A&P 2 questions
Choose the answer that best describes HCO3-.
a bicarbonate ion
ionic bond
a bond in which electrons are completely lost or gained by the atoms involved
nonpolar covalent bond
a bond in which electrons are shared equally
polar covalent bond
a bond in which electrons are shared unequally
In general, the lipids that we refer to as oils have ________.
a high degree of unsaturated bonds
What is a dipole?
a polar molecule
Which of the following is formed once the ions in the salt crystal have completely dissociated from one another?
a solution
hydrogen bond
a type of bond important in tying differen parts of the same molecule together into a three-dimensional structure
What is the classification of a solution with a pH of 8.3?
alkaline solution
Which organic molecules form the major structural materials of the body?
proteins
Which type(s) of subatomic particles can be located within the nucleus of an atom?
protons and neutrons
Carbohydrates and proteins are built up from their basic building blocks by the ________.
removal of a water molecule between each two units
electrical energy
represented by the flow of charged particles along a conductor, or the flow of ions across a membrane
What level of protein synthesis is represented by the coiling of the protein chain backbone into an alpha helix?
secondary structure
An element has an atomic number of 17 and a mass of 35. How many protons, neutrons, and electrons does the element have?
17 protons, 18 neutrons, and 17 electrons The mass number is the sum of protons and neutrons in the atom. The atomic number is the number of protons in the atom. The number of protons equals the number of electrons in a chemically inactive atom.
What is the primary energy-transferring molecule in cells?
ATP
Which of the following is TRUE of atomic weight?
Atomic weight of an element is approximately equal to the mass number of its most abundant isotope.
In a covalent bond,
Atoms share one or more pairs of electrons.
Which of the following would be regarded as an organic molecule?
CH4 Carbon is in it
Although his cholesterol levels were not high, Mr. Martinez read that cholesterol was bad for his health, so he eliminated all foods and food products containing this molecule. He later found that his cholesterol level dropped only 20%. Why did it not drop more?
Cholesterol is produced naturally by the liver, in addition to being ingested in foods.
Choose the correctly matched pair.
DNA and RNA are nucleic acids; they are built from nucleotides.
Which of the following does NOT describe enzymes?
Enzymes work by raising the energy of activation.
Suspensions may also be called emulsions.
False Colloids, not suspensions may also be called emulsions.
Nonpolar molecules are the result of unequal electron pair sharing.
False Polar molecules are the result of unequal electron pair sharing. Nonpolar molecules are electrically balanced due to the equal sharing of electrons between the atoms of the molecules.
A 23-year-old male was riding his road bike in 100-degree heat, when he suddenly became nauseated and weak. He called 911 from his cell phone. When the ambulance came, the paramedics started intravenous therapy for severe dehydration. Which physical property and which physiological role of water caused the dehydration, and why?
High heat of vaporization; water was lost when evaporating from the skin to cool the body.
Which bonds often bind different parts of a molecule into a specific three-dimensional shape?
Hydrogen
Select the correct statement about isotopes.
Isotopes of the same element have the same atomic number but differ in their atomic masses.
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.
Which of the following is NOT a difference between a compound and a mixture?
Mixtures are homogeneous while compounds are heterogeneous.
Which of the following elements is necessary for proper conduction of nervous impulses?
Na
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.
Which of the following distinguishes hydrogen bonds from covalent bonds?
Only hydrogen bonds can form between molecules.
What explains the negative charge on the oxygen atom within the water molecule?
Oxygen atoms have a stronger pull on the electrons shared within a covalent bond formed between oxygen and hydrogen.
The basic structural material of the body consists of ________.
Proteins
Each specific amino acid has a unique ______.
R group
Why is it possible to safely drink a solution that contains a 50:50 mixture of equal concentrations of a strong acid and a strong base, either of which, if ingested separately, would be very caustic and damaging?
Salt and water are formed when a strong acid and base are mixed.
Which of the following does describe enzymes?
Some enzymes are protein plus a cofactor. Each enzyme is chemically specific. Some enzymes are purely protein.
Mixtures differ from compounds in several important ways.
The chief difference between mixtures and compounds is that no chemical bonding occurs between the components of a mixture. The properties of atoms and molecules are not changed when they become part of a mixture. (2) Depending on the mixture, its components can be separated by physical means, straining, filtering, evaporation, and so on. Compounds, by contrast, can be separated into their constituent atoms only by chemical means (breaking bonds). (3) Some mixtures are homogenous, while others are heterogeneous. All compounds are homogeneous.
Which of the following is true of polar covalent bonds?
The electrons are shared unequally.
Which of the following is TRUE regarding the pH of a solution?
The more hydrogen ions in a solution, the more acidic the solution is.
A 65-year-old patient came to the emergency room with complaints of severe heartburn unrelieved by taking a "large handful" of antacids. Would you expect the pH to be relatively high, low, or normal for the patient's stomach contents, and why?
The pH would be high. Antacids are basic, and too many antacids would result in a relatively alkaline state.
Which of the following is NOT one of the three basic steps involved in enzyme activity?
The substrate absorbs chemical energy from the enzyme after binding to its active site.
What does the formula C6H12O6 mean?
There are 12 hydrogen, 6 carbon, and 6 oxygen atoms.
Which of the following is not true of proteins?
They appear to be the molecular carriers of coded hereditary information.
ATP is an unstable, high-energy molecule that provides body cells with a form of energy that is immediately usable.
True
The major function of RNA is to carry out the genetic instructions for protein synthesis.
True
Which of the following is not a result of hydrogen bonds?
