answer.
Why doesn't an antibiotic work for treating the flu symptoms in a patient?
Select the best answer.
Explanation:
Antibiotics are effective against bacterial infections, not viral infections like the flu. Influenza is caused by a virus, and antibiotics do not work against viruses. Using antibiotics inappropriately, such as for viral infections, can lead to antibiotic resistance and other adverse effects. Therefore, it is important to use antibiotics only when prescribed by a healthcare professional for bacterial infections.
Why is the nucleus important in a cell?
Select the best answer.
Explanation:
The correct answer is A. The nucleus is crucial in a cell because it stores the DNA, which contains the genetic information necessary for directing the cell's activities and determining its characteristics. The nucleus does not provide structural support, synthesize proteins, or produce energy from food; these functions are carried out by other cell organelles. Therefore, the main role of the nucleus is to safeguard and regulate the genetic material of the cell, ensuring proper cell function and inheritance of traits.
Why does cellular respiration occur?
Select the best answer.
Explanation:
Cellular respiration is the metabolic process in which cells convert nutrients, such as glucose, into energy in the form of ATP (adenosine triphosphate). This energy is crucial for the cell to perform its various functions and maintain life processes. Options A, B, and D do not accurately describe the purpose of cellular respiration, which is primarily about energy production to support cellular activities.
Anaerobic respiration happens in.............because..............
Select the best answer.
Explanation:
Anaerobic respiration occurs in bacteria because they live in environments with low oxygen levels. In the absence of oxygen, these organisms utilize anaerobic respiration to generate energy. Animals and plants primarily rely on aerobic respiration, which requires oxygen to produce energy efficiently. Plants do not lack sunlight; they can perform photosynthesis to derive energy. Animals do require energy but predominantly use aerobic respiration when oxygen is available.
Do all bacteria have negative effects and cause infections?
Select the best answer.
Explanation:
Not all bacteria have negative effects and cause infections. While some bacteria can lead to infections, many bacteria are beneficial and essential for various processes in nature and our bodies. Bacteria have diverse roles in ecosystems, including positive impacts like aiding digestion and nutrient recycling. Understanding the balance of beneficial and harmful bacteria is crucial for appreciating their significance in our lives.
Which of the following statements about antibiotics is not true?
Select the best answer.
Explanation:
Antibiotics are medications used to treat bacterial infections by either killing the bacteria or inhibiting their growth. Options A and B correctly describe the mechanisms of action of antibiotics, making them true statements. Option C is incorrect as antibiotics are meant to reduce bacterial growth, not cause more bacteria to grow. Option D is also true as antibiotics specifically target bacterial infections and do not work on viruses or other pathogens.
Which characteristic is true of prokaryotic cells?
Select the best answer.
Explanation:
Prokaryotic cells are characterized by the absence of a nucleus; instead, they have a nucleoid region where the genetic material is located. Prokaryotic cells often have a capsule, a protective layer outside the cell wall that plays a role in protection and adherence to surfaces. While eukaryotic cells have membrane-bound organelles, prokaryotic cells lack these membrane-bound structures. Prokaryotic cells are capable of movement, facilitated by structures like flagella or pili.
Select the cell parts that are present in plant cells but not animal cells (there may be more than one answer):
Select the best answer.
Explanation:
Chloroplasts are unique to plant cells and are responsible for photosynthesis, a process that converts light energy into chemical energy. Animal cells do not contain chloroplasts as they do not perform photosynthesis. Therefore, the correct answer is D - Chloroplast. The cell membrane is found in both plant and animal cells, serving as a protective barrier, while the cell wall is a rigid structure present in plant cells that provides support and protection. Ribosomes are cellular structures responsible for protein synthesis and are present in both plant and animal cells.
Where can epithelial tissue be found?
Select the best answer.
Explanation:
Epithelial tissue is a type of tissue that covers the surfaces of the body, inside and out. It forms the lining of various organs such as the skin, respiratory tract, gastrointestinal tract, and more. Therefore, epithelial tissue can be found in organ linings, making choice A the correct answer.
What are the three types of muscle tissue?
Select the best answer.
Explanation:
The correct answer is B: Smooth, skeletal, cardiac. Muscle tissue is classified into three main types: smooth muscle, skeletal muscle, and cardiac muscle. Smooth muscles are found in the walls of internal organs, blood vessels, and the digestive tract. Skeletal muscles are attached to bones and help in body movements. Cardiac muscles are found in the heart and are responsible for its rhythmic contractions.
What type of tissue is fat composed of?
Select the best answer.
Explanation:
The correct answer is A: Connective tissue. Fat tissue, also known as adipose tissue, is a type of connective tissue that stores energy in the form of fat. It provides insulation and serves as a reserve of energy. Muscle tissue (choice B) is responsible for movement, nervous tissue (choice C) transmits electrical signals throughout the body, and epithelial tissue (choice D) covers and protects body surfaces.
Which type of cells possess a cell membrane?
Select the best answer.
Explanation:
The cell membrane is a fundamental structure found in all cells, serving as a protective barrier and regulating the passage of substances in and out of the cell. Therefore, both prokaryotic and eukaryotic cells have a cell membrane. This makes option C the correct choice.
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