A&P Ch.2
Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electrical charge of a calcium ion? +2 -2 +1 -1
+2
The symbol 2H means __________.
2 atoms of Hydrogen
If oxygen has an atomic weight of 16, what is the molecular weight of an oxygen molecule? 2 8 16 32
32
From the following choices, select the one that diagrams a typical decomposition reaction. C + D > CD A + B > AB AB > A + B AB + CD > AD + CB
AB > A + B
Nucleotides are the building blocks of DNA and RNA. One nucleotide is also used in the high-energy molecule __________. adenosine triphosphate (ATP) cytosine triphosphate adenosine diphosphate guanosine diphosphate (GDP)
ATP
Which of the following molecules is a high-energy compound containing high-energy bonds between phosphate groups?
ATP
Which of the following nucleic acids determines our inherited characteristics and contains the genetic code for all cells in an organism?
DNA
Nucleic acids are formed from subunits called __________.
Nucleotides
What is the primary function of monosaccharides such as glucose?
They are used as a metabolic fuel to produce energy for the body.
A molecule of water (H2O) is formed by what type of bond? a. polar covalent bonds b. weak bonds c. ionic covalent bonds d. nonpolar covalent bonds
a
Adenosine triphosphate is considered a high-energy compound. But how is that energy transferred to the cellular machinery? a. The covalent bond between phosphates is broken down, releasing energy. b. Decay of ATP allows the release of pent-up energy. c. ATP is generated from anabolic reactions. Therefore, it builds up electrons to transfer. d. ATPase is used to combine phosphate molecules. This in turn provides energy for metabolism.
a
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? a. 8 protons, 8 electrons, and 10 neutrons c. 26 total subatomic particles c. 8 protons, 8 neutrons, and 8 electrons d. The atomic number and the mass number do not provide enough information to determine how many of each subatomic particle is present.
a
As part of his diagnostic testing, baby Sean underwent a sweat chloride test that measures the levels of NaCl in the sweat from the skin on the forearm. How does the bond between NaCl form? a. When Na donates an electron to Cl, the Na atom becomes a cation and the Cl atom an anion. Since (+) and (-) charges attract each other, the Na+ and the Cl-; ions associate together, forming an ionic bond. b. Na atoms have a single electron in their valence, while Cl atoms have seven valence electrons. By sharing a pair of atoms and forming a covalent bond, both Cl and Na satisfy their valence shell requirements. c. The positive Na cation forms a hydrogen bond with the negative Cl anion. d. Cl atoms only need one electron to complete their valence shells, while Na atoms have a single electron in their valence shells. Na and Cl atoms form a covalent bond by sharing a pair of electrons. But since the Cl atom has a greater electronegativity than the Na atom, the electrons are shared unequally; thus, they form a polar covalent bond.
a
Before an enzyme can work, a __________ molecule must bind at the __________ site. a. substrate; active b. product; neutral c. calcium; regulatory d. carboxyl; anionic
a
Chemical reactions that absorb energy are said to be __________. a. endergonic b. exothermic c. thermal d. exergonic
a
In chemical notation, the symbol Mg2+ means __________. a. a magnesium atom that has lost two electrons b. two magnesium cations c. a magnesium atom that has lost two protons d. a magnesium atom that has gained two protons
a
Ionic bonds, such as in sodium chloride, __________. a. are formed by the association of ions with opposite charges b. are bonds created by the gaining of electrons c. are formed by the association of ions with the same charge d. share electrons
a
Juan had his broken arm in a cast for six weeks. When it was removed, he noticed that he had lost a lot of muscle mass. The loss of the muscle protein is considered what type of reaction? a. catabolic b. anabolic c. irreversible d. synthesis
a
On a camping trip, you are sitting by a pond, watching the fire. You observe a particle of ash fall and hit the surface of the water. It sits there for a moment before sinking and dissolving. Why was it able to sit there for a few seconds? a. The surface tension created by the hydrogen bonds between water molecules kept it from entering the water. b. The temperature of the ash was so much hotter than the water that it evaporated the water at that spot. c. The carbon in the ash does not interact with hydrogen bonds. d. The surface tension formed from the hydrogen bonds between water molecules was low. As a result, the ash could not penetrate the water.
