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General features of cells - Coggle Diagram
General features of cells
Overview of cell structure
Prokaryotes (simple cell structure, no nucleus)
Bacteria
Outside plasma membrane
Glycocalyx- traps water, gives protection, help evade immune system
Appendages- Pilli(attachment), flagella(movement)
Cell wall- provides support and protection
Inside plasma membrane
Nucleoid region where DNA is located
Ribosomes synthesizes proteins
Cytoplasm
Archaea
often found in extreme environments, less common, small cells
Eukaryotes (complex cells, dna enclosed in membrane bound nucleus, internal membranes form organelles
Cytoplasm everything inside the plasma membrane including cytosol, endomembrane system and semiautonomous organelles
Cytosol- outside cell organelles but inside plasma membrane
The nucleus and the endomembrane system
Network of membranes enclosing nucleus, endoplasmic reticulum , Golgi apparatus, lysosomes, peroxisomes and vacuoles.
Golgi apparatus- stack of flattened membrane bound compartments, vesicles transport materials between stacks. helps in secretion, processing, protein sorting
Endoplasmic reticulum- network of membranes that form flattened fluid tubules or cisternae
Rough ER: studded with ribosomes, involved in protein synthesis and sorting
Smooth ER: detoxification, carbohydrate metabolism, calcium balance, phospholipids synthesis, lipid modification
Lysosomes- contain acid hydrolases, helps in break down of proteins, carbohydrates, nucleic acids, lipids. digestion of substances through endocytosis. recycle worn-out organelles by autophagy
Vacuoles
Central vacuoles: in plants for storage, and support
Contractile vacuoles in protists expelling water
Phagocytic vacuoles in protists and white blood cells for degradation
Peroxisomes- catalyse reactions that breakdown molecules by removing hydrogen or adding oxygen
Plasma membrane - membrane transport in and out of the cell, cell signalling using receptors, cell adhesion.
Semiautonomous organelles- Grow and divide to reproduce themselves, rely on cell for synthesis of internal component
Nucleus
Nuclear matrix- (filamentous network= nuclear lamina + internal nuclear matrix)
Ribosome assembly- occurs in nucleolus
Chromosomes- composed of DNA and protiens called chrmatin
Nuclear envelope
Double membrane structure enclosing nucleus
Outer membrane of the envelop is continuous with the er membrane
Nuclear pores provide passageways
Cytoskeleton
Microtubules- long hollow cylindrical structures ( alpha and beta tubulin, 25 nm)
Actin filaments- microfilaments (actin, 7nm)
Intermediate filaments ( keratin, Lamin, 10nm)
Motor proteins: uses ATP, three domains- head, hinge, tail
Kind of movement
Motor protein remains in place, filament moves
Motor protein and filament restrained, action of the motor protein exerts a force that bend the filament.
Carries cargo along filament
Molecular synthesis and breakdown
Metabolism: sum of all chemical reactions carried out by cells
Anabolism- synthesis of cellular molecules and macromolecules
Cytosol plays central role in coordinating metabolic activities of eukaryotic cells.
Catabolism- Breakdown molecules into smaller components