Biology A: Preparing for Test Unit 2
An atom that has gained or lost electrons is called an ion. True or False
True
The symbol Na+ represents a sodium atom that has lost an electron. True or False
True
An atom with six electrons in its n = 2 shell will become an ion with a charge of: + 6 - 6 + 2 - 2
- 2
The largest molecules in organisms are: carbohydrates proteins lipids nucleic acids
nucleic acids
The largest organic molecules are _________________.
nucleic acids
Many gases exist as ________________ molecules of an element.
diatomic
If the outer energy level of the atom is full, it ________ react readily with other atoms. does does not
does not
Atoms are electrically _________________ because they have the same number of protons and electrons.
neutral
The _____ carries no electrical charge in the atom. electron proton gluon neutron
neutron
The three subatomic particles are protons, electrons, and ______________________.
neutrons
Which organic compound serves this function? enzymes carbohydrates lipids nucleic acids proteins
proteins
The _____ carries a positive charge in the atom. electron proton gluon neutron
proton
Atomic mass is determined by the number of neutrons plus ____________________.
protons
When an atom loses an electron, it becomes ____________________ charged
positively
nucleic acids
"blueprint" molecules
From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Hydrogen (1) 0 -1 +1 -2 +2
+1
An ion which has lost two electrons has a charge of: 0 -2 +2 -6
+2
From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Magnesium (12) 0 -1 +1 -2 +2
+2
A strong acid has a pH approaching: 0 8 5 14
0
How many electrons does carbon lack in its outer shell? 1 2 3 4
4
In a protein molecule, the number of amino acid molecules may be as many as: 5 500 50 5,000
5,000
_________________ are compounds that produce H+ ions in solution.
Acids
double-stranded
DNA
A plant must supply energy through photosynthesis in order for its complex starch molecules to turn to simple sugar. True or False
False
(Select all that apply.) The four classes of organic molecules are _____. carbon carbohydrates polymers lipids nucleic acids amino acids proteins fatty acids
carbohydrates lipids nucleic acids proteins
All organic molecules contain the element _____. hydrogen oxygen nitrogen carbon
carbon
The n = 2 shell of an atom contains a maximum of: two electrons seven electrons eight electrons eleven electrons
eight electrons
The _____ carries a negative charge in the atom. electron proton gluon neutron
electron
ionic bonding
electron exchange
covalent bonding
electron sharing
The reactivity of an atom is due to the number and arrangement of _________________ in the outer energy level.
electrons
most highly concentrated energy source
fats
The atomic mass of an atom with six electrons, eight neutrons, and six protons is: six fourteen eight twenty
fourteen
The bonds that link many water molecules together to form a water drop are: ionic nuclear hydrogen covalent
hydrogen
The weak type of bonding which attracts molecules to molecules is: ionic hydrogen covalent nuclear
hydrogen
decomposition
hydrolysis
If an atom loses or gains an electron, it is called a(n)______________ .
ion
Atoms which transfer electrons can combine to form a(n) ____________________ bond.
ionic
transfer of electrons
ionic
Which organic compound has this component? steroids carbohydrates lipids nucleic acids proteins
lipids
Which organic compound serves this function? insulation against cold carbohydrates lipids nucleic acids proteins
lipids
Which organic compound serves this function? lamp oil carbohydrates lipids nucleic acids proteins
lipids
Which organic compound serves this function? most highly concentrated energy carbohydrates lipids nucleic acids proteins
lipids
Amino acids are the building blocks of _________________.
proteins
Enzyme, antibody, hormone, and muscle are roles played by: carbohydrates proteins lipids nucleic acids
proteins
Which organic compound serves this function? antibodies carbohydrates lipids nucleic acids proteins
proteins
The total number of elements that have been identified is: 20 92 52 118
118
Which is not a compound? H2 H2O 6CaO 5HCl
H2
A substance that releases hydrogen ions in water is a base. True or False
False
All proteins carry the genetic codes which determine the structure and function of an organism. True or False
False
An organism can live without enzymes. True or False
False
Because enzymes have high specificity, fewer than fifteen are required by any organism. True or False
False
Chemical reactions in cells are faster than the same reactions outside cells. True or False
False
Water is an example of a compound. True or False
True
a new substance formed by the combination of two or more different atoms
compound
The principal elements found in living things are carbon, hydrogen, oxygen, and ____________________.
