1. Cells and Tissues

2. Cells and Tissues
Carry out all chemical activities needed to sustain life
Cells are the building blocks of all living things
Tissues are groups of cells that are similar in structure and function
For Example: muscle tissue

3. Anatomy of the Cell Cells are not all the same
All cells share general structures
All cells have three main regions
Nucleus
Cytosol (cytoplasm)
Plasma membrane

4. The Nucleus Control center of the cell Three regions
Contains genetic material (DNA)
Three regions
Nuclear envelope (membrane)
Nucleolus (plural nucleoli)
Chromatin (DNA coiled around protein – protein acts as support for fragile DNA)

5. The Nucleus

6. The Nucleus continued…
Nuclear envelope ( or nuclear membrane)
Barrier of the nucleus; separates in from out
Consists of a double membrane
Contains nuclear pores that allow for exchange of material with the rest of the cell

7. The Nucleus continued….
Nucleoli
Nucleus contains one or more nucleoli
Sites of ribosome production
Ribosomes move into the cytoplasm through nuclear pores
Nucleolus

8. The Nucleus continued….
Chromatin
Composed of DNA and protein
Present when the cell is not dividing
Scattered throughout the nucleus
Coils and shortens to form chromosomes when the cell divides (protects fragile DNA during cell separation)

9. Plasma Membrane Barrier for cell contents
Controls what exits and enters the cell through osmosis and diffusion
Also contains proteins, cholesterol, and glycoproteins (proteins with sugar attached)

10. Plasma Membrane
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Membrane Structure

11. Plasma Membrane Specializations
Microvilli
Finger-like projections that increase surface area for absorption
Microvilli are present in our intestines; helps absorp nutrients and water we consume by eating

12. Cytoplasm or Cytosol
Cytoplasm is the material outside the nucleus and inside the plasma membrane
It’s the fluid that all organelles are suspended in

13. Cytoplasm Contains three major elements Cytosol Organelles Inclusions
Fluid that suspends other elements (jello)
Organelles
machinery of the cell
“Little organs” that perform functions for the cell
Inclusions
Chemical substances such as stored nutrients or cell products like waste

14. Cytoplasmic Organelles

15. Cytoplasmic Organelles
Mitochondria
“Powerhouses” of the cell
Change shape continuously
Carry out reactions where oxygen is used to break down food
Provides energy for cell

16. Cytoplasmic Organelles
Ribosomes
Made of protein and RNA
Sites of protein production
Found at two locations
Free in the cytoplasm
On Rough ER

17. Cytoplasmic Organelles
Endoplasmic reticulum (ER)
Fluid-filled tubes for carrying substances
Two types of ER
Rough endoplasmic reticulum
Covered with ribosomes
Makes proteins
Smooth endoplasmic reticulum
Functions in lipid and steroid production and also detoxifies drugs and pesticides that invade the cell

18. Rough Endoplasmic Reticulum
Ribosome
Protein
Protein inside transport vesicle
Transport vesicle buds off
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein).
The protein is packaged in a tiny membranous sac called a transport vesicle.
The transport vesicle buds from the rough ER and travels to the Golgi apparatus for further processing or goes directly to the plasma membrane where its contents are secreted.

19. Cytoplasmic Organelles
Golgi apparatus
Modifies and packages proteins
Produces different types of packages
Secretory vesicles
Cell membrane components
Lysosomes

20. Pathway 3 Pathway 2 Pathway 1 Rough ER Proteins in cisterna Cisterna
Membrane
Lysosome fuses with ingested substances
Transport vesicle
Golgi vesicle containing digestive enzymes becomes a lysosome
Pathway 3
Pathway 2
Golgi apparatus
Secretory vesicles
Pathway 1
Golgi vesicle containing membrane components fuses with the plasma membrane
Proteins
Golgi vesicle containing proteins to be secreted becomes a secretory vesicle
Secretion by exocytosis
Plasma membrane
Extracellular fluid

21. Lysosomes
Contain enzymes that digest worn-out or nonusable materials within the cell

22. Cytoplasmic Organelles
Peroxisomes
Membranous sacs of oxidase enzymes
Detoxify harmful substances such as alcohol, hydrogen peroxide and formaldehyde
Break down free radicals (highly reactive chemicals)

23. Cytoskeleton
Network of protein structures that extend throughout the cytoplasm
Provides the cell with an internal framework which keeps the cell 3-Dimensional

24. Cellular Projections Not found in all cells Used for movement
Cilia move materials across the cell surface
Located in the respiratory system to move mucus
Flagella propel the cell
The only flagellated cell in the human body is sperm