Structure & Function of Organelles in a Cell

1. Structure & Function of Organelles in a Cell

2. 2 main types of cells • Prokaryotes: Unicellular organisms without a nucleus and without most organelles (bacteria= very simple) • Eukaryotes:Organisms whose cells contain a membrane-bound nucleus and other membrane-bound organelles • Eukaryotic cells contain many cell parts called organelles. The structure of the organelle helps determine how it functions. • Contains: Plants, Animals, Fungi, and Protists

3. Review • Remember the different kingdoms? • Plants: Organisms that are multicellular and photosynthetic • Animals: Organisms that are multicellular and ingest their food • Fungi: Organisms that absorb nutrients after decomposing organic material (includes molds, yeast, mushrooms, etc). • Protists: Organisms that are unicellular and sometimes colonial and less often multicellular (typically include protozoans and most algae).

4. Organelles and their Function – Cell Wall • Found in Eukaryotic cells EXCEPT ANIMAL CELLS and Prokaryotic Cells • Stiff, rigid structure that protects plant cells from injury and provides skeletal support. • Supports the cell structure • Predict what kinds of cells would have cell wall. • All plant cells, fungi cells, as well as prokaryotic cells • What would happen if we removed this organelle? • Without the cell wall these cells would lack protection as well as structural support.

5. Organelles and their Function – Cell Membrane • Found in Eukaryotic and Prokaryotic cells • Phospholipid bilayer that regulates what goes in and out of the cell and maintains basic shape; surrounds EVERY cell • Regulates what goes in and out • Predict what kinds of cells would have a cytoskeleton. • All cells have a cell membrane • What would happen if we removed this organelle? • Anything and everything could go in and out of the cell causing inappropriate concentrations of chemicals on either side of the membrane

6. Organelles and their Function – Cytoskeleton • Found in Eukaryotic and Prokaryotic cells • Holds structure of the cell and aid in mechanical transport and signaling within the cell; located throughout the cytoplasm • Maintains cell structure • Predict what kinds of cells would have a cytoskeleton. • All cells have a cytoskeleton • What would happen if we removed this organelle? • Organelles would not be where they needed to be and cell would not maintain appropriate structure

7. Organelles and their Function – Cytoskeleton PARTS • microfilaments: part of the cytoskeleton that aids in cell contraction; made of actin protein • microtubules: part of the cytoskeleton; made of tubulin protein • Centrioles: cylindrical structures, found in animal cells only, composed of groupings of microtubules; they move apart to help form the spindle, which then distributes the chromosomes in dividing cells.

8. Organelles and their Function – Cilia/Flagella/Pseudopodia • Found in some Eukaryotic and Prokaryotic cells • structures outside of the cell that aid in motility; extension of the cytoskeleton • Enables movement/locomotion • Predict what kinds of cells would have locomotion. • Found in cells that need to move or help to move things • Cilia-pond protists use for movement and cell that line parts of the respiratory tract- move liquid and debris out of the respiratory system. • Flagella- movement, pseudopodia- movement • What would happen if we removed this organelle? • Limited movement (if any), couldn’t find food, evade predators

9. Cilia, Flagella, Pseudopodia

10. Organelles and their Function – Cytoplasm • Found in Eukaryotic and Prokaryotic cells • fluid that surrounds the organelles in the cell- keeps organelles in place • Fluid to suspend organelles • Predict what kinds of cells would have a cytoskeleton. • All cells have cytoplasm • What would happen if we removed this organelle? • Organelles could collide causing damage, materials could not easily move throughout the cell, water concentrations would be wrong

11. Organelles and their Function – Nucleus • Found in most Eukaryotic cells • Holds DNA and RNA (chromatin/chromosomes); controls function of the cell by controlling protein synthesis; holds nucleolus • Holds DNA to make proteins (chromosomes) • Nucleolus: inside the nucleus where protein synthesis begins (formation of ribosomal RNA = formation of ribosomes) • Predict what kinds of cells would have a nucleus. • All cells that need to make proteins and have DNA for cell replication (mitosis) • What would happen if we removed this organelle? • No protein production, no DNA for future cells

