1. What makes the information in one DNA molecule different from the information in another
DNA molecule?
A. the unique sequence of nucleotides
B. the unique shape of the double helix
C. the unique order of sugars and phosphates
D. the unique amino acids used in the molecule
2. In living organisms, DNA consists of two complementary strands wound together in a specific
structure called a ______.
A. triple bond
B. spiral helix
C. beta sheet
D. double helix
3. When a cell needs a particular protein synthesized, messenger RNA (mRNA) is produced
from DNA through transcription.
How is genetic information "read" from mRNA?
A. as ribose
B. as uracil
C. as amino acids
D. as codons
4. The picture below shows the process of transcription.
During transcription, enzymes bind to a molecule of DNA.
Then, the enzymes unwind and separate the DNA's double helical strands. As the molecule
unwinds, complementary nucleotides pair with one of the DNA strands to form
A. an RNA molecule.
B. an identical strand of DNA.
C. a protein molecule.
D. a DNA polymerase.
5. Which of the following best describes the product of DNA transcription?
A. an RNA molecule
B. a protein
C. a chromosome
D. a DNA molecule
A codon is a set of three nucleotides that correspond to a specific amino acid. The table below
shows various DNA codons and their corresponding amino acids.
Amino Acid
DNA Codon(s)
Alanine
GCT, GCC, GCA, GCG
Arginine
AGA, AGG, CGT, CGC, CGA, CGG
Asparagine
AAT, AAC
Aspartic Acid
GAT, GAC
Cysteine
TGT, TGC
Glutamic Acid
GAA, GAG
Glutamine
CAA, CAG
Glycine
GGT, GGC, GGA, GGG
Histadine
CAT, CAC
Isoleucine
ATT, ATC, ATA
Leucine
CTT, CTC, CTA, CTG, TTA, TTG
Lysine
AAA, AAG
Methionine (Start) ATG
Phenylalanine
TTT, TTC
Proline
CCT, CCC, CCA, CCG
Serine
TCT, TCC, TCA, TCG, AGT, AGC
Threonine
ACT, ACC, ACA, ACG
Tryptophan
TGG
Tyrosine
TAT, TAC
Valine
GTT, GTC, GTA, GTG
Stop
TAA, TAG, TGA
6. In the DNA strand below, two nucleotides were reversed during replication.
What will happen when the replicated DNA strand is translated into proteins?
A. No proteins will be formed at all.
B. The same protein, isoleucine, will be formed.
C. Nothing will happen.
D. Tyrosine will be formed instead of isoleucine.
7. Which choice below correctly shows the base pairing rules in DNA?
A.
A-C
T-G
B.
A-T
G-C
C.
A-G
C-T
D.
A-U
G-C
8. The DNA of a cell is organized into structures. What are these structures called?
A. nuclei
B. vacuoles
C. mitochondria
D. chromosomes
9. The sequence of bases on one strand of a DNA molecule is ATTGCCCATG. What will be the
sequence on the complementary strand?
A. CGGTAAACGT
B. ATTGCCCATG
C. GCCATTTGCA
D. TAACGGGTAC
10. What are the three main components of a DNA molecule?
A. a sugar, a water molecule, and a nitrogenous base
B. a sugar, a phosphate group, and a nitrogenous base
C. a sugar, a nucleotide, and an amino acid
D. a sugar, a phosphate group, and an amino acid
12. When mitosis occurs, the DNA inside the cell's nucleus must replicate. The new cell that is
formed has an identical copy of its parent cell's DNA. That means it has the same information
coded in its genes. During DNA replication, how is an accurate new copy of DNA formed?
DNA polymerases add nucleotides to the exposed base pairs according to base-pairing
A. rules.
B.
Replication forks ensure that DNA polymerases cannot attach to the old DNA molecule.
During DNA replication uracil bases hold the place of all thymine bases until the newly
C. formed double helix is able to form hydrogen bonds.
DNA helicases add nucleotides to the exposed bases and ensure the formation of
D. hydrogen bonds.
13. Which component of DNA makes up the "language" of genetic code?
A. sugars
B. phosphate groups
C. nitrogenous bases
D. amino acids
14. Cells store genetic information in DNA. That genetic information is used to
synthesize _______.
