Cell Theory
What are the three principles of cell theory?
1) All living things are made of cells. 2) Cells are the basic unit of structure and function in living things. 3) All cells come from pre-existing cells.
What’s the main difference between active and passive transport?
Active transport requires energy (ATP); passive transport does not.
What are the two main purposes of cell division?
Growth and repair/replacement of damaged or old cells.
Define homeostasis
Maintaining a stable internal environment despite external changes.
What element does “O” represent on the periodic table?
Oxygen
This organelle is known as the powerhouse of the cell because it produces ATP.
Mitochondria
The movement of water through a selectively permeable membrane is called ____.
Osmosis
During which phase do chromosomes line up in the middle of the cell?
Metaphase
A group of similar cells working together to perform a specific function is called a ____.
Tissue
What is the only planet in our solar system known to rotate on its side?
Uranus
Compare prokaryotic and eukaryotic cells using one key difference.
Prokaryotes have no nucleus or membrane-bound organelles; eukaryotes do.
Describe what happens to an animal cell placed in a hypertonic solution.
Water leaves the cell; it shrinks (crenates) due to higher solute concentration outside.
Differentiate between cytokinesis in plant and animal cells.
In animals, a cleavage furrow forms; in plants, a cell plate forms.
What is a stem cell, and why are they important?
An undifferentiated cell that can become any type of specialized cell; key to growth and repair.
Which animal can sleep for up to three years if food is scarce?
A snail
Name two organelles that are found in plant cells but not in animal cells, and explain their function.
Chloroplasts (photosynthesis) and cell wall (structure and support).
Explain how the cell membrane helps maintain homeostasis through transport processes.
It controls what enters and leaves the cell, regulating internal balance through selective permeability.
Explain how checkpoints in the cell cycle help prevent cancer.
They ensure DNA is replicated correctly and that cells only divide when conditions are right — preventing uncontrolled growth.
Define differentiation and give one example of when it occurs in development.
Process where unspecialized cells become specialized; ex: stem cells → nerve or muscle cells.
What’s the hardest natural substance on Earth?
Diamond
Explain how the structure of the endoplasmic reticulum and Golgi apparatus help the cell maintain homeostasis.
The ER synthesizes and transports proteins and lipids; the Golgi modifies, packages, and ships these molecules — ensuring the cell’s internal balance.
Compare endocytosis and exocytosis, and give one example of each process.
Endocytosis brings materials into the cell (ex: engulfing bacteria). Exocytosis releases materials (ex: neurotransmitter release).
What happens to normal cell regulation when cancer develops?
Regulatory genes mutate, causing uncontrolled division; cells ignore checkpoints and apoptosis signals.
Explain the term metastasis and its relationship to cancer.
Metastasis is the spread of cancer cells to other body parts through blood or lymph systems.
In the Marvel movies, what type of metal is Captain America’s shield made from?
Vibranium