Water and Chemistry
What do we call the unequal distribution of electrical charge in a molecule?
A polar molecule, like water, has regions with partial positive and negative charges due to an unequal sharing of electrons within the covalent bonds of the molecule.
This is a small molecular building block that can join with others to form a polymer.
What is a monomer?
Name the monosaccharide that cells commonly use as an energy source.
What is GLUCOSE?!
This lipid consists of one glycerol molecule attached to three fatty acids and is important for long-term energy stroage.
What is a triglyceride?
Name the building blocks of proteins and the variable group that distinguishes one from another.
What are amino acids and their variable R groups?
Water molecules attract one another because the partially positive hydrogen of one is attracted to the partially negative oxygen of another. Name this attraction.
What is a hydrogen bond?
A hydrogen bond is not a true bond like covalent or ionic, but it is a particularly strong electrostatic attraction between polar molecules.
This process uses water to break a covalent bond between the smaller units of a large biological molecule.
What is hydrolysis?
Name the main glucose-storage polysaccharide in plants and the main one in animals.
What is starch (plants) and glycogen (animals)?
This lipid typically has two nonpolar fatty acid tails and a polar phosphate-containing head.
What is a phospholipid?
Name the covalent bonds that connect amino acids in a polypeptide.
What is a peptide bond?
Carbon has this many valence electrons and can typically form this many covalent bonds
What is four valence electrons?
Carbon is in main group 4 which suggests its number of valence electrons.
Two smaller molecules join, forming. covalent bond and releasing a water molecule. Name the process.
What is dehydration synthesis?
Name the structural polysaccharide found in plant cell walls and the one found in arthropod exoskeletons or fungal cells.
What is cellulose (plants) and chitin (arthropods and fungi)?
One fatty acid has no carbon-carbon double bonds; another has a double bond that creates a kink/bend. Identify each and explain their differnet packing.
What is saturated (no C=C double bond) and unsaturated (one or more C=C double bonds) fatty acids?
Saturated fats pack more tightly/densely than unsaturated because of their flat shape (saturated) versus the bent shape (unsaturated). Saturated fats are typically solid at room temp and unsaturated are liquid.
Name the building blocks of DNA and RNA, and identify their three compenents.
What are nucleotides, which are composed of a phosphate group, sugar, and a nitrogenous base?
Three solutions start at pH 7. After equal amount sof acid are added, solution A drops to 3.0, B drops to 6.6, and C drops to 5.2. Which has the greatest buffering capacity?
What is solution B?
Solution B, because it experiences the smallest change in pH (0.4 units). Remember a buffer prevents pH from changing drastically when a reasonable amount of acid/base are added.
In one type of bonding, electrons are transferred to create oppositely charged ions. In another, electrons are shared. Name both and identify which one is which.
What is ionic and covalent bonding?
Ionic is the bond between ions (transfer of electron(s) from metal to nonmetal), while covalent is the bond created through the sharing of electrons (between nonmetal atoms).
Starch and cellulose are both made of glucose. Explain why humans can digest starch but not cellulose.
What is the difference in their bonding structure?
Will also accept: What is lacking of the enzyme cellulose?
Starch and cellulose are both polysaccharides composed long chains of glucose. It is the difference in how these glucose molecules are bonded that creates these different polymers that have different functions.
Describe how phospholipids arrange themselves in water, including where their hydrophilic heads adn hydrophobic tails point.
What is a phospholipid bilayer?
Heads face the watery environment on both sides, while tails point inward toward one anther, forming a bilayer.
Name the four levels of protein structure in order and describe the main feature of each.
What is primary (amino acid sequence), secondary (hydrogen bonding btw amino acid functional groups), tertiary (R group interactions), and quaternary (multiple polypeptide subunits coming together)?
Oxygen pulls shared electrons closer to itself in a water molecule. Name the type of O-H bond and explain why water has partial charges.
What is a polar (covalent) bond due to a difference in electronegativity?
An O-H polar covalent bond is polar because oxygen is more electronegative than hydrogen, pulling the electrons closer to it creating the partial charges on either side of the bond/molecule.
A student eats bread and eggs. Explain which reaction helps digest the starch and proteins and why the reaction is necessary.
What is hydrolysis?
Hydrolysis is necessary to breakdown the polysaccharide starch into glucose which can be used by cells (or stored as glycogen for later), and to breakdown the egg polypeptides into individual amino acids so that cells and/or the body can use those amino acids to build up their own unique proteins.
A scientist finds a highly branched polymer of glucose in an animal's muscle cell. Identify the likely molecule and explain how its structure supports its function.
What is glycogen?
Glycogen's branching structure provides many sites for enzymes to release glucose for energy.
Compared to carbohydrates, what is one major advantage of lipids when it comes to storing energy?
Lipids store more than twice as much energy per gram as carbohydrates
A mutation replaces one amino acid with another that has different chemical properties. Which protein structural level definitely changes, and why might the proteins function change?
What is a change in the primary structure?
Primary structure definitely changes. Different R-group interactions may alter folding and shape, potentially affecting functions; not every substitution is harmful.