a
The letter "P" in the name of the energy molecule ATP stands for __________. a. phosphate b. power c. peptide d. protein
a
The mass number of an atom is defined as the __________. a. number of protons plus the number of neutrons in the nucleus b. total number of all electrons in the electron shells c. number of neutrons in the nucleus d. number of protons plus neutrons plus electrons in an atom
a
Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel? a. 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. b. Water acts as a cofactor for enzymes that dissolve the salt. c. When water is added to the NaCl, NaCl is broken down by adding OH- to one element and H+ to the other. This is known as hydrolysis.
a
What are the three basic components of a single nucleotide of a nucleic acid? a. sugar, phosphate group, and nitrogen base b. pentose, ribose, and deoxyribose c. purines, pyrimidines, and sugar d. guanine, cytosine, and thymine
a
Which of the following is NOT a carbohydrate? a. polypeptide b. glucose c. sucrose d. glycogen
a
Which of the following statement about water's ability to help us maintain homeostasis is incorrect? a. When heated, liquid water is easily converted into water vapor. b. It takes a lot of heat energy to change the temperature of water. c. When water in sweat evaporates, it removes heat from our body. d. Water molecules exhibit hydrogen bonding and are hard to separate from each other.
a
Which of the following statements about water is true? a. Water molecules form hydration spheres around ions. b. Water is composed of nonpolar covalent molecules. c. Water composes the smallest portion of total body weight. d. Water is a poor solvent.
a
Which of the following statements concerning enzymes is FALSE? a. Enzymes are consumed during a reaction. b. Enzymes are proteins. c. Enzymes lower the activation energy of a reaction. d. Enzymes function as biological catalysts.
a
Why is water particularly effective as a solvent? a. Its polarity creates positive and negative regions that interact with many types of molecules. b. Cations and anions are produced by hydration. c. It has a high heat capacity that dissolves molecules. d. Hydrophobic molecules have many polar covalent bonds.
a
Which of the solutions below is the most acidic? a solution with a pH of 12 a solution with a pH of 2 a solution with a pH of 8 a solution with a pH of 5
a solution with a pH of 2
The smallest stable units of matter are called __________. a. atoms b. electrons c. molecules d. protons
a. atoms
Which of the following is a solute that releases hydrogen ions from a solution and lowers the pH of that solution? a salt a buffer an acid a base
acid
A DNA molecule consists of a pair of chains of nucleotides, hydrogen bonded to each other. The hydrogen bonding is very specific. The only two nitrogenous bases that will hydrogen bond in DNA are __________.
adenine and thymine
Proteins differ from carbohydrates because proteins __________.
always contain nitrogen
Which of the following is a solute that releases hydrogen ions from a solution and lowers the pH of that solution? a salt a buffer a base an acid
an acid
A type of reaction in which simple molecules are bonded together to make a larger, more complicated molecule is called a(n) __________ reaction. catabolic decomposition anabolic hydrolysis
anabolic
The smallest stable units of matter are called __________.
atoms
The smallest stable units of matter are called __________. protons electrons atoms molecules
atoms
Baby Sean has cystic fibrosis, which causes thick mucus secretions that can block ducts like the pancreatic duct, leading to insufficient enzymes in the small intestine. Why are these enzymes important? a. There are no consequences because there are other enzymes available to catalyze the decomposition reactions. b. Digestive enzymes catalyze decomposition reactions of complex food molecules into absorbable fragments; without its enzyme, a substrate cannot be degraded. c. Digestive enzymes are protein molecules that are required to transport food molecules across the intestinal walls for efficient absorption of nutrients. d. Digestive enzymes catalyze dehydration synthesis reactions that generate important macromolecules like polysaccharides.
