Basic Cell Chemicals and Molecules

The pH range is maintained between 7.35 and 7.45.

They are only effective within a small pH range of about 1-2 pH units.

pH influences enzymatic activity and alters the structure of proteins, affecting their efficiency.

<p>A buffer solution is a mixture of a weak acid and its conjugate base that maintains a relatively constant pH.</p> Signup and view all the answers

<p>Many organisms can only survive in specific pH environments tailored to their biological needs.</p> Signup and view all the answers

<p>In covalent bonding, valence electrons are shared as pairs between bonded atoms.</p> Signup and view all the answers

<p>Polar covalent bonding involves atoms of different electronegativities, resulting in a partial charge, while pure covalent bonding occurs between identical nonmetals without charge separation.</p> Signup and view all the answers

<p>An ionic bond is formed when valence electrons are completely transferred from one atom to another, typically between metals and nonmetals with significant electronegativity differences.</p> Signup and view all the answers

<p>Hydrogen bonds are attractive forces between a hydrogen atom bonded to an electronegative atom and another electronegative atom in a different molecule.</p> Signup and view all the answers

<p>An acid is defined as a proton (H+) donor, while a base is a proton (H+) acceptor.</p> Signup and view all the answers

<p>pH is expressed as the negative logarithm of hydronium ion concentration, meaning lower pH values correspond to higher [H+] concentrations.</p> Signup and view all the answers

<p>pH can be measured using a pH meter, and it is crucial to standardize (calibrate) the meter before use to ensure accuracy.</p> Signup and view all the answers

<p>During neutralization, hydrogen ions (H+) from the acid react with hydroxide ions (OH-) from the base to produce water.</p> Signup and view all the answers

<p>The primary fluid medium of cells is water, which is typically found in a concentration of 70% to 85%.</p> Signup and view all the answers

<p>The two types of proteins are structural proteins, exemplified by intracellular filaments, and functional proteins, such as enzymes.</p> Signup and view all the answers

<p>Ions provide inorganic chemicals for cellular reactions and are essential for transmitting electrochemical impulses in nerve and muscle fibers.</p> Signup and view all the answers

<p>Phospholipids and cholesterol are key types of lipids found in cell membranes, providing structure and forming barriers between cell compartments.</p> Signup and view all the answers

<p>Proteins constitute about 10% to 20% of the mass of most cells.</p> Signup and view all the answers

<p>The typical stored carbohydrate in human cells is glycogen, an insoluble polymer of glucose.</p> Signup and view all the answers

<p>In fat cells, triglycerides can account for as much as 95% of the cell mass, serving as the body’s main storehouse for energy.</p> Signup and view all the answers

<p>Most human cells do not store large amounts of carbohydrates because they primarily rely on glucose present in the extracellular fluid for energy.</p> Signup and view all the answers

<p>The primary components are H2PO4- and HPO42-.</p> Signup and view all the answers

<p>The pKa of histidine when incorporated into a protein can be as high as 7.0, enabling effective buffering around pH 7.</p> Signup and view all the answers

<p>The concentration of bicarbonate ions (HCO3-) must be 20 times larger than that of carbonic acid (H2CO3).</p> Signup and view all the answers

<p>The pH of blood plasma increases because rapid breathing leads to excessive loss of carbon dioxide, reducing carbonic acid concentration.</p> Signup and view all the answers

<p>Protein buffers help maintain a constant pH inside cells and also play a role in buffering in extracellular fluids.</p> Signup and view all the answers

<p>The carbonic acid buffer system serves as the main extracellular buffer.</p> Signup and view all the answers

<p>The pKa of phosphoric acid is 2.1, which is too low for effective buffering at pH 7.</p> Signup and view all the answers

<p>Maintaining low levels of carbonic acid prevents disruption of osmotic balance between plasma and intracellular fluids.</p> Signup and view all the answers

<p>The buffer solution will shift the equilibrium to increase the concentration of HA and decrease the concentration of A-.</p> Signup and view all the answers

<p>The addition of a base will consume HA, leading to a decrease in HA and an increase in A-.</p> Signup and view all the answers

<p>The Henderson-Hasselbalch equation relates the pH of a buffer solution to the pKa and the ratio of the concentrations of the base and acid.</p> Signup and view all the answers

<p>Ka indicates the strength of the acid; a smaller Ka value suggests a weaker acid, thus influencing the concentrations and pH of the buffer system.</p> Signup and view all the answers

<p>At equilibrium, the product concentrations [H+] and [A-] are established such that the equilibrium constant Ka holds true.</p> Signup and view all the answers

<p>Buffer capacity is the ability of a buffer solution to resist pH changes upon the addition of acids or bases.</p> Signup and view all the answers

<p>A buffer remains effective as long as sufficient concentrations of both HA and A- are present in the solution.</p> Signup and view all the answers

<p>Le Chatelier's principle states that if a change is imposed on a system at equilibrium, the system will adjust to counteract that change.</p> Signup and view all the answers