Exam 1:Homeostasis, Cells & Biomolecules, Membrane Transport

• Homeostasis is the ability to maintain a constant internal environment.
• Physiological properties that must be controlled

  • body temperature = 30°C or 98.6°F
  • Blood pressure
  • Blood glucose
• You perform an experiment where you take a blood pressure once each hour for 24 hours. What do you predict the line should look like?

  A

  
• Negative feedback= restores change back to normal

  • Used more to maintain homeostasis
• Positive Feedback= enhances change, makes it larger
• Effector= muscles and glands which bring about the desired response to restore the set point of the controlled variable
• Sensor = also called a RECEPTOR. Monitors the controlled variable for the set point. If different than the set point it will inform the control center
• Stimulus --> Sensor --> Control Center --> Effector
• Stimulus = a set point that is beyond the desirable range
• Control center= brain, spinal cord. Also called the integrator. This center compares the actual value to the set pint, if they are different an error signal is generated.
• Dehydration synthesis= combining small molecules into larger molecules. 


  Example:

  
• Hydrolysis = turning large molecules into smaller molecules (monomers) 


  Example:

  
• Catabolic= hydrolysis (digestion)

  • Large --> Small
  • Releases energy, requires water
• Metabolism: sum of all chemical reactions that occur within an organism
• Anabolic: dehydration synthesis (condensation)

  • Small --> Large
  • Requires energy, releases water
• Carbohydrates: carbons, hydrogens, oxygens

  • 1:2:1
  • Monosaccharide- one sugar
  • Disaccharide- 2 monomers, these are simple sugars
• Monosaccharides: immediate source of energy
• Process of dehydration synthesis joins two monosaccharides to form a disaccharide
• Disaccharide: short energy storage
• Polysaccharide: long term energy storade
• Cellulose: fiber in plants that cant be digested
• Starch: in plants and is digestable
• Glycogen: in animals, highly branched, made and stored in liver and skeletal muscle.
• Lipids: carbon, hydrogen, oxygen

  • no ratio
  • Triglycerides, cholesterol, phospholipids, prostaglandins
  • nonpolar molecules
• Triglycerides: long term energy storage, composed of glycerol backbone & 3 fatty acids
• Saturated: max number of H molecules, exist at room temp as a solid, no double bonds on Carbons.
• Unsaturated: does not have maximum # of H atoms, double bonds between carbons, exists as a liquid.
• Phospholipids: forms membranes, composed of head and 2 fatty acids.
• Phospholipid head: charged, polar, hydrophilic, lipophobic
• Fatty acid tails: uncharged, nonpolar, hydrophobic, lipophilic
• Amphipathic: contains polar and nonpolar
• Cholesterol: serves a lot of functions, has 4 interlocking C rings, necessary for diets, can stabilize membranes at high temperatures, fluidity to membrane at lower temperatures.
• Steroids: made from cholesterol, all steroids are hormones, not all hormones are steroids
• Nucleus: contains genetic info (DNA), blueprints for proteins
• Smooth ER: synthesizes lipids, stores calcium ions.
• Cytoplasm: intracellular fluid ICF
• Rough ER: contains ribosomes, associated with protein synthesis via modification
• Ribosome: protein synthesis
• Cell membrane: separates ICF and ECF
• Mitochondrion: organelles that generate ATP (energy currency)