Tuesday, March 06, 2007

Bio 101: 3

Okay, now it gets a bit more interesting.

Chapter 3.

The Fucking Chemistry of Life

1. Organisms consist of matter and energy.

2. All matter can be broken down into Elements. There are 92 naturally-occurring elements and 17 synthetic ones. Twenty-five elements are essential to life. The ones that you need large amounts of- such as carbon, oxygen, nitrogen, and hydrogen- are Bulk Elements. The ones that you need smaller amounts of are called Trace Elements.
3. The smallest piece of an element is an Atom. Atoms consist of three major subatomic particles: the nucleus consists of the Protons and Neutrons. This is surrounded by Electrons. The Atomic Number above the element symbol shows the number of Protons. The Atomic Weight is the total number of Protons and Neutrons in the nucleus. An Isotope of an Element has the same number of Protons, but a different number of Neutrons, and so a different weight.
4. Electrons move constantly; they occupy volumes of space called electron orbitals, which form levels of energy called energy shells. An Atom's tendency to fill its outermost shell with valence electrons drives Atoms to bond and form Molecules.
5. Covalent Bonds: Atoms sharing electrons. Form between atoms that have three, four, or five valence electrons. Carbon Atoms form up to four covalent bonds and build hydrocarbons. Nonpolar covalent bond: Atom shares electrons equally. Polar: Electrons are attracted more towards one atom's nucleus than to the other.
6. Ionic Bond: An Atom with one, two, or three valence electrons loses them to an atom with seven, six, or five valence electrons, respectively; the resulting bonds form a lattice of positively and negatively charged ions. Ionic bonds in organisms are weak. And stupid.
7. Hydrogen Bond: Hydrogen in one molecule is drawn to part of a neighboring molecule because of unequal electrical charge.
8. Van der Waals Attractions: Occur between parts of molecules that are temporarily negatively charged.
9. Most biochemical reactions occur in an aqueous environment. Water is cohesive and adhesive, allowing many substances to dissolve in it. It helps regulate temperature because of its high heat capacity. pH is a measure of the H+ concentration, or how acidic or basic a solution is. An Acid ( a molecule that releases hydrogen ions into water) adds H+ to a solution, lowering the pH below 7. A Base adds OH-, raising pH to between 7 and 14. Buffer systems consisting of weak acid-and-base pairs maintain the pH level of body fluids.
10 Carbohydrates: Carbon, hydrogen, and oxygen in the ration 1:2:1. They provide energy and support. Monosaccharides contain three to seven carbons and differ from each other in how their atoms are bonded. Two monosaccharides combine to form a disaccharide by dehydration synthesis. Polysaccharides are long polymers of monosaccharides (sugars) linked by dehydration synthesis. Disaccharides are sugars consisting of two monosaccharides.
11. Lipids: Contain carbon, hydrogen, and oxygen, but with less oxygen than carbohydrates. They include fats and oils. Triglycerides consist of glycerol and three fatty acids, which may be saturated (no double bonds), unsaturated (at least one double bond), or polysaturated (more than one double bond). Saturated fats are more solid- double bonds make a lipid oily at room temperature. Unsaturated fats are more healthy to eat. Steroids are lipids with four carbon rings.
12. Proteins: Consist of 20 types of amino acids, each of which contains: a hydrogen atom, an amino group (A nitrogen atom single-bonded to two hydrogen atoms), an acid or carboxyl group (A carbon atom double-bonded to an oxygen and single-bonded to a hydroxyl group), and an R group (An amino acid side chain) bonded to a central atom. Amino acids form by joining peptide bonds through dehydration synthesis. A protein's conformation, or three-dimensional shape is vital to its function and is determined by the amino acid sequence (primary structure), and interactions between amino acids close together (secondary structure) and far apart (tertiary structure) in the sequence.
13. Nucleic Acid: A biochemical that encodes an amino acid sequence. DNA and RNA are polymers consisting of a sugar-phosphate backbone and sequences of nitrogenous bases (). DNA includes deoxyribose and the bases adenine, cytosine, guanine, and thymine. RNA contains ribose and has uracil instead of thymine. A nucleotide, a nucleic acid monomer, consists of a phosphate, a base, and a sugar. DNA can replicate. DNA carries genetic information. RNA translates the information to enable the cell to synthesize information.
14. Adenine & Guanine: The two purine (double-ring structured organic molecule) nitrogenous bases in DNA and RNA. Cytosine & Thymine: The two pyrimidine (single-ring structure) nitrogeous bases in DNA and RNA.
15. Amino Acid: Again, it's an organic molecule with a central carbon atom bonded to a hydrogen atom, an amino group, a carboxylic acid, and an R group.
Got that? At least now we're getting into chemicals.


gregvw said...

Ugh. I had to learn of this stuff back in HS and early university classes. Originally, I thought I wanted to be a biochemist, but it turned out that I was mostly interested in consuming chemicals and that biology is, in fact, the worst smelling academic discipline.

That and there was a disturbing trend of being given progressively larger pickled organisms to dissect.

Math, on the other hand, smells only like chalk dust and a faint whiff of ozone.

Rufus said...

History smells like old papers. It's a bit moldy, but a good smell overall.

Becky said...

psst... In #3, the definition of atomic weight should be the number of protons and neutrons, not protons and electrons. No electrons are present in the nucleus. That we know of. Yet. You never know what those wacky atomic scientists are gonna find next.

Rufus said...

Ah yes. This is the danger of blogging about biology while drinking Smithwick's Ale.