RICHARD genetic

• The nucleus function

  • houses the genetic material
  • synthesis of mRNA rRNA tRNA
• the nucleus structure

  1. nuclear pores
  2. chromatin
  3. nucleolus
  4. nucleoplasm
  5. nuclear envelope

  
• nucleoplasm contain

  protein and DNA
• nucleolus is involves

  in ribosome synthesis
• nuclear envelope consists of

  1. nuclear pores -transport into out of cell
  2. nuclear lamina -support inner membrane
• nucleolus

  • fibrillar centre - inactive DNA
  • dense fibrillation components-pre rRNA for transcription
  • granular component - mature ribosome
• chromatin

  • packaging DNA (histones , scaffold protein )type
  • heterochromatin dense- inactive gene
  • euchromatin less dense- active gene
• SRY gene on Y chromosome

  • transcriptive factor protein - testis determining factor
  • switch on/off expression of many gene
• chromatin are arranged as repeated unite called 


  nucleosomes
• a supercooled DNA molcule is more compact than normal DNA helix
• a enzyme that alter supercoiling of double strand DNA

  called

  topoisomerases
• packaging of DNA

  • naked DNA arranged into nucleosomes
  • nucleosomes are supercoiled in compact fibres
  • fibres are arranged into loop attached to chromosome scaffolding protein
• divided chromosome condense into short homologous pair structure 


  dyad
• the cytosol

  • 70% water
  • organelles float in
  • plasma membrane separates them from external
  • 200/400mg protein
• category of cytosol protein

  • soluble globular protein
  • filamentous protein structure -makeup cytoskeleton
• cytoskeleton filaments are 


  long polymers of single monomeric protein

  strength- allow cell to adapt non spherical shapes
• cytoskeletal types

  • actin filaments
  • intermediate filaments
  • microtubules
• cell use their to generate cell polarity 


  cytoskeleton
• globular monomers of actin (G actin) use 


  energy of ATP to polymerize and form long thin helical fibres (F actin)
• capping protein at the end of actin role


  control assemble or promote disassembly
• intermediate filaments IFs

  • stable
  • long term structural framework
• microtubules

  • long straight
  • hollow cylinders
  • built by a and b tubulin
• the cytoskeleton prevents cell

  • relaxing into spheres
  • ensure that cell components arrive , remain
  • correct cellular destinations
• function of ER

  • synthesis - intercellular +secreted lipid & protins
  • protein maturation
  • storage
• the ER


  Network of phospholipid bilayer arranged into tubes vesicles and sac (cisternae)
• rough and smooth er vesicle can be separated by

  density gradient centerfugation

  rough more dense then smooth
• smooth ER

  • no ribosome
  • lipid metabolism
  • Ca storage
• Rough ER

  • cisternae outer surface has ribosome
  • protein synthesis/maturation
• protein maturation 


  polymers joined by peptide bonds into long chain
• protein sequence dictates conformation (shape) dictates function
• phosphorlation 


  kinase enzyme catalyse attachment of phosphates to AA residues
• methylation


  attachment of methyl group to AA
• myristoylation


  attachment of FA to protein
• glycosylation 


  attachment of sugar to protein
• proteolytic cleavage 


  removal of poly-peptide that are not required in mature protein
• Golgi apparatus 


  flattened membrane bound cisternae
• Golgi stacks 


  protein and break them into different transport vesicles that are dispatched to final destination
• Golgi makes sure 


  protein mature correctly

  help to determine destination protin sent
• Golgi sythesis


  glycolipids and sphingomyelin
• matured molecules are sorted into 


  Cargo are delivered to cellular location