Chapter 2 Study Module Flashcards
Enzymes
proteins, catalysts, accelerate chemical reactions
Most inorganic compounds are…
ionically bonded
The unequal sharing of electrons in a molecule of water is an example of __________.
a polar covalent bond
The attraction between cations and anions is important in __________.
ionic bonds
The symbol H2O means that each molecule of water is composed of __________.
two hydrogen ions and one oxygen atom
A + B > AB is an example of a(n) __________ reaction.
synthesis
If oxygen has an atomic weight of 16, what is the molecular weight of an oxygen molecule?
32
The mass number of an atom is defined as the __________.
number of protons plus the number of neutrons in the nucleus
What are isotopes of an element?
Atoms whose nuclei contain the same number of protons, but different numbers of neutrons
The substances dissolved in a solution are called __________.
solutes
A pure chemical substance made up of atoms of two or more types of elements in a fixed proportion is specifically called __________.
a compound
If the second energy level of an atom has one electron, how many more electrons does it need in order for that energy level to be filled to its maximum capacity?
Seven
What is the term for a chemical that dissociates into anions and cations that are neither hydroxide nor hydrogen ions?
Salt
An anion is a….
negatively charged atom or group of atoms
In chemical notation, the symbol 2H means __________.
two atoms of hydrogen
The subatomic particle that is found in the nucleus of an atom and has a positive charge is __________.
proton
From the following choices, select the one that diagrams a typical decomposition reaction.
AB > A + B
C + D > CD
A + B > AB
AB + CD > AD + CB
AB > A + B
The chemical properties of every element are determined by __________.
the number and arrangement of electrons in the outer energy level
Atomic number is defined as __________.
the number of protons in the nucleus
A solute that dissociates to release hydrogen ions into solution and thus causes a decrease in pH is __________.
an acid
The smallest stable units of matter are called __________.
atoms
Chemicals that must be in our diet in order for the body to function normally are called _______.
nutrients
What type of chemical bond is formed when two atoms share electrons?
covalent bond
The presence of an appropriate enzyme affects only the __________.
rate of the reaction
Enzymes catalyze reactions by __________.
decreasing the activation energy
Which of the following is the property of water that allows it to absorb and retain heat?
high heat capacity
Which of the following statements about inorganic molecules is false?
They contain carbon and hydrogen atoms as their primary structural elements.
Water is an important inorganic molecule that accounts for most of our body weight.
They include acids and bases.
They include oxygen.
They contain carbon and hydrogen atoms as their primary structural elements.
The major difference between inorganic and organic compounds is that inorganic compounds are usually __________.
not composed of carbon and hydrogen
Why is water particularly effective as a solvent?
Its polarity creates positive and negative regions that interact with many types of molecules.
Which of the solutions below is the most acidic?
a solution with a pH of 2
Which property of water allows us to maintain a constant body temperature?
high heat capacity
Which of the following statement about water’s ability to help us maintain homeostasis is FALSE?
When heated, liquid water is easily converted into water vapor.
When you put table salt into a glass of water, it dissolves. The best term for this breaking of ionic bonds and the separation of these ions is __________.
dissociation or ionization
Water is the primary solvent in our body fluids. Which statement about water and its solvent properties as solvent is correct?
The oxygen end of the water molecule is partially negatively charged and the hydrogen end is partially positively charged.
The action of a buffer to maintain pH within normal limits involves __________.
removing or replacing hydrogen ions
Acidosis is defined as __________.
blood pH below 7.35
When we consume food and process it in our cells, we extract energy from it. A type of chemical reaction in which the amount of energy released is greater than the activation energy needed to start the reaction is called a(n) __________.
exergonic reaction
Dissolved ions that can conduct an electrical current in a solution are called _________________.
electrolytes
Which of the following is a type of molecule that releases hydrogen ions into a solution and lowers the pH of that solution?
an acid
A chemical that can release free hydroxide ions or accept free hydrogen ions is a(n) __________.
base
Buffers help maintain ____, prevent ______, and _____
maintain homeostasis, prevent large changes in pH, and neutralize solutions donating hydrogen ions or accepting hydrogen ions
Which type of bond has the most important effects on the properties of water and the shapes of complex molecules?
