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Cells. Structure and Function. Introduction to cells. Cell Theory all living things are composed of one or more cells cells are the basic units of structure and function in an organism cells come only from existing cells. Size limited by outer surface area and volume
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Cells Structure and Function
Introduction to cells • Cell Theory • all living things are composed of one or more cells • cells are the basic units of structure and function in an organism • cells come only from existing cells
Size limited by outer surface area and volume why is this important? Shape form reflects function nerve cells skin cell Internal Organization internal structures organelles cell membrane nucleus Eukaryotes plant animal Prokaryotes Cell Diversity
Organelles mitochondrion ribosome endoplasmic reticulum golgi apparatus lysosome Microfilaments cillia nucleus vacuole plastid Parts of the Eukaryotic Cell
Mitochondria • Transfers energy from organic compounds to ATP • ATP drives most of the chemical reactions that occur in the cell • more in cells that have high energy requirements
Ribosome • Most numerous organelle • assemblage of two organic compounds • protein and RNA • Free or attached • two parts
Endoplasmic Reticulum • Membranous tubules and sacs • intercellular highway, path for molecules to move from one part of the cell to another • two types • rough • makes protein • smooth • steroids • calcium levels • liver breakdown
Golgi Apparatus • Packaging, processing and secreting • system of membranes • modifies proteins for export
lysosomes • Small spherical organelles that enclose hydrolytic enzymes • early development • digestion • old organelles • viruses • bacteria
cytoskeleton • Maintains shape and size • network of long protein strands located in the cyotsol • Microfilaments • actin • muscle contraction • microtubules • spindle fibers
Cilia and flagella • Hair like organelles that extend from the surface of the cell • play a role in movement • Cilia • short and present in large numbers • line cells • Flagella • long and less numerous • whipping back and forth
Nucleus • Nuclear matrix • nuclear envelop • chromatin • chromosomes • nuclear pores • nucleolus • ribosomes made
Plant cells • Three additional structures • cell walls • vacuoles • plastids
Cell Wall • Made of cellulose • pores in structure allow for transport of ions and molecules • Lies outside the cell membrane • helps support and protect the cell • secondary wall • between primary and membrane • stops growth • wood
Vacuoles • Fluid filled organelles • store enzymes • metabolic waste • can occupy up to 90% • apple
plastids • Two membrane bound organelles • Store • starch • fat • pigments • types • chloroplasts
chloroplast • Thylakoid • flattened membranous sacs • sunlight is converted into chemical energy • give leaves and fruit and flower color
Tissues organs organ systems Evolution of Multicellular organism colonial organisms specialized in performing functions cell in cell Multicellular Organization