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Cells, image, [Diagram of a cell]. (n.d.). https://www.britannica…

- - - - Store genetic material of cell for cell divison
      - Nucleolus in nucleus assmble ribosomal subunits for protein synthesis
    - - Structure
        
        Double helix
        
        DNA coil around histones (complex form of DNA and specific proteins ) to form nucleosome
        
        Functions of DNA coiling around histones
        
        To switch on/off genes
        
        Prevent DNA damage/ for stability of DNA
        
        For protection, packing and expression of the genetic material
        
        Structure of nuclesome
        
        "Beads on a string" structure
        
        Nucleosome coil around one another to form tightly condensed chromosome
        
        Chromosomes are tightly condensed form of chromatin for cell division
        
        2 more items...
    - - Structure
        
        Double membrane to enclose nucleus that contains genetic materials
        
        Outer membrane is continuous with endoplasmic reticulum
        
        Not completely sealed, has nuclear pores
        
        Functions of nuclear pore
        
        Permit exchanges of materials between nucleoplasm and cytoplasm
        
        Passageway for molecules to move in and out of the nucleus
    - - Structure
        
        Consists of rRNA
      - Function
        
        For assmbly of ribosomal subunits (consist of rRNA and ribosomal protein)
        
        How?
        
        Ribosomal protein in cytoplasm transported to nuceolus in nucleus via nuclear pore
        
        Ribosomal protein is then assembled with rRNA in nucloelus to form ribosomal subunit
        
        Assembled ribosomal subunit need to be transported back to the cytoplasm where they are used for protein synthesis
  - - - Continuous with outer membrane of nuclear envelope
      - Network of membrane structures that formed flattened fluid tubules (cisternae)
    - - Smooth endoplasmic reticulum
        
        Structure
        
        Surface has ribosomes
        
        Functions
        
        Provide surface area for metabolic processing eg
        
        Detoxification of toxic substances such as alcohol
        
        Carbohydrate metabolism
        
        Synthesis of lipid, especially phospholipids
      - Rough endoplasmic reticulum
        
        Structure
        
        No ribosomes on surface
        
        Functions
        
        Sort proteins to different part of cell using membrane vesicles
        
        Insert newly made proteins into ER membrane
        
        Attach carbohydrate to proteins and lipids
  - - - System of vesicles and stacks of flattened membrane (cisternae) that enclose a compartment
      - From "pinching off" from ER
        
        pinched off vesicles from RER can merge to form cis Golgi
        
        Vesicles from RER may contain proteins that need to undergo further post translational modification (processing and packaging of proteins)
        
        Cargo in vesicles move from cis Golgi -> medial Golgi -> trans Golgi, closer to plasma membrane
        
        Cargo moves to plasma membrane, fuse and merge with plasma membrane to release content of vesicle out of the cell
      - 3. Cis Golgi, stacks nearest to ER
        
        medial Golgi, middle of stacks
        
        trans Golgi, stacks nearest to plasma membrane
    - - Collect and package proteins from ER and direct these proteins to
        
        Plasma membrane to form parts of plasma membrane
        
        Plasma membrane to be merged together with plasma membrane for secretion of content in vesicles out of cell
      - Protein packaging & processing = post translational modification
        
        After proteins are made, sugar residues and phosphate groups are added to proteins
  - - - Contain hyrolytic enzymes that hydrolyse different type of biomolecules eg proteins
      - pH in lysosome is low as optimal working pH for lytic acid is low
      - small round vesicles found ONLY in animal cells
        
        Produced from Golgi apparatus by 'pinching off' vesicles from Trans Golgi
    - - Digestion of proteins, lipids and nucleic acid by lytic enzymes
      - Digestion of substances taken up from outside of cell via endocytosis
      - Recycling of worn out organelles
- - - - Contain double membrane
        
        Inner membrane is highly invaginated to form cristae
        
        Cristae increase surface area for better efficiency of reactions taking place on inner membrane
        
        Inner membrane also encloses mitochondrioal matrix
    - - To produce energy in the form of ATP via cellular respiration at cristae
  - - - Structure
        
        Double membrane bound organelle
        
        Has thylakoid membrane system that has multiple flattened compartments that look like flat discs
        
        Each thylakoid can be stacked up to form granum
        
        Space within inner membrane but outside of thylakoid membrane = stroma
        
        Calvin cycle takes placess
        
        Series of cyclical biochemical reaction to produce simple sugar/ carbohydrate
        
        Process
        
        ATP from light reactions in the thylakoid membrane system will be fed into Calvin cycle and together with gaseous carbon dioxide, ATP and carbon dioxide will be converted into simple sugars
        
        Each disc cocntains chlorophyll
      - Function
        
        Chlorophyll in chloroplast capture light energy to produce ATP and oxygen
        
        Energy produced is used to make carbohydrates from carbon dioxide