Bio H semester 1 final questions from test + quizzes

JSerra address

26351 Junipero Serra Rd San Juan Capistrano, CA 92675

A beryllium atom has 4 protons, 5 neutrons, and 4 electrons. What is the mass number of this atom?
a) 4
b) 5
c) 8
d) 9
e) 13

d) 9

the three basic components of an atom are
a) protons, neutrons, and ions
b) protons, neutrons, and electrons
c) protons, neutrinos, and ions
d) protium, deuterium, and tritium

b) protons, neutrons, electrons

an element is determined by the number of
a) atoms
b) electrons
c) neutrons
d) protons

d) protons

the nucleus of an atom consists of
a) electrons
b) neutrons
c) protons and neutrons
d) protons, neutrons, and electrons

c) protons and neutrons

A single proton has what charge
a) no charge
b) positive charge
c) negative charge
d) either a positive or negative charge

b) positive

Which two particles would be attracted to each other?
a) electrons and neutrons
b) electrons and protons
c) protons and neutrons
d) all particles are attracted to each other

b) electrons and protons

the atomic number of an atom is
a) the number of electrons plus the number of protons
b) the number of neutrons
c) the number of protons
d) the number of protons plus the number of neutrons

c) the number of protons

changing the number of neutrons of an atom creates an
a) isotope
b) element
c) ion
d) charge

a) isotope

when an element transfers electrons, the atom becomes an
a) isotope
b) ion
c) element
d) atomic mass

b) ion

when two molecules are attracted to one another, it creates a
a) isotope
b) ionic bond
c) covalent bond
d) hydrogen bond

d) hydrogen bond

what type of bond is formed when one atom shares its orbital and electrons equally
a) polar covalent bond
b) hydrogen bond
c) ionic bond
d) non-polar covalent bond

d) non-polar covalent bond

Which four of the 25 essential elements make up approximately 96% of living matter
a) carbon, oxygen, sulfur, calcium
b) carbon, hydrogen, nitrogen, oxygen
c) oxygen, hydrogen, calcium, sodium
d) carbon, sodium, chlorine, nitrogen
e) carbon, sulfur, phosphorus, hydrogen

b) carbon, hydrogen, nitrogen, oxygen

which of the following indicates the number of protons in an atom's nucleus
a) mass weight
b) mass number
c) atomic mass
d) atomic number
e) atomic weight

d) atomic number

the mass number of an element can be easily approximated by adding together the number of ______ in an atom of that element
a) energy levels
b) protons and neutrons
c) protons and electrons
d) neutrons and electrons
e) isotopes

b) protons and neutrons

what is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
a) 46
b) 16
c) 15
d) 30
e) 31

e) 31

calcium has an atomic number of 20 and an atomic mass of 40. therefore, a calcium atom must have
a) 40 electrons
b) 20 protons
c) 40 neutrons
d) a and b only
e) a, b, and, c

b) 20 protons

Different atomic forms of an element contain the same number of protons but a different number of neutrons. What are these different atomic forms called?
a) ions
b) neutronic atoms
c) isotopes
d) isomers
e) radioactive atoms

c) isotopes

how do isotopes of the same element differ from each other?
a) number of electrons
b) number of neutrons
c) amount of radioactivity
d) number of protons
e) valence electron distribution

number of neutrons

one difference between carbon 12 (12/6 c) and carbon-14 (14/6 C) is that carbon 14 has
a) two more electrons than carbon-12
b) two more protons than carbon-12
c) two more neutrons than carbon-12
d) b and c only
e) a and c only

c) two more neutrons than carbon 12

the atomic number of carbon is 6. carbon 14 is heavier than carbon 12 because the atomic nucleus of carbon 14 contains _____ neutrons
a) 7
b) 8
c) 6
d) 12
e) 14

b) 8

atoms whose outer electron shells contain eight electrons tend to
a) be isotopes and very radioactive
b) be unstable and chemically very reactive
c) form covalent bonds in aqueous solutions
d) form ionic bonds in aqueous solutions
e) be stable and chemically nonreactive, or inert

e) be stable and chemically nonreactive, or inert

when two atoms share their electrons equally, they will interact to form
a) equal numbers of isotopes
b) ionic bonds
c) ions
d) polar covalent bonds
e) nonpolar covalent bonds

e) nonpolar covalent bonds

What results from an unequal sharing of electrons between atoms?
a) a polar covalent bond
b) a hydrogen bond
c) a nonpolar covalent bond
d) a hydrophobic interaction
e) an ionic bond

a) polar covalent bond

which of the following molecules contains the strongest polar covalent bond?
a) CH4
b) H2
c) H20
d) CO2
e) O2

c) H2O

what is the difference between covalent bonds and ionic bonds?

a) covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of neutrons between atoms
b) covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of electrons between atoms
c) covalent bonds involve the sharing of neutrons between atoms, and ionic bonds involve the sharing of electrons between atoms
d) covalent bonds involve the transfer of electrons between atoms, and ionic bonds involve the sharing of neutrons between atoms
e) covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms

e) covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms

which of the following results from a transfer of electron(s) between atoms?
a) nonpolar covalent bond
b) hydrophobic interaction
c) ionic bond
d) hydrogen bond
e) polar covalent bond

c) ionic bond

which of the following explains most specifically the attraction of water molecules to one another
a) ionic bond
b) hydrophobic interaction
c) polar covalent bond
d) hydrogen bond
e) nonpolar covalent bond

d) hydrogen bond

in a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
a) ionic bonds
b) van der Waals interactions
c) hydrogen bonds
d) polar covalent bonds
e) nonpolar covalent bonds

d) polar covalent bonds

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
a) a hydrogen bond
b) an ionic bond
c) a hydrophilic bond
d) a hydrophobic bond
e) a covalent bond

a) a hydrogen bond

which of the following effects is produced by the high surface tension of water?
a) a water strider can walk across the surface of a small pond
b) water can act as a solvent
c) lakes don't freeze solid in winter, despite low temperatures
d) the pH of water remains exactly neutral
e) organisms resist temperature changes, although they give off heat due to chemical reactions

a) a water strider can walk across the surface of a small pond

Hydrophobic substances such as vegetable oil are
a) nonpolar substances that repel water molecules
b) charged molecules that hydrogen-bond with water molecules
c) nonpolar substances that have an attraction for water molecules
d) polar substances that repel water molecules
e) polar substances that have an affinity for water

c) nonpolar substances that repel water molecules

which of the following solutions has the greatest concentration of hydrogen ions?
a) gastric juice at pH 2
b) tomato juice at pH 4
c) vinegar at pH 3
d) household bleach at pH 12
e) black coffee at pH 5

a) gastric juice at ph 2

which of the following solutions has the greatest concentration of hydroxyl ions (OH-)?
a) urine at pH 6
b) vinegar at pH 3
c) seawater at pH 8
d) tomato juice at pH 4
e) lemon juice at pH 2

c) seawater at pH 8

Which of the following statements is true about buffer solutions?
a) they maintain a constant pH when acids are added to them but non when bases are added to them
b) they maintain a constant pH of exactly 7 in all living cells and biological fluids
c) they maintain a constant pH when bases are added to them but not when acids are added to them
d) they maintain a relatively constant pH when either acids or bases are added to them
e) they are found only in living systems and biological fluids

d) they maintain a relatively constant ph when either acids or bases are added to them

Pure, freshly-distilled water has a pH of 7. This means that
a) the concentration of h+ ions in the water is 7 times the concentration of OH- ions in the water
b) there are no h+ ions in the water
c) the concentration of OH- in the water is 7 times the concentration of H+ ions in the water
d) there are no OH- ions in the water
e) the concentration of H= ions in the water equals the concentration of OH- ions in the water

e) the concentration of h+ ions in the water equals the concentration of oh- ions in the water

hydroxyl

-OH

carbonyl

C = O

carboxyl

-COOH

amino

-NH2

sulfhydryl

-SH

phosophate

-PO4

methol

CH3

methane

CH4

Monosaccharide+monosaccharide--->__________+water
a) polypeptide
b) fat
c) polysaccharide
d) disaccharide
e) nucleic acid

disaccharide

How do glucose and fructose differ?
a) fructose has more hydrogen
b) they are structurally identical in every way
c) they have the same formula but different structures
d) glucose has more hydrogen
e) glucose has more double bonds

