BIOLOGY 189 STUDY GUIDE EXAM 2025/2026 QUESTIONS
AND SOLUTIONS GRADED A+ TIP
✔✔Rosalind Franklin - ✔✔Used X-ray diffraction to discover the double-helical structure
of DNA.
✔✔Watson and Crick - ✔✔Developed the double helix model of DNA.
✔✔Avery - ✔✔genes are composed of DNA , DNA (not proteins) can transform the
properties of cells
✔✔Erwin Chargaff - ✔✔the ratios of adenine (A) to thymine (T) and guanine (G) to
cytosine (C) are equal.
✔✔What are HeLa cells? Where did they come from? What kind of cells are they? Why
are they used? - ✔✔HeLa cells were the first human cells that researchers could grow
and multiply endlessly in the lab. They are cancer cells from cervical cancer.
✔✔What are the cell cycle stages? - ✔✔Interphase G1, G0, S, G2,Mitosis, cytoplasmic
division
✔✔Which stages are specifically part of mitosis? - ✔✔Prophase, metaphase, anaphase,
and telophase.
✔✔What cells undergo mitosis? - ✔✔somatic cells
✔✔What cells undergo meiosis? - ✔✔gametes
✔✔What are they major steps of mitosis? - ✔✔Prophase:, the nuclear envelope break
down, chromosomes attach to spindle fibers by their centromeres Metaphase:
chromosomes line up in the middle) Anaphase: sister chromatids are pulled to opposite
poles of the cell Telophase: nuclear envelope reforms, chromosomes unfold into
chromatin,
✔✔What are they major steps of meiosis? - ✔✔prophase1:chromosomes pack tightly,
attach to spindle poles Metaphase1: chromosomes line up in the middle Anaphase1:
sister chromatids are pulled to opposite poles of the cell Telophase1: nuclear envelope
reforms, chromosomes unfold into chromatin, ( repeat with starting with prophase 2)
✔✔In which stage do cells typically spend most of their life? - ✔✔Interphase
✔✔What is crossing over? - ✔✔the exchange of genes between homologous
chromosomes, resulting in a mixture of parental characteristics in offspring.
, ✔✔Does crossing over occur in mitosis? - ✔✔No, only in meiosis
✔✔What is a karyotype? - ✔✔an individual's complete set of chromosomes
✔✔What chromosome pairs is assigned female? - ✔✔XX
✔✔What chromosome pairs is assigned male? - ✔✔XY
✔✔What is the total chromosome number in humans? - ✔✔46
✔✔What is the difference between diploid cells and haploid cells? - ✔✔The number of
chromosome sets that are found in the nucleus
✔✔Does mitosis result in diploid or haploid cells? - ✔✔Diploid
✔✔Does meiosis result in diploid or haploid cells? - ✔✔haploid
✔✔Is the number of chromosomes in diploid cells half, double, or quadruple that of
haploid cells? - ✔✔Haploid cells have half the number of chromosomes (n) as diploid -
a haploid cell contains only one complete set of chromosomes.
✔✔What is an autosome? - ✔✔Any chromosome that is not a sex chromosome
✔✔What is a sex chromosome? - ✔✔a chromosome involved with determining the sex
of an organism, typically one of two kinds.
✔✔What is nondisjunction? - ✔✔Failure for chromosomes to separate properly.
✔✔When does nondisjunction occur? - ✔✔when chromosomes fail to separate during
meiosis
✔✔In which stage of the cell cycle is DNA replicated? - ✔✔S phase
✔✔What is down syndrome caused by? what is the result? - ✔✔Trisomy 21,distinct
facial appearance, intellectual disability, developmental delays
✔✔What is Marfan's syndrome? - ✔✔genetic condition that affects the body's
connective tissue.
✔✔Why are males more likely to exhibit X-linked disorders such as Fragile X
syndrome? - ✔✔Because females have two copies of the X chromosome and males
have only one X chromosome
AND SOLUTIONS GRADED A+ TIP
✔✔Rosalind Franklin - ✔✔Used X-ray diffraction to discover the double-helical structure
of DNA.
✔✔Watson and Crick - ✔✔Developed the double helix model of DNA.
✔✔Avery - ✔✔genes are composed of DNA , DNA (not proteins) can transform the
properties of cells
✔✔Erwin Chargaff - ✔✔the ratios of adenine (A) to thymine (T) and guanine (G) to
cytosine (C) are equal.
✔✔What are HeLa cells? Where did they come from? What kind of cells are they? Why
are they used? - ✔✔HeLa cells were the first human cells that researchers could grow
and multiply endlessly in the lab. They are cancer cells from cervical cancer.
✔✔What are the cell cycle stages? - ✔✔Interphase G1, G0, S, G2,Mitosis, cytoplasmic
division
✔✔Which stages are specifically part of mitosis? - ✔✔Prophase, metaphase, anaphase,
and telophase.
✔✔What cells undergo mitosis? - ✔✔somatic cells
✔✔What cells undergo meiosis? - ✔✔gametes
✔✔What are they major steps of mitosis? - ✔✔Prophase:, the nuclear envelope break
down, chromosomes attach to spindle fibers by their centromeres Metaphase:
chromosomes line up in the middle) Anaphase: sister chromatids are pulled to opposite
poles of the cell Telophase: nuclear envelope reforms, chromosomes unfold into
chromatin,
✔✔What are they major steps of meiosis? - ✔✔prophase1:chromosomes pack tightly,
attach to spindle poles Metaphase1: chromosomes line up in the middle Anaphase1:
sister chromatids are pulled to opposite poles of the cell Telophase1: nuclear envelope
reforms, chromosomes unfold into chromatin, ( repeat with starting with prophase 2)
✔✔In which stage do cells typically spend most of their life? - ✔✔Interphase
✔✔What is crossing over? - ✔✔the exchange of genes between homologous
chromosomes, resulting in a mixture of parental characteristics in offspring.
, ✔✔Does crossing over occur in mitosis? - ✔✔No, only in meiosis
✔✔What is a karyotype? - ✔✔an individual's complete set of chromosomes
✔✔What chromosome pairs is assigned female? - ✔✔XX
✔✔What chromosome pairs is assigned male? - ✔✔XY
✔✔What is the total chromosome number in humans? - ✔✔46
✔✔What is the difference between diploid cells and haploid cells? - ✔✔The number of
chromosome sets that are found in the nucleus
✔✔Does mitosis result in diploid or haploid cells? - ✔✔Diploid
✔✔Does meiosis result in diploid or haploid cells? - ✔✔haploid
✔✔Is the number of chromosomes in diploid cells half, double, or quadruple that of
haploid cells? - ✔✔Haploid cells have half the number of chromosomes (n) as diploid -
a haploid cell contains only one complete set of chromosomes.
✔✔What is an autosome? - ✔✔Any chromosome that is not a sex chromosome
✔✔What is a sex chromosome? - ✔✔a chromosome involved with determining the sex
of an organism, typically one of two kinds.
✔✔What is nondisjunction? - ✔✔Failure for chromosomes to separate properly.
✔✔When does nondisjunction occur? - ✔✔when chromosomes fail to separate during
meiosis
✔✔In which stage of the cell cycle is DNA replicated? - ✔✔S phase
✔✔What is down syndrome caused by? what is the result? - ✔✔Trisomy 21,distinct
facial appearance, intellectual disability, developmental delays
✔✔What is Marfan's syndrome? - ✔✔genetic condition that affects the body's
connective tissue.
✔✔Why are males more likely to exhibit X-linked disorders such as Fragile X
syndrome? - ✔✔Because females have two copies of the X chromosome and males
have only one X chromosome
