Practice Exceptions To Cell Theory (1.2) - Cell Theory - IB 12 Biology
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Exceptions to Cell Theory

Practice - Exceptions to Cell Theory - 1.2

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Practice Questions

Test your understanding with targeted questions

Question 1 Easy

Name one exception to the cell theory.

  • Answer: Striated muscle fibers, giant algae (e.g., Acetabularia), or aseptate fungal hyphae.
  • Hint: Think of unusually large or multinucleated structures that don't fit the "one nucleus, one cell" rule.

💡 Hint: Think of unusually large or multinucleated structures that don't fit the "one nucleus, one cell" rule.

Question 2 Easy

What is unusual about striated muscle fibers?

  • Answer: They are multinucleated (contain many nuclei) and are much larger than typical cells (can be 30mm or longer).
  • Hint: Consider the number of "control centers" and the physical length of the fiber.

💡 Hint: Consider the number of "control centers" and the physical length of the fiber.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

Which of the following is a recognized exception to the cell theory because it lacks internal partitions?

  • Type: mcq
  • Options: Red blood cell, Bacteria, Aseptate fungal hyphae, Skin cell
  • Correct Answer: Aseptate fungal hyphae
  • Explanation: Aseptate hyphae are not divided into individual cells by septa; instead, they exist as a continuous mass of cytoplasm with many nuclei.
  • Hint: Look for the option that describes a structure without internal "walls."
Red blood cell
Bacteria
Aseptate fungal hyphae
Skin cell * **Correct Answer**: Aseptate fungal hyphae * **Explanation**: Aseptate hyphae are not divided into individual cells by septa; instead
they exist as a continuous mass of cytoplasm with many nuclei. * **Hint**: Look for the option that describes a structure without internal "walls."

💡 Hint: Look for the option that describes a structure without internal "walls."

Question 2

True or False: Every individual unit of life described by cell theory must contain only one nucleus.

  • Type: boolean
  • Options: True, False
  • Correct Answer: False
  • Explanation: Striated muscle fibers and aseptate hyphae are multinucleated, meaning they contain many nuclei within a single membrane.
  • Hint: Recall the structure of a human muscle fiber.
True
False * **Correct Answer**: False * **Explanation**: Striated muscle fibers and aseptate hyphae are multinucleated
meaning they contain many nuclei within a single membrane. * **Hint**: Recall the structure of a human muscle fiber.

💡 Hint: Recall the structure of a human muscle fiber.

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Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

Explore how the existence of exceptions to the cell theory supports the idea that scientific theories are dynamic and adaptable.

  • Solution: Scientific theories are based on the best available evidence. When exceptions like Acetabularia are discovered, the theory isn't discarded; instead, the definition of a "cell" is broadened. This shows that science is a process of constant refinement rather than a collection of static, unchanging rules.
  • Hint: Think about how a map changes when a new island is discovered.

💡 Hint: Think about how a map changes when a new island is discovered.

Challenge 2 Hard

Propose how understanding exceptions like Acetabularia could impact future research in developmental biology or genetics.

  • Solution: Because Acetabularia is so large yet contains only one nucleus (located in its base), it is an ideal model for studying how a single nucleus controls the growth of distant parts of a cell. Researchers can use it to study gene expression and regeneration without the complexity of a multicellular system.
  • Hint: Think of the advantage of having a "giant" version of a cell for laboratory experiments.

💡 Hint: Think of the advantage of having a "giant" version of a cell for laboratory experiments.

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Reference links

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