1. Functions of the Cell Basic unit of life Protection and support
Movement
Communication
Cell metabolism and energy release
Inheritance

2. Cell Characteristics Plasma Membrane Outer cell boundary
Substances inside the cell membrane are intracellular
Substances outside the cell are extracellular.
Encloses an supports the cell contents.

3. Plasma Membrane
It attaches cells to the extracellular environment or to other cells.
The ability of cells to recognize and communicate with each other take place through the plasma membrane
It determines what moves into and out of cells.

4. Plasma Membrane
Ion movement by cells results in a charge difference across the plasma membrane called the MEMBRANE POTENTIAL
The outside of the plasma membrane is positively charged compared to the inside because there are more positively charged ions immediately on the outside of the plasma membrane and more negatively charged ions inside.

5. Plasma Membrane
The membrane potential allows cells to function like tiny batteries with a positive and negative pole.
It is an important feature of a living cell’s normal function.

6. Plasma Membrane Consists of: 45% -50% lipids 45% - 50% proteins
4% - 8% carbohydrates
The carbohydrates combine with lipids to form glycolipids
The proteins combine with lipids to form glycoproteins.

7. Membrane Lipids 1st: Phosoplipids Form lipid bilayer
Double layer of lipid molecules
They have a polar head (exposed to water inside and outside the cells) and a non polar tail (face one another in the interior of the plasma membrane.

8. Membrane Lipids 2nd: Cholesterol
Interspersed among the phospholipids and accounts for about 1/3 of the total lipids in the plasma membrane.
The amount of cholesterol in a given membrane is a major factor in determining the fluid nature of the membrane. Which is critical to its function.

9. Membrane Lipids Phospholipids form a lipid bilayer
Hydrophilic (water-loving) polar heads
Hydrophobic (water-fearing) nonpolar heads
Cholesterol: Determines fluid nature of membrane

10. Membrane Proteins
Many functions of the plasma membrane are determined by its proteins.
FLUID-MOSAIC MODEL:
The plasma membrane is neither rigid nor static in structure.
It is highly flexible and can change its shape and composition through time.

11. Movement through the Plasma Membrane
Diffusion
Osmosis
Filtration
Mediated transport mechanisms
Facilitated diffusion
Active transport
Secondary active transport

12. Osmosis
Diffusion of water (solvent) across a selectively permeable membrane
Important because large volume changes caused by water movement disrupt normal cell function
Cell shrinkage or swelling
Isotonic: cell neither shrinks nor swells
Hypertonic: cell shrinks (crenation)
Hypotonic: cell swells (lysis)

13. Filtration Works like a sieve
Depends on pressure difference on either side of partition
Moves from side of greater pressure to lower
Example: In kidneys in urine formation

14. Endocytosis Internalization of substances by formation of a vesicle
Types
Phagocytosis
Pinocytosis
Receptor-mediated endocytosis

15. Pinocytosis

16. Exocytosis Accumulated vesicle secretions expelled from cell Examples
Secretion of digestive enzymes by pancreas
Secretion of mucus by salivary glands
Secretion of mild by mammary glands

17. Cell Characteristics Cytoplasm Cytosol Cytoskeleton
Cytoplasmic inclusions

18. Cytoplasm Cellular material outside nucleus but inside plasma membrane
Cytosol: Fluid portion
Cytoskeleton: Supports the cell
Microtubules
Microfilaments
Intermediate filaments
Cytoplasmic inclusions

19. Organelles Small specialized structures for particular functions
Most have membranes that separates interior of organelles from cytoplasm
Related to specific structure and function of the cell

20. Centrioles In specialized zone near nucleus: Centrosome
Each unit consists of microtubules
Before cell division, centrioles divide, move to ends of cell and become spindle fibers

21. Cilia Appendages projecting from cell surfaces Capable of movement
Moves materials over the cell surface

22. Flagella Similar to cilia but longer Usually only one exists per cell
Move the cell itself in wavelike fashion
Example: Sperm cell

23. Microvilli Extension of plasma membrane Increase the cell surface
Normally many on each cell
One tenth to one twentieth size of cilia
Do not move

24. Ribosomes Sites of protein synthesis
Composed of a large and small subunit
Types
Free
Attached to endoplasmic reticulum

25. Endoplasmic Reticulum
Types
Rough
Attached ribosomes
Proteins produced and modified
Smooth
Not attached ribosomes
Manufacture lipids
Cisternae: Interior spaces isolated from rest of cytoplasm

26. Golgi Apparatus
Modification, packaging, distribution of proteins and lipids for secretion or internal use
Flattened membrane sacs stacked on each other

27. Mitochondria Provide energy for cell Major site of ATP synthesis
Membranes
Cristae: Infoldings of inner membrane
Matrix: Substance located in space formed by inner membrane
Mitochondria

28. Nucleus DNA dispersed throughout Consists of :
Nuclear envelope: Separates nucleus from cytoplasm and regulates movement of materials in and out
Chromatin: Condenses to form chromosomes during cell division
Nucleolus: Assembly site of large and small ribosomal units

29. Chromosome Structure

30. Overview of Cell Metabolism

31. Overview of Protein Synthesis

32. Overview of Protein Synthesis
Transcription
Copies DNA to form mRNA
tRNA carries amino acids to ribosome
Translation
Synthesis of a protein at ribosome

33. Translation

34. Cell Life Cycle Interphase Phase between cell divisions Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Division of cell cytoplasm

35. Mitosis

36. Mitosis

37. Meiosis

38. Cellular Aspects of Aging
Cellular clock
Death genes
DNA damage
Free radicals
Mitochondrial damage