A. genes
B. carbohydrates
C. proteins
D. polysaccharides
16. All cells contain DNA, which provides information for the cells to make
A. different kinds of proteins.
B. different kinds of DNA.
C. new types of genes.
D. new types of organisms.
17. DNA contains all the information a cell needs in order to make certain proteins. Where are
the protein-synthesizing instructions stored on a DNA molecule?
A.
B.
C.
The phosphate group in a strand of DNA codes for the production of amino acids.
The deoxyribose portion of certain genes codes for the production of certain proteins.
Certain sequences of nucleotides code for the production of specific proteins.
Every gene on certain chromosomes codes for the production of different kinds of uracil,
D. which then promotes protein synthesis.
18. What is a major difference between DNA replication and DNA transcription?
A.
RNA molecules produced by transcription are much shorter in length than DNA
molecules produced by replication.
B.
DNA transcription only occurs in multicellular organisms, while DNA replication occurs
in all organisms.
C.
DNA replication involves the nitrogenous base uracil, while DNA transcription involves
the nitrogenous base thymine.
D.
DNA replication takes place in the nucleus, while DNA transcription takes place in the
cytoplasm.
19. Which of the following molecules is the subunit of DNA that links together to form strands
of DNA?
A. a polymerase
B. a codon
C. a nucleotide
D. a phosphate base
20. Every trait you see on an organism is a result of that organism's DNA instructing the
organism's cells. How does the information stored in DNA's nucleotides translate into traits such
as eye color and ear shape?
A.
B.
Traits are determined by codons that are stored in groups of nucleotides.
Traits are determined by a group of enzymes known as DNA helicases.
Traits are determined by the presence or absence of lac operons along a series of
C. nucleotides.
Traits are determined by proteins that are built according to the instructions stored in
D. genes.
23. Sometimes, during the process of replication, the DNA code is copied incorrectly, and an
incorrect nucleotide is attached to the new strand of DNA.
This incorrect copy is known as a
A. codon.
B. mutation.
C. protein.
D. duplicate.
25. How are complementary strands of DNA held together?
A. with hydrogen bonds connecting complementary sugars
B. with hydrogen bonds connecting complementary bases
C. with phosphodiester bonds connecting sugars and phosphate groups
D. with ionic bonds between sugars and phosphate groups
26.
During the process shown above, the two strands of one DNA molecule are unwound. Then,
DNA polymerases add complementary nucleotides to each strand which results in the formation
of two identical DNA molecules.
This process is known as DNA _______.
A. transcription
B. translation
C. cloning
D. replication
27. In eukaryotic organisms, DNA transcription occurs in the _______ of a cell.
A. nucleus
B. mitochondria
C. cytoplasm
D. ribosome
28. When new cells are formed through the process of mitosis, the number of chromosomes in
the new cells
A. remains the same as in the parent cell.
B. increases every time the cell divides.
C. decreases every time the cell divides.
D. is half of that of the parent cell.
29. The nucleotide of DNA is one large molecule composed of three smaller molecules. Which
of the following sets of molecules bond together to form a nucleotide?
A. deoxyribose, a nitrogen base, a phosphate group
B. a purine, a pyrimidine, and a five-carbon sugar
C. a nitrogen atom, a phosphate atom, and a five-carbon sugar
D. adenine, thymine, and cytosine
30. In DNA, the structure and size of the four nitrogen bases allows only for one kind of base to
pair with one other kind. This is called the base-pairing rule. Which of the following shows how
bases pair in complementary strands of DNA?
A. A-G and T-C
B. A-C and T-G
C. A-A and T-T
D. A-T and C-G
32. The first step in the process of gene expression is transcription. What is the product of
transcription during gene expression?
A. a codon
B. a molecule of RNA
C. an RNA polymerase
D. a molecule of thymine