UF BSC2005 Exam #2 Study Guide
Questions with Solved Solutions 2026-
2027 Updated.
What does DNA stand for? How does this name correspond to its molecular structure (also
review from Module 2)? - Answer Deoxyribonucleic Acid; the de- symbolizes the double helix
structure
What are chromosomes? What do they look like in prokaryotes vs. eukaryotes? - Answer
Chromosome - is a single, large DNA molecule wound around proteins.
Prokaryotes: cytoplasm in an area called the nucleoid. Eukaryotes: nucleus
How many types of chromosomes do humans have? How many total chromosomes? - Answer
Human cells have 23 pairs of chromosomes. we inherit one chromosome of each pair from our
mother and the other from our father, for a total of 46 chromosomes
What are homologous chromosomes? What are chromatids? - Answer A homologous pair
consists of one paternal and one maternal chromosome at the same site
A chromatid is one of the two identical halves of a chromosome that has been replicated in
preparation for cell division
Explain the difference between haploid and diploid organisms / cells. - Answer Diploid
organism have two of each type (most species; animals)
Haploid only have one copy of each chromosome (commonly in plants, bees, ants males)
How is diploidy maintained during reproduction? - Answer At fertilization, male and female
gametes fuse to restore diploidy in a zygote
Diploidy and Sex Reproduction
Haploid egg + haploid sperm = diploid embryo
- Chromosomes have to match properly
- Two many or too few means failure or down syndrome, etc.
What are the four types of nitrogenous bases? Which ones pair with each other? Be able to use
Chargaff's rule to determine the nucleotide composition of a segment of DNA - Answer
Adenine, Thymine, Guanine, Cytosine
CR: A = T, C = G
, What was Rosalind Franklin's role in determining the structure of DNA? - Answer She used x-
ray crystallography to determine the double helix structure of DNA
What does it mean to say that DNA is a double helix? What is the structure of each of the
strands? - Answer Structure
- Double helix of linked nucleotides joined by hydrogen bonds
- Ladder like, sugars (deoxyribose) and phosphates on the outside, nitrogenous bases are the
rungs, joined by hydrogen bonds
- Two strands are opposite each other, running in anti-parallel directions
What are the chromatids? When during cell division do they form, and how? When do they
separate? - Answer Chromatids form during interphase when they are duplicated, then they
are separated in Anaphase of mitosis
Interphase - Answer - prep steps
- cell does its "work"
- DNA is replicated so the chromosomes in the nucleus each consist of two connected copies
(called sister chromatids)
- chromosomes are long stringy and condensed
- animal cell makes centrosome
Prophase - Answer - chromosomes condense
- mitotic spindle forms
- nucleolus disappears and nuclear envelope breaks down
- some of the microtubules begin to "capture" chromosomes
Metaphase - Answer chromosomes line up in the middle
Anaphase - Answer the sister chromatids are pulled towards opposite sides and separate
Telophase - Answer - two new nuclei form
- nuclear membranes and nucleoli reappear
- chromosomes return to stringy form
Cytokinesis - Answer - Cytoplasm divides
- Splits into two cells
Questions with Solved Solutions 2026-
2027 Updated.
What does DNA stand for? How does this name correspond to its molecular structure (also
review from Module 2)? - Answer Deoxyribonucleic Acid; the de- symbolizes the double helix
structure
What are chromosomes? What do they look like in prokaryotes vs. eukaryotes? - Answer
Chromosome - is a single, large DNA molecule wound around proteins.
Prokaryotes: cytoplasm in an area called the nucleoid. Eukaryotes: nucleus
How many types of chromosomes do humans have? How many total chromosomes? - Answer
Human cells have 23 pairs of chromosomes. we inherit one chromosome of each pair from our
mother and the other from our father, for a total of 46 chromosomes
What are homologous chromosomes? What are chromatids? - Answer A homologous pair
consists of one paternal and one maternal chromosome at the same site
A chromatid is one of the two identical halves of a chromosome that has been replicated in
preparation for cell division
Explain the difference between haploid and diploid organisms / cells. - Answer Diploid
organism have two of each type (most species; animals)
Haploid only have one copy of each chromosome (commonly in plants, bees, ants males)
How is diploidy maintained during reproduction? - Answer At fertilization, male and female
gametes fuse to restore diploidy in a zygote
Diploidy and Sex Reproduction
Haploid egg + haploid sperm = diploid embryo
- Chromosomes have to match properly
- Two many or too few means failure or down syndrome, etc.
What are the four types of nitrogenous bases? Which ones pair with each other? Be able to use
Chargaff's rule to determine the nucleotide composition of a segment of DNA - Answer
Adenine, Thymine, Guanine, Cytosine
CR: A = T, C = G
, What was Rosalind Franklin's role in determining the structure of DNA? - Answer She used x-
ray crystallography to determine the double helix structure of DNA
What does it mean to say that DNA is a double helix? What is the structure of each of the
strands? - Answer Structure
- Double helix of linked nucleotides joined by hydrogen bonds
- Ladder like, sugars (deoxyribose) and phosphates on the outside, nitrogenous bases are the
rungs, joined by hydrogen bonds
- Two strands are opposite each other, running in anti-parallel directions
What are the chromatids? When during cell division do they form, and how? When do they
separate? - Answer Chromatids form during interphase when they are duplicated, then they
are separated in Anaphase of mitosis
Interphase - Answer - prep steps
- cell does its "work"
- DNA is replicated so the chromosomes in the nucleus each consist of two connected copies
(called sister chromatids)
- chromosomes are long stringy and condensed
- animal cell makes centrosome
Prophase - Answer - chromosomes condense
- mitotic spindle forms
- nucleolus disappears and nuclear envelope breaks down
- some of the microtubules begin to "capture" chromosomes
Metaphase - Answer chromosomes line up in the middle
Anaphase - Answer the sister chromatids are pulled towards opposite sides and separate
Telophase - Answer - two new nuclei form
- nuclear membranes and nucleoli reappear
- chromosomes return to stringy form
Cytokinesis - Answer - Cytoplasm divides
- Splits into two cells
