1. Introduction to the Cell
Learning Outcome B2
Introduction to the Cell

2. Cell Theory
Modern Biology considers the cell theory one of its main ideas:
The cell is the basic unit of life
All organisms are composed of one or more cells
All cells come from living things

3. Cell Theory Cells can be divided into two groups:
Prokaryotic cells – organelles are not surrounded by a membrane.
Example – bacteria
Eukaryotic cells – organelles are surrounded by membranes.
Example – multicellular organisms and some unicellular organisms

4. Prokaryotic Cell

5. Eukaryotic Cell

6. Bacteria
Over 5000 different species and can be found everywhere on Earth.
Can be harmful and helpful to humans
Example – diseases
Example – antibiotics
Classified based on shape:
Cocci – sphere-shaped
Bacilli – rod-shaped
Spirilla – spiral shaped

7. Cocci Bacteria

8. Bascilli Bacteria

9. Viruses Example – HIV, chicken pox, cold sores, flu
Not considered to be living because they can only reproduce within a host.
Do not have a nucleus or any other organelles.
Only have a ring of DNA, so reproduction can occur.

10. Virus

11. Types of Cells
There are two types of cells:
plant
animal

12. Composition of Cells Cells are made up of organelles.
Organelle– is a structure within a cell that carries out functions that allow a cell to survive.
Take up 5-30% of a cell , the rest of the cell is composed of water.
Many organelles are covered by a membrane, which is a thing covering.

13. Types of Organelles
Cell Membrane – a membrane that covers the entire cell, that controls and regulates what enters and exits the cell.

14. Types of Organelles
Cytoplasm – is a jelly-like substance within the cell that contains organelles, water and other materials essential for life.

15. Types of Organelles
Nucleus – is the control centre of the cell and it contains DNA (deoxyribonucleic acid), which is the hereditary material of an organism.

16. Types of Organelles
Mitochondria – is an organelle that produces energy via cellular respiration.
It takes energy from the food we eat (metabolism).

17. Types of Organelles Ribosomes – make proteins.
Some ribosomes are attached to the endoplasmic reticulum, while some are floating in the cytoplasm.

18. Types of Organelles
Endoplasmic Reticulum – is a network of folded membrane channels.
Have a large surface are in a small space.

19. Types of Organelles
Golgi Body (AKA – Golgi Apparatus) – is an organelle that sorts proteins an packs them into membrane-wrapped structures called vesicles.

20. Types of Organelles
Vesicles – carry water, nutrients, and proteins into and out of the cell.

21. Types of Organelles
Vacuoles – are an organelle used to store water in plants, and wastes in animal cells.
The vacuoles in plant cells are large, while in animal cells they are very small.

22. Types of Organelles
Lysosomes – are vesicles that contain digestive enzymes that break down food particles, cell wastes and worn-out cell parts.

23. Plant vs. Animal Cells
There are several differences between plant and animal cells.
Only plants cells have:
Cell Wall – this is a tough rigid structure that surrounds the cell membrane, and it gives plant cells their box shape.
The cell wall protects the cell by supporting the growing cell.
Chloroplasts – trap energy from the sun and change it to chemical energy.
Photosynthesis – Light + CO2 + H2O  food (glucose) + O2