bio paper 2

• Homeostasis


  An organism's ability to regulate internal conditions even when external conditions change
• Importance of homeostasis


  • Allows crucial chemical reactions involving enzymes to happen at an Optimum rate
  • Regulates blood glucose concentration, temperature, and water levels
• Nervous system regulation of homeostasis

  1. Receptor detects stimulus

  2. Electrical signal travels to spine through sensory and relay neurons

  3. Signal travels across synapse by neurotransmitter

  4. Signal goes to brain

  5. Conscious decision to act

  6. Signal goes back to effector via relay and motor neurons
• Reflex


  Signal bypasses the brain and goes straight through the spine to the effector
• Effectors


  Glands that produce specific chemicals the body needs
• Investigating reaction time


  1. Hold ruler between finger and thumb

  2. Drop ruler without warning

  3. Measure distance fallen before caught

  4. Repeat multiple times and take mean average
• Parts of the brain

  • Cerebral cortex - responsible for higher level functions like memory, speech, and problem solving
  • Cerebellum - responsible for motor skills, movement, balance, and coordination
  • Medulla oblongata - controls unconscious actions like heart rate and breathing
• MRI scans


  Magnetic resonance imaging - way of seeing brain activity safely
• Accommodation in the eye

  1. For far objects: Ciliary muscles relax, suspensory ligaments tighten, lens becomes thin

  2. For near objects: Ciliary muscles contract, suspensory ligaments slacken, lens becomes fatter
• Pupil


  Hole in the iris that can change size depending on light intensity
• Retina


  Contains rods (detect light intensity) and cones (detect color)
• Thermoregulation


  1. Brain senses blood temperature

  2. Sends nervous and hormonal signals to effectors

  3. Effectors cause body to lose or retain heat
• Endocrine system


  System of glands that produce hormones that travel to effectors via the blood
• Pituitary gland


  Main or master gland that produces hormones in response to stimuli
• Insulin


  Hormone produced by the pancreas that causes glucose to move from blood into cells
• Glucagon


  Hormone produced by the pancreas that causes the liver and muscles to turn glycogen back into glucose
• Type 1 diabetes


  Pancreas can't produce enough insulin
• Type 2 diabetes


  Cells no longer absorb glucose properly
• Water and nitrogen balance

  1. Body loses water through exhaling, sweating, urinating

  2. Kidneys remove excess water from blood and mix with urea to form urine

  3. Antidiuretic hormone (ADH) regulates water reabsorption in kidneys
• Dialysis


  Process that does the job of non-functioning kidneys
• Menstrual cycle


  1. FSH causes egg maturation and estrogen production

  2. LH causes egg release

  3. Progesterone maintains uterus lining
• IVF


  In vitro fertilization - eggs harvested and fertilized in lab, then implanted
• Adrenaline


  Hormone that increases heart and breathing rate in stressful situations
• Thyroxin


  Hormone secreted by thyroid that controls metabolic rate
• Plant hormones


  Gibberellins - promote seed germination, flowering, fruit growth

  Auxins - control shoot and root growth, phototropism, geotropism

  Ethene - induces fruit ripening
• Meiosis


  Chromosomes copied, paired, genes swapped, cell divides twice to form haploid gametes
• Asexual reproduction


  Daughter cells genetically identical to parent
• Genome


  All the genetic material in an organism
• Gene


  Section of DNA that codes for a specific protein
• Human Genome Project


  Mapped out what every gene is responsible for coding
• Genotype


  Genetic code stored in DNA
• Phenotype


  How the genetic code is expressed in characteristics
• Nucleotides


  Monomers that make up DNA
• Asexual reproduction


  Only one parent is needed
• Organisms that can do both asexual and sexual reproduction


  • Parasite that causes malaria
  • Some fungi
• DNA


  A two-stranded polymer in a double helix shape
• Gene


  A section of DNA that codes for a specific protein
• The Human Genome Project completed its initial goal in 2003 when scientists mapped out what every Gene is responsible for coding
• Genotype


  The code stored in your DNA
• Phenotype


  How the genotype is expressed in your characteristics and physiology