CELL ORGANELLES AND FEATURES

THE PLASMA MEMBRANE Also called the cell membrane The cell structure that encloses the cell and regulates the passage of materials between the cell and its environment Allows nutrients into the cell Allows waste to leave the cell Also aids in protection and support of the cell.

STRUCTURE OF CELL MEMBRANE Made primarily of phospholipids Have polar, hydrophilic “water-loving” head Have a nonpolar, hydrophobic “water-fearing” tail Water molecule surround the cell membrane The phospholipids form into a phospholipid bilayer Cholesterol is found in the membrane to make it more rigid and prevent it from freezing at low temperatures

MEMBRANE PROTEINS Cell membranes contain specific proteins Integral proteins are embedded within the bilayer Peripheral proteins are on the only one side of the bilayer and are not embedded into it

FLUID MOSAIC MODEL The phospholipid bilayer behaves like a fluid, more than a solid. The phospholipid bilayer allows other molecules to “float” in the membrane.

 Gel-like material that fills the cell.  In prokaryotic cells all the processes that keep the cell alive happen right in the cytoplasm.  Eukaryotic cells have organelles in which those processes happen. Cytoplasm video clip. CYTOPLASM

 It is a supporting network of long, thin protein fibers that also provide an anchor for organelles.  Microtubules - long hollow protein cylinders  Microfilaments – thin protein threads Still images CYTOSKELETON

THE NUCLEUS Most of the functions of a eukaryotic ell are controlled by the nucleus Contains the chromosomes which are composed of DNA (deoxyribonucleic acid) Surrounded by a double membrane called the nuclear envelop Nuclear envelop contains proteins lined nuclear pores that are passage ways for RNA and other materials to enter/exit the cell

NUCLEOLUS A denser area of the nucleus Site where DNA is concentrated

MITOCHONDRIA The “ power house ” of the cell Has its own DNA Sites of cellular respiration, a process which supplies the cell with ATP (Adenosine triphosphate) Bound by a double membrane The inner membrane had many folds called cristae that carry out cellular respiration

RIBOSOMES Small, roughly spherical organelles that are responsible for making proteins. Ribosomes do not have a membrane Some are found freely floating in the cytosol Others are attached to the rough endoplasmic reticulum

ENDOPLASMIC RETICULUM (ER) A complex, extensive network that transports materials throughout the inside of a cell. Two Types: Rough ER has ribosomes attached to the surface is ribosome-studded. Produces proteins and phospholipids Smooth ER has no attached ribosomes. Builds lipids like cholesterol

GOLGI APPARATUS Contains sacs that receive materials from the ER. Modifies, collects, packages, and distributes molecules within the cell or outside the cell.

VESICLES Small, round sacs that are surrounded by a single membrane

LYSOSOMES Contain chemicals called enzymes necessary for digesting certain materials in the cell Break down old worn out cell parts Can break down macromolecules Responsible for breaking down cells when it is time for the cell to die Play an important role in maintaining the overall health of an organisms by destroying cells that are no longer functioning correctly

 A small group of microtubules that help in cell division occurs. Video clip CENTRIOLES

 “Storage” spaces  A sac to store food, water,carbohydrates, enzymes, salts and other materials needed by the cell.  Vacuoles in animal cells (if they are present) are much smaller than those in plant cells. Video clip VACUOLE

ORGANELLES FOUND IN PLANT CELLS

 Found in plants, fungi and some bacteria  Cell structure that surrounds the cell membrane for protection and support  Allows for specific substances to pass in and out of the cell.  Made of cellulose Video clip CELL WALL

Why do plants need cell walls? Cell walls provide structural support for plants like a Skelton provides structural support for your. Without cell walls, plants would not be able to stand up What is important about cellulose? It is a macromolecule that humans cannot digest because they do not have the necessary enzymes; therefore, it passes through your digestive system as “fiber,” cleaning out the intestines.

 Contain the green pigment, chlorophyll, which absorbs energy from the Sun to convert carbon dioxide and water into sugar through the process of photosynthesis. Video clip CHLOROPLAST

Animal cellsPlant cells Vacuole small or absent Glycogen as food storage Nucleus at the center Large central vacuole Starch as food storage Nucleus near cell wall DIFFERENCES BETWEEN PLANT CELLS AND ANIMAL CELLS

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

25 SIMILARITIES BETWEEN PLANT CELLS AND ANIMAL CELLS Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

26 DIFFERENCES BETWEEN PLANT CELLS AND ANIMAL CELLS Animal cellsPlant cells Relatively smaller in size Irregular shape No cell wall Relatively larger in size Regular shape Cell wall present