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Cell Bio & Biochem Pt. 3 - Coggle Diagram

- - - - Nucleus
        
        DNA replication (DNA --> DNA)
        
        Transcription (DNA --> RNA) ... migrates into cytosol
      - Cytosol
        
        Translation (RNA --> protiens) on rER and sER
    - - AT & GC (complimentary pairing)
      - U is swapped for T in RNA
    - - In Eukaryotes
        
        DNA is found on 46 chromosome
    - - each sugar associated w/ a base
  - - - diploid cells
        
        mitosis of cells
        
        migration and differentiation and specicalize
        
        tissues and organs form
        
        allows the foetus to function physiologically
    - - DNA (genes) code for proteins
        
        Structural protiens
        
        physical traits
        
        Enzymatic protiens
        
        metabolic traits
        
        Hormonal proteins
        
        control of growth and development
      - DNA replicates, transcribes and repairs
  - - - Parental strand becomes the template strand and a new strand is synthesised with complimentary bases
      - S and S' strands are the parental
        
        template S synthesises for a new S'
        
        template S' synthesises for a new S
      - Synthesised in the 5' --> 3' direction
    - - Parental strands are separated by DNA helicase
      - DNA polymermase (I, II, III) add complementary bases
      - Leading strand
        
        Synthesised continuously by DNA pol III
      - Lagging strand
        
        Synthesised in fragments by DNA pol III
        
        fragments called = Okazaki fragments
        
        RNA fragments
        
        DNA pol I removes RNA and fills in gap w/ DNA
        
        Fragments join togther by DNA ligase
    - - Possibility for one error per replication of full genome (1 in billion)
        
        High fidelity of DNA replication is critical for maintenance of intact DNA
      - DNA polymerase proofreading
        
        DNA exonuclease activity removes base error
        
        allows for DNA replication to continue
        
        Ex. C base is incorporated into the base pair with A (not T)
      - Mismatch Repair
        
        errors missed by polymerase proofreading
        
        Muts and MutL
        
        Detect nicks (error)
        
        They bind and remove a portion of the strand
        
        DNA is resynthesised
  - - - Role of mRNA
        
        Carriers gene code from nuclues to the ribosome sin the cytosol
        
        Altered mRNA transcription are key in producing the effects of hormones
      - Some genes are transcribed more than others and produce more protiens or less and this determines its effect
    - - DNA is unwound and RNA transcribes a template strand w/ complimentary bases (5' --> 3')
    - - 5' Cap
        
        protects mRNA from degradation
      - RNA splicing
        
        removes non-coding sequences (INTRONS) and leaves the coding (EXONS)
      - 3' polyadenylation (AAAA)
        
        protects the mRNA from degradation
  - - - Recognises START Codons to begin transcription (AUG)
      - Three sites of activity (EPA) in the 50S subunit
        
        E = Exit
        
        tRNA leaves
        
        P = peptidyl
        
        amino acids are join by peptide bonds
        
        A = aminoacyl
        
        tRNA carrying the a.a binds to the codon on mRNA
      - Recognises the STOP codons = terminates translation
    - - Aminoacids are coupled to tRNA
      - tRNA has an anti-codon which is complementary to the codon on mRNA
  - - - Connective tissue and Bone
      - Resists tensile forces due to multidirection fibers
    - - Modifications following peptide cleavage
        
        hydroxylation
        
        Proline (this hydoxylation requires Vitamin C)
        
        deficiency of Vit C = results in scurvy
        
        glycosylation
        
        lysine
      - Self-assemply of three chains (triple helix) in the Procollagen form
      - Secretion of procollagen outside of the cell, propetides are removed and is then reassembled to for COLLAGEN
    - - it will affect the folding of the protein in its quraternary structure
        
        Osteogenesis Imperfecta
        
        Abnormal jaw sizes
        
        open bites, malocclusion
        
        Missing teeth
        
        Dentinogenesis imperfecta
- - - - S phase (DNA synthesis)
      - G1 and G2 phase
        
        (Gap allows for growth and doubling of cell components)
        
        Checkpoints
        
        Start Checkpoint (G1/S)
        
        extracellular enviornment favourable for growth and DNA is not damaged
        
        G2/M Checkpoint
        
        enviorment favourable and DNA replication completed
      - M phase (division)
        
        Mitosis (nulcear division)
        
        Prophase, prometaphase, metaphase, anaphase and telophase
        
        Checkpoint with the Meta to Anaphase transition
        
        correct spindle formations
        
        Cytokinesis (cytoplasm division)
        
        Anaphase --> Teleophase
      - Cell Cycle Control
        
        Mitogen
        
        Activates transcription factors to activate the DNA to do from G1 to S phase
        
        Ex. Growth factors
        
        Stimulates cells to enter cell cycle
        
        Checkpoints
        
        G1/S, G2/M and M(meta/Anaphase) Checkpoints
        
        Arrested Cell Cyle
        
        protein p53 - under normal conditions is brokendown rapidly, but if DNA da,age occurs, it can be left active which will synthesis p21 protein wjhich inhibits cell cycle
- - - - Caused by lack of growth signals or hormones
      - Cell Changes: shrinking and convolution
      - Nulcear Changes: DNA framentation
      - No cell lysis no inflammatory response
  - - - Caused by: hypoxia, physical or chemical damage
      - Cell Changes: swelling and lysis
      - sequale: inflammation
- - - - Ligands that can alter the phentype of a stem cell
      - MyoD
        
        turns a fibroblast into a multinucleated muscle cell
  - - - Pluripotent = can be converted into no. differnetiated cells
    - - Can be differentiated into any cell in the whole body
    - - Fibroblasts have been able to be reconvernted into multipotent cells and they can then be differentiated into cells use for testing drug sensitivity or transplant of tissue
      - Dental Stem Cells?
        
        mesenchymal cells found in the pulp, PDL and follicle
        
        They can be differentiated into adiopogenic, neurogenic, osteo/odontogenmic cell lineages
- - - - growth/enviornmental fcators that regulate cell growth
    - - (DNA repair)
  - - - Failed fidelity
      - DNA replication errors/ Free radicals
    - - ionising radiation
        
        chnages bases in DNA, breaks in double strands
      - non-ioising
        
        alter DNA
    - - translocation
  - - - Mutations can accumulated w/ age
      - oncogenes = cancer causing genes
    - - i. Growth factors
      - ii. Growth factor receptors
      - iii. Intracellular transducers/receptor
      - iv. Transcription factors
      - vi. tumor suppression genes
      - vii. increase probability of gene mutations
      - v. anti-apoptosis proteins
    - - Base excision or nucleotide excision repair damaged DNA
      - Mutations in these genes will cause mutations to accumulate
      - BRCA1/2 = Breast and ovarian cancer
    - - ONLY ONE ALLELE IS NEEDED FOR PHENOTYPE
        
        50% affeceted offspring
      - ex. Huntington's disease, Dwarfism, Polydactyly
      - Proteins that promote cell division = proto-oncogenes
        
        only need one allele mutated to become oncogenic
    - - BOTH ALLELS REQUIRED FOR PHENOTYPE
        
        25% affected, 50% carriers
      - ex. Cystic fibrosis, albinism
      - Proteins that inhibit cell division = tumor suppressor genes
        
        eg. p53
        
        need mutations in both alleles to become oncogenic