University of Michigan
3 BAL · 171 OIB
★ ★
M College of Literature, Science & the Arts — Department of Biology
EST. 1817
ARTES · SCIENTIA · VERITAS
Bio 171 Lab exam 3
C E L L D I V I S I O N · P C R · G E L E L E CT R O P H O R E S I S · G E N E T I CS L A B O RATO RY
INSTITUTION University of Michigan PROGRAM Bachelor of Science — Biology
COURSE CODE BIO 171 COURSE TITLE Introduction to Molecular &
Cellular Biology
ACADEMIC YEAR EXAM TITLE Bio 171 Lab exam 3
TOTAL QUESTIONS 49 Questions FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This laboratory examination covers mitosis, meiosis, PCR, gel electrophoresis, Alu sequences, and
fundamental genetics concepts.
▸ Questions address cell division stages, chromosome numbers, DNA amplification techniques, and
laboratory procedures.
▸ Correct answers and explanatory rationales appear below each question for review purposes.
▸ All content reflects standard introductory biology laboratory curriculum for BIO 171 at the University of
Michigan.
, SECTION I — CELL DIVISION & MOLECULAR BIOLOGY
Questions 1 – 49
LABORATORY
1. A gene is best defined as:
A. The physical appearance of an organism
B. A segment of DNA on a chromosome that codes for a specific trait
C. The complete set of chromosomes in a cell
D. A reproductive cell such as sperm or egg
CORRECT ANSWER B — A segment of DNA on a chromosome that codes for a specific trait
RATIONALE A gene is a specific sequence of DNA located at a particular locus on a
chromosome that codes for a functional product, typically a protein. The
phenotype (option A) is the observable trait. The karyotype (option C) is the
complete chromosome set. Gametes (option D) are reproductive cells. Genes are
the fundamental units of heredity that determine traits through their expression.
2. What is the Alu insert?
A. A type of PCR primer used in DNA amplification
B. A transposon ("jumping gene") that is copied and inserted into a primate gene sequence
C. An enzyme that separates DNA strands during replication
D. A protein that binds to DNA during gel electrophoresis
CORRECT ANSWER B — A transposon ("jumping gene") that is copied and inserted into a
primate gene sequence
RATIONALE Alu elements are short interspersed nuclear elements (SINEs) — transposable
elements approximately 300 base pairs long that are unique to primates. They are
the most abundant mobile genetic elements in the human genome, with
approximately 1 million copies. Alu sequences can insert into genes, potentially
causing mutations, and are used in population genetics and forensic studies.
They are "jumping genes" because they can copy themselves and insert
elsewhere in the genome.
, 3. Somatic cells are:
A. Reproductive cells such as sperm and eggs
B. Any cells in the body other than reproductive cells
C. Cells found only in the gonads
D. Haploid cells produced by meiosis
CORRECT ANSWER B — Any cells in the body other than reproductive cells
RATIONALE Somatic cells comprise all body cells except the germline cells (gametes and their
precursors). They are diploid (2n) in humans, containing 46 chromosomes.
Somatic cells divide by mitosis for growth, repair, and maintenance. Gametes
(option A) are reproductive cells. Gonads (option C) are the organs that produce
gametes. Meiosis (option D) produces haploid gametes, not somatic cells.
4. Chromosomes are in their duplicated form in which phase?
A. G1 phase of interphase
B. G2 phase of interphase
C. Anaphase of mitosis
D. Telophase of mitosis
CORRECT ANSWER B — G2 phase of interphase
RATIONALE DNA replication occurs during S phase of interphase. After S phase, each
chromosome consists of two identical sister chromatids held together at the
centromere. These duplicated chromosomes persist through G2 phase and into
mitosis until anaphase, when sister chromatids separate. In G1 (before S phase),
chromosomes are unduplicated — each consists of a single chromatid.
3 BAL · 171 OIB
★ ★
M College of Literature, Science & the Arts — Department of Biology
EST. 1817
ARTES · SCIENTIA · VERITAS
Bio 171 Lab exam 3
C E L L D I V I S I O N · P C R · G E L E L E CT R O P H O R E S I S · G E N E T I CS L A B O RATO RY
INSTITUTION University of Michigan PROGRAM Bachelor of Science — Biology
COURSE CODE BIO 171 COURSE TITLE Introduction to Molecular &
Cellular Biology
ACADEMIC YEAR EXAM TITLE Bio 171 Lab exam 3
TOTAL QUESTIONS 49 Questions FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This laboratory examination covers mitosis, meiosis, PCR, gel electrophoresis, Alu sequences, and
fundamental genetics concepts.
▸ Questions address cell division stages, chromosome numbers, DNA amplification techniques, and
laboratory procedures.
▸ Correct answers and explanatory rationales appear below each question for review purposes.
▸ All content reflects standard introductory biology laboratory curriculum for BIO 171 at the University of
Michigan.
, SECTION I — CELL DIVISION & MOLECULAR BIOLOGY
Questions 1 – 49
LABORATORY
1. A gene is best defined as:
A. The physical appearance of an organism
B. A segment of DNA on a chromosome that codes for a specific trait
C. The complete set of chromosomes in a cell
D. A reproductive cell such as sperm or egg
CORRECT ANSWER B — A segment of DNA on a chromosome that codes for a specific trait
RATIONALE A gene is a specific sequence of DNA located at a particular locus on a
chromosome that codes for a functional product, typically a protein. The
phenotype (option A) is the observable trait. The karyotype (option C) is the
complete chromosome set. Gametes (option D) are reproductive cells. Genes are
the fundamental units of heredity that determine traits through their expression.
2. What is the Alu insert?
A. A type of PCR primer used in DNA amplification
B. A transposon ("jumping gene") that is copied and inserted into a primate gene sequence
C. An enzyme that separates DNA strands during replication
D. A protein that binds to DNA during gel electrophoresis
CORRECT ANSWER B — A transposon ("jumping gene") that is copied and inserted into a
primate gene sequence
RATIONALE Alu elements are short interspersed nuclear elements (SINEs) — transposable
elements approximately 300 base pairs long that are unique to primates. They are
the most abundant mobile genetic elements in the human genome, with
approximately 1 million copies. Alu sequences can insert into genes, potentially
causing mutations, and are used in population genetics and forensic studies.
They are "jumping genes" because they can copy themselves and insert
elsewhere in the genome.
, 3. Somatic cells are:
A. Reproductive cells such as sperm and eggs
B. Any cells in the body other than reproductive cells
C. Cells found only in the gonads
D. Haploid cells produced by meiosis
CORRECT ANSWER B — Any cells in the body other than reproductive cells
RATIONALE Somatic cells comprise all body cells except the germline cells (gametes and their
precursors). They are diploid (2n) in humans, containing 46 chromosomes.
Somatic cells divide by mitosis for growth, repair, and maintenance. Gametes
(option A) are reproductive cells. Gonads (option C) are the organs that produce
gametes. Meiosis (option D) produces haploid gametes, not somatic cells.
4. Chromosomes are in their duplicated form in which phase?
A. G1 phase of interphase
B. G2 phase of interphase
C. Anaphase of mitosis
D. Telophase of mitosis
CORRECT ANSWER B — G2 phase of interphase
RATIONALE DNA replication occurs during S phase of interphase. After S phase, each
chromosome consists of two identical sister chromatids held together at the
centromere. These duplicated chromosomes persist through G2 phase and into
mitosis until anaphase, when sister chromatids separate. In G1 (before S phase),
chromosomes are unduplicated — each consists of a single chromatid.
