Cell Theory
All living things are made of these.
Cells
This organelle controls many cell activities and contains DNA.
Nucleus
These blood cells carry oxygen using hemoglobin.
Red Blood Cells
Looking at cork, this scientist coined the term “cell.”
Robert Hooke
This is the smallest level in the organization of a multicellular organism.
Cell
This is the smallest unit that can carry out all life processes.
The cell
This organelle releases usable energy from food.
Mitochondrion
These cells help defend the body against germs.
White blood cells
This scientist observed living microorganisms through a microscope.
Antonie van Leeuwenhoek
A group of similar cells working together forms this.
Tissue
Where do new cells come from?
Pre-existing Cells
This flexible barrier controls what enters and leaves the cell.
Cell membrane
These cells carry messages through the body.
Nerve cells, or neurons
This scientist concluded that plants are made of cells.
Matthias Schleiden
Different tissues working together form this.
Organ
Name one major idea of cell theory.
All living things are made of cells; cells are the basic unit of life; or all cells come from existing cells.
This plant-cell organelle captures sunlight for photosynthesis.
Chloroplast
These plant cells have thin extensions that help absorb water and minerals from soil.
Root hair cells
This scientist concluded that animals are made of cells.
Theodor Schwann
A group of organs working together to perform major functions forms this.
Organ system
Cells are the first level of organization. Which part of the cell theory does this support?
Cells are the basic unit of life
This organelle breaks down waste and dead cells. (Hint: Only in animal cells)
Lysosomes
A red blood cell’s flexible, flattened shape helps it squeeze through narrow blood vessels. What does this show about specialized cells?
A cell’s structure helps it perform its function.
This scientist stated that all cells come from existing cells.
Rudolf Virchow
Put these levels in order from smallest to largest: organ, organism, cell, tissue, organ system.
Cell, tissue, organ, organ system, organism