nitrogen
How many atoms are in the following molecules of ammonia: 3(NH3) three four 8 12
12
The atomic mass of an element whose atoms consist of eight protons, nine neutrons, and eight electrons is: 8 16 17 25
17
The number of hydrogen atoms in 6NH3 is _________________.
18
Lipids are water soluble True or False
False
Carbon forms _________________ bonds.
covalent
a substance consisting of only one type of atom
element
When a salt dissolves in water, it produces either a hydrogen ion or a hydroxyl ion. True or False
False
DNA "rung"
Paired set
The number of protons in an atom determines the __________________.
element
From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Oxygen (8) 0 -1 +1 -2 +2
-2
According to the text, how many elements have been identified? 20 92 112 118
118
If an atom has twelve electrons, how many electrons are in the n=1 energy level? How many electrons are in the n=2 energy level? How many electrons are in the n=3 energy level? n=1 shell n=2 shell n=3 shell
2 8 2
Enzyme molecules react with reactants to produce substrate molecules. True or False
False
Many elements bond to carbon by exchanging electrons. True or False
False
Of the known elements only about ten are needed by living things. True or False
False
Organic catalysts are called polysaccharides. True or False
False
Polysaccharides are simple sugars, True or False
False
Sodium and chlorine atoms combine readily because they both tend to lose electrons. True or False
False
The number of protons within an atom of an element is equal to its atomic mass. True or False
False
Water can dissolve only inorganic compounds. True or False
False
Carbohydrates are converted to energy by the process of hydrolysis. True or False
True
Lipids are composed of the same basic elements as carbohydrates. True or False
True
Of the three lipid types, phospholipids are more similar to fats. True or False
True
The DNA bases are attached to the phosphate part of the structure. True or False
True
The effect of a catalyst is the reduction of activation energy required to initiate a chemical reaction. True or False
True
Two bases of DNA connects the double chain of DNA like a step on a ladder. True or False
True
A substance which yields an anion plus a proton is a(n): salt acid base
acid
The energy required to start a chemical reaction is called: a catalyst covalence activation energy reversibility
activation energy
The heat needed for chemical reaction to take place is called _____. heat of reaction activation energy friction
activation energy
Large organic molecules which are synthesized from multiple identical subunits are: carbohydrates polymers proteins nucleic acids all of the above
all of the above
When compounds which are formed from ionic bonds decompose, the products: are usually atoms of the original reactants are usually simple molecules are usually ions of the original elements are usually of no further chemical value
are usually ions of the original elements
Substances which maintain a body's pH within narrow limits are called __________________.
buffers
Lipids are chemically most similar to: carbohydrates nucleic acids proteins amino acids
carbohydrates
Which organic compound has this component? saccharides carbohydrates lipids nucleic acids proteins
carbohydrates
Which organic compound has this component? starches carbohydrates lipids nucleic acids proteins
carbohydrates
Which organic compound has this component? sugars carbohydrates lipids nucleic acids proteins
carbohydrates
Which organic compound serves this function? most readily available energy carbohydrates lipids nucleic acids proteins
carbohydrates
(Select all that apply.) The elements most often found in organic molecules are _____. carbon sodium potassium hydrogen nitrogen magnesium oxygen
carbon hydrogen nitrogen oxygen
Four elements which comprise over 95% of the human body are: carbon, phosphorus, oxygen, hydrogen calcium, phosphorus, hydrogen, nitrogen carbon, hydrogen, oxygen, nitrogen calcium, hydrogen, oxygen, nitrogen
carbon, hydrogen, oxygen, nitrogen
A substance that helps a reaction to take place, but does not participate in the reaction is called a(n) _____. catalyst reactant product activation energy
catalyst
Nonprotein substances (such as vitamins and some metal ions) which need to be present for enzymes to function are called __________________.
