Ch. 2 Review
A chemical reaction in which bonds are broken is usually associated with ________. A) the release of energy B) the consumption of energy C) a synthesis D) forming a larger molecule Answer: A
A
A solution that has a pH of 2 could best be described as being ________. A) acidic B) basic C) neutral D) slightly acidic
A
Amino acids joining together to make a peptide is a good example of a(n) ________ reaction. A) synthesis B) decomposition C) exchange D) reversible
A
Choose the answer that best describes HCO3-. A) a bicarbonate ion B) common in the liver C) a weak acid D) a proton donor
A
Salts are always ________. A) ionic compounds B) single covalent compounds C) double covalent compounds D) hydrogen bonded
A
Select the correct statement about isotopes. A) Isotopes of the same element have the same atomic number but differ in their atomic masses. B) All the isotopes of an element have the same number of neutrons. C) All the isotopes of an element are radioactive. D) Isotopes occur only in the heavier elements.
A
Select the statement about mixtures that is correct. A) A solution contains solvent in large amounts and solute in smaller quantities. B) Solutions contain particles that settle out in time. C) Suspensions can change reversibly from liquid to solid. D) Suspensions are homogeneous mixtures of two or more components.
A
Select which reactions will usually be irreversible regarding chemical equilibrium in living systems. A) glucose to CO2 and H2O B) ADP + Pi to make ATP C) H2O + CO2 to make H2CO3 D) glucose molecules joined to make glycogen
A
What does CH4 mean? A) There is one carbon and four hydrogen atoms. B) There are four carbon and four hydrogen atoms. C) This is an inorganic molecule. D) This was involved in a redox reaction.
A
What happens in redox reactions? A) both decomposition and electron exchange occur B) the electron acceptor is oxidized C) the electron donor is reduced D) the reaction is always easily reversible
A
What is a chain of 25 amino acids called? A) polypeptide B) nucleotide C) protein D) starch
A
Which of the following describes coenzymes? A) organic molecules derived from vitamins B) two enzymes that perform the same function C) metal ions D) enzymes that work together
A
Which statement about enzymes is false? A) Enzymes raise the activation energy needed to start a reaction. B) Enzymes are composed mostly of protein. C) Enzymes are organic catalysts. D) Enzymes may be damaged by high temperature.
A
What does the polar end of a phospholipid contain
A phosphorus-containing group
The ________ molecule directly provides energy for cellular work
ATP
Are all chemical reactions reversible? If not, why aren't they all reversible?
All chemical reactions are theoretically reversible, but only if the products are not consumed.
An amino acid may act as a proton acceptor or donor. Explain.
Amino acids have two componentsa base group (proton acceptor) and an organic acid part (a proton donor).
Smallest particle of an element that retains its properties.
Atom
Hydrogen bonds are more like a type of weak ________ than true bonds
Attraction
An example of a coenzyme is ________. A) copper B) riboflavin (vitamin B2) C) iron D) zinc
B
Choose the answer that best describes fibrous proteins. A) rarely exhibit secondary structure B) are very stable and insoluble in water C) are usually called enzymes D) are cellular catalysts
B
In a DNA molecule, the phosphate serves ________. A) as a code B) to hold the molecular backbone together C) to bind the sugars to their bases D) as nucleotides
B
Select the most correct statement regarding nucleic acids. A) Three forms exist: DNA, RNA, and tDNA. B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases. C) RNA is a long, single-stranded molecule made up of the bases A, T, G, and C. D) TDNA is considered a molecular slave of DNA.
B
Sucrose is a ________. A) monosaccharide B) disaccharide C) polysaccharide D) triglyceride
B
The genetic information is coded in DNA by the ________. A) regular alteration of sugar and phosphate molecules B) sequence of the nucleotides C) three-dimensional structure of the double helix D) arrangement of the histones
B
What does the formula C6H12O6 mean? A) There are 6 calcium, 12 hydrogen, and 6 oxygen atoms. B) There are 12 hydrogen, 6 carbon, and 6 oxygen atoms. C) The molecular weight is 24. D) The substance is a colloid.
