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Basic Structure of a Cell. CELL THEORY. All living things are made of cells Cells are the basic unit of structure and function Cells come from the reproduction of existing cells (cell division). Two Main Types of Eukaryotic Cells. Animal Cell. Plant Cell. white blood cell. Amoeba.
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CELL THEORY • All living things are made of cells • Cells are the basic unit of structure and function • Cells come from the reproduction of existing cells (cell division)
Two Main Types of Eukaryotic Cells Animal Cell Plant Cell
white blood cell Amoeba red blood cell muscle cell sperm cheek cells nerve cell Paramecium Differentkinds of animal cells
Examples of Animal Cells Red blood cells Cheek cells Muscle cells
Proteins Cell membrane Protein channel Lipid bilayer Cell or Plasma Membrane(2,5) • Composed of double layer of phospholipids and proteins • Surrounds outside of ALL cells • Controls what enters or leaves the cell – selectively permeable
Cytoplasm • Jelly-like substance • Found in ALL cells • Contains organelles • Provides a place for chemical reactionsto take place
Nucleus(12,15) • Controls the activities of the cell • Contains DNA in chromosomes • Genes control cell characteristics
Nuclear Envelope/Membrane • Double membrane surrounding nucleus • Contains nuclear pores for materials to enter & leave nucleus Nuclear pores
Inside the Nucleus(14,16) The genetic material (DNA) is found DNA is condensed & wrapped around proteins forming as CHROMOSOMES in dividing cells DNA is spread out And appears as CHROMATINin non-dividing cells
Nucleolus(13,14) • Inside nucleus • Makes ribosomesthat make proteins
Endoplasmic Reticulum - ER • Connects to nuclear envelope & cell membrane • Functions in Synthesis of cell products & Transport Two kinds of ER ---ROUGH & SMOOTH
Rough Endoplasmic Reticulum (Rough ER)(11,11) • Has ribosomeson its surface • Makes membrane proteins • TRANSPORT proteins out of cell
Smooth Endoplasmic Reticulum(7,1) • Smooth ERlacks ribosomes • Makes membrane lipids (steroids) • Regulates calcium (muscle cells) • Detoxic substances (Liver)
Ribosomes(10,10) • Made of PROTEINS • “Protein factories” for cell • Join amino acids to make proteins • Process called protein synthesis
Ribosomes Can be attached to Rough ER OR Be free (unattached) in the cytoplasm
Golgi Bodies (8,12) • Stacks of flattened sacs (PANCAKES) • Modify, sort, & package molecules for storage OR transport out of cell • Vesicles pinch off the ends CIS TRANS vesicle
Golgi Animation Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES
Lysosomes(3,7) • Contain digestive enzymes • Break down food, bacteria, and worn out cell parts
Cytoskeleton(5,6) • Helps cell maintain cell shape • Also help move organelles around • Made of proteins • Ex. Microfilaments • Ex. Microtubules
Mitochondrion(plural = mitochondria)(4,3) • “Powerhouse” of the cell • Generate cellular energy (ATP) • Site of CELLULAR RESPIRATION • Has its own DNA • What kind of cells would have MORE mitochondria?
What do mitochondria do? “Power plant” of the cell Burns glucose to release energy (ATP) Stores energy as ATP
Cilia & Flagella • Function in moving cells and movement of particles across a membrane • Cilia -short and many (spirit fingers) • Flagella - longer and fewer (ex sperm tail)
Cilia Moving Away Dust Particles from the LungsRespiratory System
Centrioles (1) • Found only in animalcells • Made of bundle of microtubules • Appear during cell division • Help to pull chromosomes apart
Vacuoles (8) • Storage of wastes, water, and nutrients • Small or absent in animal cells • Plant cells have a large Central Vacuole • No vacuoles in bacterial cells
Onion Epidermal Cells Guard Cells root hair Root Hair Cell Different kinds of plant cells
Examples of Plant cells Guard Cells Pollen Xylem cells
Cell Wall (4) • Supportsandprotectscell • Found outside of the cell membrane • Found in plants, fungi, & bacteria • cellulose in plants • peptidoglycan in bacteria • chitin in Fungi
Chloroplasts (9) • Plant cells ONLY • Contain chlorophyll • Photosynthesis – (energy from sunlight makes food (glucose) • Contains its own DNA
Differences between plant cells and animal cells Animal cells Plant cells Irregular shape Regular shape No cell wall Cell wall present Have chloroplast No chloroplast Large central vacuole Vacuole small or absent Glycogen as food storage Starch as food storage
Cell Types • Cells can only be observed under microscope • Three Basic types of cells include: Bacterial Cell Animal Cell Plant Cell
Number of Cells Although ALL living things are made of cells, organisms may be: • Unicellular – composed of one cell • Multicellular- composed of many cells that may organize into tissues, etc.
Prokaryotes • Cells that lack a nucleus or membrane-bound organelles • Nucleoid region (center) contains the DNA • Single, circular chromosome • Surrounded by cell membrane & cell wall • Contain ribosomes • E.x. bacteria
Eukaryotes • Cells that HAVE a nucleus and membrane-bound organelles Contain 3 basic cell structures: • Nucleus • Cell Membrane • Cytoplasm with organelles • E.x. protists, fungi, plants, and animals
Which Cell Type is Larger? _________ > _____________ > ___________ Plant cell Animal cell bacteria
Cell Size Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?
Factors Affecting Cell Size • Surface area (plasma membrane surface) is determined by multiplying length times width (L x W) • Volume of a cell is determined by multiplying length times width times height (L x W x H) • Therefore, Volume increases FASTER than the surface area
Cell Size • When the surface area is no longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide • Therefore, the cells of an organism are close in size
Cell Size Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse? About the same size, but … The elephant has MANY MORE cells than a mouse!