b
From the description of baby Sean's stool, what macromolecules do you suspect are NOT being digested? a. nucleic acids only b. lipids and carbohydrates c. carbohydrates and nucleic acids d. proteins only
b
In plasma, a typical body fluid, protein floating around would be considered to be which of the following? a. a solvent b. a solute, specifically both a colloid and an electrolyte c. a solute, specifically both a colloid and a nonelectrolyte
b
The chemical properties of every element are determined by __________. a. the atomic weight of the atom b. the number and arrangement of electrons in the outer energy level c. the number of protons in the nucleus d. the number of protons and neutrons in the nucleus
b
Which of the following is not produced through chemical bonding? a. the heart b. atoms c. cells d. adipose (fat) tissue
b
Which of these is NOT a property of glucose? a. It is formed from C, H, and O atoms. b. It is a disaccharide. c. It is the body's most important fuel. d. It is a monosaccharide.
b
Which statement about buffers is incorrect? a. Buffers neutralize solutions donating hydrogen ions or accepting hydrogen ions. b. Buffers are composed of a strong acid and a strong base. c. Buffers prevent large changes in pH. d. Buffers help maintain homeostasis.
b
The attraction between cations and anions is important in __________. a. nonpolar covalent bonds b. ionic bonds c. double covalent bonds d. polar covalent bonds
b. ionic bonds
A chemical that can release free hydroxide ions or accept free hydrogen ions is a(n) __________. salt base proton donor acid
base
A __________ is to a nucleic acid as an amino acid is to a polypeptide. a. base b. pyrimidine c. nucleotide d. purine
c
A solution containing more hydrogen ions than hydroxide ions is __________. a. basic b. in equilibrium c. acidic d. neutral
c
Certain types of fats are modified fatty acids that coordinate and direct local cellular activities. These important regulatory chemicals are called __________. a. leukotrienes b. glycolipids c. prostaglandins d. steroids
c
Compared with the other major organic compounds, nucleic acids are unique in that they __________. a. are found only in the nuclei of cells b. control the metabolic activities of a cell c. store and process information at the molecular level d. contain nitrogen
c
Cortisol is a type of lipid hormone. Which type of lipid would cortisol be classified as? a. triglyceride b. phospholipid c. steroid
c
Covalent bonds: a. involve the sharing of 8 pairs of electrons. b. always result in equal distribution of electrons between the atoms. c. involve the sharing of one to three pairs of electrons. d. always result in slight electrical charges at different atoms.
c
Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water? a. Water has a high heat of vaporization. b. Water acts as a cushion. c. Water acts as a reactant. d. Water acts as a lubricant.
c
Formation of hydrogen bonds requires hydrogen atoms and what else? a. ionic bonds b. oxygen c. polar covalent bonds d. water
c
How do ions form ionic bonds? a. Two atoms come together to share their electrons. b. Ions of the same type are drawn together because they are attracted to their own kind. c. Ions of opposite electrical charges are attracted to each other to balance the charges. d. One atom swaps all of its negative electrons for all of the other atom's positive protons.
c
The alpha-helix is an example of the __________ level of protein structure. a. tertiary b. primary c. secondary d. quaternary
c
The ideal medium for the absorption and/or transport of inorganic and organic compounds is __________. a. blood b. oil c. water d. lymph
c
The major difference between inorganic and organic compounds is that inorganic compounds are usually __________. a. large molecules that are soluble in water b. structurally made up of carbon, hydrogen, and oxygen c. not structurally made from carbon and hydrogen d. insoluble in water
c
Water is the primary solvent in our body fluids. Which statement about water and its solvent properties is correct? a. Fats and oils are hydrophilic. b. Chemicals that dissolve in water are hydrophobic. c. The oxygen end of the water molecule is negatively charged and the hydrogen end is positively charged. d. Water is an ion because it is polar.
c
Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest? a. hydrogen, covalent, ionic b. ionic, hydrogen, covalent c. covalent, ionic, hydrogen d. hydrogen, ionic, covalent
c
Which of the following distinguishes hydrogen bonds from covalent bonds? a. Only hydrogen bonds can form within molecules. b. Only ionic bonds can form within molecules. c. Only hydrogen bonds can form between molecules. d. Only covalent bonds can form between molecules.
