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Living Things and Cells Structures that make things be “alive”
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Life Processes: What makes something “alive”? ALL living things do these six processes: 1. Take in nutrients. 2. Use energy 3. Produce wastes. 4. Grow 5. Reproduce 6. Respond to their environment
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Cell Size
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Characteristics of All Cells A surrounding membrane Protoplasm – cell contents in thick fluid Organelles – structures for cell function Control center with DNA
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vTwo cell types – Prokaryotes (Prokaryotic Cells) – Eukaryotes (Eukaryotic Cells)
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Prokaryotic Cells First cell type on earth Cell type of Bacteria and Archaea
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Prokaryotic Cells No membrane bound nucleus Nucleoid = region of DNA concentration Organelles not bound by membranes
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Eukaryotic Cells Nucleus bound by membrane Include fungi, protists, plant, and animal cells Possess many organelles Protozoan
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Two Types of Eukaryotic Cells 1.Animal Cell 2.Plant Cell vBoth cells function similarly
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Cell Organelles Organelle = “little organs” – Specialized structures that perform specific jobs in the cell Found only in eukaryotic cells Many are “membrane-bound” (a membrane surrounds the organelle) All the stuff in between the organelles is cytosol Everything in a cell except the nucleus is cytoplasm
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Plasma (Cell) Membrane Contains cell contents Double layer of phospholipids & proteins
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Phospholipids Polar – Hydrophylic head – Hydrophobic tail Interacts with water
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Movement Across the Plasma Membrane A few molecules move freely – Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules – Proteins embedded in lipid bilayer – Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins
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Membrane Proteins 1. Channels or transporters – Move molecules in one direction 2. Receptors – Recognize certain chemicals
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Membrane Proteins 3. Glycoproteins – Identify cell type 4. Enzymes – Catalyze production of substances
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Cell Wall Rigid, protective barrier (maintains cell shape) Found in plant and bacterial cells Located outside of the cell membrane Made of cellulose (Carbohydrate fiber)
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Cytoplasm Viscous fluid containing organelles components of cytoplasm – Interconnected filaments & fibers – Fluid = cytosol – Organelles (not nucleus) – storage substances
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Cytoskeleton Filaments & fibers Made of 3 fiber types – Microfilaments – Microtubules – Intermediate filaments 3 functions: – mechanical support – anchor organelles – help move substances
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Nucleus Control center of the cell Stores DNA (chromosomes) Surrounded by the nuclear membrane – Pores let material in and out Also contains the Nucleolus, which makes ribosomes
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Nuclear Envelope Separates nucleus from rest of cell Double membrane Has pores
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DNA Hereditary material Chromosomes – DNA – Protiens – Form for cell division Chromatin
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Nucleolus Most cells have 2 or more Directs synthesis of RNA Forms ribosomes
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Endoplasmic Reticulum Transport system for materials in cell Two Types: Rough ER: covered with ribosomes; site of protein synthesis Smooth ER: NO ribosomes; it makes hormones & lipids
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Ribosome Smallest organelle NOT surrounded by a membrane Makes proteins according to DNA instructions. Two Types: – Free ribosomes: float free in cytosol – Bound ribosomes: attached to rough ER That looks familiar…what is a polypeptide?
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Golgi Apparatus Delivery system of the cell Collects, modifies, and packages molecules in the cell Distributes and transports molecules in vesicles
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Lysosomes Clean-up crew of the cell Contain digestive enzymes that break down macromolecules for the cell to use Removes waste particles
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Vacuoles Storage tank Holds water, food, enzymes, wastes, etc Large central vacuole usually in plant cells – Supports cell shape in plants Many smaller vacuoles in animal cells
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Mitochondria “Powerhouse” of the cell Site of cellular respiration Converts energy stored in food into energy the cell needs – ATP Sugar + Oxygen Carbon dioxide + Water + ATP ATP = Adenosine triphosphate ATP = Adenosine triphosphate
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Chloroplast Site of photosynthesis Changes sunlight energy into chemical energy (glucose) Contains green pigment, chlorophyll Found only in plant cells and algae Sunlight + Carbon Dioxide + Water Sugar + Oxygen
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Review of Eukaryotic Cells Exterior Structures
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Review of Eukaryotic Cells Interior Structures
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