1. Cell Structure & Function
7.1 Life is Cellular
Cell Structure & Function

2. Discovery of the Cell
England- In1665, Robert Hooke viewed a thin slice of cork under a microscope
Reminded him of a monastery's tiny rooms, he
called them cells
Holland- In 1674, Anton van Leeuwenhoek observed microorganisms in pond water

3. Discovery of the Cell
1838 German botanist Matthias Schleiden concluded that all plants were made of cells
1939 German biologist Theodor Schwann stated that all animals were made of cells

4. Discovery of the Cell
In 17855, German physician Rudolf Virchow concluded that all cells must come from preexisting cells

5. The Cell Theory All living things are composed of cells.
Cells are the basic unit of structure and function in living things.
New cells are produced from existing cells.

6. Exploring the Cell Variety of shapes & sizes
From tiny bacteria (0.2 μm) to large amoeba (1,000 μm)
All are surrounded by a cell membrane and contain DNA

7. Prokaryotes & Eukaryotes
Nucleus- large membrane-enclosed structure that contains the cell’s genetic material (DNA)
Prokaryotes- do not contain nuclei
Eukaryotes- contain nuclei

8. Prokaryotes
Prokaryotic cells are generally smaller, simpler, and single cellular
There are many exceptions to this rule, but NONE of them have genetic material that is contained in a nucleus.
Example: BACTERIA

9. Prokaryotes Genetic material not contained in the nucleus
Carry out every activity associated with living things
Grow, reproduce, respond to stimuli

10. Eukaryotes
Eukaryotic cells are larger, more complex, and can be single or multicellular.
Genetic material is separated into nucleus
Examples: Plants, animals, fungi, and protists

11. Cell Structure & Function
7.2 Eukaryotic Cell Structure
Cell Structure & Function

12. Comparing the Cell to a Factory
Organelles- “little organs”; specialized functions
Two Major Parts:
Nucleus
Cytoplasm- portion of the cell outside the nucleus

13. Nucleus Control center; “office” Nuclear envelope
Chromatin- protein bound DNA
Chromosomes- condensed chromatin
Nucleolus- assembly of ribosomes

14. Nucleus The control center of the cell Contains most of the cell’s DNA
DNA contains instructions for making proteins and other important molecules.
The nucleus is surrounded by the nuclear envelope , composed of two membranes with thousands of pores
allows messages from the nucleus to reach the cytoplasm.

15. Nucleus
The granular material in the nucleus is called chromatin and consists of DNA bound to protein.
Most of the time, chromatin is spread throughout the nucleus. However, chromatin condenses to form chromosomes during cell division.

16. Nucleus
The small dense region in the nucleus is called the nucleolus and is the site where ribosomes begin to form.

17. Ribosomes Protein synthesizing “machine”
Makes proteins using coded instructions from the nucleus
Found throughout the cytoplasm

18. Endoplasmic Reticulum
Internal membrane system; “transport”
Lipid components of the cell membrane are assembled
Rough ER- ribosomes on surface; produce proteins for export
Smooth ER- contains enzymes responsible for cell detox

19. Golgi Apparatus A specialized stack like system of membranes
Modifies, sorts, and packages proteins made in the Rough ER
Like a “customization shop” preparing proteins for shipment

20. Lysosomes Recycles worn out cellular products; “Clean Up Crew”
Small organelles filled with enzymes
Breaks down lipids, carbs, and proteins for use elsewhere in the cell

21. Vacuoles Saclike structures; Cell “storage”
Store materials such as water, salts, proteins, and carbohydrates
Assists in maintaining homeostasis inside the cell

22. Mitochondria & Chloroplast
Produce energy for the cell; “powerhouse”
Mitochondria- convert chemical energy stored in food into compounds the cell can use
Chloroplast- capture energy from sunlight and transform it into chemical energy
photosynthesis

23. Mitochondria and Chloroplast
Only organelles that contain their own DNA
Lynn Margulis proposed that these organelles descended from prokaryotes which took up residence within the eukaryotic cell.

24. Cytoskeleton Supports the cell; maintains shape
Network of protein filaments
Also involved in movement
Microfilaments
Cilia
Flagella
Microtubules
Centrioles- aid in cell division in animal cells

25. Cell Structure & Function
7.3 Cell Boundaries
Cell Structure & Function

26. The Cell Membrane Regulates what enters and leaves the cell
Provides protection and support
Semipermeable
Made up of a double layered sheet called a lipid bilayer

27. Lipid Bilayer Lipids are made up of 2 parts:
Hydrophobic layer
Hydrophilic layer
Contains proteins throughout
Carbohydrate molecule chains attached to the proteins

28. Types of Transport Passive Transport Active Transport
Does NOT require energy
Types:
Diffusion
Facilitated Diffusion
Active Transport
DOES require energy

29. Diffusion
Causes many substances to move across a cell membrane but does not require the cell to use energy
Solutions move from high concentration to low concentration

30. Diffusion
The process of diffusion continues until a state of equilibrium is reached in which the concentration is the same throughout the system.

31. Special Type of Diffusion: Osmosis
The diffusion of water through a selectively permeable membrane

32. Solutions
In a hypertonic solution, a cell will shrink as water moves out of the cell through osmosis.
In a hypotonic solution, a cell will expand as water moves into the cell
In an isotonic solution, the size of the cell will remain the same as an equal amount of water moves into and out of the cell.

33. Osmosis – Isotonic Solution

34. Osmosis – Hypotonic Solution

35. Osmosis – Hypotonic Solution

36. Osmosis – Hypertonic Solution

37. Osmosis – Hypertonic Solution

38. Osmosis

39. Facilitated Diffusion
Molecules which cannot move through the cell membrane on their own use a protein channel to move from high concentration to low concentration

40. Active Transport
A process in which energy is required to move a molecule from low concentration to high concentration. Energy requires ATP.

41. Active Transport - Endocytosis
The process of taking large amounts of material into the cell by means of infoldings, or pockets, of the cell membrane

42. Active Transport – Endocytosis: Phagocytosis
A form of endocytosis in which large particles are taken in to the cell

43. Active Transport – Endocytosis: Pinocytosis
In a process similar to endocytosis, many cells take up liquid from the surrounding environment.
Tiny pockets form along the cell memebrane, fill with liquid, and pinch off to form vacuoles within the cell.

44. Active Transport - Exocytosis
The removal of large amounts of material from a cell

45. Cell Structure & Function
7.4 The Diversity of Cellular Life
Cell Structure & Function

46. Unicellular Organisms
Sometimes a cell IS an organism.
They do everything an organism would do
Grow
Respond
Transform energy
Reproduce
Dominant form of life on Earth

47. Multicellular Organisms
Animals and Plants
Cell Specialization- cells develop in different ways to perform different tasks

48. Levels of Organization
In order of increasing complexity
Cells
Tissues
Organs
Organ Systems

49. Levels of Organization
Tissues- group of similar cells that perform a particular function
Types in Animals
Muscle
Epithelial
Nervous
Connective

50. Levels of Organization
Organs- groups of tissues that work together to perform closely related functions

51. Levels of Organization
Organ Systems- group of organs that work together to perform a specific function