Chapter Three:The Molecules of Cells

Questions:

1.  Why are people lactose intolerant?

  A:  This is the wrong question.  The question should, in fact, be why are people lactose TOLERANT?  It is shown through research and surveys that most of the worlds population cannot easily digest dairy based products.  The ones that can are so able because of a mutation in an enzyme called "lactase," this enzyme helps to break down and easily digest dairy products.  Most people of Asian, African, and Native American descent do not have this handy mutation.  Nearly all lactose tolerant people are from european descent (a place that long depended on cattle and dairy products for survival.)

2.  What determines a proteins function?

  A:  The determining factor of a proteins function is it's molecular build.  20 amino acids can be combined in millions of different ways, providing the code for the function that certain protein is to perform.

3.  Is high-fructose corn syrup to blame for obesity?

  A: Maybe.  There are still ongoing studies trying to prove or disprove this theory, but the evidence is circumstantial.


Five Main Facts From The Reading:

1.  Proteins are essential to the structures and functions of life.
2.  A protein's specific shape determines its function.
3.  Mutations can harm or help us. (exp. sickle-cell, lactose tolerance.)
4.  A protein has four levels of structure.
5.  Fats are necessary to store energy.

This diagram shows the differences between estrogen (the female hormone,) and testosterone (the male hormone.  They only differ in chemical groups, but are otherwise very similar.

Ten Key Terms:

Isomers - compounds with the same formula but different structures.

Hydrophilic - water loving.

Hydrophobic - water fearing.

Hydroxyl Group - a hydrogen atom bonded to an oxygen atom, which is bonded to the carbon skeleton.

Carbonyl Group - a carbon atom is linked to an oxygen atom.

Carboxyl Group - a carbon double-bonded to an oxygen and also bonded to a hydroxyl gorup.

Amino Group - a nitrogen bonded to two hydrogen atoms and the carbon skeleton.

Phosphate Group - a phosphorous atom bonded to four oxygen atoms.

Methyl Group - a carbon bonded to three hydrogens.

Monosaccharides - the carbohydrate monomer (single-unit sugars.)

Sickle-cell Anemia Video: http://www.youtube.com/watch?v=8RYLu2j0Qy0

This chapter all about the molecules of cells and proteins.  It explained how and why the arrangement of around 20 amino acids can make thousands of different actions and reactions possible.  It showed the basic structures of proteins, which are composed of four layers.  It also explained how some molecules instinctively know to put the hydrophilic portions of itself on the outside, while hiding the hydrophobic particles within the structure, shielding it from any water that it could come in contact with.  This chapter was all about how the structure of molecules makes life possible.

Chapter Two: The Chemical Basis of Life

Questions:

1.  What 25 chemical elements are living organisms composed of?

  A:  Oxygen (O,) Carbon (C,) Hydrogen (H,) and Nitrogen (N) make approximately 96% of the human body as well as most other living organisms.  Calcium (Ca,) Phosphorous (P,) Potassium (K,) Sulfur (S,) Sodium (Na,) Chlorine (Cl,) and Magnesium (Mg) make up most of the remaining 4%.  Trace elements of  Boron (B,) Chromium (Cr,) Cobalt (Co,) Copper (Cu,) Fluorine (F,) Iodine (I,) Iron (Fe,) Manganese (Mn,) Molybdenum (Mo,) Selenium (Se,) Silicon (Si,) Tin (Sn,) Vanadium (V,) and Zinc (Zn) are also found, but only in minute quantities (less than 0.01%.)

2.  Why is ice less dense than liquid water?

  A:  Because of hydrogen bonds.  When water freezes each molecule forms stable hydrogen bonds with four others, holding each at "arms length."  Whereas in water, the molecules are free to move and flow, making ice hold less molecules as water of the same mass.  Therefore, the ice is less dense, and able to float atop of liquid water.

3.  What is an Ionic bond?

  A:  When two ions of opposite chargers attract each other, this attraction holds them together forming an Ionic Bond.

Five Main Facts From The Reading:

1.  Water is the solvent of life.

2.  Hydrogen bonds are weak, but important to the chemistry of life.

3.  Living organisms are composed of approximately 25 chemical elements.

4.  Elements can combine to form compounds.

5.  Electron arrangement determines the chemical properties of an atom.

This chart shows the pH levels of different foods/commonly interacted with items.  The pH level in living organisms is very important, just a slight change and the human body can only survive several minutes before their body will shut down.  

Ten Key Terms:

Electron Shells- a grouping of electrons surrounding the nucleus of an atom.

Chemical Bond - an electrical force linking atoms.