B
What is a dipole? A) a type of bond B) a polar molecule C) a type of reaction D) an organic molecule
B
What level of protein synthesis is represented by the coiling of the protein chain backbone into an alpha helix? A) primary structure B) secondary structure C) tertiary structure D) quaternary structure
B
Which bonds often bind different parts of a molecule into a specific three-dimensional shape? A) Carbon B) Hydrogen C) Oxygen D) Amino acid
B
Which of the following constitutes a long chain of simple sugars? A) monosaccharide B) polysaccharide C) protein D) nucleic acid
B
Which of the following is true regarding the concentration of solutions? A) Percent solutions are parts per 1000 parts. B) Molarity is one mole of solute per 1000 ml of solution. C) To calculate molarity, one must know the atomic number of the solute. D) To calculate molarity, one must know the atomic weight of the solvent.
B
Which property of water is demonstrated when we sweat? A) high heat capacity B) high heat of vaporization C) polar solvent properties D) reactivity E) cushioning
B
Which protein types are vitally important to cell function in all types of stressful circumstances? A) structural proteins B) molecular chaperones C) catalytic proteins D) regulatory proteins
B
________ have a bitter taste, feel slippery, and are proton acceptors.
Base
Weak acids and bases make good
Buffers
An atom with a valence of 3 may have a total of ________ electrons. A) 3 B) 8 C) 13 D) 17
C
Atom X has 17 protons. How many electrons are in its valence shell? A) 3 B) 5 C) 7 D) 10
C
Carbohydrates and proteins are built up from their basic building blocks by the ________. A) addition of a water molecule between each two units B) addition of a carbon atom between each two units C) removal of a water molecule between each two units D) removal of a nitrogen atom between each two units
C
Carbohydrates are stored in the liver and muscles in the form of ________. A) glucose B) triglycerides C) glycogen D) cholesterol
C
In liquid XYZ, you notice that light is scattered as it passes through. There is no precipitant in the bottom of the beaker, though it has been sitting for several days. What type of liquid is this? A) solution B) suspension C) colloid D) mixture
C
The chemical symbol OO means ________. A) zero equals zero B) both atoms are bonded and have zero electrons in the outer orbit C) the atoms are double bonded D) this is an ionic bond with two shared electrons
C
The four elements that make up about 96% of body matter are ________. A) carbon, oxygen, phosphorus, calcium B) nitrogen, hydrogen, calcium, sodium C) carbon, oxygen, hydrogen, nitrogen D) sodium, potassium, hydrogen, oxygen
C
The single most abundant protein in the body is ________. A) DNA B) hemoglobin C) collagen D) glucose
C
What is the ratio of fatty acids to glycerol in neutral fats? A) 1:1 B) 2:1 C) 3:1 D) 4:1
C
Which of the following is not an electrolyte? A) HCl B) Ca2CO3 C) H2O D) NaOH
C
Which of the following is not true of proteins? A) They may be denatured or coagulated by heat or acidity. B) Some types are called enzymes. C) They appear to be the molecular carriers of the coded hereditary information. D) Their function depends on the three-dimensional shape.
C
Which of the following statements is false? A) Chemical reactions proceed more quickly at higher temperatures. B) Chemical reactions progress at a faster rate when the reacting particles are present in higher numbers. C) Larger particles move faster than smaller ones and thus collide more frequently and more forcefully. D) Catalysts increase the rate of chemical reactions.
C
Electrically charged particle due to loss of an electron.
Cation
When the bonds of ATP are broken, energy is released to do cellular work.
Chemical Energy
Explain why chemical reactions in the body are often irreversible.
Chemical reactions that release energy cannot be reversed unless energy is put back into the system. Also, the body may use the chemicals solely for its energy, such as glucose, or some reactions produce molecules in excessive quantities (like CO2 and NH4) that the body needs to discard.
Heterogeneous, will not settle
Colloid
Dry Ice
Compound
Water
Compound
Molecules such as methane that are made of atoms that share electrons have ________ bonds.
Covalent
In a DNA molecule, guanine would connect to ________.
