Chapter 7 Explain the cell theory. Name the basic cell structures. Describe prokaryotes and eukaryotes.

Cell Structures and functions

1. Cell membrane Function – controls what enters and exits the cell; also provides protection and support for the cell. Structure – phospholipid bilayer (two layers of phospholipids with carbohydrate chains and protein channels). Selectively permeable barrier. Found in all cells Similar to the gates of a gated community, or a fence

LIPID TAILS ARE HYDROPHOBIC HYDROPHILIC  HYDROPHOBIC  Image by Riedell

Oil and water don’t mix! Image from: http://employees.csbsju.edu/hjakubowski/classes/ch112/lipids/micbilayer.gif

2. Cytoplasm Structure – clear, thick, jellylike material inside the cell. Contains cytoskeleton fibers (microtubules and microfilaments) Function – supports, protects, and helps transport organelles inside the cell Found in all cells Similar to the interstates, highways, roads, and the support beams in buildings

3. Nucleus Structure – has a nucleolus (where the making of proteins begins), chromatin (grainy mixture of DNA and protein), chromosomes (condensed chromatin) and nuclear envelope Function – controls most cell processes and contains the hereditary material DNA Found in eukaryotic cells, plant and animal cells Similar to the boss, city hall, library

4. Nuclear envelope Structure – flexible, selectively permeable, double membrane Function – controls movement of materials in/out of nucleus Found in all eukaryotic cells Similar to a gate/door

5. NUCLEOLUS Dark spot in nucleus Makes RNA for ribosomes Image from: http://lifesci.rutgers.edu/~babiarz/histo/cell/nuc3L.jpg Dark spot in nucleus Makes RNA for ribosomes

6. Centrioles Structure - a cylinder of microtubule pairs; found in pairs near the nucleus Function – separates chromosome pairs during cell division Found only in animal cells

7. Mitochondria Structure – peanut shaped, double membrane (outer is smooth and inner is folded) Function – breaks down glucose (food) molecules to release energy Found in all eukaryotic cells Similar to MLGW or other similar power company

8. Ribosomes Structure – small bodies free or attached to ER and made of protein and rRNA Function – synthesizes (assembles or makes) proteins Found in all cells Similar to a construction site

9. ROUGH ENDOPLASMIC RETICULUM (Rough ER) Animation from: http://vilenski.org/science/safari/cellstructure/er.html Makes membrane proteins and proteins for export out of cell Image from: http://www.biologyclass.net/endoplasmic.jpe

ROUGH ENDOPLASMIC RETICULUM (ER) Has RIBOSOMES attached Proteins are made on ribosomes and inserted into Rough ER to be modified and transported Image from: http://fig.cox.miami.edu/~cmallery/150/cells/ER.jpg

10. SMOOTH ENDOPLASMIC RETICULUM (smooth ER) Has NO ribosomes attached Has enzymes for special tasks

SMOOTH ENDOPLASMIC RETICULUM (smooth ER) Image from:http://www.accs.net/users/kriel/chapter%20eight/smooth%20er.gif Makes membrane lipids (steroids) Regulates calcium (muscle cells) Destroys toxic substances (Liver)

11. Golgi Apparatus Structure – stacks of flattened sacs Function – package and export proteins, modify proteins (attaches carbohydrates and lipids to proteins) made by the cells in the ER. Found in all eukaryotic cells Similar to a shipping company (UPS/Post Office)

12. Lysosome Structure – small, round organelle with a single membrane Function – digests old cell parts; breaks down larger molecules into smaller molecules Found mostly in animal cells and only occasionally in plant cells Similar to a garbage/recycling company

WHAT’S SPECIAL ABOUT PLANT CELLS? Cell wall HUGE vacuoles Chloroplasts No centrioles Plant vs Animal cells

13. Cell wall Structure – rigid structure made up mostly of cellulose fibers Function – to provide support and protection for the cell. Found only in plant, bacteria, and fungi cells Similar to gates of a gated community/fence

14. Vacuoles Structure – fluid-filled sacs (the largest organelle in a plant cell) Function - store food, water, and waste Found in eukaryotic cells; plant cells have one large vacuole and animal cells have multiple small vacuoles. Similar to storage company or water tower

15. Chloroplasts Structure – green, oval containing chlorophyll; double membrane with inner membrane modified into sacs Function – uses solar energy to make food (glucose) and release oxygen. Found in plants and algae Similar to solar energy panels

FLAGELLA & CILIA Made of PROTEINS called MICROTUBULES (9 + 2 arrangement) Image from: http://www.stchs.org/science/courses/sbioa/metenergy/flagella.jpg

FLAGELLA Help in cell movement

CILIA Animation from: http://web.jjay.cuny.edu/~acarpi/NSC/13-cells.htm Move cell itself

CILIA FLAGELLA WHAT’S THE DIFFERENCE? Many short Few Long Animation from: http://web.jjay.cuny.edu/~acarpi/NSC/13-cells.htm Few Long

Lowest Level Highest Level

Transportation through the Cell Membrane Active transport moves substance against the concentration gradient (from low concentration to high concentration) Passive transport moves substances with the concentration gradient (from high concentration to low)

The Cell Membrane What are the main functions of the cell membrane The Cell Membrane What are the main functions of the cell membrane? It regulates what enters and leaves the cell and provides protection and support What does it mean that a cell membrane has a “lipid bilayer”? It is composed of two “bi” layers of lipid molecules with protein molecules that help certain substances to enter or exit the cell. It also has carbohydrates that behave as identity markers (name tags).