Hydrogen bond
A type of reaction in which simple molecules are bonded together to make a larger, more complicated molecule is called a(n) __________ reaction.
anabolic
The ideal medium for most absorption and/or transport of inorganic and organic compounds in the human body is ________.
water
Which of the following statements about the pH scale is FALSE?
A pH of 0 means there are no free hydrogen ions in the solution.
The pH scale is a logarithmic scale based on powers of 10.
A solution with a pH of 2 has 100 times more free hydrogen ions than a solution with a pH of 4.
A solution with a pH of 7 has an equal number of hydrogen and hydroxide ions.
A pH of 0 means there are no free hydrogen ions in the solution.
To maintain homeostasis in the human body, the normal pH range of the blood must remain at __________.
7.35-7.45
pH measures the concentration of __________ in a solution.
free hydrogen ions
Which of the following is the most specific term for the type of chemical reaction that breaks a molecule into smaller fragments by breaking its chemical bonds?
Decomposition reaction
After a meal, our bodies will store carbohydrates in the liver and skeletal muscle cells. These stored carbohydrates are stored in the form of __________.
glycogen
Which type of protein generally forms extended sheets or strands and usually plays a structural role in cells?
fibrous protein
Which molecule is a compound containing bonds between phosphate groups?
ATP
The continuous removal and replacement of organic molecules in a cell are part of the process of __________.
metabolic turnover
Certain types of fats are modified fatty acids that coordinate and direct local cellular activities. These important regulatory chemicals are called __________.
prostaglandins
The reaction involved in joining two simple sugars together to form a disaccharide requires __________.
the removal of water to create a more complex molecule
Which type of lipid provides the energy reserve that is stored in our bodies?
Triglycerides or neutral fats
Organic catalysts made by a living cell to increase the rates of reactions are called __________.
Enzymes
The type of bond that holds amino acids together in a chain is called a(n) __________.
peptide bond
Carbohydrates are very important to the body because they serve as primary sources of __________.
energy
Compared with other major organic compounds, nucleic acids are unique because they __________.
store and process information at the molecular level
Comparing the structure and functions of DNA and RNA, which of the following statements is most accurate?
DNA copies itself as RNA and this copy is actually used to build specific proteins.
Why does the hemoglobin molecule qualify as a quaternary protein structure?
It has four interacting globular subunits.
Which nucleic acid determines our inherited characteristics and contains the genetic code for all cells in an organism?
DNA
Which of the following is not a carbohydrate?
polypeptide
sucrose
glycogen
glucose
polypeptide
What is the most important high-energy compound found in the human body?
ATP
A molecule that is hydrophobic __________.
could be a fat or an oil
A DNA molecule consists of two polynucleotide strands hydrogen bonded to each other. The hydrogen bonding is very specific. Which of the following nitrogenous bases will form complementary base pairs in DNA?
adenine and thymine
Which of the following categories of lipids function as hormones?
steroids
Proteins differ from carbohydrates because proteins __________.
always contain nitrogen
Which of the following functions is NOT a usual function of proteins in our body?
Energy reserve
Proteins are composed of subunits called __________.
amino acids
What is the primary function of monosaccharides such as glucose?
They are used as a metabolic fuel to supply energy for the body.
Which of the following is not a lipid?
deoxyribonucleic acid
eicosanoid
steroid
triglyceride
deoxyribonucleic acid
A carbohydrate molecule is made up of __________.
carbon, hydrogen, and oxygen
What happens to an enzyme that is subjected to extremely high temperatures?
It becomes denatured
Why are lipid deposits important as energy reserves?
Lipids provide twice as much energy as carbohydrates.
