ATI TEAS 7
Biology
1. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear
- A. Pink
- B. Blue
- C. Red
- D. Purple
Correct answer: D
Rationale: Rationale: The Gram stain is a differential staining technique that divides bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. As a result, Gram-positive bacteria appear purple under the microscope after staining. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, causing them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain.
2. Certain medications can suppress the immune system to treat autoimmune diseases or prevent organ rejection after transplants. What is a potential risk associated with immunosuppressive drugs?
- A. Increased risk of developing allergies
- B. Increased susceptibility to infections
- C. Both a and b
- D. Neither a nor b
Correct answer: C
Rationale: The correct answer is C: 'Both a and b.' Immunocompromised individuals, who take immunosuppressive drugs, are at an increased risk of developing allergies due to the altered immune response. Additionally, these drugs suppress the immune system's ability to fight off infections, making individuals more susceptible to various pathogens. Therefore, both increased risk of developing allergies and increased susceptibility to infections are potential risks associated with immunosuppressive drugs, making option C the correct choice.
3. Which property of matter remains constant regardless of changes in gravity?
- A. Mass
- B. Weight
- C. Volume
- D. Density
Correct answer: A
Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in gravity. Weight, on the other hand, is the force of gravity acting on an object's mass and can vary depending on the strength of gravity. Volume is the amount of space an object occupies, which can change depending on the environment, and density is the mass of an object per unit volume, which can also change with variations in gravity.
4. What is the tough, fibrous tissue that connects bones at joints called?
- A. Cartilage
- B. Ligaments
- C. Tendons
- D. Fascia
Correct answer: B
Rationale: The correct answer is B: Ligaments. Ligaments are the tough, fibrous tissue that connects bones at joints. They provide stability and support to the joints, preventing excessive movement that could result in injury. Cartilage is a smooth, rubbery tissue that covers the ends of bones and cushions joints. Tendons are fibrous cords that attach muscles to bones, allowing for movement. Fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, providing support and protection. Therefore, in this case, the term that specifically refers to the tissue connecting bones at joints is ligaments.
5. Which of the following is an example of a nonpolar solvent?
- A. Water
- B. Ethanol
- C. Acetone
- D. Hydrochloric acid
Correct answer: B
Rationale: Rationale: - Water (option A) is a polar solvent due to its uneven distribution of charge, with the oxygen atom being partially negative and the hydrogen atoms being partially positive. - Ethanol (option B) is a nonpolar solvent because it has a symmetrical molecular structure that does not result in significant charge separation. - Acetone (option C) is a polar solvent as it contains a carbonyl group that results in a partial negative charge on the oxygen atom. - Hydrochloric acid (option D) is a polar solvent due to the presence of the highly electronegative chlorine atom, which results in a partial negative charge.
6. Which property of a wave determines its pitch in sound waves?
- A. Amplitude
- B. Frequency
- C. Wavelength
- D. Speed
Correct answer: B
Rationale: The pitch of a sound wave is determined by its frequency. Frequency refers to the number of cycles of a wave that occur in a unit of time, usually measured in hertz (Hz). Higher frequencies correspond to higher pitches, while lower frequencies correspond to lower pitches. Amplitude refers to the height of a wave and is related to the loudness of the sound. Wavelength is the distance between two consecutive points in a wave that are in phase, and speed is the rate at which a wave travels through a medium.
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