Biología En Ingles

Biology
Reading Notes

Chapter 4: Carbon and the Molecular Diversity of Life
Organic Chemistry is the study of carbon compounds:
* Organic chemistry: the branch of chemistry that specializes in the study of carbon compounds.
* Vitalism: the belief in a life force outside the jurisdiction of physical and chemical laws
* Mechanism: the view that all natural phenomena, including theprocesses of life, are governed by the physical and chemical laws.
* The foundation of chemistry is not some intangible force, but the unique chemical versatility of the element carbon.
* Tetravalence: one facet of the carbon’s versatility that makes large, complex molecules possible.
Molecular Diversity Arising from Carbon Skeleton Variation:
* Hydrocarbons:
* Hydrocarbons:organic molecules consisting only of carbon and hydrogen.
* Are not prevalent in living organisms, many of a cell’s organic molecules have regions consisting of only carbon and hydrogen.
* Can undergo reactions that release a relatively large amount of energy.
* Isomers:
* Isomers: compounds that have the same numbers of atoms of the same elements but different structuresand hence different properties.
* Enantiomers:
* Molecules that are mirror images of each other.
* The middle carbon is called an asymmetric carbon because it is attached to four different atoms or groups of atoms.
* The four groups can be arranged in space about the asymmetric carbon in two different ways that are mirror images.
* Geometric isomers:* Have same covalent partnerships, but they differ in their spatial arrangements.
* Arise from the inflexibility of double bonds, which, unlike single bonds, will not allow the atoms they join to rotate freely about the bond axis.
* The subtle difference in shape between geometric isomers can dramatically affect the biological activities of organic molecules.
*Structural isomers:
* Differ in the covalent arrangements of their atoms.
* The number of possible isomers increases tremendously as carbon skeletons increase in size.
* Structural isomers may also differ in the location of double bonds.
The Functional Groups Most Important in the Chemistry of Life:
* Functional Groups: the components of organic molecules that aremost commonly involved in chemical reactions.
* Attachments that replace one or more of the hydrogens bonded to the carbon skeleton to the hydrocarbon.
* 6 most important functional groups (hydrophilic):
* Hydroxyl: is a polar result of the electronegative oxygen atom drawing electrons toward itself. Attracts water molecules, helping dissolve organic compounds such as sugars.
*Carbonyl: a ketone and an aldehyde may be structural isomers with different properties, as is the case for acetone and propanal.
* Carboxyl: has an acidic property because it is a source of hydrogen ions. The covalent bond between oxygen and hydrogen is so polar that hydrogen ions tend to dissociate reversibly. In cells, found in the ionic form, which is called a carboxylate group.* Amino: acts as a base; can pick up a proton from the surrounding solution. Ionized, with a charge of +1, under cellular conditions.
* Sulfhydryl: Two sulfhydryl groups can interact to help stabilize protein structure.
* Phosphate: Makes the molecule of which it is a part an anion (negatively charged ion). Can transfer energy between organic molecules.
ATP: An Important Source ofEnergy for Cellular Processes:
* Adenosine Triphosphate (ATP): is the primary energy-transferring molecule in the cell.
* Is a more complicated organic phosphate.

Chapter 5: The Structure and Function of Macromolecules
The Molecules of Life:
* Macromolecule: protein that consists of thousands of covalently connected atoms that form a molecular colossus with a mass of over 100,000...