1. Ch 4 – A Tour of the Cell
The cell is the basic unit of structure and function in the body.
Prokaryote v. Eukaryote
Are smaller than eukaryotic cells
Lack internal structures surrounded by membranes
Lack a nucleus
There are three principal parts:
plasma membrane (plasmalemma)
cytoplasm and organelles
nucleus..

2. Prokaryotic
flagella
Nucleoid region (DNA)
Ribosomes
Plasma
membrane
Cell wall
Capsule
Pili

3. Cytoskeleton
Ribosomes
Centriole
Lysosome
Flagellum
Not in most
plant cells
Nucleus
Smooth
endoplasmic
reticulum (ER)
Golgi
apparatus
Rough
Mitochondrion
Plasma
membrane

4. Cytoskeleton
Mitochondrion
Nucleus
Rough endoplamsic reticulum (ER)
Ribosomes
Smooth
endoplasmic
reticulum (ER)
Golgi apparatus
Plasmodesmata
Plasma
membrane
Chloroplast
Cell wall
Central
vacuole
Not in animal cells

5. The plasma membrane is composed of a phospholipid bilayer with embedded proteins.
Hydrophilic
region of
protein
Phospholipid
bilayer
Hydrophobic
region of protein
(b) Fluid mosaic model of membrane

6. The functions of plasma membrane include:
selectively permeable and surrounds the cellular contents.
regulates the passage of materials into and out of the cell.
participates in intercellular communications..

7. Transport of materials across the plasma membrane
In general:
large macromolecules cannot cross the membrane
charged molecules cannot cross the membrane
small, non-charged molecules can cross
water can cross..

8. The cytoplasm (cytosol) is the gelatinous material inside the cell membrane but outside the nucleus.
The cytoplasm contains organelles which are sub-cellular structures that perform discrete functions. True organelles are bounded by a phospholipid membrane..

9. The nucleus is a double-membrane organelle containing the nucleic acids (DNA) and at least one nucleolus (contains ribosomal RNA).
This organelle stores the genetic infor-mation and contains the blueprints for almost all protein syntheses.
DNA RNA protein..

10. Ribosomes
Chromatic
Nuclear
envelope
Nucleolus
Pore

11. Organelles of a Typical Cell
Ribosome
Production of proteins – located attached to ER or free-floating
Endoplasmic
Reticulum (ER)
*Rough
*Smooth
Passageway for materials
Produces proteins & processes molecules for secretion
Produces lipids & detoxifies drugs & stores Ca++
Golgi Apparatus
Packages material for export & processes macromolecules
Vacuole & vesicle
Storage..

12. Contains digestive enzymes. Each contains one specific enzyme.
Lysosome
Contains digestive enzymes. Each contains one specific enzyme.
Chloroplasts
Carries out photosynthesis:
6CO2 + 6H2O C6H12O6 + 6O2
Mitochondria
Aerobic cellular respiration:
C6H12O6 + 6O CO2 + 6H2O +ATP
Cilia, flagella, microvilli
Surface projections – increase surface area & produce movement..

13. CELL-CELL INTERACTIONS
Plant cells are encased by cell walls
These provide support for the plant cells
Walls of two adjacent
plant cells
Vacuole
Plasmodesmata
(channels between cells)

14. Animal cells lack cell walls
They secrete a sticky covering called the extracellular matrix
This layer helps hold cells together
Animal cells connect by various types of junctions
Tight junctions
Adhering junctions
Communicating junctions

15. Extracellular matrix
(a) Tight junctions
(b) Anchoring
junctions
(c) Communicating
Plasma membranes
of adjacent cells