1 / 42

Eukaryotic cells and their organelles Plant cells and animal cells have many

Eukaryotic cells and their organelles Plant cells and animal cells have many common organelles- and a few unique ones What are the major differences between prokaryotic and eukaryotic cells?. Presence of a nucleus “Internal membrane system” produces special

marcy
Download Presentation

Eukaryotic cells and their organelles Plant cells and animal cells have many

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Eukaryotic cells and their organelles Plant cells and animal cells have many common organelles- and a few unique ones What are the major differences between prokaryotic and eukaryotic cells?

  2. Presence of a nucleus “Internal membrane system” produces special compartments for cell functions Tubules and filaments involved in motility Exocytosis and endocytosis Chromosome formation Mitosis vs. cell fission RNA processing

  3. The nucleus double membrane fused by nuclear pores pores are lined by pore complexes regulate movement of mRNA, ribosomes, enzymes, etc.

  4. Ribosomes- free or attached to endoplasmic reticulum Free ribosomes produce intracellular proteins (structural and enzymes) Attached ribosome-secreted

  5. Endoplasmic reticulum is rough or smooth Rough ER is covered with ribosomes Ribosomes synthesize polypeptide chains processed and formed in RER Proteins are modified in the ER glycosylation enzymes Secreted and plasma membrane proteins are made in the RER

  6. Smooth ER Synthesis of lipids and steroids Glycogen synthesis in liver Drug detoxification , esp. in liver SER synthesis is inducible (so is RER) Muscle cells- “sarcoplasmic reticulum” sequesters and releases calcium

  7. The Golgi apparatus receives proteins from the ER Golgi is oriented cis-trans Vesicles transport proteins from RER and fuse Vesicles bud off from Golgi to transport proteins to their destination Processing continues in Golgi: glycosylation, phosphate groups, etc. Can synthesize (and process) saccharides

  8. Mitochondria and chloroplasts convert energy to forms that cells can use Have their own ribosomes and DNA; inherited from maternal parent in sexual reproduction Have double membranes Mitochondria are found in most eukaryotic cells (not RBCs) Chloroplasts are found in photosynthetic tissues- plants and algae

  9. Chloroplasts are a type of plastid Amyloplasts store starch Chromoplasts store pigment

  10. Lysosomes contain hydrolytic enzymes that digest large biomolecules Enzymes are synthesized similarly to secreted proteins “tagged” as lysosomal with mannose-6-phosphate Packaged into vesicles and transported to “endosomes” Discovered by Christian de Duve, 1950s

  11. Digestive function was observed before lysosomes were DeDuve was looking for an enzyme involved in carbohydrate metabolism (location in liver) Used acid phosphatase as control enzyme Used differential centrifugation to find the former enzyme (in microsomes)

  12. Findings with acid phosphatase: Activity increased after a few days Acid phosphatase seemed to pellet with mito- chondrial portion. Activity increased upon exposure to detergents (I.e., enzyme was within a membrane-bound particle) Slower centrifugation showed that activity was NOT associated with mitochondrion Acid phosphatase was associated with other hydrolytic enzymes

  13. Hypothesis: enzymes were packaged together in membrane-bound organelle Presence of lysosomes later confirmed by electron microscopy

  14. Peroxisomes Animal cells: Detoxification, esp. in liver and kidney Breakdown of fatty acids (small ones can be handled in mitochondria, but slowly) adrenoleukodystrophy- sex-linked enzyme deficiency; fatal Glyoxysomes (seeds) store fat and contain enzymes that convert it to sugar

  15. Leaf peroxisomes photorespiration (along with mitochondria and chloroplasts) tends to occur in hot dry conditions

  16. Vacuoles especially important in aquatic organisms Contractile Food (in variety of cells) Central vacuole (tonoplast membrane) may be most conspicuous part of plant cell

  17. Cytoskeleton Organization and motility of cell cilia and flagella movement of organelles within cells cytoplasmic streaming

  18. Microfilaments (actin)- movement Support structure just inside cell membrane Muscle contraction: sliding filaments Pseudopodia

  19. Intermediate harder to classify Important for stability rather than movement

  20. Cell wall Plants, bacteria, fungi, some protists Bacteria- peptidoglycan Fungi- chitin

  21. Extracellular matrix Support Adhesion Movement Regulation

  22. Interactions involved in adhesion Integrin-fibronectin L-selectin-mucin (proteoglycan)

  23. Intercellular junctions Organzie cells into tissues Enables these cells to “communicate” with each other: Movement of water and nutrients Electrical/chemical signals Plasmodesmata in plants In animals:

More Related