Chapter 2 - The Chemistry of Life
__________ is a compound that accepts H+ ions, removing them from a solution.
A base
_________resists changes in the pH of a solution. It consists of a weak acid that releases hydrogen ions if the pH starts to rise, together with a weak base that accepts extra hydrogen ions if the pH starts to decrease.
A buffer
Which of the following represents an exchange reaction?
AB + CD → AD + BC
When the third phosphate is cleaved off by hydrolysis, the energy liberated from the highly exergonic reaction drives other cellular reactions and processes.
ATP
_______ includes an adenosine group (adenine and a ribose) along with three phosphate groups.
ATP
_______ is an energy carrier throughout the cell.
ATP
Where does an enzyme bind to a substrate?
Active site
__________is a compound that releases H+ ions into a solution.
An acid
___________ is a biological catalyst that increases the rate of a chemical reaction by reducing its activation energy.
An enzyme
The three main types of reactions are catabolic, exchange, and anabolic. _________ reactions build smaller molecules into larger ones.
Anabolic
What is the function of a buffer?
Buffers prevent large swings in pH when an acid or base is added to a solution.
The three main types of reactions are catabolic, exchange, and anabolic. _________ reactions break molecules into smaller parts.
Catabolic
______ has the five-carbon sugar deoxyribose.
DNA
_______ includes thymine as one of its bases
DNA
______remains in the nucleus.
DNA
___________ is in the movement of ions.
Electrical energy
What happens in oxidation-reduction (redox) reactions?
Electron exchange occurs.
_________ require more energy than they release.
Endergonic reactions
Enzymes are catalysts, chemicals that speed up chemical reactions. The conditions inside most cells do not allow reactions to proceed quickly enough to support life. For example, temperatures inside organisms are not hot enough for chemical reactions to take place quickly. Enzymes increase the rates of biological chemical reactions. A cell uses which of the following to accelerate chemical reactions enabling its metabolic machinery to operate?
Enzymes
The three main types of reactions are catabolic, exchange, and anabolic. ____________ reactions, one or more atoms or electrons from the reactants are exchanged for others.
Exchange
_________ release more energy than they require.
Exergonic reactions
Enzymes bind with substrates at their active sites and are permanently altered by the binding process.
False
In a solution, the solute dissolves the solvent.
False
Solutions with a pH less than 7 are considered basic or alkaline.
False
____________ bonds are weak attractions between the partially positive pole (typically an H) of one polar covalent molecule and the partially negative pole of another
Hydrogen
____________ molecules are those with fully or partially charged ends (ions or polar molecules, respectively) that are attracted to the partially positive or negative poles of water molecules.
Hydrophilic
_________molecules are nonpolar.
Hydrophobic
______________ are atoms of the same element that have the same number of protons but different numbers of neutrons. For this reason, they have the same atomic numbers but different mass numbers.
Isotopes
____________is associated with movement, while potential energy is stored.
Kinetic energy
__________ is in the movement of substances or body parts.
Mechanical Energy
What are the building blocks of carbohydrates?
Monosaccharides
____________ molecules lack positive and negative poles, so there are no charges to which other molecules could be attracted.
Nonpolar covalent
___________ have just two fatty acids, with a polar phosphate group replacing the third fatty acid. For this reason, they are amphiphilic: The fatty acid end is hydrophobic, but the phosphate end is hydrophilic.
Phospholipids
___________ is the sequence of amino acids in the polypeptide chain.
Primary structure
An enzyme is a ________.
Protein
__________ is the relationship between polypeptides in proteins that contain more than one.
Quaternary structure
______ can leave the nucleus.
RNA
________ has a ribose sugar.
RNA
________ includes uracil as one of its bases.
RNA
____________ is the local folding structure of the polypeptide, such as alpha helix or beta-pleated sheet.
Secondary structure
__________ are lipids composed of four joined hydrocarbon rings.
Steroids
___________ is the three-dimensional shape produced by the large-scale folding of the polypeptide.
Tertiary structure
________ is a convenient way to express the H+ concentration in a solution.
The pH scale
When is hydrolysis used?
To break apart macromolecules
__________ have three fatty acids attached to a glycerol backbone. They are hydrophobic.
Triglycerides
______________ electrons are the electrons of an atom's outermost electron shell, or valence shell. They determine how the atom will interact chemically with other atoms
Valence
mixture
a combination of two or more substances in which none of the components is chemically altered.
element
a substance that cannot be chemically broken down into simpler substances.
