slide set 2

  1. gene expression/ transcription
    rosalind franklin = real DNA hero

    transcription DNA sequence is enzymatically copied by an RNA polymerase to produce mRNA

    • transcription = price that leads to translation of genetic code into a functional peptide or protein
    • DNA is unwound by DNA helices
    • RNA polymerase binds and recognizes the start site
    • RNA nucleotides (uracil rather than thymine) base pair with the DNA
    • form chain of mRNA
  2. Transcription
    • transcription factors
    • proteins that assist the RNA polymerase in recognizing promoters

    • transcription factors are divided into 2 types
    • 1. gene specific transcription = activate specific genes
    • ex. estrogen receptors = estrogen target gene specific
    • 2. general transcriptions factors = required to activate all genes
  3. regulation of CREM and transcription
    cAMP response element modulator - CREM is a transcription factor

    • CREM null mice = infertile
    • CREM required to make sperm
  4. DNA to protein
    • 1 gene activation
    • 2.transcription
    • 3.mRNA processing
    • 4. translation
    • 5. post-translational modification
  5. membrane transporters
    • Channel proteins (create a water filled pore)
    • can be classified into:
    • 1. gated channels
    • 2. open channels

    • Carrier proteins (never form an open channel between the 2 sides of the membrane)
    • can be classified into
    • 1. uniport carriers (Glu goes thru)
    • 2. symport carriers (Na and Glu go thru)
    • have cotransporters
    • 3. antiport carriers (Na goes in and K goes out)(ATP needed)
    • have cotransporters
  6. active transport processes
    require energy (ATP) from cells

    • Transport by pumps
    • pump are membrane transporters that move a substance again the concentration gradient
    • ex. Ca pumps, Na-K pumps

    • Transport by vesicles
    • allows substances to enter or leave the interior of a cell without actually moving through its plasma membrane
  7. Primary active transport
    • Extracellular fluid
    • ↑ Na  and ↓K

    • Intracellular fluid
    • ↓ Na and ↑ K
  8. secondary active transport
    • Mecanism of the SGLT transporter
    • 1. Na binds to the carrier
    • 2. Na creates a site for Glucose
    • 3. Binding of glucose changes the carrier confirmation
    • 4. Na is released into the cytosol. Glucose follows
  9. epithelial transport
    • epithelium is either leaky or tight
    • capillaries - all dissolved molecules can pass through
    • kidney - held by tight barrier
    • substances must enter cell and pass through it

    selectively regulates exchanges of ions and nutrients 

    • absorptions = from external to internal
    • secretion = from internal to external

    transporting epithelial characteristics = thicker membrane modifications, cell junctions, mitochondria
  10. secretory epthelium
    • exocrine glands =  release into the external environment, skin, airways, digestive
    • release into ducts

    endocrine glands = release hormone into the blood stream
  11. transcytosis across the capillary endothelium
    • 1. plasma proteins are concentrated in the caveolae, which then undergo endocytosis and form vesicles 
    • 2. vesicles cross the cells with help from the cytoskeleton
    • 3. vesicle contents are released in the interstitial fluid by exocytosis

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  12. cystic fibrosis case study
    • alvins symptoms:
    • chronic cough, diarhea, wheeze
    • runny nose

    pathophysiology of CF = characterized by defective epithelial ion transport

    • abnormal transport of Cl and Na across epithelium in all exocrine tissues, leading to think viscous secretions in the lungs, pancreas, liver, intestine and reproductive tract
    • ↑ salt content in sweat glands secretions
  13. what are the genetic and molecular causes of CF?
    • faulty gene = on chromosome 7
    • malfunction of gene coding for the CF transmembrane conductance regulator (CFTR)
    • malfunction leads to defective cAMP activated Cl-Na channel on the surface of epithelial cells
    • NaCl becomes trapped in cell
    • pulls the water in and results in dehydrated mucus
    • lungs are the most affected organs
    • 70-80% of patients lack receptor?*
  14. what are the accepted treatments for children and adults with CF?
    • airway clearance therapy
    • antibiotics
    • bronchial dilators
    • vitamin supplements
    • enzyme to aid digestion
  15. different classes of proteins
    • structural proteins
    • enzymes
    • membrane receptor proteins

    • transporters
    • channel proteins
    • carrier porteins
  16. membrane receptor
    ligand = binds to a cell membrane receptor protein

    ligand-receptor complex = triggers intracellular response
  17. vesicule transport
    • Phagocytosis
    • cell engulfs bacterium or other particle into phagosome

    • Endocytosis
    • the plasma membrane "traps" some extracellular material and brings it into the cell in a vesicle
    • active process that can only be non selective (pinocytosis) or highly selective
    • potocytosis = uses cavaolae
    • receptor mediated uses clathrin coated pits
  18. what are the 2 types of endocytosis?
    • 1. Phagocytosis
    • "condition of cell eating"
    • large particle are engulfed by the plasma membrane and enter the cell in veiscles
    • vesicles fuse with lysosomes, where the particles are digested

    • 2. Pinocytosis
    • "condition of cell drinking"
    • fluid and substances dissolved in it enter the cell
  19. receptor mediated endocytosis
    • 1. ligand brings to receptor
    • 2. receptor ligand migrates to clathrin coated pit
    • 3. endocytosis
    • 4. vesicle loses clathrin coat
    • 5. receptors and ligands separate
    • 6. ligands go to lysosome or Golgi for processing
    • 7. transport vesicle with receptors
    •  moves in the cell membrane
    • 8. transport vesicle and cell membrane fuse (membrane recycling)

    then it restarts again

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  20. active transport exocytosis
    • Exocytosis
    • process by which large molecules love the cell even though they are too large to move out through the plasma membrane
    • enclosed in many vesicles, pulled by the cytoskeleton to the plasma membrane, where the contents are released
Card Set
slide set 2