1. STRUCTURES AND FUNCTIONS OF EUKARYOTIC CELLS

2. STRUCTURES AND FUNCTIONS OF EUKARYOTIC CELLS
Recall: The kingdoms fungi, protista, plantae and animalia are all composed of eukaryotic cells
Similarities:
Membrane bound nucleus with DNA
Cell membrane composed of a phospholipid bilayer
Cytoplasm filled interior (everything outside the nucleus but within the cell membrane – cytosol, organelles, molecules, ions)

3. ANIMAL CELL

4. PLANT CELL

5. NUCLEUS Contains DNA CHROMATIN: uncondensed DNA mixed with proteins
CHROMOSOME: condensed DNA molecule with an equal mass of protein
Quantity varies between species (Ex: Humans have 46)
Only visible during cell division

6. NUCLEUS

7. NUCLEUS
NUCLEOPLASM: thick fluid filling the nucleus NUCLEAR MATRIX: network of protein fibres providing internal structure and support

8. NUCLEUS
NUCLEOLUS: non-membrane bound, denser region in the nucleus filled with RNA and proteins NUCLEAR ENVELOPE: double membrane composed of a phospholipid bilayer which surrounds the nucleus LUMEN: space between the bilayer NUCLEAR PORE COMPLEXES: groups of proteins that form openings in the nuclear envelope; allow small particles and ions to travel freely

9. NUCLEUS

10. ENDOPLASMIC RETICULUM (ER)
Complex membrane-bound tubules and sacs attached to the nuclear envelope
SMOOTH ENDOPLASMIC RETICULUM (SER): endoplasmic reticulum without ribosomes
Site of synthesis for lipids and lipid containing molecules
Site specific functions (Ex: liver SER detoxifies drugs and alcohol, gonad SER produces testesterone and estrogen)
ROUGH ENDOPLASMIC RETICULUM (RER): ER surface studded with ribosomes
- Site of protein synthesis

11. ENDOPLASMIC RETICULUM (ER)

12. ENDOPLASMIC RETICULUM (ER)

13. RIBOSOMES Structure composed of RNA and proteins
Structure is different in eukaryotic and prokaryotic cells
Responsible for protein synthesis
Ribosomes attached to RER: proteins for cell membrane and cell export
Free floating ribosomes: proteins carrying out functions in the cytosol

14. RIBOSOMES

15. RIBOSOMES

16. GOLGI APPARATUS
Stack of curved membrane sacs Packages, processes, sorts and distributes proteins, lipids and other substances within a cell Produce lysosomes (animal cells only)

17. LYSOSOMES
Membrane-enclosed sacs containing over 40 digestive enzymes (pH ~5)
Catalyze hydrolysis reactions, break down macromolecules for parts to be reused in cell
Break down old or no longer needed parts in cell
Break down bacteria and other foreign particles

18. PEROXISOMES
Membrane enclosed sacs containing enzymes that catalyze redox redox reactions
Break down biological molecules and toxic molecules
Found in large numbers in the liver to oxidize and break down alcohol
Commonly produce hydrogen peroxide (H2O2) and so contain catalase to break it down into water and oxygen gas
Can sometimes synthesize molecules (Ex: liver peroxisomes produce cholesterol and bile)

19. PEROXISOMES

20. VESICLES AND VACUOLES
VESICLE: membrane bound sacs used for the transport and storage of substances in the cell
Formed by pinching off from cell membranes and organelle membranes
Can fuse with cell membranes and organelle membranes to release their contents
Animal Cell: Many small vesicles
Plant cell: Single large central vesicle (Vacuole)

21. VESICLES AND VACUOLES

22. VACUOLE
Found in plant cells Stores water, ions, sugars, amino acids, and macromolecules Contains enzymes that break down macromolecules and wastes Determines turgor pressure in plants

23. ENDOMEMBRANE SYSTEM: PROTEIN MODIFICATION AND TRANSPORT
Consists of:
Nuclear envelope
Endoplasmic Reticulum
Golgi Apparatus
Vesicles
Function: synthesizing, product-processing and transportation section of cell; compartmentalizes cell

24. ENDOMEMBRANE SYSTEM: PROTEIN MODIFICATION AND TRANSPORT

25. ENDOMEMBRANE SYSTEM: PROTEIN MODIFICATION AND TRANSPORT
Ribosomes on RER synthesizes polypeptides which are released into the lumen of RER
Polypeptides travel through SER where they are stored and processed
When ready for transport, pieces of SER pinch off into vesicles containing the protein
Vesicles transport from SER to cis face of golgi apparatus
Vesicle contents are released into the golgi apparatus where some proteins are stored and others are further modified
Pieces of golgi apparatus pinch off from the trans face of the golgi apparatus and travel to the cell membrane or other destinations in the cell

26. ENDOMEMBRANE SYSTEM: PROTEIN MODIFICATION AND TRANSPORT
- Also used in transport of lipids and lipid containing molecules from SER

27. CHLOROPLASTS
Organelles containing the photosynthetic pigment chlorophyll, which absorbs light energy (plant cells only) - Double membrane, own DNA STROMA: thick liquid in the inner membrane THYLAKOIDS: flattened disks containing chlorophyll GRANUM: stack of thylakoids

28. MITOCHONDRIA
Break down high-energy organic molecules to convert stored energy into usable energy
Double membrane, own DNA
CRISTAE: folds of inner membrane
MATRIX: fluid filled space in inner membrane

29. CELL WALL
Rigid layer surrounding plant, fungi, and many types of protists
Provides protection and support
Composed of polysaccharides and/or glycoproteins

30. CYTOSKELETON
Internal network of protein fibres that extend through the cytoplasm
Provides structure and anchors cell membrane and organelles in place
Act as tracks for vesicles and other organelles to move along
For some cells, provides appendages that enable the cell to propel itself

31. CYTOSKELETON

32. CILIA AND FLAGELLA
Appendages on the outside of of some eukaryotic cells Composed of an internal shaft made of microtubules covered with an outer membrane that is a continuation of the cell membrane Used for movement FLAGELLA: One or two longer appendages CILIA: many shorter appendages

33. CILIA AND FLAGELLA