Cell Structures I Prokaryotic vs Eukaryotic Cells CELLS

Cell Structures

I. Prokaryotic vs. Eukaryotic Cells CELLS Prokaryotic Smaller • No True Nucleus - Genetic material is found in cytoplasm. • No specialized organelles *except ribosomes EX: Bacteria & Archaea Eukaryotic Larger • True Nucleus - Genetic material is bound by a membrane • Contain specialized organelles EX: Plants, Animals, Protists, & Fungi

Animal Cell

Plant Cell wall

Structure Cell Wall Function/Other Info • Support & protection • Lies outside cell membrane • Not in animal cells • In Plants, made of cellulose • In Fungi, made of chitin • In Bacteria, made of peptidoglycan • Controls what enters/ leaves the cell (selectively permeable) Cell Membrane • Composed of lipids & proteins *Transport & Excretion

Structure Cytoskeleton Function/Other Info • Supporting network of long, thin protein fibers in cytoplasm • Made of microtubules and microfilaments – Microtubules: made of protein tubulin, form rigid skeleton, assist in moving substances within cell (organelles, vesicles, chromosomes); also help build centrioles, cilia and flagella (hair-like structures used for cell movement) – Microfilaments: made of protein actin, give cell shape, enable entire cell or parts of cell to move *Movement, Transport

Cilia Flagella

Structure Cytoplasm Nucleus Function/Other Info • Watery fluid between membrane and nucleus that contains organelles • Contains hereditary information (DNA) • Surrounded by nuclear membrane/envelope • Dense nucleolus produces ribosomes *Regulation

Structure Ribosome Function • PROTEIN SYNTHESIS* • Rough ER has ribosomes attached that will Endoplasmic produce proteins for export from the cell Reticulum • Smooth ER synthesizes carbohydrates and lipids, detoxifies harmful substances

Structure Golgi Body Function • Modifies, sorts, and packages proteins into sacs called vesicles, which can fuse with the cell’s plasma membrane to release proteins into the membrane or outside environment (attaches carbohydrates & lipids to proteins)

Structure Vacuole Centrioles Function • Stores food, water, wastes • Large in plant cells; Small in animal cells • Contractile Vacuole in some freshwater Protists – pumps excess water out of cell • Produce spindle fibers (microtubules) to help separate chromosomes during cell division (reproduction) • Animal cells only

Structure Lysosome Function • Contain digestive enzymes to break down food, old organelles, bacteria, viruses • Some Protists & Animal cells only *Nutrition

Structure Chloroplast Mitochondria “Powerhouse” Function • Use energy from sunlight to make glucose & oxygen (photosynthesis) • Not in animal cells • Contains chlorophyll (green pigment) to absorb sunlight *Nutrition • Release energy from glucose to produce ATP *Aerobic Respiration

*Endosymbiosis- One organism lives inside the cell of another organism to the benefit of both. *Endosymbiotic Theory- Mitochondria and chloroplasts are thought to have evolved from bacteria that were engulfed by larger cells. Evidence: • They have their own DNA • They can make their own proteins • They can self-replicate • They have an inner and outer membrane (inner = original bacterial membrane; outer = vesicle when engulfed by larger cell)