CH2 study questions] Flashcards
Chemical energy is __________.
energy stored in bonds between atoms and
a form of potential energy
Which of the following is an example of the conversion of potential energy into kinetic energy?
Synthesis of ATP from glucose
ATP hydrolysis to drive muscle contraction
Digestion of protein in the stomach
Pumping ions across a cell membrane
ATP hydrolysis to drive muscle contraction
The four elements that comprise 96% of living matter are __________.
carbon, hydrogen, nitrogen, oxygen
An atom’s nucleus contains __________.
protons and neutrons
The element lithium has 3 protons and 4 neutrons in its nucleus. Its mass number is __________.
7
When atoms of two different elements bind together, they form a(n) __________.
compound
Which of the following mixture(s) are homogeneous?
Colloids
Solutions
Suspensions
Both colloids and suspensions
solutions
The most important determinant of an atom’s bonding behavior is __________.
the number of valence shell electrons
When atoms gain electrons, __________.
the atoms become negatively charged
Ionic bonds connect atoms together by __________.
charge attractions
Covalent bonds occur when __________.
electrons are shared between atoms
An atom will tend to be electronegative if __________.
it lacks only 1–2 electrons in the valence shell
Water, H2O, is a polar molecule. Oxygen is electronegative and hydrogen is electropositive. This means that __________.
the oxygen pulls electrons away from hydrogen and becomes more negative
Hydrogen bonds are similar to ionic bonds because __________.
they both are due to opposite charge attractions
In a chemical reaction, ___________ join to form __________.
reactants; products
Water’s unique properties like high heat capacity, high heat of vaporization, and universal solvent can be attributed to its __________.
ability to form hydrogen bonds
When chemical equilibrium is reached, __________.
no further net change in the amounts of reactants and products occurs
What will be the effect on a chemical reaction if the concentration of reactants is increased?
The speed of the reaction will increase.
A substance that is very acidic may have a pH of 1 or 2. This means that the acidic substance __________.
has a high concentration of H+ ions
A buffer will release H+ ions if the blood pH __________.
rises (becomes more basic)
The four major organic compounds that comprise our bodies are __________.
proteins, carbohydrates, lipids, nucleic acids
The major function of carbohydrates in the body is __________.
as cellular fuel
Which type of reaction occurs when biological molecules are broken down?
Hydrolysis
The three major subclasses of lipids include phospholipids, steroids, and __________.
triglycerides
The major building blocks for proteins are __________.
amino acids
Functions of proteins do not include acting as __________.
genes
The quaternary level of protein structure involves __________.
aggregations of polypeptides forming a complex protein
An enzyme’s ____________ is the molecule upon which an enzyme acts.
substrate
Increasing the concentration of an enzyme’s substrate (up to a point) would ___________ the reaction.
speed up
The major building blocks of nucleic acids are __________.
nucleotides
The four DNA nucleotides are __________.
adenine, thymine, cytosine, guanine
Which of the following is not a metabolic function of ATP?
Providing energy for diffusion
Substances that cannot be broken down into simpler substances are defined as ________.
elements
Energy in action is defined as _______ energy.
kinetic
When you row a boat, your arms provide which type of energy?
mechanical
When energy is converted from one form to another, some of the original energy is “lost” as ________.
heat
Which of the following is not one of the four major elements in the human body?
Hydrogen
Calcium
Nitrogen
Oxygen
calcium
The atomic number is always equal to the number of _______ in an atom.
protons
Isotopes have the same number of _______ but differ in the number of ________.
Isotopes have the same number of _______ but differ in the number of ________.
If an atom gains an electron, the resulting charge of that atom is more _________.
negative
Which spontaneously decompose into more stable atoms?
Radioisotopes
Which of the following is not a compound?
H2O
NaCl
O2
C6H12O6
o2
The following are electrons in the electron shells of four atoms. Which atom would most likely be reactive?
2, 8, 7
An ionic bond is formed between _______.
a cation and an anion
Which type of bond is formed when electrons are shared unequally between atoms?
Polar covalent
Which of the following statements is true of solvents?
They are usually solids.
They are present in smaller amounts in a solution.
Water is the main solvent in the body.
They are tiny particles.
Water is the main solvent in the body.
Building muscle tissue is an example of which type of reaction?
synthesis
All of the following affect the rate of a reaction except __________.
density
Bonds are broken during which type of reaction?
Catabolic
An enzyme is an example of a _________.
catalyst
Which of the following is not a reason for the irreversibility of chemical reactions in cells?
Chemical reactions that release energy would require energy to be reversed.
A product might be continually removed from the reaction site.
Biological reactions can only proceed in a single direction.
A product might be expelled from
the body.
Biological reactions can only proceed in a single direction.
A steroid is an example of _________.
lipid
Which of the following is not a function of water?
Body temperature regulation
Source of electrolytes
Universal solvent
Protection from mechanical damage
Source of electrolytes
Which pH indicates a weak base?
- 0
- 8
- 4
- 0
7.4
Which of the following describes the tertiary structure of proteins?
α-helical or β-pleated regions of the polypeptide chain folded upon one another
A substance that dissociates into cations and hydroxyl ions is __________.
a base
Which substance is the primary energy-transferring molecule in the cell?
ATP
know the structure of lipid
mountain
know structure of functional protein
loop
know structure of nucleotide
valence bonds
know structure of polysaccharide
chain monosaccharides
know structure of monosaccharide
hexgonal box
know polymer structure
.
