CELL BIOLOGY: THE BUILDING BLOCKS OF LIFE
An overview of cells, their parts, and how they function in living organisms.
Prepared by: Ma. Johanna B. Testa, LPT
CELL THEORY
- All living things are composed of cells.
- The cell is the basic unit of structure and function in living things.
- All cells come from pre-existing cells.
Introduced by Schleiden, Schwann, and Virchow.
LEVELS OF ORGANIZATION IN AN ORGANISM
From simplest to most complex:
1. Cell – smallest unit of life
2. Tissue – group of similar cells
3. Organ – group of tissues working together
4. Organ System – group of organs
5. Organism – entire living thing
ORGANISM
- a living thing
PROKARYOTIC VS. EUKARYOTIC CELLS
BASIC CELL PARTS
Cell Membrane: controls what enters and leaves the cell
Cytoplasm: jelly-like fluid that holds organelles
Nucleus: contains genetic material (DNA)
ORGANELLES AND THEIR FUNCTIONS
Mitochondria: powerhouse of the cell, produces energy (ATP)
Ribosomes: synthesize proteins
Endoplasmic Reticulum (ER): transports materials
• Rough ER: with ribosomes
• Smooth ER: no ribosomes
ORGANELLES AND THEIR FUNCTIONS
Golgi Apparatus: packages and ships proteins
Lysosomes: contain digestive enzymes
Vacuoles: store water, nutrients, or waste
Chloroplasts (plant cells): site of photosynthesis
Cell Wall (plant cells): provides structure and protection
PLANT CELL DIAGRAM
ANIMAL CELL DIAGRAM
COMPARING PLANT AND ANIMAL CELLS
Both have nucleus, membrane, mitochondria, ER, etc.
Only plants have chloroplasts, cell wall, large central vacuole
Animal cells may have small vacuoles, lysosomes more common
REVIEW QUESTIONS
1. What are the 3 parts of the cell theory?
2. Which organelle is responsible for energy production?
3. What structure is found only in plant cells?
4. Put in order: cell, organ, tissue, system, organism
REFERENCES
Khan Academy: Cells and Organelles
Britannica Kids: Cell Theory and Function
McGraw-Hill Science: Introduction to Cells