Two hydrogen atoms join together to form a molecule of hydrogen gas.
Which of the following statements is false?
When the hydrogen ion concentration decreases, the hydroxyl ion concentration also decreases.
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.
matter
anything that occupies space and has mass
Choose the answer that best describes fibrous proteins.
are very stable and insoluble in water
Which of the following is not produced through chemical bonding?
atoms
If an oxygen atom were to form a chemical bond in which it gained two electrons, it would ______.
become more stable
Which of the following is an example of a suspension?
blood
mixture
blood
energy
can be measured only by its effects on matter
Water ________.
can form hydrogen bonds
element
carbon
The four elements that make up about 96% of body matter are ________.
carbon, oxygen, hydrogen, nitrogen
Which of the following does describe uses for the ATP molecule?
chemical work mechanical work transport across membranes
Sucrose is a ________.
disaccharide
compound 1
dry ice (frozen carbon dioxide)
cation
electrically charged particle due to loss of an electron
radiant energy
energy that travels in waves. part of the electromagnetic spectrum
Carbohydrates are stored in the liver and muscles in the form of ________.
glycogen
colloids
heterogeneous, will not settle
suspensions
heterogeneous, will settle
Which property of water is demonstrated when we sweat?
high heat of vaporization
solutions
homogeneous, will not settle or scatter light
Which of the following is NOT one of the three major types of chemical reactions?
hyperbolic Most chemical reactions exhibit one of three recognizable patterns. They are either synthesis, decomposition, or exchange reactions.
Kidneys play a major role in helping to maintain proper levels of Na+ and K+ ions in the blood. If the kidneys fail to function properly, one of the direct consequences would be_________.
impaired nerve impulse transmission
Covalent bonds:
involve the sharing of one to three pairs of electrons.
Salts are always ________.
ionic compounds
weight
is a function of, and varies with, gravity
mechanical energy
legs moving the pedals of a bicycle
although a man who weighs 175 pounds on Earth would be lighter on the moon and heavier on Jupiter, his ___ would not be different
mass
Which protein types are vitally important to cell function in all types of stressful circumstances?
molecular chaperones
neutron
neutral subatomic particle
Which subatomic particles contribute to an atom's mass number but not its atomic number?
neutrons
Which of the following is NOT a compound?
oxygen gas
Which of the following does not describe uses for the ATP molecule?
pigment structure
The lines drawn between hydrogen (H) atoms and the oxygen (O) atom in the structural diagram presented in the right of the figure each represent a ______.
polar covalent bond A covalent bond in which electrons are shared unequally is termed a polar covalent bond.
A molecule of water (H2O) is formed by what type of bond?
polar covalent bonds
Formation of hydrogen bonds requires hydrogen atoms and what else?
polar covalent bonds
What is a chain of more than 50 amino acids called?
protein
The superscript preceding each hydrogen atomic symbol (H) represents which of the following? 1H
the atomic mass of the corresponding atom
The chemical symbol O=O means ________.
the atoms are double bonded
Which of the following best defines covalent bonds?
the bond formed when shared electrons occupy a single orbital common to both atoms within a molecule
A chemical reaction in which bonds are broken is usually associated with ________.
the release of energy
What is the most significant factor in the formation of a covalent bond?
the sharing of electron pairs between two atoms
Which of the following is not considered a factor in influencing a reaction?
time
Which parts of atoms can interact (react) to form chemical bonds?
valence electrons
What is the most abundant and important inorganic compound in living material?
water
compound
water
chemical energy
when the bonds of ATP are broken, energy is released to do cellular work
The numbers listed represent the number of electrons in the first, second, and third energy levels, respectively. On this basis, which of the following is an unstable or reactive atom?
2, 8, 1
How many hydrogen atoms will nitrogen bond with to form a stable molecule?
3 Nitrogen has 5 electrons in its valence (outermost) electron shell. Therefore, it will form covalent bonds with three hydrogen atoms. Each single covalent bond includes the sharing of three pairs of electrons. The three electrons contributed by the hydrogen atoms will fill the valence shell of nitrogen.
Atom X has 17 protons. How many electrons are in its valence shell?
7
Except for elements 1 and 2, all other elements are stable with how many electrons in their outermost (valence) energy level?
8
An atom of oxygen has an atomic number of 8 and a mass number of 18. How many of each type of subatomic particle does it contain?
8 protons, 8 electrons, and 10 neutrons
What is the difference between kinetic and potential energy?
Kinetic energy is energy in action, while potential energy is stored energy.
The single most abundant protein in the body is ________.
collagen
You notice that you cannot read your book through a test tube of fluid held against the print, making it so blurred as to be unreadable. There is no precipitant in the bottom of the beaker, though it has been sitting for several days in a rack. What type of liquid is this?
colloid
Which of the following is considered a factor in influencing a reaction?
concentration temperature particle size
Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest?
covalent, ionic, hydrogen
What type of chemical bond joins sodium (element 11) and chlorine (element 17)?
ionic Sodium gives up its valence shell electron (becoming a cation) to drop back to a stable energy level, and chlorine gains one electron (becoming an anion) to fill its valence shell and become stable.
The genetic information is coded in DNA by the ________.
sequence of the nucleotides
molecule
smallest particle of a compound that still retains its properties
atom
smallest particle of an element that retains its properties
Which of the following is the major positive ion outside cells?
sodium
Which of the following best describes an isotope?
structurally variant atoms, which have the same number of protons and electrons, but differ in the number of neutrons they contain
Amino acids joining together to make a peptide is a good example of a(n) ________ reaction.
synthesis