The document discusses key concepts in biology and human energy use. It covers: 1) The structure and functions of animal and plant cells, including organelles like mitochondria, chloroplasts, and the endomembrane system. 2) Different forms of energy like chemical, electrical, mechanical, light, and heat. Energy can change forms but is never created or destroyed. 3) How living things use and transform energy, with glucose being broken down to make ATP which powers cellular work via enzymatic reactions. The second law of thermodynamics holds that entropy increases with all energy transfers.

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.--