Which of the following cytoskeletal elements is composed of tubulin and is involved in cell division?
A. Collagen fibers
B. Microtubules
C. Microfilaments
D. Intermediate filaments
Answer: Option B
Solution (By JKExamLibrary)
Microtubules are hollow, tube-like structures made of the protein tubulin. They are a major component of the cytoskeleton and play a crucial role in maintaining cell shape, intracellular transport, and cell division by forming the mitotic spindle that separates chromosomes during mitosis and meiosis.
Explanation:
Alveoli have a rich capillary network for O₂/CO₂ exchange. Inhalation is active (diaphragm contracts), trachea divides into two bronchi (not bronchioles).
Explanation:
The living state and all vital functions first become evident at the cellular level. While macromolecules are present in both living and non-living systems, it is the organized interaction of these molecules within a cell that manifests life. Cells are the fundamental structural and functional units of life.
Consider the following statements about ecosystem:
1. Producers are autotrophs.
2. Consumers are heterotrophs.
3. Decomposers recycle nutrients.
Which of the above is/are correct?
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