c) they have the same formula but different structures

which of the following is an example of a polysaccharide?
a) starch
b) sucrose
c) maltose
d) glucose
e) fructose

a) starch

a glycerol with three fatty acids attached is referred to as a
a) steroid
b) nucleic acid
c) prostaglandin
d) fat
e) protein

d) fat

what name is given to the reaction glycerol +fatty acid -> monoglyceride +water
a) denaturation
b) catabolism
c) dehydration reaction
d) hydrogenation
e) hydrolysis

c) dehydration reaction

By definition, what type of fatty acid has double bonds?
a) triglyceride
b) steroid
c) unsaturated
d) monoglyceride
e) saturated

c) unsaturated

Proteins are polymers constructed from __________ monomers.
a) hydrocarbon
b) 5-carbon ring
c) nucleotide
d) peptide
e) amino acid

e) amino acid

amino acids consist of
a) a central hydrogen, a nitrogen atom, a hydroxyl group, and a carbonyl group
b) a central nitrogen, a carbon atom, an amino group, and a carbonyl group
c) a central carbon, a hydrogen atom, a hydroxyl group, and a carbonyl group
d) a central hydrogen, a nitrogen atom, an amino group, and a carboxyl group
e) a central carbon, a hydrogen atom, an amino group, and a carboxyl group

e) a central carbon, a hydrogen atom, an amino group, and a carboxyl group

what is the name given to the reaction that breaks peptide bonds?
a) hydrogenation
b) dehydration reaction
c) anabolism
d) hydrolysis
e) denaturation

d) hydrolysis

the linear sequence of monomers in a polypeptide chain is referred to as its ________ structure
a) quaternary
b) pentamerous
c) secondary
d) primary
e) tertiary

d) primary

a protein's function is dependent on its
a) pH
b) temperature
c) shape
d) weight
e) size

c) shape

Destruction of a protein's shape is called __________.
a) hydrolysis
b) hydrogenation
c) dehydration reaction
d) denaturation
e) anabolism

d) denaturation

How does RNA differ from DNA?

a) rna contains uracil; dna contains thymine
b) rna contains one less -OH than does DNA
c) rna is double-stranded; dna is single stranded
d) rna is a polymer of amino acids; dna is a polymer of nucleotides
e) in RNA G pairs with T; in DNA G pairs with C

A) RNA contains uracil; DNA contains thymine.

Fatty acids are _________
a) composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio
2) components of DNA
c) nonpolar
d) composed of carbon, hydrogen, glycerol, and a phosphate group
e) composed of four linked rings

c) nonpolar

which of these is an amino group?
a) -COOH
b) -SH
c) -NH2
d) -OH
e) -C=O

c) -NH2

which of the following is not a polymer?
a) glucose
b) dna
c) chitin
d) starch
e) cellulose

a) glucose

what is the chemical mechanism by which cells make polymers from monomers?
a) phosphodiester linkages
b) dehydration reactions
c) ionic bonding of monomers
d) hydrolysis
e) the formation of disulfide bridges between monomers

b) dehydration reactions

how many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
a) 12
b) 9
c) 8
d) 10
e) 11

d) 10

what would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
a) C6 H10 O5
b) C18 H 30 O15
c) C18 H 36 O18
d) C3 H6 O3
e) C18 H10 O15

b)C18 H30 O15

Which of the following statements is false for the class of biological molecules known as lipids?
a) they contain more energy than proteins and carbohydrates
b) they are not true polymers
c) they are soluble in water
d) they are an important constituent of cell membranes
e) they contain waxes and steroids

c) they are soluble in water

What is a triacylglycerol?
a) a molecule formed from three alcohols by dehyration reactions
b) a lipid that makes up much of the plasma membrane
c) a carbohydrate with three sugars joined together by glycosidic linkages
d) a lipid made with three fatty acids and glycerol
e) a protein with tertiary structure

d) a lipid made with three fatty acids and glycerol

Which of the following is true regarding saturated fatty acids?

