lOMoARcPSD|11837912
BIOL 141 Unit 3 Study Guide
Foundations of Biology: Cells, Energy and Organisms (University of Maryland
Baltimore County)
, lOMoARcPSD|11837912
BIOL 141 Study Guide – updated 4/26/17
Chapter 12
1. What is a chromosome? What is a chromatid? How do sister chromatids differ from
homologous chromosomes?
A chromosome is a gene-carrying structure consisting of a single long molecule of double stranded
DNA and associated proteins. Each of the double stranded DNA copies in a replicated chromosome is
called a Chromatid. Sister chromatids have the same genes and alleles, while homologous have the same
genes but different alleles.
2. Draw a diagram showing the phases of the cell cycle. Describe the key events that occur during
each stage.
………. G1, S, G2, M. DNA synthesis in S phase, chromosomes replicated. M phase is mitosis.
3. When during the cell cycle are chromosomes duplicated? If a diploid cell has 4 pairs of chromosomes (2n
= 8) during G1, how many DNA double helices will be present in G1? in G2? in metaphase? in each
BIOL 141 Unit 3 Study Guide
Foundations of Biology: Cells, Energy and Organisms (University of Maryland
Baltimore County)
, lOMoARcPSD|11837912
BIOL 141 Study Guide – updated 4/26/17
Chapter 12
1. What is a chromosome? What is a chromatid? How do sister chromatids differ from
homologous chromosomes?
A chromosome is a gene-carrying structure consisting of a single long molecule of double stranded
DNA and associated proteins. Each of the double stranded DNA copies in a replicated chromosome is
called a Chromatid. Sister chromatids have the same genes and alleles, while homologous have the same
genes but different alleles.
2. Draw a diagram showing the phases of the cell cycle. Describe the key events that occur during
each stage.
………. G1, S, G2, M. DNA synthesis in S phase, chromosomes replicated. M phase is mitosis.
3. When during the cell cycle are chromosomes duplicated? If a diploid cell has 4 pairs of chromosomes (2n
= 8) during G1, how many DNA double helices will be present in G1? in G2? in metaphase? in each
