Unit One
What is the pH of a solution with a hydroxide ion concentration [OH-] of 10-13 M?
1
oven cleaner (pH 13) is approximately _________ times more acidic or basic than baking soda (pH 9) 4; basic 4; acidic 100; basic 1,000; basic 10,000; basic
10,000; basic
How many neutrons are there in an ion with 100 electrons, a charge of -1, and a mass number of 200?
101
What is the hydroxide ion concentration in pure water?
10^-7 M
Iodine has an atomic number of 53. The most common isotope of iodine is 127I. Radioactive iodine (131I) is commonly used in medical situations for the diagnosis and treatment of thyroid conditions. Which of the following statements is/are true about these isotopes? 127I has 53 protons. 131I has 53 protons. 127I has 74 neutrons. 131I has 74 neutrons. 127I has 53 electrons. 131I has 78 electrons.
127I has 53 protons. 131I has 53 protons. 127I has 74 neutrons. 127I has 53 electrons.
What would be the pH of a substance that has 10,000x more hydroxide ions (OH-) than a substance with a pH of 9?
13
The atomic number of potassium is 19. How many electrons are in a potassium ion(K+)?
18
Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, in elemental form, a calcium atom must have 20 protons. 40 protons. 20 electrons. 40 electrons. 20 neutrons. 40 neutrons.
20 protons 20 electrons 20 neutrons
if a DNA sample was composed of 30% thymine, what would be the percent of guanine?
20%
How many water molecules would it take to completely hydrolyze a polysaccharide comprised of 25 glucose monomers?
24
How many kilocalories are required to change the temperature 1,000 grams of water 25°C?
25
What is the mass number of an ion with 101 electrons, 151 neutrons, and a -1 charge?
251
What is the mass number of an ion with 109 electrons, 149 neutrons, and a +1 charge?
259
In a hydrocarbon with only single bonds and 12 carbons, how many hydrogens are there?
26
What is the mass number of an ion with 108 electrons, 159 neutrons, and a +1 charge?
268
What is the mass number of an ion with 109 electrons, 159 neutrons, and a +1 charge?
269
antiparallel orientation of DNA
3' end of one strand is bound to the 5' end of the second strand
Suppose you build a fire with a bag of Cheetos that has 300,000 calories. You use the fire to heat a 10 kilogram pot of water. In degrees Celcius, what will be the approximate increase in the temperature of the water?
30
What is the approximate atomic mass, in daltons, of an atom with 16 neutrons, 15 protons, and 15 electrons?
31
14C is a radioactive isotope of carbon (atomic number 6). How many electrons are in the valence shell of 14C?
4
What is the pH of a solution with a hydroxide ion concentration [OH-] of 10-10 M?
4
a DNA sample was composed of 10% thymine, what would be the percentage of guanine?
40%
What is the pH of a solution with a hydroxide ion concentration [OH-] of 10-8 M?
6
How many molecules of glycerol are in 4L of a 0.25M solution of glycerol?
6.02 x 10^23
How many calories are needed to raise the temperature of 1 kilogram of water 7°C?
7,000
Elemental chlorine has an atomic number of 17. How many electrons are in the valence shell of a chloride ion (Cl-)?
8
Suppose it takes 4 calories to change a light bulb. How many kilocalories would it take to change 2,000 light bulbs?
8
What is the pH of a solution with a hydroxide ion concentration [OH-] of 10-6 M?
8
How many water molecules do you need to completely hydrolyze a polymer that is 100 monomers long?
99
purine
Adenine and guanine
Which function group behaves as a base?
Amino
A molecule with the formula CH3CH(NH2)COOH is probably a(n) Amino acid Nucleic acid Hydrocarbon Fatty acid Carbohydrate
Amino acid
isotopes
Atoms of the same element that have different numbers of neutrons
One of the buffers that contributes to pH stability in human blood is carbonic acid, H2CO3, which is formed when CO2, the waste product of cellular respiration, reacts with water in blood. Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus: CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+ Which of the following will occur if the pH of the blood decreases? Carbonic acid will dissociate into a bicarbonate ions and hydrogen ions. Bicarbonate ions will join to hydrogen ions, forming carbonic acid. The forward reaction will be favored. The reverse reaction will be favored. Respiration rate will increase. Respiration rate will decrease. You will immediately die.
