2Prokaryotic Cells Does not have a “true” nucleus Lacks membrane bound organellesUsually unicellularBacteria are prokaryotic
3Eukaryotic Cells Includes animals, plants, fungi and protists DNA contained in membrane-bound nucleusContains cell membrane comprised of a phospholipid bilayer (double layer)Cytoplasm is the jelly-like interior consisting of everything outside the nucleus but within the cell membrane.Cytosol is the fluid
5Cell Membrane Phospholipid bilayer Selectively permeable – allows some materials in while keeping other materials out of the cell
6Nucleusorganelle bounded by a double –layered porous membrane called the nuclear membrane/envelope.control center of the cellContains the cell’s genetic material or DNA (deoxyribonucleic acid)Nucleolus - darker area within the nucleus that manufactures rRNA (ribosomal ribonucleic acid) present in ribosomes
7Nucleus The nuclear envelope contains many openings called pores. Small particles such as water and ions travel freely through the openings, but the passage of macromolecules such as RNA is controlled by the poresThe nuclear envelope is connected to the endoplasmic reticulum
8Cytoplasmic Organelles Endoplasmic Reticulum (ER) – small tubules or canals branching from the nucleus that allow the transportation of materials within the cellSmooth ER – ribosomes absent, synthesize lipidsRough ER – ribosomes present, synthesize proteins that are part of membranes or intended to be exported from the cellRibosomes – synthesize proteins that function in the cytosol
9The Endomembrane System Consists of the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, and vesiclesThese organelles are connected and work together to carry out many processes in the cell
10The endomembrane system modifies and transports proteins
11Functions of the Endomembrane System Ribosomes on the surface of the ER produce polypeptides and released into the lumenManufactured polypeptides travel to smooth ER, where they are stored and processed. When proteins are ready for transport, smooth ER pinches off to form vesicles containing the proteins.
12Endomembrane SystemVesicles from the smooth ER travel across the cell to the cis face of the Golgi Apparatus. The vesicles merge with the membrane of the Golgi Apparatus and release their contents.Golgi Complex- Flattened stacks of membrane that receive, modify and transport proteins from the ER.
13Endomembrane SystemWhen the modified proteins are ready for transport, pieces of the Golgi pinch off from the trans face to form vesicles. The vesicles transport the proteins to the cell membrane or other destinations.
14Lysosomes Peroxisomes Membrane bound sacs performing a digestive functionEnzymes in peroxisomes are oxidases that catalyze redox reactionsLiver contains many peroxisomes to break down alcoholForm by budding off from ERPresent in animal cells onlyMembrane bound sacs performing a digestive functionContains enzymes to digest food, wastes, invading bacteria and breaks down old organellesPresent in animal cells onlyGolgi apparatus produces lysosomesTay – Sachs disease
15VacuolesFunctions include storage and support through turgor pressure (the pressure exerted by water on cell membrane and cell wall).fluid-filled space that stores water, food and wastes.Very large organelle in plant cells, but small in animal cells
16Plastids: Chloroplasts Make food for the cell through photosynthesisChloroplasts contain chlorophyll to trap light energy needed for photosynthesisPresent in plant cells but not in animal cellsChromoplasts – type of plastid that stores orange and yellow pigments found in fruits and flowersAmyloplasts – type of plastid that stores starch in potatoes.
17Chloroplast Structure Stroma – fluid of the chloroplast containing enzymesThylakoids – disks containing chlorophyllGrana (sng: granum)-stack of thylakoids
18MitochondriaProvides stored energy (ATP) for the cell in a process called cellular respirationCristae – inner folds provide large surface area containing enzymes to speed up cellular respiration.Matrix – inner liquid solutionIntermembrane Space – space between outer membrane and cristae
19Endosymbiotic TheoryBoth mitochondria and chloroplasts contain their own DNA (mt DNA is circular like that of bacteria), reproduce on their own and are about the same size of a bacteria.Dr. Lynn Margulis in 1960 proposed that mitochondria and chloroplasts were once separate organisms: bacterial cells and algal cells respectively that invaded other eukaryotic cells approximately 1.4 billion years ago
20Cell Wall Composed mainly of cellulose in plant cells Provides structure and support for the cellPresent in plant cells, fungus and bacteria but not in animal cells.The antibiotic penicillin prevents the formation of bacterial cell walls.
21Cytoskeleton3 types of protein fibers: microfilaments, intermediate filaments,microtubulesExtend throughout the cytosol to maintain cell shape, anchor organelles and facilitate movement of organelles
22Plant Cell vs Animal Cells Plant CellsAnimal CellsCell wall and ChloroplastspresentabsentVacuolelargesmallPeroxisomes and LysosomesShapeboxedspherical
23Red Blood CellsRed blood cells are formed in bone marrow. These oxygen carrying cells expel their nuclei to make more room for oxygen in the cell.DNA testing in blood uses white blood cells instead.
24Cilia and FlagellaAre appendages that develop on the outside of eukaryotic cellsFlagellum – whiplike tail used for cell movementCilia – tiny hairs also used for locomotionIn humans cilia allow particles to move out of the respiratory tractIn paramecia cilia propel food toward a feeding groove