a) they are the predominant fatty acid in corn oil
b) they are usually liquid at room temperature
c) they are usually produced by plants
d) they are the principal molecules in lard and butter
e) they have double bonds between carbon atoms of the fatty acids

d) they are the principal molecules in lard and butter

the bonding of two amino acid molecules to form a larger molecule requires
a) the release of a water molecule
b) the addition of a nitrogen atom
c) the addition of a water molecule
d) the release of a carbon dioxide molecule
e) both b and c

c) the release of a water molecule

There are 20 different amino acids. What makes one amino acid different from another?
a) different alpha carbons
b) different side chains (R groups) attached to an alpha carbon
c) different carboxyl groups attached to an alpha carbon
d) different amino groups attached to an alpha carbon
e) different asymmetric carbons

b) different side chains (R groups) attached to an alpha carbon

the bonding of two amino acid molecules to form a larger molecule requires which of the following?
a) formation of a hydrogen bond
b) addition of a water molecule
c) removal of a water molecule
d) formation of an ionic bond
e) both a and c

e) both A and C
formation of a hydrogen bond
AND
removal of a water molecule

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
a) 100
b) 99
c) 101
d) 97
e) 98

b) 99

Which bonds are created during the formation of the primary structure of a protein?
a) phosphodiester bonds
b) disulfide bonds
c) hydrogen bonds
d) peptide bonds
e) a, b, and c

peptide bonds

What maintains the secondary structure of a protein?
a) phosphodiester bonds
b) hydrogen bonds
c) disulfide bonds
d) peptide bonds
e) ionic bonds

b) hydrogen bonds

the alpha helix and the B pleated sheet are both common polypeptide forms found in which level of protein structure?
a) secondary
b) tertiary
c) quaternary
d) primary
e) all of the above

a) secondary

the tertiary structure of a protein is the

a) bonding together of several polypeptide chains by weak bonds
b) order in which amino acids are joined in a polypeptide chain
c) unique three-dimensional shape of the fully folded polypeptide
d) overall protein structure resulting from the aggregation of two or more polypeptide subunits
e) organization of a polypeptide chain into an alpha helix or B pleated sheet

c) unique three-dimensional shape of the fully folded polypeptide

Altering which of the following levels of structural organization could change the function of a protein?
a) secondary
b) primary
c) tertiary
d) quaternary
e) all of the above

e) all of the above

what is the term used for a change in a protein's three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds?
a) destabilization
b) denaturation
c) stabilization
d) renaturation
e) hydrolysis

b) denaturation

what is the term used for a protein molecule that assists in the proper folding of other proteins?
a) chaperonin
b) enzyme protein
c) renaturing protein
d) tertiary protein
e) denaturing protein

a) chaperonin

which of the following descriptions best fits the class of molecules known as nucleotides?
a) a nitrogenous base and a phosphate group
b) a phosphate group and an adenine or uracil
c) a nitrogenous base and a pentose sugar
d) a pentose sugar and a purine or pyrimidine
e) a nitrogenous base, a phosphate group, and a pentose sugar

e) a nitrogenous base, a phosphate group, and a pentose sugar

which of the following statements best summarizes the structural differences between dna and rna?
a) RNA is a protein, whereas DNA is a nucleic acid
b) RNA is a double helix, but DNA is single-stranded
c) DNA is a protein, whereas RNA is a nucleic acid
d) DNA nucleotides contains different sugar than RNA nucleotides
e) a and d are correct

d) dna nucleotides contain a different sugar than rna nucleotides

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
a) 5'UGCAAU3'
b) 3'TAACGT5'
c) 3'UAACGU5'
d) 5'UAACGU3'
e) 5'TAACGT3'

b) 3'TAACGT5'

which of the following is a diverse group of hydrophobic molecules?
a) proteins
b) nucleic acids
c) lipids
d) carbohydrates

c) lipids

which of the following store and transmit hereditary information?
a) carbohydrates
b) lipids
c) nucleic acids
d) proteins

c) nucleic acids

Enzymes are
A) carbohydrates.
B) lipids.
C) proteins.
D) nucleic acids.

