Regents 4 -- 5.4.24

• Homeostasis


  A dynamic equilibrium that sustains life
• Disease


  A failure of homeostasis
• Pathogens


  • Viruses
  • Bacteria
  • Fungi
  • Parasites
• Cancer


  Uncontrolled cell division caused by gene mutations
• Causes of disease


  • Inheritance
  • Toxic substances
  • Poor nutrition
  • Organ malfunction
  • Personal behavior
• Immune system


  Protects against antigens associated with pathogens or foreign substances and some cancer cells

  
• Immune response


  1. White blood cells engulf invaders

  2. Produce antibodies that attack or mark invaders for killing

  3. Some specialized white blood cells remain to fight future invasions

  
• Antibodies


  Have specific shapes that only work against a particular pathogen

  
• Vaccinations


  Use weakened or dead pathogens to stimulate the immune system to produce antibodies, preparing the body to fight subsequent invasions

  
• AIDS


  Viral disease that damages the immune system, leaving the body unable to deal with multiple infectious agents and cancerous cells

  
• AIDS


  HIV (virus) attacks white blood cells and weakens the immune system, making the body less able to defend itself from other infections

  
• Prevention of AIDS: Avoid transfer of body fluids from sexual contact or sharing needles for injecting drugs
• Allergic reactions


  Caused by the body's immune responses to usually harmless environmental substances
• Immunosuppressant drugs


  Used to keep white blood cells from attacking a donated organ, but make the individual more susceptible to pathogens

  
• Cloned cells from the person needing the transplant can be used because they have the same DNA (and same proteins)
• Pathogens


  Microbes that enter the body, causing disease
• Cancer


  Uncontrolled division of abnormal cells
• Allergy


  Disorder where the immune system attacks a usually harmless environmental substance
• Allergic reaction to peanut butter: Body recognized an antigen in peanut butter and produced an immune response
• Immune response to chicken pox virus


  1. Antigens stimulate the production of antibodies

  2. White blood cells fight the virus

  3. Recovery from chicken pox does not protect against other diseases like measles

  4. Chicken pox vaccination does not cause illness
• AIDS


  Infectious disease caused by a virus that attacks the immune system
• AIDS weakens the immune system


  Makes the body less able to defend itself from other infections
• Ways to prevent/control infectious diseases like AIDS


  • Avoid transfer of body fluids
  • Vaccination
• Vaccine


  Contains weakened or dead pathogens to stimulate the immune system

  
• Vaccine immunity


  Prepares the body to fight subsequent invasions by the same pathogen

  
• Advantage of vaccines over antibiotics for bacterial diseases: Vaccines promote immunity
• Disadvantage of antibiotics for bacterial diseases: They can weaken the immune system
• Transplants are risky procedures that can deprive parts of the body of oxygen and nutrients, and may result in the immune system rejecting the transplanted organ
• Immunosuppressant drugs


  Given to transplant patients to prevent immune system rejection, but weaken the ability to fight disease
• Stem cell-derived transplants


  Would not be foreign material and therefore would not be rejected by the patient's immune system
• Genes are inherited from parents and contain the coded instructions for an organism's traits
• DNA replication


  The chemical and structural properties of DNA allow genetic information to be encoded and replicated

  
• Protein synthesis


  Cells use the genetic information in DNA to direct the synthesis of proteins that carry out the work of the cell
• Offspring resemble parents because they inherit similar genes that code for the production of similar proteins
• Mutations

  Any alteration of the DNA sequence, which can change the shape and function of the resulting protein

  
• Mutations can occur by random chance or be caused by radiation and chemicals
• Gene expression can be changed by the environment, even though the DNA in each body cell is essentially identical
• e protein determines its function
• Offspring resemble their parents because they inherit similar genes that code for the production of proteins that form similar structures and perform similar functions
• Mutation


  Any alteration (change) of the DNA sequence