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. You observe that plants in a greenhouse grow faster when exposed to red light compared to blue light. What is the next best step in your investigation?
- A. Increase the intensity of the blue light.
- B. Decrease the intensity of the red light.
- C. Grow plants in complete darkness.
- D. Grow plants exposed to both red and blue light at equal intensities.
Correct answer: D
Rationale: The next best step in the investigation would be to grow plants exposed to both red and blue light at equal intensities. This will help determine if the observed growth difference is due to the specific wavelength of light (red vs. blue) or if it is related to the intensity of light. By exposing plants to both red and blue light at equal intensities, you can compare their growth rates and determine if one wavelength has a greater effect on plant growth.
3. Fertilization of the egg by sperm typically occurs in the:
- A. Ovary
- B. Fallopian tube
- C. Uterus
- D. Vagina
Correct answer: B
Rationale: The correct answer is B: Fallopian tube. Fertilization of the egg by sperm typically occurs in the fallopian tube. After ovulation, the egg travels through the fallopian tube where it can meet sperm for fertilization. The fallopian tube provides an ideal environment for fertilization to occur due to its proximity to the ovaries and the uterus. The other options, A: Ovary, C: Uterus, and D: Vagina, are not the typical sites for fertilization to take place. Therefore, the fallopian tube is the most appropriate location for the union of egg and sperm to form a zygote.
4. What is the term for the time it takes for a wave to complete one full cycle?
- A. Frequency
- B. Amplitude
- C. Period
- D. Wavelength
Correct answer: c
Rationale: The period of a wave is the time taken for one complete oscillation or cycle.
5. Biodiversity is important for healthy ecosystems because it:
- A. Increases competition for resources
- B. Provides stability and resilience to disturbances
- C. Slows down nutrient cycling
- D. Reduces the number of decomposers
Correct answer: B
Rationale: Rationale: Biodiversity refers to the variety of living organisms in a particular area. A diverse ecosystem is better able to withstand and recover from disturbances such as natural disasters, climate change, or human impacts. This is because different species play unique roles in the ecosystem, and a higher level of biodiversity means there are more species available to fulfill these roles. For example, if one species is negatively affected by a disturbance, other species may be able to compensate for its loss, maintaining the overall functioning of the ecosystem. Therefore, biodiversity provides stability and resilience to disturbances, making ecosystems healthier and more sustainable.
6. What type of joint allows for the most movement?
- A. Ball-and-socket joint (shoulder)
- B. Hinge joint (elbow)
- C. Fibrocartilaginous joint (wrists)
- D. Suture joint (skull)
Correct answer: A
Rationale: Rationale: A ball-and-socket joint allows for the most movement among the options provided. This type of joint is characterized by a rounded end of one bone fitting into a cup-like socket of another bone, allowing for a wide range of motion in multiple directions. The shoulder joint is a prime example of a ball-and-socket joint, enabling movements such as flexion, extension, abduction, adduction, and rotation. In contrast, a hinge joint (option B) like the elbow primarily allows for movement in one plane (flexion and extension). Fibrocartilaginous joints (option C) like the wrists have limited movement due to the presence of cartilage between the bones. Suture joints (option D) in the skull are immovable joints that provide structural support but do not allow for significant movement.
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