Bio 1A Final

• "7" requirements for life

  Maintain Boundaries

  Movement

  Responsiveness

  Digestion

  Metabolism

  Excretion

  Reproduction

  Growth
• Integumentary system


  external body covering
• Muscular system


  allows for locomotion
• Endocrine system


  slow acting control system that secretes hormones
• Respiratory system


  keeps blood supplied with oxygen and removes carbon dioxide
• set point


  physiological value or range around which the system fluctuates
• receptor


  mechanism to detect/sense when conditions deviate from set point
• control center


  structure that interprets input from receptor and initiates changes through effector
• effector


  structure that brings about change to alter stimulus
• negative feedback loop


  response moves variable in opposite direction as initial stimulus

  variable fluctuates around set point
• positive feedback loop


  response moves variable in same direction as initial stimulus

  variable increases until climactic event then body returns to homeostasis
• Core concepts of physiology

  • Homeostasis
  • Structure and Function
  • Cell membrane
  • Independency of cells
  • Gradients and Permeability
  • Levels of organization
  • System integration
• Homeostasis

  maintenance of relatively constant internal environment
• Structure and Function

  Understanding of structure illuminates function, vise versa
• Cell membrane

  complex structures that determine what/how substances enter and leave the cell
• Independency of cells

  different cells contribute to homeostasis in different ways
• Gradients and permeability

  transport of ions, molecules, fluids, and gas is a central process
• Levels of organization

  understanding physiological functions requires understanding of every level of organism
• System integration

  understanding function of organism requires consideration of interactions of cells, tissues, organs, and organ systems
• Ligand

  molecule that binds to receptor
• Receptor

  protein that receives and transduce signals
• Cell signaling

  1. Signal Reception: chemical signal
  2. Signal Transduction: receptor protein conformational change initiates signal transduction
  3. Cellular Response: transducer signal is converted into response
• Direct contact

  molecules on plasma membrane of one cell recognized by the plasma membrane of a neighboring cell
• Synaptic signaling

  neurotransmitters released from neuron travel across synapse to neighboring neuron
• Paracrine signaling

  specific cell secretes signaling molecule that affects nearby cells
• Endocrine signaling

  hormones travel via circulatory system to affect distant cells
• Membrane receptors


  1. G coupled
  2. channel linked
  3. enzyme linked
• G coupled receptors

  active when bound to GTP

  inactive when bound to GDP
• Channel linked receptor

  signaling molecules (ligands) bind to ion channel so ions can pass through

  ie. ligand gated ion channels
• Enzyme linked membrane receptor

  intracellular portion becomes active when signaling molecule binds o extracellular binding domain

  activated receptor can preform catalytic reactions
• Intracellular receptors

  hormones cross plasma membrane to bind to receptor, causing conformational change that unbinds inhibitor

  hormone-receptor complex enters nucleus and binds to DNA to regulate gene expression
• protein-kinase

  adds phosphate group from ATP to proteins
• phophotases

  remove phosphate groups from proteins
• second messengers

  small molecules and ions that relay signals received by cell surface receptors to effector proteins

  participate in pathway initiations by G protein coupled receptors and Receptor Tyrosine Kinases

  Cyclic AMP and calcium ions are the most common

  enzymes amplify signals
• Adenylyl cyclase

  converts ATP into cAMP
• Phospholipase C

  converts PIP2 into DAG and IP3
• DAG and cAMP

  activate protein kinases
• Calmodulin

  cytoplasmic protein that binds to calcium, this complex then binds to other proteins and can activate them
• Receptor Tyrosine Kinases

  1. Ligand binds to transmembrane RTK protein
  2. Causes 2 receptors to dimerize (come together) and phosphorylate each other
  3. Activate downstream signaling: response proteins bind to phosphotyrosine on receptor which can phosphorylate other response proteins
• afferent

  information coming into nervous system