Bicarbonate ions will join to hydrogen ions, forming carbonic acid. The reverse reaction will be favored. Respiration rate will increase.
What would be the molecular formula for a polymer made by linking ten of the molecules from the previous question together?
C40H62O31
What is the formula for a typical monosaccharide that has four carbons? C4H10O4 C4H8O4 C4H6O4 C4H4O4 none of these
C4H8O4
Which includes all the others? Glycogen Starch Carbohydrate Monosaccharide Polysaccharide Disaccharide Cellulose
Carbohydrate
One of the buffers that contributes to pH stability in human blood is carbonic acid, H2CO3, which is formed when CO2, the waste product of cellular respiration, reacts with water in blood. Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus: CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+ Which of the following will occur if the pH of the blood increases? Carbonic acid will dissociate into a bicarbonate ions and hydrogen ions. Bicarbonate ions will join to hydrogen ions, forming carbonic acid. The forward reaction will be favored. The reverse reaction will be favored. Respiration rate will increase. Respiration rate will decrease. You will immediately die.
Carbonic acid will dissociate into a bicarbonate ions and hydrogen ions. The forward reaction will be favored. Respiration rate will decrease.
hydrocarbon generic formula
CnH2n+2
What type of bond joins together hydrogen atoms?
Covalent bonds
nucleic acid types
DNA and RNA
central dogma of molecular biology
DNA to mRNA (transcription) to protein (translation)
The loss of the tertiary structure of a protein is specifically referred to as...
Denaturation
An energy level of electrons at a characteristic average distance from the nucleus of an atom is specifically referred to as an...
Electron shell
Which is not a polymer? Glucose DNA Adenine Cellulose Starch
Glucose and adenine
hydronium ion
H3O+
What functional group is a characteristic of alcohol?
Hydroxyl
hydroxide ion
OH-
The tertiary structure of a protein is not directly dependent on Bonds between sulfur atoms Hydrophobic interactions Peptide bonds Ionic bonds Hydrogen bonds
Peptide bonds
During transcription, what type of bonds are formed?
Phosphodiester bonds
Name two large biological molecules that we have discussed in class that contain a phosphate functional group
Phospholipids and nucleic acids
Which of the following statements about the ends of a polynucleotide strand of DNA are correct? The 5' end has a hydroxyl group attached to the number 5 carbon of ribose. The 5' end has a phosphate group attached to the number 5 carbon of deoxyribose. The 3' end has a hydroxyl group attached to the number 3 carbon of ribose. The 3' end has a phosphate group attached to the number 3 carbon of ribose. Both the 5' and 3' ends are identical.
The 5' end has a phosphate group attached to the number 5 carbon of deoxyribose. The 3' end has a hydroxyl group attached to the number 3 carbon of ribose.
If the pH of a solution is decreased from 9 to 8, which of the following has occurred? The concentration of H+ has decreased 10-fold (10x) from what it was at pH 9. The concentration of H+ has increased 10-fold (10x) from what it was at pH 9. The concentration of OH- has decreased 10-fold (10x) from what it was at pH 9. The concentration of OH- has increased 10-fold (10x) from what it was at pH 9. The pH has become more acidic. The pH has become more basic.
The concentration of H+ has increased 10-fold (10x) from what it was at pH 9. The concentration of OH- has decreased 10-fold (10x) from what it was at pH 9. The pH has become more acidic.
The bonding of two amino acid molecules to form a larger molecule requires The addition of a nitrogen atom The addition of a carbonyl group The release of a carbon dioxide molecule The addition of a water molecule The release of a water molecule
The release of a water molecule
Fats consist of which of the following? a pentose sugar a glycerol molecule fatty acid chains a carboxyl group coming off a central carbon atom a nitrogenous base a phosphate group an amino group coming off a central carbon atom a variable side chain coming off a central carbon atom
a glycerol molecule fatty acid chains
solution
a homogeneous mixture of two or more substances
Macromolecules
a large molecule made of subunits called monomers and polymers
When ammonia (NH3) is put into water, the following reaction occurs: NH3 + H2O ↔ NH4+ + OH-. Based on this information, we can conclude that the pH of ammonia is above 7. below 7. exactly 7. -7. There is no way to know from this information.
