Based on the large numbers of offspring produced by many organisms, Darwin proposed that mortality was high and only a few individuals survived to reproduce. He referred to the differential reproductive success of individuals with particular variations as
A key point in Darwin's explanation of evolution is that
any trait that confers even a small increase in the probability that its possessor will survive and reproduce will be strongly favored and will spread through the population.
The initial accumulation of oxygen in the atmosphere was the result of photosynthesis from an organism most like modern
Scientists group species on an evolutionary tree that is based on
(the fossil record. physical structures. genomic sequencing.)All of the above
After observing that fish live in clean water but not in polluted water, researchers state that "polluted water kills fish." This statement is an example of
Oceans were a good environment for early organisms because they
shielded organisms from ultraviolet light.
Phosphorus has an atomic number of 15 and an atomic mass of 31. How many neutrons does phosphorus have?
Because atoms can have the same number of protons but a different number of neutrons, elements have
Which of the following statements about the difference between ionic bonds and covalent bonds is true?
Electron sharing is more equal in the covalent bond.
What determines if a molecule is polar, nonpolar, or ionic?
The differences in the electronegativities of the atoms
A covalent bond is the sharing of _______ between atoms, whereas an ionic bond is the _______.
electrons; transfer of electrons from one atom to another
Cholesterol is composed primarily of carbon and hydrogen atoms. Therefore, one would expect cholesterol to be
insoluble in water.
Which of the following correctly states an unusual property of water?
The hydrogen bonds between water molecules continually form and break.
Sweating is a useful cooling device for humans because water
takes up a great deal of heat in changing from its liquid state to its gaseous state.
When sodium hydroxide (NaOH) is added to water, it ionizes, releasing OH- and Na+ ions. The resulting solution is
Which contains more molecules, a mole of hydrogen or a mole of carbon?
Both contain the same number of molecules.
How would you make 100 ml of an aqueous solution with a 0.25 M concentration of a compound that has a molecular weight of 200 daltons?
Take 5 grams of the compound and add water until the volume equals 100 ml.
Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, the H+ ions are used up as they combine with the bicarbonate ions. When this happens, the pH of the blood
does not change.
In condensation reactions, the atoms that make up a water molecule are derived from
both of the reactants.
The side chain of leucine is a hydrocarbon. In a folded protein, where would you expect to find leucine?
(In the interior of a cytoplasmic enzyme. On the exterior of a protein embedded in a membrane.) Both a and b
A(n) _______ protein is a protein that has become nonfunctional due to the loss of its three-dimensional structure.
A type of protein that functions by helping other proteins fold correctly is called a
Lactose, or milk sugar, which is composed of one glucose unit and one galactose unit, can be classified as a
Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _______, whereas starch _______.
is highly branched; is moderately branched
(insoluble in water. important for energy storage. hydrophobic. important constituents of biological membranes.) All of the above
In a biological membrane, the phospholipids are arranged with the fatty acid chains facing the interior of the membrane. As a result, the interior of the membrane is
The bases of nucleic acids are purines or pyrimidines. Purines and pyrimidines are distinguished by the fact that
purines are double-ring structures, whereas pyrimidines are single-ring structures.
Which of the following is not a difference between DNA and RNA?
DNA is a polymer, whereas RNA is a monomer.
What is the nucleotide sequence of the complementary strand of the DNA molecule: A A T G C G A?
T T A C G C T
The central dogma of molecular biology states that
the information flow in a cell is from DNA to RNA to protein.