c
Which of the following is not a result of hydrogen bonds? a. An enzyme has a unique shape that allows it to bond only with specific molecules. b. Some hair is straight, some wavy, and some very curly. c. Two hydrogen atoms join together to form a molecule of hydrogen gas. d. Two strands of DNA are linked together taking a shape similar to a ladder.
c
Which of the following is true of polar covalent bonds? a. The same number of electrons are gained by one atom as are lost by another. b. They are rather weak bonds. c. The electrons are shared unequally. d. Electrons are shared equally.
c
Which of the following statements about enzymes is false? a. they are catalysts. b. They accelerate chemical reactions. c. They raise the activation energy required to start a chemical reaction. d. They are proteins.
c
Which of these compounds is part of every cell in a living organism? a. proteins b. phospholipids water c. All of these compounds are found in every cell in a living organism.
c
Why is water particularly effective as a solvent? a. Cations and anions are produced by hydration. b. It has a high heat capacity that dissolves molecules. c. Its polarity creates positive and negative regions that interact with many types of molecules. d. Hydrophobic molecules have many polar covalent bonds.
c
A carbohydrate molecule is made up of __________. carbon, hydrogen, and nitrogen fatty acids carbon, hydrogen, and oxygen carbon, calcium, and sodium
carbon, hydrogen, and oxygen
A pure chemical substance made of atoms of two of more types of element is most specifically called __________.
compound
A pure chemical substance made up of atoms of two or more types of elements is most specifically called __________.
compound
A molecule that is hydrophobic __________. interacts readily with water easily dissolves in water could be a fat or an oil does not interact readily with most lipids
could be a fat or an oil
What type of chemical bond is formed when two atoms share electrons? Ionic bond Covalent bond Hydrogen bond Isotope bond
covalent
What type of chemical bond is formed when two atoms share electrons?
covalent bond
What type of chemical bond is formed when two atoms share electrons? Hydrogen bond Isotope bond Ionic bond Covalent bond
covalent bond
Cholesterol is an important lipid derivative in our bodies. Which of the following is not a function associated with cholesterol? a. maintain plasma membrane integrity b. serve as a precursor for testosterone c. important for cell growth and division d. coordinate and direct local cellular activities
d
Comparing the structure and functions of DNA and RNA, which of the following statements is most accurate? a. The pentose sugar in DNA nucleotides is ribose. b. RNA contains a pair of nucleotide chains. c. DNA always contains the nitrogenous base uracil. d. DNA copies itself as RNA and this copy is actually used to build specific proteins.
d
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? a. calcium b. sodium c. potassium d. chloride
d
If an atom loses an electron, it becomes a __________. a. positively charged anion b. negatively charged anion c. negatively charged cation d. positively charged cation
d
In a covalent bond, a. An atom loses electrons to another to gain stability. b. An atom gains one or more electrons from another atom to gain stability. c. Adjacent atoms share a single electron. d. Atoms share one or more pairs of electrons.
d
In sickle cell anemia, there is a replacement in the amino acid sequence of hemoglobin of glutamic acid by valine. What is the difference between glutamic acid and valine? a. Valine does not form a correct peptide bond. b. The protein resulting from this substitution binds more oxygen. c. Glutamic acid has a lower pH than valine, so the resulting protein is more acidic. d. The R groups between the amino acids are different.
d
Think about a 10% saline solution (saline refers to salt.). Which of the following is a correct statement? a. It contains 10% solvent and 90% water. b. It contains 10% solvent and 90% solute. c. It contains 10% salt and 90% solution. d. It contains 10% solute and 90% solvent.
d
Water molecules are formed by __________. a. ionic bonds b. nonpolar covalent bonds c. Hydrogen bonds d. polar covalent bonds
d
What is an ion? a. an atom that has lost one or more neutrons b. an atom that loses all of its protons c. an atom that is sharing electrons with another atom d. an atom that has either gained or lost electron(s)
d
Which of the following statements about the pH scale is incorrect? a. A solution with a pH of 2 has 100 times more free hydrogen ions than a solution with a pH of 4. b. A solution with a pH of 7 has an equal number of hydrogen and hydroxide ions. c. The pH scale is a logarithmic scale based on the number 10. d. A pH of 0 means there are no free hydrogen ions in the solution.
