Cell Theory All living matter is composed of one or more The cell is the structural and functional unit of life All cells come from pre-existing cell

Transcription

1 Cell Theory All living matter is composed of one or more The cell is the structural and functional unit of life All cells come from pre-existing cell Prokeryotic Bacteria or archaea Cell wall, small circular DNA(in the nucleoid region) Lack a nucleus and other membrane bound organelle Unicellular Eukaryotic Plant, animal, fungus, or protest Large linear DNA Has a nucleus and other membrane bounded organelles Unicellular or multicellular (generally larger) Prokeryotic and Eukaryotic, both have: Cell membrane Cytosol (cytoplasn-gel) Ribosomes (Protein)(Different in size)

2 Why are cells so same? Cell volume to surface are ratios favor small size Small cells with larger surface area and less volume promote a more efficient transfer of nutrients in and waste products out of a cell Cell (Plasma) Membrane Separates the cell from the environment Boundary layer for regulating the movement of materials in/out of a cell Cytoplasm or Cytosol Cell substances between the cell membrane and the nucleus The fluid part of a cell Contains the organelles Organelles small organs Formed body in a cell with a specialized function Important in organizational structure of cells

3 Why is the compartmental organization of organelles lead it to be more efficient? Each organelle contain their own membrane(s) and enzymes so the many metabolic processes can occur in the cell at the same time without conflicting with one another Nucleus Most noticeable organelle Usually spherical, but can be lobed or irregular in shape Structure: Nuclear Membrane Nuclear Pores Nucleolus Chromatin Functions: Control center of the cell Contains the genetic instructions(dna) Nuclear Membrane Double lipid bilayer membrane Inner membrane supported by a protein matrix which gives the shape to the nucleus (nuclear lamina) Nuclear Pores Regular holes through both membranes Protein complex gives shape Allows materials in/out of nucleus

4 Nucleolus Dark staining area in the nucleus 0-4 per nucleus Storage area for ribosomes Chromatin Chrom-colored /Tin-threads DNA and protein in a loose format Will form the cell s chromosomes (46) Ribosomes Endomembrane System Structure Two subunits made of protein and rrna No membrane Functions Protein synthesis Location Free in the cytoplasm-make proteins for use in the cytosol Membrane bound(r.er)-make proteins that are exported from the cell Membranes that are related through direct physical continuity or by the transfer of membrane segments called vesicles. Includes the nuclear membrane, ER, and the Golgi Apparatus

5 Endoplasmic Reticulum ER Makes up to ½ of the total membrane in cells Often continuous with the nuclear membrane Structure Folded sheets or tubes of membranes Very fluid in structure with the membranes constantly changing size and shape(based on protein being built) Types of Endoplasmic Reticulum Smooth ER No ribosomes Used for lipid synthesis, carbohydrate storage, detoxification of poisons Rough ER With ribosomes Make secretory proteins (ones that will be exported from the cell) Golgi Apparatus Structure Parallel array of flattened cisternae(pita bread) 3-20 per cell based on protein production Outgrowth of the ER system Function of Golgi Apparatus Cis Face receives protein products from the ER Processing- modification of ER proteins Distribution- packaging of ER products for transport Trans Face use vesicles to ship out modified products to cells

6 Golgi Vesicles Lipid based Small sacs of membranes that bud off the Golgi body Transportation vehicle for the modified ER products Lysosomes Single membrane vesicles found in animal cells only Made from the Golgi apparatus Functions Breakdown and degradation of cellular materials Contains hydrolytic enzymes for the breakdown of fats, proteins, polysaccharides, and nucleic acids Over 40 types known Lysosomes 2 Important in cell recycling (autophagy) and also in programmed cell death (apoptosis) Missing enzymes may cause various genetic enzymes diseases Examples: Tay-Sacks (missing enzymes to break down lipids, so the accumulate in brain cells)

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