what is the lowest level of biological organization that the biologists consider to be alive?
your body contains the smallest amount of what element?
which of the following about the mass number of an atom is correct?
A. its is an approximation of the total mass of an atom, called the atomic mass
B. it equals the number of electrons in an atom
C. it is the sum of the protons and neutrons in the atomic nucleus
D. it equals the number of protons in an atom
E. A and C are correct
E. a and c are correct
T or F: the method of scientific inquiry that describes natural structures and processes as accurately as possible is known as discovery science.
T or F: theories are much broader in scope than hypotheses and are supported by a large body of evidence.
What results from the transfer of electrons between atoms?
Electrons exist only at fixed levels of potential energy. however, if an atom absorbs sufficient energy, a possible result is that?
an electron may move to an electron shell farther out from the nucleus.
# 7 on test
#7 on test
8-11 on the test
OXYGEN IS A _____, WHILE THE OXYGEN WE BREATH (O2) IS A(N) _______, AND THE CARBON DIOXIDE WE EXHALE IS A(N) ___________
element, molecule, compound
the chemical activity of an atom:
depends on the electrons on the outermost energy levels
when electrons are shared equally between atoms, they form
a nonpolar covalent bond
changing the _______ would change it into an atom of a different element:
the number of protons in the nucleus of the atom
sometimes atoms form molecules by sharing two pairs of valence electrons. when this occurs, the atoms are said to be joined by:
a double covalent bond
T or F: A covalent bond is a strong molecular interaction
T or F: a van der waals interaction is considered to be a weak molecular interaction
T or F: collectively van der waals interactions can be very strong
T or F: an ionic bond in water is a weak molecular interaction
what is true of the following reaction?
3H2+N2 <--> 2NH3
ammonia is being formed and decomposed
what best describes equilibrium?
forward and reverse reactions continue with no effect on the concentrations of the reactants and products
T or F: Protons have no electrical charge while electrons have a negative charge
what is an example of something that is not hydrophilic?
the water in a pond has a pH of 5, the hydroxide concentration would be ?
pure freshly-distilled water has a pH of 7, this means that:
the concentration of H+ ions in the water equals the concentration of the OH- ions in water
what gives rise to the cohesiveness of water molecules and its high surface tension?
why does ice float in liquid water?
hydrogen bonds stabilize and keep the molecule of ice farther apart than water molecules of liquid water
based on your knowledge of the polarity of water molecules, the solute molecule is most likely
consider to solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that the concentration of hydrogen ions in solution X is:
1000 times as great as the concentration of hydrogen ions in solution Y
many mammals control their body temp. by sweating. which property of water is most directly responsible for the ability to sweat to lower body temp
the absorption of heat by the breaking of hydrogen bonds
which of the following solutions has the greatest concentration of hydroxyl ions [OH-]?
A. lemon juice at pH of 2
B. vinegar at pH of 3
C. tomato juice at pH 4
D. urine at pH 6
E. seawater at pH 8
E. seawater at pH 8
hydrogens are insoluble in water because:
the majority of their bonds are non-polar covalent carbon-to-hydrogen linkages
thalidomide and l-dopa are examples of pharmaceutical drugs that occur as enantiomers or molecules that
are mirror images of one another
which functional groups can act as acids?
carboxyl and phosphate
which action could produce a carbonyl group?
the replacement of the -OH of a carboxyl group with hydrogen
the hydrogenation of vegetable oil results in which of the following?
A. Saturated fats and unsaturated fats with trans double bonds
B. an increased contribution to arteriosclerosis
c. the oil (fat) being a solid at room temp
glucose is an _______ while fructose is an _________
what is true about starch and cellulose?
they are both polymers of glucose
the monomers of maltose are joined by a _________ glycosidic linkage, and the monomers of sucrose are joined by a ___________ glycosidic linkage,
what is a highly branched storage polysaccharide found in the liver and muscles of humans?