Cell Organelles Honors Biology I Cell Organelles Organelle
Cell Organelles Honors Biology I
Cell Organelles • Organelle= “little organ”
Cell Walls • Not found in Animal cells • Support structure • Made of cellulose • Plasmodesmata allow materials to pass from one cell to the next
Centrioles • • Found only in animals Formed from protein tubulin Found near nucleus in the centrosome Help organize cell division
Cytoskeleton • “support and transport structure” • Network of protein filaments • 1. Microfilaments – Thread-like – Made of protein actin • 2. Microtubules – Hollow structures – Made of protein tubulin – Important during cell division when moving chromosomes
Plasma Membrane • We have already covered this!
Cilia • Numerous hair-like extensions of the cell membrane • Type of microtubule • used for locomotion and aid in feeding • Ex: respiratory cells
Flagella • Long whip-like extensions of the cell membrane • Type of microtubule • Used for locomotion • Ex: sperm cells
Nucleus: Main Office • “control center” • Contains DNA • Nuclear envelope – Composed of 2 membranes – Contains nuclear pores that allow material to move in and out of nucleus
• Chromatin – DNA bound to protein – Condenses into chromosomes during cell division • Nucleolus – Produces ribosomes • Cells normally contain a single nucleus – Cells such as liver and muscle cells have more than one due to amount of organelles that need controlling
Cytoplasm vs cytosol • All the stuff in between the organelles is cytosol • Everything in a cell except the nucleus is cytoplasm
Ribosomes • “machines” • Makes proteins • Consists of ribosomal RNA and protein • Free Ribosomes – Found in the cytosol – Make proteins for use in that cell • Attached Ribosomes – Attached to rough ER – Make proteins to be transported elsewhere or to be inserted in the membrane
Endoplasmic Reticulum • “conveyor belt” • Consists of a series of membraneous tubules that connect to the nuclear envelope • Rough ER has ribosomes and carries proteins throughout the cell • Smooth ER does NOT have ribosomes and makes membrane lipids and detoxifies drugs – Liver cells have large amounts of smooth ER
Vesicles • Transport organelles – Endocytosis and exocytosis – Protein transport
Golgi Apparatus • “mail room” • Stack of membraneous sacks • Receives proteins from the Rough ER and then modifies, sorts and packages them in vesicles for storage or transport
Vacuoles • “storage” • Sac-like membrane bound structures • Store water, salts, proteins, carbohydrates etc. • Plant cells have a large central Vacuole – Pressure inside offers support to plant structures • Animal cells have smaller vacuoles
Chloroplasts • • “solar power” Only found in Plant cells Double membrane Site where photosynthesis takes place • Contains chlorophyll pigment that absorbs light • Have their own DNA
Mitochondria • “Powerhouse” • Double membrane organelle – outer membrane – Inner membrane: contains folds called Cristae which increases surface area for cellular respiration to take place • Convert chemical energy stored in food into compounds that the cell can use
• Inherited from your mom • Contain their own DNA • Numerous in muscle cells
Lysosomes • “clean up crew” • Small organelles filled with enzymes • Digests lipids, carbohydrates and proteins so that they can be used by the cell • Get rid of “worn-out” organelles
Endosymbiotic Theory • Lynn Margulis suggested that mitochodria and chloroplasts are descendants of prokaryotes • Large prokaryotes consumed smaller prokaryote which developed a symbiotic relationship – Evolution of first eukaryote
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