The tendency for water molecules to stick or cling to another surface is called ________.
adhesion
An _________ is a molecule consisting of a central carbon with a hydrogen on one side, an amino group on the other, a carboxyl group at the other end, and an R group that differs for each of the 20 amino acids.
amino acid
releases a hydrogen proton in solution
an acid
matter
anything that has mass and takes up space.
All atoms of an element have the same number of protons and the same _________
atomic number
What chemical binds free hydrogen ions in solution?
base
Monomers are composed of carbon, hydrogen, and oxygen in a 1C:2H:1O ratio.
carbohydrate
Sucrose, glucose, galactose, and cellulose are examples
carbohydrates
an energy relationship between atoms
chemical bond
_________ is contained in chemical bonds.
chemical energy
Which solution is the most likely to have a pH of 3 or 4?
coffee
A ___________has particles small enough to stay dispersed, but still large enough to scatter light (making the mixture cloudy).
colloid
when electrons are shared between elements
covalent bond
Two monosaccharides are linked by ___________ , in which one loses a hydrogen atom and the other loses a hydroxyl group, resulting in the formation of a water molecule.
dehydration synthesis
The three ________ in carbohydrates are carbon, hydrogen, and oxygen, in the ratio 1C:2H:1O.
elements
Water has a ______ capacity, so it helps to maintain a consistent internal body temperature.
high
The addition of a water molecule to a disaccharide, a process called __________, splits the disaccharide into two monosaccharides.
hydrolysis
Triglycerides are__________.
hydrophobic
The elements are arranged in the periodic table in order of ______________ atomic number, distributed in rows so all the elements in a column have similar properties. Metals are on the _______ and nonmetals are on the right.
increasing, left
Atoms that satisfy the octet rule are said to be __________.
inert
A(n) ____________ bond is the bond between two oppositely charged ions.
ionic
If a protein denatures, then _________.
it has unfolded and lost its three-dimensional structure
Examples include phosopholipids, triglycerides, and steroids.
lipid
Monomer is the fatty acid
lipid
Examples include phosopholipids, triglycerides, and steroids
lipids
The most numerous atoms in ________ are carbon and hydrogen; oxygen and sometimes other elements are also present. Because C—C and C—H bonds are nonpolar, lipids are nonpolar.
lipids
macromolecules also called fats
lipids
A _______________is a combination of two or more substances in which none of the components is chemically altered.
mixture
A _________ is a single subunit of a type of biological molecule
monomer
Building blocks of organic molecules are known as __________.
monomers
Nucleotides are the monomers that form deoxyribonucleic acid and ribonucleic acid. DNA & RNA.
nucleic acid
A ________ consists of a nitrogenous base (C, G, A, T, or U), a five-carbon sugar (ribose or deoxyribose), and a phosphate group
nucleotide
Factors that affect the _________ of collisions occurring between the reacting molecules will influence the reaction rate. Such factors include temperature, state and concentration of the reactants, and the presence or absence of a catalyst.
number
An ionic bond forms when one or more electrons are transferred from a metal to a nonmetal so that both obey the _______ . The resulting positive cation and negative anion attract one another, forming an ionic bond.
octet (or duet) rule
The four most common elements, comprising 96% of the body's mass, are __________.
oxygen, nitrogen, hydrogen, carbon
The three types of mixtures differ in the size of the _______________.
particles
Amino acids are linked by dehydration synthesis reactions that form __________ between them.
peptide bonds
_____________ bonds have an unequal distribution of electrons shared by atoms with different electronegativities.
polar covalent
A _________ is made of several monomers linked together.
polymer
Amino acids are the monomers
protein
macromolecules made up of amino acid subunits
proteins
A _________ is a metal cation and a nonmetal anion held together by ionic bonds.
salt
In a mixture of salt water, the salt is called the _____________.
solute
A _____________ has the smallest particles, not visible with a microscope
solution
Each enzyme acts on one specific _______ to catalyze a particular reaction.
substrate
What contributes to the calculation of the mass number?
sum of protons and neutrons
A ____________ has particles large enough to settle out eventually.
suspension
atom
the smallest particle of matter that retains the unique properties of that element.
Ionic bonds result from __________.
the transfer of electrons from a metal to a nonmetal
What predicts the element to which an atom belongs?
total number of protons
A base is a hydrogen ion acceptor while an acid is a hydrogen ion donor.
true
In a solution, the solute dissolves the solvent.
true
