1. Chapter 7 Cell Structure and Function

2. Cell Theory All living things are made of cells
Cells are the basic units of structure and function in living things
New cells are produced from existing cells

3. How do we see cells? The microscope: Light microscope
Produce magnified images by focusing visible light rays
Magnifies up to 1,500 X using visible light
Electron microscope
Produce magnified images by focusing beams of electrons
Magnifies up to 1,500,000 X using electrons
Traditionally require a vacuum to operate, cannot see living cells

4. How Big are Cells? Cells come in a large variety of shapes and sizes
Most are between 5 and 50 micrometers

5. Two Major Cell Types Prokaryotes Very small cells WITHOUT a nucleus
Bacteria

6. Two Major Cell Types Eukaryotes
Larger more complex cells with one or more nuclei
Everything not bacteria

7. Two Major Cell Types

8. Parts of the Cell Cytoplasm Nucleus Ribosomes
Endoplasmic reticulum (ER)- rough and smooth
Golgi apparatus
Lysosomes (and vacuoles)
Mitochondria
Cytoskeleton and Centrioles
Cell membrane and cell wall
Specialized parts (chloroplasts, cilia, flaggella)

9. The Parts of the Cell
Organelles are the membrane bound structure in a eukaryote that carries out some function for the cell. Ex. nucleus and mitochondria
Cytoplasm is the gel-like substance outside the nucleus

10. The Nucleus
A large membrane-enclosed structure containing DNA

11. The Nucleus
DNA appears granular most of the time and is called chromatin; it condenses to form chromosomes during cell division
Two major parts of the nucleus
Nuclear envelope is a double membrane with pores that surrounds the nucleus
Nucleolus is the dense region of the nucleus where ribosomes are made (most nuclei have a nucleolus)

12. Ribosomes
Ribosomes are the small particles of RNA and protein where proteins are made in the cell

13. The Endoplasmic Reticulum (ER)
The ER is the site where lipid parts of the cell membrane are assembled, as well as proteins and other materials that are exported from the cell
Two types:
Rough ER has ribosomes and functions in protein production (synthesis)
Smooth ER has no ribosomes and functions in lipid production or detoxification

14. The Endoplasmic Reticulum (ER)

15. The Golgi Apparatus
The Golgi functions to modify, sort, and package proteins and other materials for storage in the cell or secretion from the cell

16. The Golgi Apparatus

17. Mitochondria
Mitochondria helps convert food energy into cellular energy

18. Lysosomes and Vacuoles
Lysosomes are enzyme filled organelles that function to digest food for the cell and to get rid of old organelles
Vacuoles are important in storage (water, salts, proteins, carbs)

19. Chloroplasts
Chloroplasts capture energy from sunlight and convert it into chemical energy

20. Cytoskeleton and Centrioles
Cytoskeleton is the network of protein filaments that maintain the cell’s shape and aid in movement
Centrioles help organize cell division (not found in plants)

21. Cilia and Flagella
Cilia are short projections made from the microtubules that function in movement
Flagella are long projections from the microtubules that function in movement

22. Cell Wall
Provides support and protection in bacteria, plants, fungi, and some Protists (Not Animals)
Made of cellulose in plants

23. Cell Wall

24. Cell Membrane (Plasma membrane)
The cell membrane regulates what enters and leaves the cell and also provides protection and support
Found in all cells and made of phospholipids

25. Diffusion and the Cell Membrane
Diffusion is the movement of particles from an area of higher concentration to lower concentration
Requires NO energy

26. Diffusion and the Cell Membrane
Concentration is the mass divided by the volume (mass/volume) grams/mL, or g/cm3
Osmosis is the diffusion of water through a selectively permeable membrane

27. Diffusion and the Cell Membrane

28. Diffusion and the Cell Membrane
Isotonic solution is one that the concentrations are the same on both sides of the membrane
Hypertonic solution is the more concentrated solution (more sugar molecules)
Hypotonic solution is the less concentrated solution (less sugar molecules)
Water will net diffuse to the side that is more concentrated

29. Diffusion and the Cell Membrane

30. Diffusion and the Cell Membrane

31. Diffusion and the Cell Membrane
Facilitated diffusion is the diffusion through protein channels without using energy

32. Diffusion and the Cell Membrane
Active transport is the movement of particles that requires energy
Passive transport is the movement of particles without using energy

33. Diffusion and the Cell Membrane

34. Diffusion and the Cell Membrane
Endocytosis takes material into a cell by engulfment (requires energy); a vacuole forms on the inside of the cell after engulfment
Phagocytosis takes food or solid particles into the cell
Pinocytosis takes liquid into the cell
Exocytosis releases material from a cell (requires energy)

35. Diffusion and the Cell Membrane

36. Unicellular vs. Multicellular
Unicellular organisms is an organism made of one cell. Examples: Bacteria and many Protists
Multicellular organisms is an organism made of many cells that are specialized

37. Cell Differentiation (Specialization)
Cell differentiation occurs when cells develop in alternative ways to perform different tasks
Go Go Stem Cells
Example: Red blood cells are specialized to transport oxygen. Pancreatic cells produce certain proteins. Guard cells in plants open and close the stomata
Stem cell animation

38. Organization of Life
Cell- collection of living matter enclosed by a barrier; basic unit of life
Tissues- group of similar cells that perform a particular function
Organ- many group of tissues that work together to function as an organ
Organ system- a group of organs that work together perform a specific function, like digestion

39. Organization of Life