Download Biology DNA MCAS questions

BIOLOGY
DNA MCAS
QUESTIONS
Which of the following statements describes a DNA
molecule?
A. It contains the base uracil.
B. It has a double helix shape.
C. It contains five phosphate groups per nucleotide.
D. It has a backbone of twenty different
nucleotides.

The diagram below shows a pair of DNA
nucleotides. The nitrogenous base guanine (G) is
labeled.
Which nitrogenous base pairs with guanine?
A. adenine (A)
B. cytosine (C)
C. thymine (T)
D. uracil (U)

Radon is a radioactive gas that is sometimes
present in homes. If radon is inhaled, its decay
products are deposited in the lungs. Radioactive
particles can penetrate cells and cause changes to
the cells’ DNA. These changes in DNA are an
example of which of the following?
A. homeostasis
B. mitosis
C. mutation
D. transcription
 In
a molecule of double-stranded DNA,
the amount of adenine present is always
equal to the amount of
A. cytosine.
B. guanine.
C. thymine.
D. uracil.

Which of the following describes the function of
DNA?
A. encoding genetic information
B. storing energy in chemical bonds
C. speeding up biochemical reactions
D. destroying substances that enter the cell
The diagram represents a process that occurs
in the nucleus of a eukaryotic cell.
Which of the following statements describes
what is happening in this process?
A. Molecules of RNA are forming
chromosomes.
B. A molecule of mRNA is directing the
production of tRNA.
C. Molecules of DNA are being packaged for
export to the ribosomes.
D. A molecule of DNA is being replicated to
make two identical copies.
In phenylketonuria (PKU), an enzyme that
converts one amino acid into another does not work
properly. Which of the following is the most likely
cause of this genetic condition?
A. an error in the transcription of the gene for the
enzyme
B. a mutation in the DNA sequence that codes for the
enzyme
C. an excess of the amino acids necessary to produce
the enzyme
D. a structural variation in the amino acid modified
by the enzyme

The table below presents a variety of mRNA three-base
sequences (codons) and the amino acids for which these
sequences code.
 Based on the information in the table, which of the
following changes is least likely to produce a phenotypic
change in an organism?
1 Base
2 base
3 base
Amino Acid
A. GAU to GGU
of mRNA of mRNA of mRNA
G
A
A
Glutamic acid
B. GAU to GUU
C
Aspartic acid
C. GAU to GAA
G
Glutamic acid
D. GAU to GAC
U
Aspartic acid

st
nd
G
U
rd
A
Glycine
C
Glycine
G
Glycine
U
Glycine
A
Valine
C
Valine
G
Valine
U
Valine
 Which
of the following units are
repeatedly joined together to form a
strand of DNA?
A. amino acids
B. fatty acids
C. nucleotides
D. polysaccharides

The diagram below represents the beginning and end
products of a process that occurs in the nucleus of a
cell.
Which process does the diagram represent?
A. recombination
B. replication
C. transcription
D. translation

A
laboratory technique called polymerase
chain reaction (PCR) produces millions of
copies of a DNA molecule in only a few
hours. PCR is most similar to which of the
following cellular processes?
A. mitosis
B. replication
C. transcription
D. translocation
 During
DNA replication, the wrong
nucleotide was inserted in the DNA
sequence. Which of the following
terms describes this situation?
 A.
mutation
 B. regeneration
 C. transcription
 D. translation

Huntington’s disease (HD) is a hereditary disease
that destroys brain cells. In individuals with HD,
the functioning of a specific protein is altered, and
this leads to the disease’s effects. Which of the
following is the most likely cause of the altered
protein function in individuals with HD?
A. a mutation in the DNA sequence that codes for the
protein
B. an increase in the amount of fat rather than
protein in the diet
C. a decrease in the amount of glucose and amino
acids in the blood
D. a structural abnormality in the endoplasmic
reticulum of brain cells
 Which
of the following features of
DNA is most important in
determining the traits of an
organism?
A. the direction of the helical twist
B. the number of deoxyribose sugars
C. the sequence of nitrogenous bases
D. the strength of the hydrogen bonds

Which of the following models most accurately
represents the structure of DNA?
 In
a eukaryotic cell, which of the following
processes directly involves DNA?
A. translation
B. cellular respiration
C. active transport of ions
D. replication of chromosomes
A portion of one strand of a DNA molecule has
the sequence shown below.
ACCTGAAGG
 Assuming there are no mutations in this portion
of the DNA, what is the corresponding sequence
on the complementary DNA strand?

A. ACCTGAAGG
B. GTTCAGGAA
C. TGGACTTCC
D. TGGACUUCC