10 16 09 Notes
- 1. Biology and Human Concerns Notes 10-16-2009 Animal Cells Extracellular Matrix – holds cells together. Cytoskeleton – structural framework of cell. Tracks for transportation inside cell Mitochondria – synthesization of ATP. Nuclear envelope – houses nucleus Nucleus – houses DNA. 2 metres of DNA inside nucleus. DNA template for mRNA In cytoplasm, mRNA is attached to ribosome, protein is built as ribosome moves along mRNA. Endomembrane system – protein processing and other metabolic activities. Endoplasmic reticulum part of the endomembrane system Rough ER covered in ribosomes Smooth ER lack in ribosomes – manufactures lipids Rough ER – manufactures proteins. Some vesicles fuse with golgi apparatus, further processing occurs. Packaged, and transported along cytoskeleton tracks. Plant Cells Cell Wall – made of cellulose, outside of plasma membrane Central vacuole – regulates cytoplasm, creates internal pressure Chloroplasts – responsible for photosynthesis. Light energy chemical energy. *completion of information for midterm exam, up to page 79. 55 multiple choice questions. Room 4M47*
- 2. Enzymes (page 80) Biological Catalysts Energy => the ability to do work. Work => the change in anything. Energy can be converted to one form to another. Kinetic energy => the energy of motion Potential energy => stored energy by position or structure Ex. Energy stored in spring by winding tighter Location – ex. Water storage behind floodgates. This transfers energy to become kinetic energy. Conservation of energy => Energy can neither be created or destroyed. Energy transferred from one type to another. Ex. Bow and arrow. Low potential energy to high potential energy when bow string is tightened. --Muscle cells store glucose, broken down in mitochondria, made into ATP. Muscle shortens, arm moves, bow releases, stored energy released through arrow. -Friction heats up arrow. (Ex. Space shuttle) energy absorbed into target. Types of Energy: -Chemical => energy stored in chemical bonds ex. Glucose, fructose, gasoline -Electrical => amount of charge from one location to another. Connect location with conductor, charge flows from high charge to low charge. -Mechanical => energy of moving parts. Ex. Chemical energy burned in pistons / bending of elbow or knee, generate force. The body’s mechanical movements are mechanical energy / riding a bike. -Light => light energy is the source of energy plants use in photosynthesis. -Heat => energy that can’t do any work. “Useless”. Energy Conversions -Battery’s chemical energy converted into mechanical energy to run propeller. -Amount of energy in system does not change 10 stored = 2 heat + 4 heat + 4 wind First Law of Thermodynamics
- 3. -Energy can be transferred and transformed, but it cannot be created nor destroyed. -That is: the amount of energy remains constant. When energy is consumed, it must be replenished. In the case of living things, we must take in energy in the form of chemical bond energy (food) so we can have energy. Ex. Water and CO2 molecules coming out of the cheetah’s nose used to be glucose energy. No energy – no movement/death. Energy transformations in a cell (Diagram bottom of page 81.) Second Law of Thermodynamics -Every energy transfer or transformation increases the entropy of the universe. -Entropy => random, useless energy, cannot do work. Ex. “heat”. (“Less order, more random”). -Most energy form every reaction is lost to entropy. (Battery example). Ex. 85% of energy in glucose is lost, never gets made into ATP. 15% gets stored into ATP molecules. Muscles heat up to create ATP. Most of the body’s energy is used to keep itself warm. --Universe: entropy always increasing, free energy always decreasing. Eventually universe will go cold, dark, all molecular motion will stop.--