Cytosine
Heat shock proteins (hsp) are a type of protein called ________. A) coenzymes B) cofactors C) eicosanoids D) chaperonins
D
If atom X has an atomic number of 74 it would have which of the following? A) 37 protons and 37 neutrons B) 37 electrons C) 74 protons D) 37 protons and 37 electrons
D
In general, the lipids that we refer to as oils have ________. A) a high water content B) long fatty acid chains C) a high degree of saturated bonds D) a high degree of unsaturated bonds
D
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? A) 2, 8, 8 B) 2, 8 C) 2 D) 2, 8, 1
D
Two good examples of a colloid would be Jell-O® and ________. A) blood B) toenails C) urine D) cytosol
D
Which of the following does not describe the ATP molecule? A) chemical work B) mechanical work C) transport D) pigments
D
Which of the following is a neutralization reaction? A) HCl → H+ + Cl- B) NaOH → Na+ + OH- C) NH3 + H+ → NH4+2 D) HCl + NaOH → NaCl + H2O
D
Which of the following is an example of a suspension? A) cytoplasm B) salt water C) rubbing alcohol D) blood
D
Which of the following is not considered a factor in influencing a reaction? A) temperature B) concentration C) particle size D) time
D
Which of the following is the major positive ion outside cells? A) nitrogen B) hydrogen C) potassium D) sodium
D
Which of the following would be regarded as an organic molecule? A) H2O B) NaCl C) NaOH D) CH4
D
________ is fat soluble, produced in the skin on exposure to UV radiation, and necessary for normal bone growth and function. A) Vitamin K B) Cortisol C) Vitamin A D) Vitamin D
D
AB → A + B is an example of a(n) ________ reaction.
Decomposition
Which of the following is not a role of molecular chaperonins? A) prevent accidental, premature, or incorrect folding of polypeptide chains B) aid the desired folding and association process of polypeptides C) help to translocate proteins and certain metal ions across cell membranes D) promote the breakdown of damaged or denatured proteins E) act as a biological catalyst
E
Represented by the flow of charged particles along a conductor, or the flow of ions across a membrane.
Electrical Energy
Carbon
Element
Can be measured only by its effects on matter.
Energy
A dipeptide can be broken into two amino acids by dehydration synthesis.t/f
False
About 60% to 80% of the volume of most living cells consists of organic compounds. T/F
False
Chemical properties are determined primarily by neutrons. T/F
False
Covalent bonds are generally less stable than ionic bonds.t/f
False
Hydrogen bonds are comparatively strong bonds.t/f
False
Isotopes differ from each other only in the number of electrons contained. T/F
False
Lipids are a poor source of stored energy. T/F
False
Protons and electrons exist in every atom nucleus except hydrogen. Is this statement true or false and why?
FalseHydrogen has one proton and one electron. It is the neutron that hydrogen does not have.
Starch is the stored carbohydrate in plants, while ________ is the stored carbohydrate in animals.
Glycogen
When a set of electrodes connected to a lightbulb is placed in a solution of dextrose and a current is applied, the lightbulb does not light up. When the same unit is placed in HCl, it does. Why?
HCl ionizes to form current-conducting electrolytes. Dextrose does not ionize, and therefore does not conduct current.
Which metals have a toxic effect on the body
Heavy
What properties does water have that make it a very versatile fluid?
High heat capacity, high heat of vaporization, polarity and solvent properties, reactivity, and cushioning.
A type of bond important in tying different parts of the same molecule together into a three-dimensional structure.
Hydrogen Bond
What type of chemical bond can form between an element with 11 protons and an element with 17 protons?
Ionic
A bond in which electrons are completely lost or gained by the atoms involved.
Ionic Bond
All chemical reactions are theoretically reversible. Comment on this statement.
It is possible to reverse any reaction if the products are still present. Those that are only slightly exergonic are easily reversible. Some would require an enormous amount of energy to reverse. In the simple reaction Na + Cl → NaCl the amount of energy it takes to reverse table salt to chlorine gas and sodium metal is enormous. The reversing of the covalently bonded sugar molecule once it is reduced to ATP molecules is even harder or next to impossible
What advantages does ATP have in being the energy currency molecule?
