1. Eukaryotes vs Prokaryotes Plasma Membrane

2.  All cells contain organelles  Small, specialized structures  Has a specific function in the cell  Prokaryotes  Do not contain any membrane-bound organelles  Most unicellular organisms  Example: bacteria  Eukaryotes  Contain membrane-bound organelles  Most multicellular oranisms  Example: humans  Note: amoebas, algae and yeast are unicellular but eukaryotes

3. Eukaryotic cells are generally 1- 100 time bigger than prokaryotes

6.  Organelle= “little organ”  Found only inside eukaryotic cells  Everything in a cell except the nucleus is cytoplasm  Clear, gelatinous fluid inside the cell

7.  Boundary of the cell  Made of a phospholipid bilayer

8.  Acts as skeleton and muscle  Provides shape and structure  Helps move organelles around the cell  Made of three types of filaments

9.  Control center of the cell  Contains chromatin, strands of genetic material ( DNA ) that condense to make chromosomes  Surrounded by a double membrane  Usually the easiest organelle to see under a microscope  Usually one per cell

10.  Inside the nucleus  Makes ribosomes

11.  Site of protein synthesis  Found attached to rough ER or floating free in cytoplasm  Produced in a part of the nucleus called the nucleolus That looks familiar…what is a polypeptide?

12.  A.k.a. “ER”  Connected to nuclear membrane  Highway of the cell  Rough ER: studded with ribosomes; it makes proteins  Smooth ER: no ribosomes; it makes lipids

13.  Looks like a stack of plates  Stores, modifies and packages proteins  Molecules transported to and from the Golgi by means of vesicles

14.  Garbage disposal of the cell  Contain digestive enzymes that break down wastes Which organelles do lysosomes work with?

15.  “Powerhouse of the cell”  Cellular respiration occurs here to release energy for the cell to use  Bound by a double membrane  Has its own strand of DNA Which type of cell do you think has the most mitochondria present?

16.  Found in plant and bacterial cells  Rigid, protective barrier  Located outside of the cell membrane  Made of cellulose (fiber)

17.  Found only in plant cells  Contains the green pigment chlorophyll  Site of food (glucose) production  Bound by a double membrane

18.  Large central vacuole usually in plant cells  Many smaller vacuoles in animal cells  Storage container for water, food, enzymes, wastes, pigments, etc.

19.  Aids in cell division  Usually found only in animal cells  Made of microtubules Where else have we talked about microtubules?

20.  Which organelle is the control center of the cell? Nucleus  Which organelle holds the cell together? Cell membrane  Which organelles are not found in animal cells? Cell wall, central vacuole, chloroplasts  Which organelle helps plant cells make food? Chloroplasts  What does E.R. stand for? Endoplasmic reticulum

22.  Flexible boundary between the cell and its environment  Allows a steady supply of nutrients (ie: glucose, amino acids, lipids) to come into the cell no matter what the external conditions are

23.  Too much of any nutrient can be harmful to the cell  If levels become too high  the excess is removed through the plasma membrane  Maintains cells balance (homeostasis)

24.  Selective permeability: a process in which a membrane allows some molecules to pass through while keeping others out  Similar to a window screen (lets fresh air in but keeps most insects out)  Water is allowed to freely enter but other particles such as sodium and calcium ions must be allowed into the cell only at certain times

25.  Recall: Lipids are large molecules composed of  Glycerol + 3 fatty acids  If a phosphate group replaces a fatty acid then a phospholipid is formed.  Glycerol + 2 fatty acids + phosphate group Polar Head (includes phosphate group Nonpolar tail (fatty acids) Phospolipid Molecule

26.  Has 2 layers of phospholipids back to back

27.  Drawing must be similar to drawing on page 177 and must include:  A title  Labeled parts  Colored  On back of drawing:  Facts about the phospholipid bilayer  All bold faced words (include definitions)  Additional Facts should include information you think is important? (at least 8 facts in addition to bold faced words)

28.  2 fatty acid tails – nonpolar (hydrophobic)  Avoids water  Head containing phosphate group – polar (hydrophilic)  Allows the cell membrane to interact with its watery environment  Water molecules will not easily move through the barrieer because they are stopped by the water insoluble layer of fatty acid tails.

29.  Fluid Mosaic Model  Model of plasma membrane – describes the plasma membrane as a phospholipid bilayer with embedded proteins  Phospholipids move within the membrane just like water molecules move with currents in a lake  Proteins also move (like boats with their decks above water and hulls below)  Proteins create a “mosaic” or pattern

30.  Other components of the membrane:  Cholesterol  Helps to stabilize the phospholipids by preventing fatty acid tails from sticking together  Transport proteins  Span the entire membrane  Help form the selectively permeable membrane that regulates which molecules enter and which molecules leave  Move needed substances and waste through the plasma membrane