d
Which parts of atoms can interact (react) to form chemical bonds? a. protons b. the orbitals c. the nucleus of each atom d. valence electrons
d
Which of the following statements is correct? a. There is always the same number of protons as neutrons b. because of the protons and electrons in their structure, atoms always have some excess charge c. atoms are normally neutral d. an anion is a negatively charged atom or group of atoms
d. an anion is a negatively charged atom or group of atoms
Which of the following is the most specific term for the type of chemical reaction that breaks a molecule into smaller fragments by breaking its chemical bonds?
decomposition reaction
An enzyme can catalyze a reaction by __________. decreasing the activation energy synthesizing carbohydrates breaking down proteins increasing the activation energy
decreasing activation energy
An enzyme can catalyze a reaction by __________.
decreasing the activation energy
When you put table salt into a glass of water, it dissolves. The best term for this breaking of ionic bonds and the separation of these ions is __________. digestion polarity dissociation or ionization solution
dissociation or ionization
The term for dissolved ions in a solution is __________. electrolytes colloids hydrophobic ions solvent
electrolytes
Which of the following functions is not a normal function of proteins in our body?
energy reserve
Organic catalysts made by a living cell to promote a specific reaction are called __________. enzymes nucleic acids metabolites buffers
enzymes
When we consume food and process it in our cells, we extract energy from it. A type of chemical reaction in which the amount of energy released is greater than the activation energy needed to start the reaction is called a(n) __________. synthesis reaction endergonic reaction anabolic reaction exergonic reaction
exergonic reaction
Which type of protein generally forms extended sheets or strands and usually plays structural roles in the cells?
fibrous protein
Which property of water allows us to maintain a constant body temperature? Water is a good solvent. High heat capacity Water participates in chemical reactions. Water is a good lubricant.
high heat capacity
Which type of bond has the most important effects on the properties of water and the shapes of complex molecules? Polar covalent bond Hydrogen bond Covalent bond Ionic bond
hydrogen bond
pH measures the concentration of __________ in a solution.
hydrogen ions
Why does the hemoglobin molecule qualify as a quaternary protein structure?
it has four interacting globular units
The continuous removal and replacement of organic molecules in a cell are part of the process of __________.
metabolic turnover
__________ molecules store and process genetic information. Lipid Ionic Protein Nucleic acid
nucleic acid
Chemicals that must be in our diet in order for the body to function normally are __________.
nutrients
The unequal sharing of electrons in a molecule of water is an example of __________.
polar covalent bond
The subatomic particle that is found in the nucleus of an atom and has a positive charge is __________.
proton
The presence of an appropriate enzyme affects only the __________. products that will be formed from the reaction rate of the reaction rate of the reaction, the direction of the reaction, and the products that will be formed from the reaction direction of the reaction
rate of the reaction
The action of a buffer to maintain pH within normal limits consists primarily of __________. removing or replacing sodium ions adding weak acids removing or replacing hydrogen ions replacing bicarbonate ions
removing or replacing hydrogen ions
What is the term for a chemical that dissociates into anions and cations that are not hydroxide or hydrogen ions when put in water? Buffer Acid Base Salt
salt
If the second energy level of an atom has one electron, how many more electrons does it need in order to be filled to its maximum capacity? One Two Five Seven
seven
The dissolved substances in a solution are called __________.
solutes
Which of the following categories of lipid includes certain types of hormones?
steroids
Consider sweetened ice tea. Which of the following is a solute? sugar ice the beverage itself water
sugar
A + B > AB is an example of a(n) __________ reaction.
synthesis
Atomic number is defined as __________.
the number of protons in the nucleus
When an ionic bond forms, which part(s) of the atoms are directly involved? the outermost electrons both the protons and the electrons the protons the neutrons
the outermost electrons
Two simple sugars joined together form a disaccharide. The reaction involved requires __________.
the removal of water to create a more complex molecule
The lipid in the human body that is a stored energy source found inside cells is in the form of __________.
triglycerides
Which type of lipid provides the energy reserve that is stored in our bodies?
triglycerides or neutral fats