Overview
This lecture introduces cells as the building blocks of all living organisms, explores the structure and components of animal and plant cells, and explains key differences between them.
What Are Cells?
- All living organisms are made up of tiny building blocks called cells.
- Most cells are microscopic and require a microscope to be seen.
- The two main cell types discussed are animal cells and plant cells.
Animal Cell Components
- Animal cells have four main parts: cell membrane, cytoplasm, mitochondria, and nucleus.
- The cell membrane controls what enters and leaves the cell.
- The cytoplasm is a jelly-like substance where chemical reactions occur and other components float.
- Mitochondria are sites of respiration and produce energy for the cell (the cell's powerhouse).
- The nucleus controls cell activities and contains genetic material for making new cells.
Plant Cell Components
- Plant cells have a more regular, rectangular structure for added support.
- Plant cells contain all the features of animal cells: nucleus, cell membrane, cytoplasm, and mitochondria.
- Plant cells also have three extra features: cell wall, vacuole, and chloroplasts.
- The cell wall, made of cellulose, provides strength and keeps the cell rigid.
- The vacuole is a large sac containing cell sap, which keeps the cell firm.
- Chloroplasts contain chlorophyll to absorb sunlight, enabling photosynthesis.
Key Terms & Definitions
- Cell — The basic building block of all living organisms.
- Cell Membrane — The barrier that controls entry and exit of substances in the cell.
- Cytoplasm — Jelly-like fluid where the cell’s chemical reactions take place.
- Mitochondria — Organelles where respiration occurs to produce the cell's energy.
- Nucleus — The control center of the cell containing genetic information.
- Cell Wall — A tough outer layer in plant cells made of cellulose, providing support.
- Vacuole — A fluid-filled sac in plant cells containing cell sap for firmness.
- Chloroplast — Organelle in plant cells, containing chlorophyll to capture light for photosynthesis.
- Cellulose — A strong fiber making up the plant cell wall.
- Chlorophyll — Green pigment in chloroplasts that absorbs sunlight for photosynthesis.
Action Items / Next Steps
- Review diagrams of animal and plant cells, labeling each component.
- Memorize the functions of each cell part for both animal and plant cells.