* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 3 The Basic Structure of a Cell
Survey
Document related concepts
Biochemical switches in the cell cycle wikipedia , lookup
Tissue engineering wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Signal transduction wikipedia , lookup
Cell encapsulation wikipedia , lookup
Programmed cell death wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell nucleus wikipedia , lookup
Cell membrane wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell growth wikipedia , lookup
Cell culture wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cytokinesis wikipedia , lookup
Transcript
Basic Structure of a Cell 1 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal Cell Plant Cell Bacterial Cell 2 Number of Cells Organisms may be: • Unicellular – composed of one cell • Multicellularcomposed of many cells that may organize 3 Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles Eukaryotes include most other cells & have a nucleus and membranebound organelles (plants, fungi, & animals) 4 Prokaryotes Nucleoid region contains the DNA •Cell membrane & cell wall • Contain ribosomes (no membrane) to make proteins in their cytoplasm 5 Eukaryotic Cell Contain 3 basic cell structures: • Nucleus • Cell Membrane • Cytoplasm with organelles 6 Two Main Types of Eukaryotic Cells Plant Cell Animal Cell 7 Organelles Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm 8 CELL WALL Cell wall Protect and support the enclosed substances (protoplasm) Resist entry of excess water into the cell Give shape to the cell 9 CELL WALL Cell wall Made of cellulose which forms very thin fibers Strong and rigid Found in plant cells 10 Cell or Plasma Membrane Cell membrane Living layer Controls the movement of materials into and out of the cell Selectively permeable 11 Surrounding the Cell Cell membrane Lies immediately against the cell wall in plant cells Made of protein and phospholipids Selectively permeable 12 Cytoplasm of a Cell Cytoplasm Jelly-like substance enclosed by cell membrane Provides a medium for chemical reactions to take place 13 More on Cytoplasm Cytoplasm Contains organelles to carry out specific jobs Examples: chloroplast & mitochondrion 14 NUCLEUS Nucleus Controls the normal activities of the cell Bounded by a nuclear membrane Contains chromosomes 15 More on the Nucleus Nucleus Each cell has fixed number of chromosomes that carry genes Genes control cell characteristics 16 Nucleolus • Cell may have 1 to 3 nucleoli • Inside nucleus • Disappears when cell divides • Makes ribosomes that make proteins 17 Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes proteins USED In the cell Rough ER has ribosomes on its surface & makes proteins to EXPORT 18 RIBOSOMES • Small specks made of RNA. • Found in cytoplasm or on the endoplasmic reticulum • Makes proteins 19 Cell Powerhouse Mitochondrion ( mitochondria ) Rod shape Site of Cellular respiration 20 In Animal Cells: Mitochondria Active cells like muscles have more mitochondria Burn sugars to produce energy ATP 21 Plant Cell Organelles Vacuole Have a large central vacuole Surrounded by tonoplast Contains cell sap Sugars, proteins, minerals, wastes, & pigments 22 Plant Cell Organelles Chloroplast Contain the green pigment chlorophyll Traps sunlight to make sugars (food) Process called photosynthesis 23 Golgi Bodies • Stacks of flattened sacs • Have a shipping side & a receiving side • Receive & modify proteins made by ER • Transport vesicles with modified proteins pinch off the ends Transport vesicle 24 Lysosome • Contain digestive enzymes • Break down food and worn out cell parts for cells • Programmed for cell death (lyse & release enzymes to break down & recycle cell parts) 25 LYSOSOME • Small cylindrical • Used during mitosis 26 Different kinds of plant cells Onion Epidermal Cells Guard Cells root hair Root Hair Cell 27 vacuole cytoplasm nucleus mitochondrion glycogen granule Animal cell No cell wall or chloroplast Stores glycogen in the cytoplasm for food energy cell membrane 28 Animal Cell Organelles • Near the nucleus • Paired structures • Help cell divide 29 Different kinds of animal cells white blood cell Amoeba red blood cell muscle cell cheek cells sperm nerve cell Paramecium 30 Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria 31 Differences between plant cells and animal cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present 32 Differences between Plant Cells and Animal Cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall 33 STRUCTURE & FUNCTION OF CELL MEMBRANE (pp. 59-60) 34 Structure & function of cell membranes • Lipids = form foundation of membranes – Separates inside of cell from outside – Selectively permeable – how phospholipids interact with H2O 35 CELL MEMBRANE AS BARRIER • Phospholipids = Phosphate group + 2 fatty acids – Polar head – phosphate group – attracted to water (hydrophilic) – 2 Non-polar tails – fatty acids – repelled by water – interior of membrane (hydrophobic) 36 • Lipid bilayer = double layer – Non-polar tails – interior – repels ions, polar molecules (sugars, proteins) 37 PROTEINS EMBEDDED IN LIPID BILAYER • What keeps proteins within lipid bilayer? – Some amino acids (remember, amino acids make up proteins) are polar / non polar – Non polar part = attracted to the interior of lipid bilayer, but repelled by H2O on either side – Polar part = attracted to H2O on either side of lipid bilayer – **DUAL ATTRACTION holds protein in lipid bilayer* 38 39 Cell Membranes Contain Different Types of Proteins 1. MARKER proteins – attached to carbohydrate on cell’s surface (help other cells recognize their cell type (heart, liver) 2. RECEPTOR proteins – recognize and bind to specific substances 3. ENZYMES – involved in important biochemical reactions 4. TRANSPORT proteins – aid in the movement of substances into and out of the cell 40