1. Cell Membrane

2. All cells have a cell membrane (Prokaryote and Eukaryote)
LET’S QUICKLY REVIEW
All cells have a cell membrane (Prokaryote and Eukaryote)
Functions:
Protects and supports the cell
maintain an internal balance called homeostasis 2

3. A. STRUCTURE of the CELL MEMBRANE
The lipid bilayer is made of three things
1. Phospholipids
2. Proteins
3. Carbohydrate Chains

4. Structure of the Cell Membrane
Outside of cell
Carbohydrate
chains
Proteins
Lipid
Bilayer
Transport
Protein
Phospholipids
Inside of cell
(cytoplasm)
Animations
of membrane structure
Go to Section: 4

5. 1. Lipid Bilayer -2 layers of phospholipids
Phosphate head is polar (water loving) “Hydrophilic”
Fatty acid tails non-polar (water fearing) Hydrophobic”
Proteins embedded in membrane
Phospholipid 5

6. Fluid Mosaic Model of the cell membrane
Polar heads love water & dissolve.
Membrane movement animation
Non-polar tails hide from water.
Carbohydrate cell markers
Proteins 6

7. 2.Proteins
a. Cell-surface markers: Identify the cell type and help cells work together.
b. Receptor proteins: Monitor environment
c. Enzymes: speeds up rate of chemical reactions in cell.
d. Transport Proteins: move materials across bilayer

8. 3. Carbohydrate Chains
Carbohydrate chains act as chemical identification cards allowing cells to identify one another

9. B. Cell Transport

10. There are two types of cell transport
1. Passive Transport -cell does not use energy
Diffusion- movement of any substance
Facilitated Diffusion- diffusion with the help of transport proteins
Osmosis – Diffusion of water
2. Active Transport -cell does use energy
Protein Pumps
Endocytosis
Exocytosis 10

11. Vocabulary
Concentration Gradient: When you have an area with many participles and an area of less particles and they move towards equilibrium.
Equilibrium: When the concentration is the same throughout.
Solvent – Dissolving agent (ex. Water)
Solute – Substance that is dissolved (ex. Kool aid mix)

12. 1. Passive Transport Cell uses no energy Molecules move randomly
Molecules spread out from an area of high concentration to an area of low concentration.
(HighLow) 12

13. Simple Diffusion Animation
A. Diffusion
Molecules move randomly from high to low concentrations trying to be balanced “ at equilibrium”
They continue to move randomly even after they are equal 13

14. Facilitated diffusion (Channel Protein) Diffusion (Lipid Bilayer)
B. Facilitated Diffusion A B
diffusion of specific particles through transport proteins found in the membrane
Facilitated diffusion (Channel Protein)
Diffusion (Lipid Bilayer)
Carrier Protein 14

15. B. Facilitated Diffusion
Glucose
molecules
Cellular Transport From a-
High
High Concentration
Channel Protein animations
Cell Membrane
Low Concentration
Protein
channel
Low
Transport Protein
Through a 
Go to Section: 15

16. C. Osmosis Osmosis animation
Osmosis: diffusion of water through a selectively permeable membrane
Water moves from high to low concentrations
Water moves freely through pores. 16

17. 2. Active Transport Cell uses energy
Movement from an area of low concentration to an area of high concentration
(Low  High) 17

18. Types of Active Transport
Sodium Potassium Pumps (Active Transport using proteins)
1. Protein Pumps -transport proteins that require energy to do work
Example: Sodium / Potassium Pumps. are important in nerve responses
Protein changes shape to move molecules: this requires energy! 18

19. Types of Active Transport
2. Endocytosis: Bulk transport INTO a cell
Uses energy
Cell membrane fold in around food particle
This is how white blood cells eat bacteria! 19

20. Types of Active Transport
c. Exocytosis: Forces material out of cell in bulk
membrane surrounding the material fuses with cell membrane
EX: Hormones or wastes released from cell
Endocytosis & Exocytosis animations 20

22. Effects of Osmosis on Life
Osmosis- diffusion of water through a selectively permeable membrane
Water is so small and there is so much of it the cell can’t control it’s movement through the cell membrane. 22

23. Hypotonic Solution
Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water)
Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)! 23

24. Hypertonic Solution
Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water)
shrinks
Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis)! 24

25. Isotonic Solution
Isotonic: The concentration of solutes in the solution is equal to the concentration of solutes inside the cell.
Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium) 25

26. B C A What type of solution are these cells in? Hypertonic Isotonic
Hypotonic 26

27. How Organisms Deal with Osmotic Pressure
Salt water fish pump salt out of their specialized gills so they do not dehydrate.
Animal cells are bathed in blood. Kidneys keep the blood isotonic by remove excess salt and water.

28. Homeostasis & Human Body Systems

29. Cell Development Humans start out as a single cell = a zygote
Zygotes divide many times and differentiate into more than 200 types of cells
1st cells produced from division are called embryonic stem cells
Can become ANY specialized cell in the body

30. Cell Development
Determination = The process where stem cells become committed to divide into only one type of cell (ex. Muscle Cell, Nerve Cell, etc.)
Differentiation = The process where committed cells acquire the structures and functions of specialized cells.

31. Cell Development Examples of Differentiation:
Sperm cells – Flagella for movement
Skeletal Muscles – Many nuclei

32. Cell Development
Some cells are killed through Apoptosis during development
Apoptosis = programmed cell death
Example = webbing between fingers in an embryo

33. Levels of Cell Organization

34. Homeostasis
Homeostasis = The regulation and maintenance of the internal environment within the narrow ranges that support human life.
Examples = Body temperature, fluids, salts, pH, nutrients & gases

35. Homeostasis Control systems in the body:
Sensors = receptors that gather information about conditions inside and outside of the body
Control Center = the brain receives information from the sensors and sends messages through a communication system

36. Homeostasis Control systems in the body:
Communication Systems = Controlled by the nervous or endocrine systems that send nerve impulses & hormones as messages to all parts of the body
Targets = any organ, tissue or cell that changes its level of activity in response to a message

37. Homeostasis Types of Feedback:
Positive Feedback = A control center uses information from sensors to increase the rate of change away from the set values.
a. Labor
b. Blood Clotting

38. Homeostasis Types of Feedback:
2. Negative Feedback = A control system counteracts any change in the body that moves conditions above or below a set point.
a. Blood sugar
b. Body temperature

39. Interactions Among Body Systems
1. Each organ system affects other organ systems
Vitamin D production involves multiple organs & organ systems

40. Interactions Among Body Systems
Thermoregulation = Regulation of body temperature

41. Interactions Among Body Systems
2. Disruption of Homeostasis
Short-Term Effects usually last a few days or weeks
Example = Recovering from the common cold
Long-Term Effects are more damaging to the body systems
Example = Type 1 & 2 Diabetes