Each student should choose one (only 1) technical term or concept from the lectures in Module 1 and write a correct definition or explanation for that term. You should focus on the words in blue bold in the power points and the figures highlighted during lectures. You will post your definition or explanation as a comment in response to this post. You will receive 1 point for your correct post. You may only submit one comment and you may not repeat or use a definition or explanation another student has previously posted, so check the comments below carefully before submitting your answer.
A polar covalent bond is a bond that occurs between nonmetal atoms. It is an unequal sharing of electrons that has a moderate electronegativity difference (0.5 to 1.7).
G-protein-coupled receptors (GPCRs): the largest and most diverse group of membrane receptors in eukaryotes. These cell surface receptors act like an inbox for messages in the form of light energy, peptides, lipids, sugars, and proteins. Such messages inform cells about the presence or absence of life-sustaining light or nutrients in their environment, or they convey information sent by other cells.
GPCRs play a role in an incredible array of functions in the human body, and increased understanding of these receptors has greatly affected modern medicine. In fact, researchers estimate that between one-third and one-half of all marketed drugs act by binding to GPCRs.
Solubility
The maximum amount of substance that will dissolve in a given amount of solvent.
Significance –
getting compounds out of the body
water soluble vitamins easily leave the body
kidneys will only excrete water soluble compounds
fat soluble vitamins are stored in the liver or in fat and are hard to get ride of
Functional groups are atoms or a group of atoms within an organic compound that have distinctive chemical properties and are linked together through covalent bonds.
Oxidation is the process in which alcohol can be converted into an aldehyde (CHO) and ketones (=O).
Electronegativity:
Electronegativity is the ability of an atom to attract bonding electrons to itself. Non-metals often have higher electronegativity compared to metals as these elements have a greater attraction for electrons. With this being said, electronegativity increases as you go up and to the right, on the periodic table. It is important to note though, that noble gases (group 18) do not have an electronegativity, as they do not form bonds.
The more strongly an atom attracts electrons, the higher its electronegativity value. Therefore, this atom would have a partial negative charge associated with it.
Receptor Tyrosine Kinases (RTKs):
RTKs mediate cell-to-cell communication and control a wide array of biological functions including cell growth, motility, differentiation, and metabolism.
These are membrane receptors which attach phosphates to a tyrosines. It can trigger multiple signal transduction pathways at the same time. Abnormal functioning of RTKs are related to many different types of cancers.
Ionic bond forms between a metal and a non-metal. It forms from the transfer of electron from one ion to another.
Acid Hydrolysis of Esters: this is when an ester (R-(C=O)-O-R) with water (H20) and produces a carboxylic acid (R-COOH) and alcohol (-OH). This reaction requires an acid catalyst such as H+.
Thiols
Thiols include compounds in which contain sulfur, or a sulfhydryl group. They contain a -SH group, similarly to alcohols that have an -OH group. The sulfhydryl group is prominent in protein structure and can be found in the covalent bonds between peptide chains. Sulfur is generally found in onions, oysters, and garlic. These items have a strong scent , as sulfur also does (Ex. produces skunk order).
Cycloalkanes
Cycloalkanes are hydrocarbons that are able to form a ring structure. They have two less hydrogen atoms than an open chain because the carbons in the ring bond to each other instead of hydrogens. The names consists of the prefix cyclo-, followed alkane name that corresponds to the number of carbons, ending with the suffix -ane. The minimum number of carbons needed to form a ring is 3, meaning cyclopropane is the simplest cycloalkane.
Alkanes
Alkanes are a class or group of organic compounds. Alkanes contain only Carbon (4 valence electrons) and Hydrogen (1 valence electron). They form only single bonds (saturated) between carbons. Alkanes are the basic skeleton to which we add functional groups.
Esterification is the formation of an ester, by the combination of an alcohol and an acid (carboxylic), with an acid catalyst and heat present.
Mitochondria is an organelle found in all cells except mature erythrocytes(RBC). It is the site for biochemical processes including oxygen use and ATP production. It has a double membrane—the outer membrane and the inner membrane which is folder inward, forming cristae in order to increase surface area.
Lysosomes are digestive compartments. They are membranous sacs of hydrolytic enzymes that can digest macromolecules (proteins, fats, polysaccharides, and nucleic acids). Lysosomes can also use these enzymes for autophagy- recycling of a cell’s own organelles which is important for the process of renewing a cell.
Non-polar covalent bonds are when atoms equally share the electrons between them. An example of a non-polar covalent bond is O2; the electrons are equally shared between each oxygen atom. The electronegativity of each atom are the same, so the affinity for attraction is the same- thus resulting in equal sharing.
The valence-shell electron-pair repulsion theory (VSEPR) describes the electron groups around a central atom. They are arranged as far apart from each other as possible. They have the least amount of repulsion of the negatively charged electrons. They also have a geometry around the central atom that determines molecular shape.
Isomer:
Isomers are compounds with the same molecular formula (same number of atoms of each element), but different atomic arrangements in space. Because of this, isomers have different physical properties like variation in chain structure (straight, branched) which causes them to have different chemical properties.
Enzymes
An enzyme is a highly specialized protein. It catalyzes reactions in biological systems by decreasing the activation energy for a specific chemical reaction. Enzymes are specific for one set of substrates or to a group of similar substrates. They are not changed or consumed during the reaction that occurs.
Inorganic vs organic compounds:
inorganic – mostly covalent bonding, nonpolar unless a more electronegative atom is present, usually low melting and boiling points, high flammability, not soluble in water unless a polar group is present
organic – many ionic bondings, some covalent, most are ionic or polar covalent, few nonpolar covalent, high melting and boiling points, low flammability, most are soluble in water unless nonpolar
Van der Waals Interactions:
This force is an attraction between molecules that are close together as a direct result of an asymmetrical distribution of electrons (from the molecules) that create an area of positive and negative charges. An example of this is a gecko climbing on a wall. This works because collection of negative charges that repel the positive charges, between the gecko’s toes and the surface of the wall, creates a strong Van der Waals interaction. This, paired with the gecko’s small body mass, allows them to walk on walls.
Intracellular Receptors
They are located within the cell (the cytosol or nucleus of the target cell). Chemical messengers are small or hydrophobic and activate the receptors by crossing the cell membrane. Some examples include, steroid and thyroid hormones in animals. Once activated the hormone receptor complex acts as a transcription factor then genes are turned on and able to code for proteins
Hydrophlic
Hydrophilic means “water loving”, which indicates an affinity for water. This enables the molecules to dissolve easier in water than in oils or hydrophobic solvents. These hydrophilic molecules are typically polar/”charged”, or have have side groups/substituents that are polar. Hydrophilic molecules have a permanent dipole moment. They are capable of hydrogen bonding.
Signal Transduction Pathways
When a receptor activates a protein, which activates another, and so on until the protein producing the response is activated (like falling dominoes)
Micelles- an amphipathic group of molecules where the nonpolar portions of the molecule form around a nonpolar molecule while the polar portions face towards a polar solvent. This allows a nonpolar molecule to become soluble in a polar solvent
Saponification
Saponification is the base promoted ester hydrolysis reaction. Esssentially, you have an ester to begin with. This could be a triglyceride, for example. Using a base like naOH, the bond between the OR group and the central carbon is cleaved, leaving the carboxylic acid salt and alcohol. This carboxylic acid salt has a polar head and a non-polar tail. These structures are what soap is made of. If there were oil on a plate when washing dishes, the nonpolar tails of these carboxylic acid salts form a micell around the grease (also nonpolar). The head is polar and faces outward of the micelle to interact with the water (since it is hydrophilic) when the plate is rinsed off.