Its energy is easy to capture and store; it releases just the right amount of energy for the cell's needs so it is protected from excessive energy release. A universal energy currency is efficient because a single system can be used by all the cells in the body.
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
Anything that occupies space and has mass.
Matter
Legs moving the pedals of a bicycle
Mechanical Energy
Blood
Mixture
A chemical bond never occurs in a mixture. Discuss this.
Mixtures come in three forms solutions, colloids, and suspensions. Components of these mixtures always retain their original makeup and can be separated into their individual components; therefore no chemical bonding has taken place.
Smallest particle of a compound that still retains its properties.
Molecule
Neutral subatomic particle
Neutron
A bond in which electrons are shared equally.
Nonpolar covalent Bond
An atom with three electrons would have a valence of ________.
One
How many phosphates would AMP have attached to it?
One
Which of the following elements is necessary for proper conduction of nervous impulses? A) Fe B) I C) P D) Na
P
How can phospholipids form a film when mixed in water?
Phospholipids have both polar and nonpolar ends. The polar end interacts with water, leaving the nonpolar end oriented in the opposite direction.
What is the major difference between polar and nonpolar covalent bonds?
Polar bonds have an unequal sharing of electrons resulting in a slight negative charge at one end of the molecule and a slight positive charge at the other end. Nonpolar bonds have an equal sharing of electrons, resulting in a balanced charge among the atoms.
A bond in which electrons are shared unequally.
Polar covalent bond
The atomic number is equal to the number of ________.
Protons (and electrons)
Energy that travels in waves. Part of the electromagnetic spectrum.
Radiant Energy
Homogeneous, will not settle
Solution
Will not scatter light
Solution
Heterogeneous, will settlle
Suspension
Describe the factors that affect chemical reaction rates.
Temperature increases kinetic energy and therefore the force of molecular collisions. Particle size: smaller particles move faster at the same temperature and therefore collide more frequently; also, smaller particles have more surface area given the same concentration of reactants. Concentration: the higher the concentration, the greater the chance of particles colliding. Catalysts increase the rate of the reaction at a given temperature. Enzymes are biological catalysts.
In the compound H2CO3, what do the numbers 2 and 3 represent?
The 2 indicates that there are two hydrogen atoms in the compound and the 3 indicates that there are three oxygen atoms in the compound.
Facts about enzymes
They are proteins. 2. They have specific binding sites for specific substrates. 3. They lower the activation barrier for a specific reaction. 4. The names end in "ase." 5. They can be denatured. 6. They can be used again and again.
A molecule consisting of one carbon atom and two oxygen atoms is correctly written as CO2. T/F
True
All organic compounds contain carbon.t/f
True
Alpha particles, although relatively weak energy particles, are second only to smoking as a cause of lung cancer.t/f
True
Buffers resist abrupt and large changes in the pH of the body by releasing or binding ions? t/f
True
Current information theorizes that omega-3 fatty acids decrease the risk of heart disease. T/F
True
Emulsions and colloids are the same thing. T/F
True
Glucose is an example of a monosaccharide.T/F
True
Mixtures are combinations of elements or compounds that are physically blended together but are not bound by chemical bonds.T/F
True
No chemical bonding occurs between the components of a mixture.t/f
True
The atomic weight is only an average of relative weights of an atom and its isotopes, and it may vary from the weight of a specific isotope. T/F
True
The fact that no chemical bonding occurs between the components of a mixture is the chief difference between mixtures and compounds.t/f
True
The lower the pH, the higher the hydrogen ion concentration. t/f
True
The pH of body fluids must remain fairly constant for the body to maintain homeostasis.t/f
True
Is a function of, and varies with, gravity
Weight
Choose the statement that is false or incorrect. A) In chemical reactions, breaking old bonds requires energy and forming new bonds releases energy. B) Exergonic reactions release more energy than they absorb. C) Endergonic reactions absorb more energy than they release. D) A key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body
a key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body
A holoenzyme is composed of an apoenzyme and a(n)
cofactor
What happens when globular proteins are denatured?
the active sites are destroyed