c) proteins

Which term precisely describes the cellular process of breaking down large molecules into smaller ones?
a) catabolism
b) catalysis
c) dehydration
d) metabolism
e) anabolism

a) catabolism

which of the following is a statement of the first law of thermodynamics?
a) the entropy of the universe is constant
b) the entropy of the universe is decreasing
c) kinetic energy is stored energy that results from the specific arrangement of matter
d) energy cannot be transferred or transformed
e) energy cannot be created or destroyed

e) energy cannot be created or destroyed

which of the following is true for all exergonic reactions?
a) the reactions are nonspontaneous
b) the products have more total energy than the reactants
c) some reactants will be converted to products
d) the reaction proceeds with a net release of free energy
e) a net input of energy from the surroundings is required for the reactions to proceed

d) the reaction proceeds with a net release of free energy

a chemical reaction that has a postive 🔺G is correctly described as
a) enthalpic
b) endothermic
c) spontaneous
d) exothermic
e) endergonic

e) endergonic

what term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways?
a) feedback regulation
b) cooperativity
c) bioenergetics
d) entropy
e) energy coupling

e) energy coupling

which of the following statements is true about enzyme-catalyzed reactions?

a) the reaction is faster than the same reaction in the absence of the enzyme
b) the reaction always goes in the direction toward chemical equilibrium
c) the free energy change of the reaction is opposite from the reaction in the absence of the enzyme
d) a and b only
e) a, b, and c

a) the reaction is faster than the same reaction in the absence of the enzyme

How can one increase the rate of a chemical reaction?
a) cool the reactants
b) add a catalyst
c) decrease the concentration of the reactants
d) increase the entropy of the reactants
e) increase the activation energy needed

b) add a catalyst

Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in

a) bringing glucose and fructose together to form sucrose
b) the release of water from sucrose from sucrose as the bond between glucose and fructose is broken
c) production of water from the sugar as bonds are broken between the glucose monomers
d) utilization of water as a covalent bond is formed between glucose and fructose to form sucrase
e) breaking the bond between glucose and fructose and forming new bonds from the atoms of water

e) breaking the bond between glucose and fructose and forming new bonds from the atoms of water

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's
a) entropy
b) endothermic level
c) heat content
d) activation energy
e) free-energy content

a) entropy

which of the following statements regarding enzymes is true?

a) enzymes increase the rate of a reaction
b) enzymes are permanently altered by the reactions they catalyze
c) enzymes decrease the free energy change of a reaction
d) enzymes change the direction of chemical reactions
e) enzymes prevent changes in substrate concentration

a) enzymes increase the rate of a reaction

The active site of an enzyme is the region that A) binds allosteric regulators of the enzyme. B) is involved in the catalytic reaction of the enzyme. C) binds noncompetitive inhibitors of the enzyme. D) is inhibited by the presence of a coenzyme or a cofactor.

b) is involved in the catalytic reaction of the enzyme

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
a) competitive inhibition
b) denaturation of the enzyme
c) saturation of the enzyme activity
d) insufficient cofactors
e) allosteric inhibition

a) competitive inhibition

which of the following is true of enzymes?

a) they increase the rate of chemical reaction by lowering activation energy barriers
b) enzyme function is independent of physical and chemical environmental factors such as pH and temperature
c) enzymes may require a nonprotein cofactor or ion for catalysis to take speed up more appreciably than if the enzymes act alone
d) enzyme function is increased if the three-dimensional structure or conformation of an enzyme is altered

a) they increase the rate of chemical reaction by lowering activation energy barriers.

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

a) competitive inhibitor of the enzyme
b) cofactor necessary for enzyme activity
c) noncompetitive inhibitor of the enzyme
d) coenzyme derived from a vitamin
e) allosteric activator of the enzyme

b) cofactor necessary for enzyme activity

When you have a severe fever, what grave consequence may occur if the fever is not controlled?
binding of enzymes to inappropriate substrates
b) change in the folding of enzymes
c) removal of amine groups from your proteins
d) destruction of your enzymes' primary structure
e) removal of the amino acids in active sites

b) change in the folding of enzymes

Catabolism is to anabolism as __________ is to __________.

a) exergonic; endergonic
b) work; energy
c) entropy; enthalpy
d) free energy; entropy
e) exergonic; spontaneous

a) exergonic; endergonic

L can form either m or n.
m can form o
o can form either p or r
p can form q
r can form s
o inhibits the reaction of L to form M
Q inhibits the reaction of O to form P
S inhibits the reaction of O to form R.
Which reaction would prevail if both Q and S were present in the cell in high concentrations?

a) L ---> M
b) M---> O
c) L-----> N
d) O---> P
e) R---> S

c) L-N