Know tertiary structure
.
know deoxyribose sugar
area
know thymine
area
know guanine
area
know phosphate
area
know hydrogen bond
area
bond which electrons are shared equally
polar covalent bond
bond in which electrons are completely lost or gained by the atoms involved
ionic bond
bond in which electrons are shared equally
nonpolar covalent bond
type of bond important in tying different parts of the same molecule together into a threedimensional
structure
hydrogen bond
Electrically charged particle due to loss of an electron
cation
Neutral subatomic particle
neutron
Smallest particle of an element that retains its properties
atom
Smallest particle of a compound that still retains its properties.
molecule
water
compound
carbon
element
dry ice
compound
blood
mixture
Can be measured only by its effects on matter
energy
Anything that occupies space and has mass
matter
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
Is a function of, and varies with, gravity
weight
Legs moving the pedals of a bicycle
mechanical energy
When the bonds of ATP are broken, energy is released to do cellular work
chemical energy
Energy that travels in waves. Part of the electromagnetic spectrum
radiant energy
Represented by the flow of charged particles along a conductor, or the flow of ions across a
membrane
electrical energy
Heterogeneous, will not settle
colloids
Heterogeneous, will settle
suspension
Homogeneous, will not settle
solutions
Will not scatter light
solutions
First one or two letters of an element’s name
atomic symbol
Number of protons in an atom
atomic number
Combined number of protons and neutrons in an atom
mass number of an element
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
It is the difference in the R group that makes each amino acid chemically unique.
t/f
true
Chemical properties are determined primarily by neutrons
t/f
false
A charged particle is generally called an ion or electrolyte
t/f
true
Isotopes differ from each other only in the number of electrons the atom contains
t/f
false
About 60% to 80% of the volume of most living cells consists of organic compounds
t/f
false
Lipids are a poor source of stored energy
t/f
false
Current information suggests that omega-3 fatty acids decrease the risk of heart disease.
t/f
true
Glucose is an example of a monosaccharide
t/f
true
Glycogen, the storage form of glucose, is primarily stored in muscle tissue only
t/f
fase
The lower the pH, the higher the hydrogen ion concentration
t/f
true
Covalent bonds are generally less stable than ionic bonds
t/f
false
Hydrogen bonds are too weak to bind atoms together to form molecules but are important
intramolecular bonds.
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 acidity of a solution reflects the free hydrogen ions in the solution
t/f
true
A chemical bond is an energy relationship between outer electrons and neighboring atoms.
t/f
true
All organic compounds contain carbon.
t/f
true
A dipeptide can be broken into two amino acids by dehydration synthesis.
t/f
false
The pH of body fluids must remain fairly constant for the body to maintain homeostasis
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
Buffers resist abrupt and large changes in the pH of the body by releasing or binding ions
t/f
true
The atomic number is equal to the number of ________.
protons, and electrons
Molecules such as methane that are made of atoms that share electrons have ________ bonds
covalent
An atom with three electrons would have a valence of ________.
one
AB → A + B is an example of a(n) ________ reaction.
decomposition
________ have a bitter taste, feel slippery, and are proton acceptors.
bases
A holoenzyme is composed of an apoenzyme and a(n) ________.
cofactor
In a DNA molecule, guanine would connect to ________.
cytosine
The ________ molecule directly provides energy for cellular work.
atp
Hydrogen bonds are more like a type of weak ________ than true bonds
atraction
Weak acids and bases make good ________.
buffers
Starch is the stored carbohydrate in plants, while ________ is the stored carbohydrate in
animals
glycogen
How many phosphates would AMP have attached to it?
1
Which metals have a toxic effect on the body?
heavy
What does the polar end of a phospholipid contain?
a phosphorus-containing group
What type of chemical bond can form between an element with 11 protons and an element
with 17 protons?
ionic
What happens when globular proteins are denatured?
activity sites are destoryed
Explain the difference between potential and kinetic energy.
Potential energy is inactive stored energy that has potential to do work. Kinetic energy
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 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
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.
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, some reactions produce molecules in excessive quantities (like CO2 and
NH4) that the body then eliminates, but which are needed to reverse a reaction.
When a set of electrodes connected to a light bulb is placed in a solution of dextrose and a
current is applied, the light bulb 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
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 incr
Protons and electrons exist in every atom nucleus except hydrogen. Is this statement true or
false and why?
False. Hydrogen has one proton and one electron. It is the neutron, not the electron that
can coexist in the nucleus and that hydrogen does not have
A chemical bond never occurs between components of 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.
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 without plantlike
systems
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.
An amino acid may act as a proton acceptor or donor. Explain
Amino acids have two components—a base group (proton acceptor) and an organic
acid part (a proton donor). Some have additional base or acid groups on the ends of their R
groups as well.
Name at least four things you know about enzymes
- They are proteins.
- They have specific binding sites for specific substrates.
- They lower the activation barrier for a specific reaction.
- The names end in “ase.”
- They can be denatured.
- They can be used again and again.
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.
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.
If all protons, electrons, and neutrons are alike, regardless of the atom considered, what
determines the unique properties of each element?
Atoms of different elements are composed of different numbers of protons, electrons,
and neutrons.
An ionic bond is formed between _______.
cation and anion
Which type of bond is formed when electrons are shared unequally between atoms?
polar covalent
Which of the following statements is true of solvents?
water is the main solvent in body
All of the following affect the rate of a reaction except __________.
density
An enzyme is an example of a _________.
catalyst
Which of the following is not a reason for the irreversibility of chemical reactions in cells?
Biological reactions can only proceed in a single direction.
A steroid is an example of _________.
lipid
Which of the following is not a function of water?
source of electron
Which of the following describes the tertiary structure of proteins?
d. α-helical or β-pleated regions of the polypeptide chain folded upon one another
A substance that dissociates into cations and hydroxyl ions is __________.
base
Which substance is the primary energy-transferring molecule in the cell?
atp
