A&P chapter 2

Except for elements with atomic number 1 and 2, all other elements are stable with how many electrons in their outermost (valence) energy level?

8

Which of the following is true regarding hydrolysis reactions?

Water is added and building blocks are released.

Part complete What is the primary energy-transferring molecule in cells?

ATP When broken (hydrolyzed), the high-energy phosphate bonds in the ATP molecule release the energy used to do cellular work.

Which of the following is not produced through chemical bonding?

Atoms Atoms react through chemical bonding to form larger structures. Chemical bonding begins with atoms; it does not produce them. All of the structures that we cover in A&P are made from atoms through chemical bonding.

If a cell were to become larger, but not gain or lose any of the chemicals inside, what would happen to the rate of chemical reactions?

Chemical reactions would slow down.

Which of the following statements is true concerning the characteristics of either compounds or mixtures?

Compounds are formed by chemical bonds between different kinds of atoms.

Which of the following factors would speed up the rate of a chemical reaction?

High concentration of reacting particles

Which of the following is an example of a decomposition reaction?

MgO2 → Mg + O2 A decomposition reaction occurs when a larger molecule is broken down into smaller molecules or its constituent atoms.

Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not?

No, because the atoms have only 6 valence electrons, but need 8 for stability. To be stable, by the Octet Rule an atom must have 8 electrons in its outermost orbital. With only 6 valence electrons, oxygen atoms are unstable and will seek ways to get or share two more electrons to become stable.

Part complete Which of the following is not a fundamental subatomic particle that forms elements?

Nucleus

Which of the following distinguishes hydrogen bonds from covalent bonds?

Only hydrogen bonds can form between molecules. Because hydrogen bonds are not true bonds, they do not always join atoms together within a single molecule. In water, for example, hydrogen bonds link water molecules together. This is referred to as an intermolecular attraction—it is between different atoms

Part complete Which organic molecules form the major structural materials of the body?

Proteins Proteins form the major structural materials of the body. Because fibrous proteins are the chief building materials of the body, they are also known as structural proteins. However, not all proteins are construction materials. Many play vital roles in cell function.

Which of the following is not a result of hydrogen bonds?

Two hydrogen atoms join together to form a molecule of hydrogen gas. Hydrogen bonds occur when there are polar covalent molecules present, but hydrogen atoms join with each other through nonpolar covalent bonds

Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water?

Water acts as a reactant. Yes, water molecules are necessary for salivary amylase to hydrolyze starch to glucose in your mouth. Thus, water acts as an important reactant.

Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel?

Water acts as a solvent because the partial negative charge on the oxygen in water attracts sodium, while the partial positive charge on hydrogen attracts chloride. This results in the separation of sodium from chloride, thus breaking the ionic bond. Yes, salt (NaCl) is an ionic compound that can be separated by the polar water molecule.

Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not?

Yes, because they can become more stable by doing so. Atoms react with other atoms to gain stability, typically by gaining, losing, or sharing electrons to attain a full outermost orbital. Atoms with full outermost electron orbitals are less likely to react and are referred to as being inert.

Part complete In plasma, a typical body fluid, protein floating around would be considered to be which of the following?

a solute, specifically both a colloid and an electrolyte Yes, colloids are large particles dispersed in body fluids. Since most proteins have a negative charge, they are also considered to be electrolytes.

Part complete What is the classification of a solution of NaOH with a pH of 8.3?

alkaline solution A pH between 0.0 and 7.0 is acidic. A pH between 7.0 and 14.0 is basic. Therefore, a solution with a pH of 8.3 is an alkaline (or basic) solution. NaOH is an example of a basic compound.

Which of the following types of chemical reactions always involves atoms or molecules combining to form a larger, more complex molecule?

synthisis

Electrolytes are charged particles called ions that are dissolved in body fluids. Which of the following ions would be considered a major anion in the body?

chloride Yes, chloride is a major extracellular anion (negative ion).

Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest?

covalent, ionic, hydrogen In covalent bonds, electrons are shared between atoms; in ionic bonds electrons are lost or gained; but hydrogen bonds are not true chemical bonds—they are weak attractions due to slight electrical imbalances. No electrons are directly involved.

All ions are __________.

electrolytes

Something with a pH of 5 would __________.

have more H+ ions than OH- ions

Sodium has one valence electron, while chlorine has seven. What type of chemical bond is most likely to occur between sodium and chlorine?

ionic

Which of the following is not a compound?

oxygen gas

Part complete Which pH is more acidic, a pH of 3, a pH of 7, or a pH of 9?

pH of 3 Yes, the lower the pH, the more acidic the fluid. pH is inversely related to the number of H+ ions. As the number of H+ ions increases (and thus the acidity increases), the pH decreases. Therefore, a pH of 3 is the most acidic of the three values given.

Formation of hydrogen bonds requires hydrogen atoms and what else?

polar covalent bonds Hydrogen gets a slight positive charge from the unequal sharing of electrons in polar covalent bonds, and it bonds to another atom with a slightly negative charge, again resulting from unequal electron sharing due to a polar covalent bond.

Cortisol is a type of lipid hormone. Which type of lipid would cortisol be classified as?

steroid Yes, cortisol is a steroid hormone synthesized from cholesterol.

Which parts of atoms can interact (react) to form chemical bonds?

valence electrons Only the outermost parts of atoms interact (react) with each other, and those are the valence electrons. If the outermost orbital is full, the atom is stable and less likely to react with another atom.

In biochemistry, and thus in the body, the universal solvent is __________.

water

Which of the following is not considered a form of matter?

x-ray