BCH 361 Sapling Hw

What is the hydroxide ion concentration in an aqueous solution w/ a H ion concentration of [H+]= 5.9 * 10^-3 M?

1.7 *10^-12 M

Which of the choices best describes a biological membrane? A. a bilayer containing lipids with hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward B. a bilayer containing lipids with hydrophobic head group oriented toward the solvent (extracellular fluid and cytosol) and hydrophilic tail groups pointing inward C. a bilayer containing lipids with hydrophilic head groups pointing inward and hydrophobic tail groups oriented toward the solvent (extracellular fluid and cytosol)

A

Which of the choices are components of biological membranes? Select all that apply. A. lipids B. proteins C. nucleic acids

A, B

Select the statements that correctly describe a buffer. A. a buffer is generally made up of a weak acid and its conjugate base B. The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid C. the Ka of a buffer does not change when any amount of an acid is added to the buffer solution D. an acid added to the buffer solution reacts with the weak base of the buffer E. the pH of a buffer solution does not change significantly when any amount of a strong acid is added

A, C, D

Which statements accurately describe the polarity and electronegativity of water? A. The O atom in a water molecule is strongly electronegative B. Water is polar, which means that it has an overall negative charge C. Water molecules are polar and thus associate with each other through H bonds C. Covalent bonds in water molecule bind its O atom to its 2 H atoms D. Strong covalent bonds are formed btw 2 or more water molecules

A, C, D

Select the phrases that accurately complete the sentence: The mitochondrion A. is a cellular scaffolding contained within a cell's cytoplasm B. has a double membrane, with ATP synthesis occurring at the inner membrane C. contains unique DNA that is diff from the cell's nuclear DNA D. is made up of pancake-like membrane stacks that package proteins in vesicles E. digests macromolecules ingested by the cell

B, C

Which statements correctly describe the rough ER? A. it is used to transport mRNA to the cell membrane B. it produces proteins that need to be modified before use C. it stores and releases calcium ions D. it is connected to membrane of nucleus E. it has ribosomes bound to it s membrane

B, D, E

Some freedivers hyperventilate before diving. Hyperventilation can change the concentration of CO2 in the blood and may increase the length of time that a person feels like he or she can hold his or her breath. How does hyperventilation affect blood pH? A. It increases CO2 and H+ in the blood, decreasing pH B. It increases CO2 and decreases H+ in blood, decreasing pH C. It decreases CO2 and H+ in the blood, increasing pH D. It decreases CO2 and increases H+ in the blood, decreasing pH

C

Why does oil not dissolve in water? A. hydrogen bonds form btw oil molecules, causing them to aggregate B. oil is less dense than water, which causes it to separate from water instead of dissolving C. water molecules form hydrogen bonds with each other and exclude oil molecules D. water molecules do not form strong attractions to nonpolar molecules, like the ones in oil

C, D

Select the descriptions that apply to the ribosome. A. a membranous network associated w. protein production B. a membranous complex which produces secretory vesicles C. a cellular structure that is responsible for the synthesis of proteins D. a membrane- bound organelle that stores digestive enzymes e. a cellular structure that is composed of both RNA and protein

C, E

Select the phrases that describe the plasma membrane. A. creates a barrier btw DNA and other intracellular structures B. provides a rigid structure that allows the cell to hold its shape C. creates a barrier btw the inside and outside of the cell D. maintains the correct ion concentration inside the cell

D, E

In the context of small molecules with similar molar masses, arrange the intermolecular force by strength. A. H bonding B. dipole-dipole interactions C. london disperson forces

Strongest-> h-bonding-> dipole-dipole interactions -> london disperson forces -> weakest

What is the H ion concentration of a solution with pH = 4.25?

[H+]= 5.6 x 10^-5 M

What is the pH of an aqueous solution with a H ion concentration of [H+]= 5.9 * 10^-3 M?

pH= 2.2