above 7
pH<7
acidic
nucleic acids
allow organisms to reproduce their complex components from one generation to the next
protein monomer
amino acids (20)
heat of vaporization
amount of heat a liquid must absorb for one gram to be converted from a liquid to a gaseous state
calorie
amount of heat it takes to raise one gram of water by one degree Celsius
kilocalorie (Calorie)
amount of heat it takes to raise one kilogram of water by one degree Celsius
specific heat
amount of heat that must be absorbed or lost for one gram of a substance to change by one degree Celsius
unsaturated fats
at least one double bond between carbon atoms in their fatty acid tails, with one fewer hydrogen atom on each bonded carbon (bent)
pH>7
basic
When vinegar (CH3COOH) is put into water, the following reaction occurs: CH3COOH + H2O ↔ CH3COO— + H+. Based on this information, we can conclude that the pH of vinegar is above 7 below 7 exactly 7 - 7 There is no way to know based on this information.
below 7
ionic bond
bond between two oppositely charged ions giving electrons
how does water moderate air temperature?
by absorbing heat from warmer air and releasing stored heat to cooler air
An atom that loses an electron becomes a(n) anion. cation. different isotope. different element. isomer.
cation
compounds
combination of two or more elements in a fixed ratio
organic compounds
compounds with carbon
what is the difference between covalent bonds and ionic bonds? covalent bonds involve the sharing of protons between atoms and ionic bonds involve the sharing of electrons between atoms covalent bonds involve the sharing of neutrons between atoms and ionic bonds involve the sharing of electrons between atoms covalent bonds involve the sharing of electrons between atoms and ionic bonds involve the electrical attraction between atoms
covalent bonds involve the sharing of electrons between atoms and ionic bonds involve the electrical attraction between atoms
pyrimidines
cytosine, thymine (DNA), uracil (RNA)
base
decreases H+ concentration
what is the chemical mechanism by which cells make polymers from monomers? phosphodiester linkages hydrolysis dehydration reactions ionic bonding of monomers the formation of disulfide bridges between monomers
dehydration reactions
electron orbital
describes the space where an electron spends most of its time
structural isomers
differ in the covalent arrangement of their atoms
An atom that loses a proton becomes a(n) anion. cation. different element. different isotope. isomer.
different element
An atom that gains a neutron becomes a(n) anion cation different element different isotope isomer
different isotope
solute
dissolved substance
solvent
dissolving agent
lipids
don't have true monomers and polymers classified by their hydrophobic behavior
Buffers are substances that help resist shifts in pH by releasing H+ in acidic solutions. donating H+ to a solution when they have been depleted. releasing OH- in basic solutions. accepting H+ when the are in excess.
donating H+ to a solution when they have been depleted. accepting H+ when the are in excess.
nitrogen is much moire electronegative than hydrogen. Which of the following statements is correct about the atoms in ammonia? each hydrogen atom has a partial positive charge the nitrogen atom has a strong positive charge the nitrogen atom has a slight negative charge the nitrogen atom atom has a partial positive charge there are covalent bonds between the hydrogen atoms
each hydrogen atom has a partial positive charge
trace elements
elements required by organisms in small amounts
phospholipids
essential component of cell membranes with 1 glycerol attached to 2 fatty acids
In order to hydrolyze a fat molecule, these bonds must be broken
ester linkages
hydro carbon examples
ethane propane butan butene benzene methyl propane cyclohexane
pH scale
expresses the concentration of H+ in a solution negative log of its H+ concentration
important lipids
fats, phospholipids, steroids
A molecule with the formula C18H36O2 is probably a carbohydrate fatty acid protein nucleic acid hydrocarbon
fatty acid
During the synthesis of glycogen, these bonds are formed
glycosidic linkages
protein secondary structure
has regions of repetitive coiling or folding from hydrogen bonding between amino acid backbones
geometric isomers
have the same covalent arrangements but have different spatial arrangements because of a double bond (cis/trans)
In order to separate two strands of a DNA double helix, these bonds must be broken.
hydrogen bonds
what elements make up 96% of living matter?