12. Organelles and their Function – Chromosomes • Found in most Eukaryotic cells (NO PROKARYOTES) • Made of DNA in the nucleus; X shaped; condense from chromatin to chromosomes in the nucleolus • Holds DNA to make proteins (chromosomes) • Predict what kinds of cells would have chromosomes. • All cells that need to divide • What would happen if we removed this organelle? • No mitosis or meiosis

13. Organelles and their Function - Ribosomes • Found in Eukaryotes and Prokaryotes • Place where amino acids are put together to make proteins (think protein synthesis); located all over the cytoplasm and on ER when cell makes many proteins • Ribosomes make proteins. • Predict what kinds of cells would have a lot of ribosomes. • Cells that need to make a lot of proteins/enzymes like muscle cells or pancreatic cells for digestion • What would happen if we removed this organelle? • Cells would not be able to create the necessary proteins used by other organelles as well as proteins that are exported to other parts of the body.

14. Organelles and their Function – Rough Endoplasmic Reticulum (RER) • Found in Eukaryotes (found near nucleus) • Folds polypeptide chains after they are built by the ribosomes; ER is “rough” due to ribosomes on them • RER folds polypeptides into proteins • Predict what kinds of cells would have RER. • Cells that need to make a lot of proteins/enzymes like muscle cells or pancreatic cells for digestion • What would happen if we removed this organelle? • Cells would lack enzyme/protein production

15. Organelles and their Function – Smooth Endoplasmic Reticulum (SER) • Found in Eukaryotes (found near nucleus) • Makes lipids (phospholipids, steroids, etc.), breaks down carbohydrates, drugs, and poisons, among others • SER makes lipids and breaks stuff down • Predict what kinds of cells would have SER. • Cells that need to break a lot of toxins down like liver cells • What would happen if we removed this organelle? • Poison the body due to build up of toxins

16. Organelles and their Function – Golgi Apparatus/Body • Found in Eukaryotes (found near cell membrane) • Completes modification of proteins; transports proteins and other materials out of the cell (through the use of vesicles) • Golgi bodies package and ship stuff • Predict what kinds of cells would have Golgi. • Cells that need to transport materials like hormones in the endocrine cells • What would happen if we removed this organelle? • No cell to cell communication due to no release of hormones

17. Organelles and their Function - Mitochondria • Found in eukaryotes • Breaks down food molecules like glucose to make ATP (cell respiration); located throughout cytoplasm. • Mitochondria are the energy source for the cell • Predict what kinds of cells would have a lot of mitochondria. • Cells that are highly active contain more mitochondria than others like muscle cells/cardiac cells • What would happen if we removed this organelle? • Without mitochondria organisms would not be able to convert carbohydrates, fats, etc. into energy.

18. Organelles and their Function – Chloroplasts • Found in Eukaryotic - PLANT CELLS ONLY • Uses energy from the sun to make food (think photosynthesis) • Makes food for the cell • Predict what kinds of cells would have chloroplasts. • Found in photosynthesis plant cells (not all plant cells) • What would happen if we removed this organelle? • No photosynthesis takes place and then no energy cycles in ecosystems based on these plants

19. Organelles and their Function – Lysosomes • Found in Eukaryotes (found in animals) • Digests food particles, wastes, cell parts, and foreign invaders • Digests food and waste/invaders • Predict what kinds of cells would have lysosomes. • Cells that are highly active in replacing old and damaged organelles (i.e. the liver cells) contain a high number of lysosomes • What would happen if we removed this organelle? • Without lysosomes the cells would never be able to replace old/damages organelles as well as digest waste materials= death of the cell

20. Organelles and their Function – Vacuoles • Found in most Eukaryotic cells • Animal cells: One or more small vacuoles for storage • Plant cells: One large vacuole for storage and support • Storage/support • Predict what kinds of cells would have vacuoles. • Most eukaryotic cells have some kind of vacuole for storage • What would happen if we removed this organelle? • Not able to stock pile proteins, carbohydrates, and water • Not able to remove excess water from the cells

21. Self-Quiz Label this cell as either a plant or animal cell? How do you know? What type of locomotion is represented here? The name and function of part N The cell part for J The function of F The component parts of D Function and name for A The name for the material inside of G Name of H and reason for its name. How do you know the difference between Golgi and ER? Polypeptide chains are made at this location.