This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “The Cytoskeleton”.
1. How many filamentous structures together comprise the cytoskeleton?
Explanation: Three filamentous structures: microtubules, microfilaments and intermediate filaments together comprise the cytoskeleton.
2. Cytoskeletal filaments are polymers of ________________
b) ribonucleic acids
c) deoxyribonucleic acids
Explanation: The three cytoskeletal elements are polymers of proteins subunits held together by weak, non-covalent bonds. This characteristic construction leads to rapid assembly and disassembly.
3. Microtubules are formed of the protein ____________
Explanation: The cytoskeleton element, microtubules are long, hollow and unbranched polymer tubes composed of the protein tubulin.
4. Microfilaments are composed of the protein ____________
Explanation: Microfilaments are solid, and thin structures organized into branching networks, composed of the protein actin. These play a role in cell motility and contractility.
5. Microtubules of a dividing cell form the mitotic spindle.
Explanation: Microtubules of a dividing cell form the mitotic spindle required for chromosome segregation. Microtubules in the nerve and epithelial cells play a role in organelle transport.
6. The cytoskeleton framework plays a role in positioning of the cell organelles.
Explanation: The internal framework of a cell (the cytoskeleton) is responsible for positioning the various organelles. This is particularly evident in polarized epithelial cells where organelles are specifically ordered from apical to the basal end of the cell.
7. Cilia and flagella are ________________
a) intermediate filaments
Explanation: Cilia and flagella are microtubule-containing locomotor organelles that protrude from the cell surface of prokaryotic organisms.
8. Which of the following are found only in animal cells?
a) intermediate filaments
Explanation: Nucleus is found in all living matter, although in contrasting morphology. Of the three cytoskeletal elements, intermediate filaments are only found in the animals.
9. Which of the following is found in the nucleus of animal cells?
b) actin filaments
d) intermediate filaments
Explanation: Intermediate filaments provide structural support to the organelle. They are found in the cytoplasm as well as the nucleus of the animal cells.
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