Sample Multiple Choice Questions
Topic
Regents Question
AP Question
Respiration
17 The graphs below show the changes in the
relative concentrations of two gases in the air
surrounding a group of mice.
Oxygen consumption can be used as a
measure of metabolic rate because
oxygen is
(A) necessary for ATP synthesis by
oxidative phosphorylation
(B) necessary to replenish glycogen
levels
(C) necessary for fermentation to take
place
(D) required by all living things
(E) required to break down the
ethanol that is produced in
muscles
Which process in the mice most likely
accounts
for the changes shown?
(1) active transport (3) respiration
(2) evaporation (4) photosynthesis
Biochemistry 36 A word equation is shown below.
Starch molecules  Simple sugars
This reaction is most directly involved in the
process of
(1) reproduction
(2) protein synthesis
(3) replication
(4) heterotrophic nutrition
Cell Types
Plants
A + B + energy  AB
Which of the following best characterizes
the reaction presented above?
(A) hydrolysis
(B) catabolism
(C) oxidative-reduction
(D) exergonic reaction
(E) endergonic reaction
Which of the following best supports the
statement that mitochondria are
descendents of endosymbiotic bacterialike cells?
(A) mitochondria and bacteria
possess similar ribosomes and
DNA
(B) mitochondria and bacteria
possess similar nuclei
(C) glycolysis occurs in both
mitochondria and bacteria
(D) both mitochondria and bacteria
have microtubules
(E) neither mitochondria nor bacteria
possess chloroplasts
With the exception of photosynthesis
In plants, the initiation of flowering in
and cell structures, Plants are not
response to photoperiod is triggered by
covered on the Living Environment exam changes in
(A) ethylene
(B) auxin
(C) gibberellic acid
(D) phytochrome
(E) cytochrome
7 The largest amount of DNA in a plant cell is
contained in
(1) a nucleus
(2) a chromosome
(3) a protein molecule
(4) an enzyme molecule
Sample Free-Response Questions: Topic – DNA
Regents Questions
Identify one environmental factor that could cause a base sequence in DNA to be
changed to a different base sequence. [1]
AP Biology
Scientists seeking to determine which molecule is responsible for the transmission of characteristics
from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable
but able to be changed, and (3) be complex enough to determine an organism’s phenotype.


Explain how DNA meets each of the three criteria stated above.
Select one of the criteria above and describe experimental evidence used to determine that
DNA is the hereditary material.
A full-credit response (22 min. per essay – no choices are given)–actual student response:
DNA replicates itself using semi-conservative replication. This means that each parent strand of
DNA will serve as the template for forming a new DNA molecule resulting in daughter molecules that
are ½ old DNA and ½ new. The DNA molecule is split down the middle by helicase, which breaks the
bonds holding the complimentary nucleotides together. Helicase functions in a 3’ to 5’ direction, with
3’ and 5’ denoting the ends of the DNA molecule. A new strand is synthesized by DNA polymerase,
which catalyzes the adding of new nucleotides to each half of the DNA molecule. Thus, each
daughter DNA molecule is identical to its parent.
The DNA molecule is held together in the middle by hydrogen bonds between the two strands, and
nucleotides are attached to one another lengthwise down the molecule by phosphodiester bonds.
Both of these bonds, plus the coiling of the molecule, contribute to its stability. However, variation is
possible due to mutation in the DNA. Mutations may be caused by a number of sources, but they all
include the changing of the sequence of nucleotides. Nucleotides may be inserted into the chain,
deleted, or translocated. Each of these mutations corresponds to a change in the structure of the
protein that the gene codes for, which may or may not have serious effects.
DNA consists of four nucleotides, adenine, guanine, cytosine, and thymine. Adenine and guanine
are purines, and have complementary structures to cytosine and thymine which are pyrimidines (A
pairs with T & C pairs with G) These four nucleotides, arranged in various sequences along a
molecule of DNA are responsible for the incredible diversity of proteins which may be produced.
Nucleotides code for proteins in triplets, or codons. Each amino acid corresponds to several different
codons. Each amino acid corresponds to several different codons. (64 codons are possible, and 20
amino acids exist, with 2 codons signaling for “stop”) The phenotype of an organism is a result of the
variations in the proteins produced in this way.
Messelsohn and Stahl performed an experiment to prove Watson and Crick’s theory of
semiconservative replication of the DNA molecule. They used a centrifuge to separate DNA from
bacteria. The DNA formed a band visible in the tube. When the DNA were grown in a medium
containing heavy nitrogen isotope (N-15), the band was in a different place. When they allowed the
bacteria to grow in the medium long enough for one generation of replication, the band formed was
between the two light and heavy bands, suggesting that it consisted of ½ light and ½ heavy DNA.
One more repication in an N-14 medium would result in only light and medium bands showing that
half of the strands were all new DNA, while the other half were hybrid light and heavy. This proved
that each time, half of the DNA served as a template for replication of a new half of the molecule.