1. The Cell
Mr. Ramos

2. Introduction to Cells
The cell is life’s basic unit of structure and function.
The cell is the smallest unit of living material that can carry out all the activities necessary for life.
Two types of cells known: Eukaryotic and Prokaryotic
Plant Cell

3. “Omnis Cellula e Cellula” Rudolf Virchow
The Cell Theory
All living things are composed of cells.
Cells are the basic unit of structure and function in living things.
New cells are produced from existing cells.
“Omnis Cellula e Cellula” Rudolf Virchow

4. Pioneers of Microbiology
Anton Van Leeuwenhoek:
Father of microscopy and microbiology
Built first practical microscope
First to see & describe bacteria, yeast, & organisms in water.
Robert Hooke:
English father of microscopy
Looked at a thin slice of cork under a microscope & noticed chambers, which he called “cells.”

5. The Compound Light Microscope
A compound light microscope uses multiple lenses
The nosepiece can holds 3 or 4 objective lenses with the power 4x, 10x, 40x, & 100x
Total magnification (power): ocular lens X objective lens x X 40x = 400x

6. Confocal Light Microscope
Confocal Light Microscopes can observe living cells in 2D by scanning them with a laser beam.

7. Only for nonliving, preserved cells and tissues
Electron Microscopes
Electron Microscopes use beams of electrons to see things smaller than cells, such as cell membranes, chromosomes, organelles, and more.
Transmission Electron Microscope (TEM): can see the internal structure of cells (e.g. organelles)
Scanning Electron Microscope (SEM): can see the full details of the 3D surface of a specimen

8. Eukaryotes vs. Prokaryotes
Eukaryotic Cells
Prokaryotic Cells
Nucleus
Yes No
Organelles
Ribosomes
DNA
Size
Generally bigger than prokaryotes
Generally smaller than
eukaryotes
Examples
Animal cells, Plant cells, Fungi, Protists
Bacteria and Archaea

9. Prokaryotes No nucleus No membrane bound organelles
Have DNA
No membrane bound organelles
Have a plasma membrane
Most have a cell wall
Have ribosomes
Smaller size
Bacteria
Archaea

10. Eukaryotic Parts and Functions
Organelles are little organs.
Nucleus: cell’s command center (home of DNA)
Nucleolus: ribosomal RNA is assembled (rRNA)
Cytoplasm: area outside of the nucleus where the organelles are found
Plasma Membrane: the cell membrane regulates what goes in and out of the cell
Rough Endoplasmic Reticulum (RER): contains ribosomes & synthesizes proteins for cells to export
Smooth Endoplasmic Reticulum (SER): does not contain ribosomes and is used to synthesize fats and detoxification of drugs

11. Eukaryotic Parts and Functions

12. Eukaryotic Parts and Functions
Ribosomes: factories for making proteins
Golgi Apparatus: modify, sort, and package proteins made in the rough endoplasmic reticulum.
Mitochondria: makes energy for the cell & contains its own DNA
Lysosomes: digest old organelles, macromolecules, and remove junk from the cell.
Vacuoles: store materials, such as water, salts, proteins, and carbohydrates. They are like a closet or kitchen cabinet.
Chloroplasts: converts sunlight into chemical energy & contains its own DNA

13. Eukaryotic Parts and Functions

14. Eukaryotic Cells: Plant Cell & Animal Cells
Plant and animal cells are both eukaryotic cells.
They contain a nucleus & most of the same organelles.
Differences:
Plants have a cell wall.
Plants have chloroplasts.
Plants have a large vacuole.
Plants do not have centrioles.

15. Plant Cell vs. Animal Cell

16. Cell Membrane
The cell membrane controls what goes into and out of a cell.
All cells have a cell membrane.
It is composed of two layers of phospholipids.
phospholipid bilayer
Cell membranes may also contain proteins & carbohydrates.
Fluid Mosaic Model

17. Cell Wall
Some eukaryotic cells and some prokaryotic cells have cell walls.
Plants, fungi, algae, and prokaryotes (bacteria & archaea)
Cell walls provide support and protection
Plant cell walls are made of cellulose.
Fungi cell walls are made of chitin.

18. Cytoskeleton The cytoskeleton is the skeleton of the cell
Microtubules, Intermediate Filaments, & Microfilaments
Microtubules contain the protein tubulin & they participate in cell division & cell movement
Examples: Centrioles, Cilia & Flagella
Microfilaments contain the protein actin and are found in muscle cells. They also support cells & help them move.

19. Cilia and Flagella
Microtubules make up cilia and flagella.

20. Cell Transportation Cells need to get things in and out
How things get in and out:
Semipermeability of the cell membrane
The size and charge of the particles
Lipid molecules can easily go through the cell membrane
Water may also go through the cell membrane, but not as easily as lipids.

21. Passive Transport: Diffusion
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
Diffusion does not use energy
Passive Transport

22. Passive Transport: Osmosis
Osmosis is the diffusion of water from an area of higher water concentration to an area of lower water concentration.
In osmosis, it is water that moves, not the particles.
Osmosis does not use energy
Passive Transport

23. Active Transport Active transport requires energy.
Movement from a lower concentration to a higher concentration
Note: this is the opposite of diffusion & osmosis

24. Endocytosis and Exocytosis
Endocytosis involves bringing things into the cell.
Phagocytosis: cell eating
Pinocytosis: cell drinking
Receptor-mediated endocytosis: brings materials in along with cell receptors.
Exocytosis involves taking things out of the cell.
These terms are only used for larger molecules that cannot get in or out of the cell through diffusion or osmosis

25. Endocytosis & Exocytosis