1. CELLS

2. Cell Theory All organisms are composed of one or more cells.
Cells are the smallest living units of all living organisms.
Cells arise only by division of a previously existing cell.

3. ALL CELLS HAVE Genetic material Cytoplasm fills cell interior –
single circular molecule of DNA in prokaryotes
double helix located in nucleus in eukaryotes – nuclear envelope (double membrane
Cytoplasm fills cell interior –
sugars, amino acids, salts
proteins
organelles
Plasma membrane encloses the cell

4. Visualizing Cells

5. Prokaryotic Cells Simplest organisms E.g. bacteria
Cytoplasm is surrounded by plasma membrane and encased in a rigid cell wall.
no distinct interior compartments
no membrane-bound organelles

6. Prokaryotic Cells Some use flagellum for locomotion (movement)
threadlike structures protruding from cell surface
Bacterial cell wall
Rotary
motor
Sheath
Flagellum

7. Eukaryotic Cells
Characterized by compartmentalisation of areas within the cell, and the presence of membrane-bound organelles.
Central vacuole – plants, storage
Vesicles (smaller)
Chromosomes - DNA and protein
Cytoskeleton (internal skeleton)
Cell walls – plants and fungi

8. Generalised Eukaryotic Cell

11. Nucleus Repository for genetic material Directs activities of the cell
Usually only one present in a cell
Nucleolus
Surface of nucleus bound by nuclear membrane
Nuclear pores –gatekeepers

12. Nucleus

13. Endoplasmic Reticulum
Rough ER - studded with ribosomes
Smooth ER - few ribosomes

14. Endoplasmic reticulum
Largest internal membrane
Functions in storage and secretion
Rough ER
Smooth ER

15. Endomembrane System Golgi apparatus
collect, package, and distribute molecules synthesised at one location in the cell and utilised at another location

16. Endomembrane System Vesicles - storage and transport
Lysosomes - contain digestive enzymes

17. Cytoplasm Extracellular fluid
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Cytoplasm
Endoplasmic
reticulum
Phagocytosis
Food
vesicle
Golgi
apparatus
Lysosomes
Transport
vesicle
Old or damaged
organelle
Plasma
membrane
Digestion of
phagocytized
food particles
or cells
Breakdown
of old
organelle
Extracellular
fluid

18. Mitochondria
A. "Powerhouse of the cell" – create energy usable for the cell

19. Chloroplasts
Contain chlorophyll: a photosynthetic pigment. Convert sunlight, carbon dioxide and water into glucose: chemical energy

20. Cytoplasm
Cytoplasm is the substance that fills the cell (excluding the nucleus). It is a jelly-like material that contains the cytosol (water, dissolved salts and organic molecules) and organelles. It is eighty percent water and usually clear in colour.

21. Plant Cells Large central vacuole Cell wall Chloroplast
often found in the centre of a plant, and serves as a storage facility for water and other materials
Cell wall
The cell wall is made up of cellulose, a complex carbohydrate
Chloroplast
Converts light energy to chemical energy