The Cell Theory

Which tenet of the Cell Theory explains why viruses are not considered living?
A. All cells arise from pre-existing cells.
B. Cells are the basic unit of structure in organisms.
C. All living organisms are composed of cells.
D. Cells contain hereditary information.

Answer: C (Key: Viruses lack cellular structure, violating this core tenet.)

What did Robert Hooke actually observe in cork that led to the term "cell"?
A. Living plant cells
B. Empty cell walls of dead plant matter
C. Bacterial colonies
D. Nuclei of eukaryotic cells

Answer: B (Key: Hooke saw nonliving cell walls, not functional cells.)

Which structure is unique to prokaryotic cells?
A. Nucleus
B. Nucleoid region
C. Mitochondria
D. Golgi apparatus

Answer: B (Key: Prokaryotes have a nucleoid, not a membrane-bound nucleus.)

How does the capsule benefit some prokaryotes?
A. It synthesizes proteins.
B. It stores genetic material.
C. It helps cells attach to surfaces.
D. It generates ATP.

Answer: C (Key: Capsules aid in adhesion to rocks, tissues, etc.)

Which feature is common to all cells (prokaryotic and eukaryotic)?
A. Cell wall
B. Membrane-bound organelles
C. Ribosomes
D. Nucleus

Answer: C (Key: Ribosomes are universal for protein synthesis.)

What major difference distinguishes eukaryotic cells?
A. Presence of a nucleoid
B. Lack of cytoplasm
C. Membrane-enclosed nucleus
D. Absence of DNA

Answer: C (Key: Eukaryotes have a true nucleus; prokaryotes do not.)

Which scientist contributed the idea that cells arise from pre-existing cells?
A. Anton van Leeuwenhoek
B. Rudolf Virchow
C. Matthias Schleiden
D. Theodor Schwann

Answer: B (Key: Virchow completed the Cell Theory with this tenet.

Why is the cell membrane essential for both cell types?
A. It houses DNA.
B. It regulates interactions with the environment.
C. It synthesizes ribosomes.
D. It forms the cell wall.

Answer: B (Key: The membrane controls what enters/exits the cell.)

Which statement aligns with the modern Cell Theory?
A. Cells vary widely in chemical composition.
B. Energy transformations occur outside cells.
C. Hereditary information is passed during cell division.
D. Viruses are exceptions to the Cell Theory.

Answer: C (Key: Modern theory includes genetic inheritance in cells.)

What key observation did Schleiden and Schwann share?
A. Cells move using flagella.
B. All plants and animals are made of cells.
C. Cells lack cytoplasm.
D. Prokaryotes evolved from eukaryotes.

Answer: B (Key: Their work established cells as the building blocks of life.)