hydrogen, oxygen, nitrogen, carbon
function groups
hydroxyl carbonyl carboxyl amino sulfhydryl phosphate methyl
acid
increases H+ concentration
enantiomers
isomers that are mirror images of each other
steroids
lipids characterized by having a carbon skeleton with four fused rings
fats (triacylglycerols)
made of 1 glycerol and 3 fatty acid molecules joined by ester linkages
matter
made up of elements
surface tension
measure of how hard it is to stretch or break a liquid's surface
dehydration reaction
monomers becoming covalently bonded
cohesion
multiple water molecules are held together by hydrogen bonds
pH=7
neutral
nucleoside
nitrogenous base + pentose sugar
what are nucleotides made of
nitrogenous base, pentose sugar, phosphate group
saturated fats
no double bonds between carbon atoms in their fatty acid tails and are "saturated" with hydrogen
How many water molecules are required to link together 40 glucose molecules? 41 40 39 38 none; water molecules will be released.
none; water molecules will be released.
nucleic acid monomer
nucleotide
Which of the following molecules contain a phosphate group? nucleotides amino acids carbohydrates phospholipids steroids
nucleotides phospholipids
polynucleotides
nucleotides linked together by phophodiester linkages
We can be sure that a mole of sucrose (C12H22O11) and a mole of the amino acid valine (C5H11NO2) are equal in their mass in daltons. mass in grams. number of molecules. number of atoms. volume.
number of molecules
relationship between [OH-] and [H+]
one goes up, the other goes down
thiols
organic compounds containing -SH
hydrocarbons
organic molecules made of only carbon and hydrogen
protein tertiary structure
overall 3D shape of a protein
inside of DNA helix
paired nitrogenous bases held together by hydrogen bonds ( AT: 2, GC: 3)
type of bond holding amino acids together
peptide bond
During the process known as translation, these bonds are formed
peptide bonds
protein polymers
peptides and polypeptides
In order to break a strand of RNA into its monomers, these bonds must be broken
phosphodiester bonds
in a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by hydrogen bonds non polar covalent bonds polar covalent bonds ionic bonds van der Waals interactions
polar covalent bonds
hydrolysis
polymers broken down to monomers
polysaccharides
polymers with hundreds to thousands of monosaccharides joined by glycosidic linkages
Protein structure
primary, secondary, tertiary, quaternary
chaperonins
proteins helping other proteins fold correctly
subatomic particles
protons, neutrons, electrons
types of nitrogenous bases
purines and pyrimidines
types of pentose sugars
ribose (RNA) and deoxyribose (DNA)
protein primary structure
sequence of amino acids
monosaccharides
simple sugars with a CH2O general formula
atoms
smallest unit of matter still containing the properties of an element
protein quaternary structure
some proteins require two or more polypeptides to aggregated to have a functional molecule
glycogen
storage polysaccharide in animals
starch
storage polysaccharide in plants
cellulose
structural polysaccharide in plants
chitin
structural polysaccharide in the exoskeleton of arthropods and the cell walls of fungi
buffer
substance minimizing the changes in concentration of H+ and OH- in a solution
elements
substances that can't be broken down by chemical reactions
carbohydrates
sugars and polymers of sugars
mass number
sum of protons and neutrons in an atom's nucleus
which statement is true of all atoms that are cations? the atom has more electrons than protons the atom has more protons than electrons the atom has fewer protons than a neutral atom of the same element the atom has more neutrons than protons none of the above are true
the atom has more protons than electrons
pure, freshly distilled water has a pH of 7. This means that there are no H+ ions in the water there are no OH- ions in the water the concentration of H+ ions and OH- ions in the water are equal the concentration of H+ ions in the water is 7 times the concentration of OH- ions in the water the concentration of OH- ions in the water is 7 times the concentration of H+ ions in the water
the concentration of H+ ions and OH- ions in the water are equal
chemical bond
the force that holds two atoms together
atomic number
the number of protons in the nucleus of an atom
disaccharides
two monosaccharides joined together by a glycosidic linkage
molecule
two or more atoms held together by covalent bonds
hydrogenerated oils
unsaturated fats that have been synthetically converted to saturated fats
trans fats
unsaturated fats with trans double bonds
hydrogen bond
weak bond between a hydrogen atom and an electronegative atom on a different molecule
van der waals interactions
weak forces resulting from electrons becoming unevenly distributed
denaturation
when a protein unravels losing its original shape, becoming biologically inactive
covalent bond
when two atoms share electrons
chemical equilibrium
where the forward reaction rate and the reverse reaction rate are equal