cofactors
Atoms that form compounds are held together by chemical bonds. The bond that includes sharing electrons with another atom is called ______________________.
covalent
When electrons are shared, the type of bonding is called: ionic nuclear hydrogen covalent
covalent
sharing of electrons
covalent
Identify the type of chemical reaction. H2CO3 H2O + CO2 decomposition exchange reversible synthesis
decomposition
When atoms combine, interactions occur between their: nuclei electrons protons neutrons
electrons
Lavoisier proposed that all matter is composed from the same _____. atoms elements molecules gases
elements
area that electrons are found around an atomic nucleus
energy level
What is expected when reactants break bonds? energy output energy input equilibrium exchange reaction
energy output
A catalyst for chemical reactions in biological systems is called a(n) ___________________.
enzyme
Protein catalysts which cause reactions to occur at temperatures and pH values which are common to living cells are called ____________________.
enzymes
A(n) __________________ reaction occurs when the bonds of the reacting compounds are broken and new combinations are formed.
exchange
Identify the type of chemical reaction. H2SO4 + 2KOHK2SO4 + 2H2O decomposition exchange reversible synthesis
exchange
Acid + base yields salt + water is an example of a(n): synthesis reaction exchange reaction decomposition reaction reversible reaction
exchange reaction
(Select all that apply.) Choose the three types of bonds introduced. ionic molecular compound covalent hydrogen oxygen
ionic covalent hydrogen
DNA has a structure similar to a: ladder wall wheel tree
ladder
Steroids are: complex carbohydrates lipids a subclass of fats a type of phospholipids
lipids
Which organic compound has this component? fats carbohydrates lipids nucleic acids proteins
lipids
Which organic compound has this component? fatty acids carbohydrates lipids nucleic acids proteins
lipids
The most abundant sources of proteins are derived from: vegetables and fruit bread and fish meat and cheese green vegetables and milk
meat and cheese
The simplest structured unit of a compound is a(n): electron atom proton molecule
molecule
the smallest complete unit of a compound or diatomic gas
molecule
simple sugars
monosaccharides
When an atom gains an electron, it becomes ___________________ charged.
negatively
A solution that contains equal numbers of hydrogen and hydroxide ions would be called: acidic basic alkaline neutral
neutral
Which organic compound has this component? DNA carbohydrates lipids nucleic acids proteins
nucleic acids
Which organic compound has this component? RNA carbohydrates lipids nucleic acids proteins
nucleic acids
Which organic compound serves this function? genetic code carbohydrates lipids nucleic acids proteins
nucleic acids
Most of the mass of an atom is contained in its _____. electrons protons nucleus neutrons
nucleus
Bonds between amino acids are what type bonds? covalent peptide hydrogen ionic
peptide
complex sugars
polysaccharides
The substance upon which an enzyme acts is called the _________________.
substrate
DNA "upright"
sugar and phosphate
A(n) _________________ reaction occurs when a molecule is formed from the bonding of atoms, ions or simpler molecules.
synthesis
Identify the type of chemical reaction. NH3 + H2ONH4OH decomposition exchange reversible synthesis
synthesis
polymerization
synthesis
Chemical reactions are the result of an atom attempting _____. to reduce the number of electrons to become electrically neutral to rearrange its configuration to result in a stable octet add sufficient electrons to complete its outer shell
to rearrange its configuration to result in a stable octet
The n = 1 shell of an atom contains a maximum of: two electrons seven electrons eight electrons eleven electrons
two electrons
The most abundant sources of carbohydrates are: vegetables butter beef fish
vegetables
Enzymes are produced only _________________________. outside the active cell in the DNA of the cell within an active cell in another cell and transported
within an active cell
