Cell structue
by natasha zikayo
1. Lysosomes
1.1. Used to breakdown waste material in cells and pathogen ingested in phagocytes
1.2. •Contains hydrolitic enzymes contained by a membrane •Works best in acidic conditions so would have little effective in neutral cytoplasm •made by golgi apparatus •breaks down proteins, carbs, lipids and nucleic acid •important in cell apoptosis
1.3. Stains dark with no distinguishable features under electron light
2. Cytoskeleton
2.1. Network of fibres throughout eukaryotic cytoplasm, stability and shape of cell
2.2. makes organelles stay in place and controls movement •intracellular movement •cellular movement- flagella has cytoskeleton • strengthening and support •Microfilament - polymers of actin protein • contractile fibres • cell movement + contraction in cytokinesis •intermediate filament, made of variety of proteins •10nm in diameter •gives mechanical and structural strength • anchor nucleus • extend between tissue and cells ie basement membrane •microtubules - globular tublin proteins polymerase and form tubes • determine cell shape • spindle fibres composed of microtubules • acts as tracks for organelles Cytoskeletal motor proteins: kinesis, myosin and dyneins are molecular motors
3. Chloroplast
3.1. Responsible for photosyntheis
3.2. • has double membrane • thylakoids are internal membranes that form stacks of grana - joined by intergranal lamelle - site of light dependent stage • chlorophyll contained in thylakoids • fluid called stroma fills space • lots found in palisade mesophyll cell • has its own dna and strach grains
4. Vaculoe
4.1. Maintains turgid and rigid structure
4.2. • surrounded by membrane- tonoplast -seletively permeable • can press against cell wall to make it turgid
5. Centrioles
5.1. Involved in organisation and assembly of spindle fibres during cell division
5.2. • made of 2 microtubules - tublin and protein subunits • two centrioles make a centromere • has positioning role in organisms with flagella and cilia
6. Golgi apparatus
6.1. Modifies and packages proteins into vesicles
6.1.1. Protein production
6.1.2. • proteins synthesised by ribosomes at Endoplasmic Reticulum •passed to cisternse where they are packaged into transport vesicles • move via cytoskeleton to fuse w cis face of golig apparatus • modified leave via the trans face secretory vesicles take to membrane • secretory vesicles fuse to cell membrane release by exocytosis • some make lysomed