What does it mean when a membrane is selectively permeable? The membrane will allow only certain materials to pass across the membrane.

Diffusion Diffusion is the movement of molecules from an area of high concentration (where there are many) to an area of low concentration (where there are few). This is a type of Passive transport since it does not require the input of additional energy.

Osmosis Osmosis is the diffusion of water molecules through a permeable membrane from an area of high concentration to an area of low concentration. Because it is the diffusion of water, it is also a type of passive transport.

Facilitated Diffusion During facilitated diffusion, the protein channels in the cell membrane help (facilitate) certain molecules like glucose (which can not simply diffuse) to pass through those protein channels into or out of the cell. Again, this is a type of diffusion, so it is also a type of passive transport (the movement of molecules is from areas of high concentration to low concentration)

Equilibrium When is equilibrium reached in a solution? When the concentration of the solute is the same on both sides of the cell membrane or throughout a solution

Endocytosis Endocytosis is the process of taking material into the cell by enfolding of the cell membrane around large molecules, clumps of food, or even whole cells. This is a type of active transport because it requires the input of additional energy and the substance is moving against the concentration gradient (from an area of low concentration to high concentration).

Exocytosis During exocytosis, the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell. Because this type of transport requires the cell to use energy and the substance is moving against the concentration gradient, exocytosis is a type of active transport.

VOCAB _____________ = substance that is dissolved in a solvent to make a solution _____________ = substance in which a solute is dissolved SOLUTE SOLVENT http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg

Images by Riedell __________________ = mass of a solute in a given volume of solution CONCENTRATION MORE The _______ molecules there are in a given volume the ____________the concentration GREATER

Use new vocab to make Koolaid Koolaid powder sugar Solutes = ______________& __________ Solvent = ____________ Koolaid drink = ______________ Water solution http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg

What if there is a difference in concentration but solute molecules can’t move across a membrane? WATER will move until concentration reaches equilibrium

Animation http://faculty.etsu.edu/currie/images/osmosis1.jpg

What will happen to an animal cell placed in different solutions? Solute concentration Greater outside than inside Lower outside than inside Equal outside and inside HYPERTONIC HYPOTONIC ISOTONIC What will happen to an animal cell placed in different solutions?

Cells try to “maintain stable internal conditions = Remember: Cells try to “maintain stable internal conditions = ____________________ HOMEOSTASIS http://bioweb.wku.edu/courses/biol121/Osmosis/Osmosis.asp So an animal cell in ISOTONIC conditions stays same size Water entering = water leaving Video Choose Blood Isotonic link

If cells can’t maintain “stable internal conditions” . . . damage can result and cells can die. http://www.the-aps.org/education/lot/cell/Quiz.htm

OSMOSIS swell and possibly burst Video LESS THAN Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis3.swf OSMOSIS Video Choose Blood Hypotonic link HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN swell and possibly burst

OSMOSIS shrinks GREATER THAN Video Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis4.swf OSMOSIS HYPERTONIC: Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks Choose Blood Hypertonic link Video

Animal cells _________ __________ = CYTOLYSIS = CRENATION http://www.stchs.org/science/courses/sbioa/metenergy/bloodcells.gif _________ __________ = CYTOLYSIS = CRENATION

Plant cells _____ keeps ___________ = PLASMOLYSIS CELL WALL http://www.stchs.org/science/courses/sbioa/metenergy/aplantturgor.gif Plant cells _____ keeps ___________ plant cells from bursting = PLASMOLYSIS CELL WALL

VACUOLES store WATER OSMOTIC PRESSURE _____________________________ = http://www.biology4kids.com/files/cell_vacuole.html OSMOTIC PRESSURE _____________________________ = Pressure exerted by the movement of water during osmosis

SO WHAT? hypotonic Bath water is ________________ compared to you Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis enters

Grocery stores spray water on their veggies to “plump them up” http://www.painetworks.com/photos/gt/gt0461.JPG

SO WHAT? If an organism can’t maintain homeostasis, it will die. SO. . . Salt water fish urinate rarely and actively pump ions out through their gills Freshwater fish urinate constantly and actively pump ions in through their gills