Cell Architecture of Animals (Eukaryotes)
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Eukaryotic Cell Architecture
Summary
- Often called phospholipid bilayer
- Comprises: Proteins, Cholesterol, Carbohydrates.
- Separates cell from external environment; controls the flow of material into and out of it.
- Aqueous solution that bathes organelles and contains a variety of molecules
- Portion of cytoplasm not contained within organelles
- Free ribosomes
- Select group of membranous organelles that regulate protein trafficking and metabolism
- Nuclear envelope with pores (double-membrane)
- Site of DNA replication and RNA synthesis (transcription)
- Contains: chromatin, nucleolus (rRNA and ribosomal proteins)
- Continuous with nuclear envelope
- Cisternae enclose a space called the ER lumen
- Rough ER: with bound ribosomes; site of protein synthesis, processing and secretion
- Smooth ER: no ribosomes; lipid synthesis, carbohydrate metabolism, detoxification
- Keeps secretory proteins separate from proteins synthesized in the cytosol
- cis side faces the nucleus, trans side where cargo exits
- Modifies, stores and secretes molecules that it receives from the ER
- Synthesizes its own macromolecules
- Vesicle that contains hydrolytic enzymes; digests endosomal cargo
- Forms when cell engulfs nutrients or other particles via endocytosis
- Two subunits: one large and one small
- Synthesize proteins via translation
- Can be bound to rough ER or free (suspended in cytosol)
- Double-membrane bound: inner membrane invaginates to form cristae
- Space within cristae: matrix (contains free ribosomes)
- Space between inner and outer membranes: intermembrane space
- Synthesizes ATP via citric acid cycle and oxidative phosphorylation (couples oxidation of nutrients with ADP phosphorylation)
- Single-membrane bound vesicle
- Produce hydrogen peroxide from detoxification of substances (i.e. alcohol)
- Microfilaments, intermediate filaments and microtubules
- Anchors organelles and provides structural framework
- Where microtubules nucleate
- Contains two small structure called centrioles
- Functions in cell division
DOUBLE MEMBRANE BOUND ORGANELLES
- Nucleus
- Mitochondria
CLINICAL CORRELATIONS
- Rough ER Network and Pancreatic beta cells
- Smooth ER and Hepatic cells
- Lysosomes and Tay-Sachs disease