Biology CHAPTER 7 CELL STRUCTURE AND FUNCTION

7.1: THE CELL THEORY: LETS MEET THE PLAYERS Anton Van Leeuwenhoek Discovered: red blood cells, bacteria, and Protista Theodor Schwann and Matthias Schleiden From Germany Credited with the Cell theory

7.1: THE CELL THEORY: LETS MEET THE PLAYERS Zacharias Janssen Credited with trying to create lenses with stronger magnification for people with poor eyesight (evolved into a lens for a scope) Robert Hooke He was the first person to have seen cork cells (using a microscope)

7.1: THE CELL THEORY 1. All known living things are made up of cells. 2. The cell is the basic structural & functional unit of all living things. 3. All cells come from pre-existing cells by division. 4. Cells contain hereditary information which is passed from cell to cell during cell division 5. All cells are basically the same in chemical composition. 6. All energy flow (metabolism & biochemistry) of life occurs within cells.

“Eu” means true Have membrane bound nucleus DNA contained in the nucleus “Pro” means without Do not have membrane bound nucleus DNA is free floating 7.1: TWO TYPES OF CELLS Prokaryotes Eukaryotes

7.2: THE PLASMA MEMBRANE  Thin, flexible boundary between the cell and its environment  Allows nutrients into the cell  Allows waste to leave the cell

Selective Permeability  The plasma membrane controls the movement of substances into and out of the cell. Plasma Membrane  Controls the amount of a substance entering the cell  Controls the amount of a substance leaving the cell

 The plasma membrane is composed of the phospholipid bilayer.  A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a phosphate group.

Fluid Mosaic Model  The phospholipid bilayer allows other molecules to “float” in the membrane. Other Components  Proteins  Cholesterol  Carbohydrates

Proteins  Transmit signals inside the cell  Act as a support structure  Provide pathways for substances to enter and leave

Cholesterol  Prevents fatty acid tails from sticking together

Carbohydrates  Identify chemical signals

Animal Cell Plant Cell Plant and Animal Cell Structures 7.3: STRUCTURES AND ORGANELLES

ANIMAL CELL

Cilia  Short, numerous projections that look like hairs Flagella  Longer and less numerous than cilia  Create movement with a whiplike motion 400x 26,367x CELL ORGANELLES

Cell Membrane found in both plants and animal cells Allows only certain materials to move into and out of the cell. Made up of a double layer of fat with some proteins scattered throughout. Is flexible. Helps to maintain a chemical balance between materials inside and outside the cell.

Cytoplasm found in both plants and animal cells Gel-like material inside the cell membrane and outside the nucleus. Where all the organelles “float” around.

Nucleus Found in both plants and animal cells The largest organelle in the cytoplasm. Directs all the activities of the cell. Surrounded by a nuclear envelope. Contains the genetic blueprints for the operations of the cell in the form of DNA.

Endoplasmic Reticulum A membrane system of folds and channels that are the site of protein and lipid synthesis. If there are ribosomes (the bumps) attached it is the Rough ER.

Mitochondria This is the energy generator for the cell. It converts fuel (sugar) into usable energy for the body. The “powerhouse” of the cell

Nucleolus This is inside of the nucleus This makes the ribosomes

Ribosomes These are either free floating in the cytoplasm or attached to the ER. They make proteins. Ribosomes are composed of RNA and protein.

Gogi Bodies Stacks of membrane covered sacs that package & move materials out of the cell.

Vacuoles Store materials and waste products temporarily in the cytoplasm. Store enzymes, food and other materials needed by the cell

Lysosomes They contain substances that digest excess or worn-out organelles and food particles. They also digest bacteria and viruses that have entered the cell.

Chloroplasts Are found ONLY in plant cells. Contain chlorophyll which is a green pigment. Trap light energy from the sun which is then changed into chemical energy in the form of SUGAR.

Cell Wall Is found only in plant cells. Is a rigid structure outside the cell membrane. Supports and protects the plant cell.

Passive Transport  Movement of particles across the cell membrane without using energy Three Modes of Passive Transport  Diffusion  Facilitated Diffusion  Osmosis 7.3: CELLULAR TRANSPORT

Diffusion  Movement of particles from an area of high concentration to an area of lower concentration Initial ConditionsDiffusion Low High Low

Diffusion animation hics/diffusion.gif hics/diffusion.gif t/diffusion.swf t/diffusion.swf hill.com/sites/ /student_view0/chapter2/animat ion__how_diffusion_works.html hill.com/sites/ /student_view0/chapter2/animat ion__how_diffusion_works.html

 Diffusion is controlled by  Temperature  Pressure  Concentration Dynamic Equilibrium  Reached when diffusion of material into the cell equals diffusion of material out of the cell  Molecules continue to move, but the overall concentration remains the same.

Diffusion in a Cell

Facilitated Diffusion  Movement of materials across the plasma membrane using proteins  nsport1.html nsport1.html

Carrier ProteinsChannel Proteins

Osmosis  Diffusion of water across a selectively permeable membrane Three Types of Solutions  Isotonic  Hypotonic  Hypertonic

Blood Cell Plant Cell Isotonic Solution  Water and dissolved substances diffuse into and out of the cell at the same rate. 11,397x

Blood Cell Hypotonic Solution  Solute concentration is higher inside the cell.  Water diffuses into the cell. Plant Cell 13,000x

Plant Cell Hypertonic Solution  Solute concentration is higher outside the cell.  Water diffuses out of the cell. Blood Cell 13,000x

Active Transport  Movement of particles across the cell membrane using energy Active Transport Using Carrier Proteins

Types of Active Transport Pumps  Na + /K + ATPase pump  Moves three Na + ions out of the cell and two K + ions into the cell  es/shared_resources/animations/ion_pump/ionpump.html es/shared_resources/animations/ion_pump/ionpump.html

Endocytosis  Process by which the cell surrounds and takes particles into the cell Exocytosis  Secretion of material out of the plasma membrane