Ion - an atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons.

Covalent bond - in which two atoms share one or more pairs of outer-shell electrons.

Electronegativity - An atom's attraction for shared electrons.

Cohesion - the tendency for molecules to stick together.

Adhesion - the clinging of one substance to another.

Heat - the amount of energy associated with the movement of atoms and molecules in a body of matter.

Temperature - measure the intensity of heat/the average speed of molecules.

Aqueous Solution - a solution in which water is the solvent.

Covalent and Ionic Bond Video:  http://www.youtube.com/watch?v=628Hq-V0aBY

     This chapter is about chemistry and how it is important to the study of life.  For example: water.  Every living organism needs water to survive, but, what is water?  Water is the result of the chemical bond between two hydrogen particles and one oxygen particle.  Without this bonding of two elements, water would not exist, and therefore, neither would we.

     It also touched on the absolute frailty of life, as an example we can use the chart shown above.  The pH system.  The pH of human blood is almost exactly 7.4.  A human being will only survive up to a few minutes if the pH in the blood drops to 7 or rises to 7.8.  A human being will only last about 3 days without water.  This chapter covered the chemical happenings that result in life, and why they are important to the study of biology.

Chapter One: Biology: Exploring Life

Questions:

1. In life's hierarchy of organization, what new properties emerge at each level?

  A: The first level to emerge is the biosphere, which is all of the environments on Earth that can support life.  Following the biosphere is the ecosystem - all of the living organisms in an area, as well as the nonliving components that the organisms interact with, such as soil, water, and air.  Next is a community, meaning the entire spectrum of organisms that inhabit a certain ecosystem.  Then it moves on to a population, which is the individuals of a species living in a certain place.  After is the organism, the individual living things.  Then we move on to the organ system, organ, tissue, cell, organelle and finally the molecule, which completes life's hierarchy of organization.

2. How are biology and society connected?

  A:  One of the biggest ways that biology is in medicine.  Biology has allowed us as a people to develop medicines that prolong the life span, along with increasing the individuals chance of survival from birth.  However, while this is often seen as a positive outcome, it can also have some detrimental consequences, such as the overpopulation of the earth that has lead to global warming.  Therefore, biology has had an affect on the society in the way that we are all now left trying to find a way to stop the affects of global warming, and make sure that the world is still here to discover.

3. How do you explain the unity and diversity of life?

  A:  Evolution and natural selection.  Natural selection easily explains the unity of life, as it is the process which edits and selects the best fit members of a species to survive, unifying those members.  Evolution explains the diversity of life, as it helps each species mold and adapt to their environment in order to best fulfill their needs.


Five Main Facts From The Reading:

1.  Evolution explains the unity and diversity of life.
2.  Evolution and Natural Selection are connected to the everyday life.
3.  Living Organisms interact with their environments, exchanging matter and energy.
4.  In life's hierarchy of organization, new properties emerge at each level.
5.  The diversity of life can be arranged into three domains.

In this diagram it shows life's hierarchy of organization, wherein new properties emerge at each level, all the way from the biosphere to macromolocules, such as DNA.

Ten Key Terms:

Biosphere - consists of all the environments on earth that support life.

Ecosystem - consists of all the organisms living in a particular area, as well as the nonliving things they interact with.

Community - the array of organisms living in an ecosystem.

Population - all the individuals of a species that live in a specified area.

Organism - individual living thing.

Producers - provide the food for a typical ecosystem.

Consumers - Consume what the producers have provided.  

Decomposers - Get rid of wastes and the remains of dead organisms, allowing new life to develop.  

Discovery Science - science that uses verifiable observations and measurements as the data.

Hypothesis-based science - Uses deductive reasoning to bring a hypothesis to it's conclusion.

Simulation of Evolution Video: http://www.youtube.com/watch?v=oCXzcPNsqGA

     So, this chapter was all about the fundamentals of biology...WHAT exactly it means to be alive.  It explored the hierarchy of life by showing us a coastal ecosystem, starting all the way from the biosphere and working its way down to the tiniest molecule.  It also showed us more in depth how the ecosystem functions, the roles played by all the organisms that work together to inhabit a certain area of the world...in this case, the plains of Africa.

     It also talked about the relationship between the science of biology and the "real," everyday world. How new discoveries both help us, and potentially harm us.  It stressed the importance of balancing science and nature, how if we try to manipulate the world around us too much it will most likely backfire and cause problems that may be beyond our ability to solve, like global warming.  

     This chapter was an introduction to the world of biology, giving us brief glimpses of what we will delve deeper into in the later chapters.