Tutor profile: Chad H.
Subject: Organic Chemistry
What is a nucleophile and what are three examples of nucleophiles?
A nucleophile is a molecule that has a strong attraction to molecules that are positively charged or molecules that can become positively charged (these are considered electrophiles). This is because they contain a high electron density. Nucelo- refers to "positive charge" and -phile means "to love". Three groups of molecules that contain a high electron density are molecules with negative charges, double/triple bonds, and lone pair electrons. Nucleophiles commonly attack electrophiles in Sn1 and Sn2 reactions.
What is the intermolecular force holding water molecules together and describe how it works.
Water also known as dihydrogen monoxide is composed of two hydrogen atoms and one oxygen atom. They are arranged in a bent geometric shape with the oxygen in the center contain two pairs of Lone pair electrons. Because of these lone pair electrons it pushes the hydrogens further down giving it a bent shape. Since the oxygen end of the molecule has more electrons and the hydrogen end has less electrons an unequal distribution of electrons is created. This is known as a dipole. The oxygen end is contains a negative dipole and the hydrogen end contains a positive dipole. Since positive dipoles attract negative dipoles two water molecules are attracted to one another. The first water molecules negative dipole on oxygen is attracted to the second water molecules positive dipole on the hydrogen. This intermolecular force is known as a hydrogen bond. This name is somewhat of a misnomer because generally a bond occurs when electrons are shared (covalent bond) or given (ionic bond). Since neither of these events are occurring a hydrogen bond is not a bond but rather a strong force holding a negative dipole to a positive dipole.
Describe each of the steps within the central dogma of biology and the major molecules used and produced.
The central dogma of biology describes one of the most important mechanisms in biology that is seen in each of the domains of life. This is the process of how an organism uses genetic information stored in DNA to create the building blocks of the body, proteins. Deoxyribonucleic acid (DNA) is a macromolecule that store genetic information in the sequence of its nucleotides, adenine, thymine, cytosine, and guanine. The DNA molecule can be transcribed (by the protein RNA polymerase) to create the new molecule ribonucleic acid (RNA). A new sequence of nucleotides are formed based on the original DNA molecule where adenine is now uracil, guanine is now cytosine, thymine is now adenine, and cytosine is now guanine. This particular RNA is called mRNA or messenger RNA. The RNA molecule goes through a series of modification and eventually is translated into a protein. This process uses ribosomes, an organelle found free floating in the cytoplasm and attached to the rough endoplasmic reticulum. The ribosomes acts as an attachment site for two molecules, mRNA and tRNA. A series of three nucleotides in a row constitutes a codon on mRNA that will link up to the corresponding anticodon on tRNA. A tRNA molecule has a amino acid attached at its ends. Therefore as the mRNA molecule moves through the ribosomes new tRNA molecules enter and attach amino acids to the previous amino acid creating a long sequence, a polypeptide. This polypeptide will undergo a series of modifications to become a fully functional protein that can be used for a wide variety of functions. Therefore overall the central dogma of biology is the going from DNA to RNA to protein using transcription and translation in between.
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