Lone Star Biology 1406 Exam 3
questions n answers graded A+
What event occurs in S stage of interphase that is crucial for normal cell division? - ANS ✔✔Cell
replicates its DNA: the genetic material of a cell is doubled before it enters mitosis or meiosis,
allowing there to be enough DNA to be split into daughter cells.
Identify the signaling molecules that stimulate cells to divide and push a cell through the
different stages of the cell cycle - ANS ✔✔Protein kinases and Cyclins
What conditions might cause a cell to halt the cell cycle at the three cell cycle checkpoints? -
ANS ✔✔If DNA is damaged and unrepairable, specific cyclins are not present, Rising levels of
P53, RB undergoes a mutation, DNA not done replicating, Chromosomes are not attached
correctly to the mitotic spindle
What cell conditions can bring about apoptosis in a cell? - ANS ✔✔Apoptosis can eliminate
infected or cancerous cells.
What are the 2 types of molecules that make up a eukaryotic chromosome? - ANS ✔✔DNA &
Protein OR C- Nucleic Acid & Proteins
How does DNA become sufficiently compacted to fit inside the nucleus? - ANS ✔✔DNA of each
chromosome is coiled, compacted, and coiled more, The DNA is wrapped around a group of
special proteins called histones, DNA strings wrap around the histone octatmer bead to create
the nucleosome.
Distinguish between chromatin and chromosome - ANS ✔✔Chromatin consists of the unraveled
condensed structure of DNA for the purpose of packaging into the nucleus. Chromosome
, consists of the highest condensed structure of the DNA double helix for the proper separation
of the genetic material.
How is a diploid cell different from a haploid cell? List examples of each. - ANS ✔✔Diploid-
Chromosomes with two sets (2n) Example: Skin, Blood, muscle cells, cells used in sexual
reproduction, sperm and ova. Haploid- cells with one set. Example: Gametes produced as a
result of meiosis.
What is the role of the mitotic spindle? How is it formed? - ANS ✔✔Structure composed of
microtubules which segregates chromosomes into the daughter cells during mitosis. Formed
during prophase, chromatin fibers become tightly coiled and condense into chromosomes.
Chromosomes line up in pairs and are joined at the centromere. In the cytoplasm, the spindle
fibers begin to form and are made of microtubules.
List the 5 major phases of mitosis and describe the events characteristic of each phase. - ANS
✔✔Interphase, Prophase, Metaphase, Anaphase, Telophase. / Cell division is only complete
after cytokinesis, which takes place during anaphase and telophase.
Compare cytokinesis in animal and plant cells. - ANS ✔✔Plant Cells: Cell wall forms / Animal
Cells: Cleavage furrow forms
What are the 2 major functions of mitotic cell division in multicellular eukaryotes such as plants
and animals? - ANS ✔✔Mitosis= cell division by which the nucleus of the cell divides. / process
of cell renewal and growth in a plant, animal or fungus.
What are stem cells? What potential uses do they have? - ANS ✔✔Cells with potential to
develop into many different types of cells in the body. The serve as a repair system for the body.
What is cancer? What actually causes cancer? - ANS ✔✔Cancer is the uncontrolled growth of
abnormal cells in the body. Cancer develops when the body's normal control mechanism stops
working. Old cells do not die and instead grow out of control, forming new, abnormal cells.
questions n answers graded A+
What event occurs in S stage of interphase that is crucial for normal cell division? - ANS ✔✔Cell
replicates its DNA: the genetic material of a cell is doubled before it enters mitosis or meiosis,
allowing there to be enough DNA to be split into daughter cells.
Identify the signaling molecules that stimulate cells to divide and push a cell through the
different stages of the cell cycle - ANS ✔✔Protein kinases and Cyclins
What conditions might cause a cell to halt the cell cycle at the three cell cycle checkpoints? -
ANS ✔✔If DNA is damaged and unrepairable, specific cyclins are not present, Rising levels of
P53, RB undergoes a mutation, DNA not done replicating, Chromosomes are not attached
correctly to the mitotic spindle
What cell conditions can bring about apoptosis in a cell? - ANS ✔✔Apoptosis can eliminate
infected or cancerous cells.
What are the 2 types of molecules that make up a eukaryotic chromosome? - ANS ✔✔DNA &
Protein OR C- Nucleic Acid & Proteins
How does DNA become sufficiently compacted to fit inside the nucleus? - ANS ✔✔DNA of each
chromosome is coiled, compacted, and coiled more, The DNA is wrapped around a group of
special proteins called histones, DNA strings wrap around the histone octatmer bead to create
the nucleosome.
Distinguish between chromatin and chromosome - ANS ✔✔Chromatin consists of the unraveled
condensed structure of DNA for the purpose of packaging into the nucleus. Chromosome
, consists of the highest condensed structure of the DNA double helix for the proper separation
of the genetic material.
How is a diploid cell different from a haploid cell? List examples of each. - ANS ✔✔Diploid-
Chromosomes with two sets (2n) Example: Skin, Blood, muscle cells, cells used in sexual
reproduction, sperm and ova. Haploid- cells with one set. Example: Gametes produced as a
result of meiosis.
What is the role of the mitotic spindle? How is it formed? - ANS ✔✔Structure composed of
microtubules which segregates chromosomes into the daughter cells during mitosis. Formed
during prophase, chromatin fibers become tightly coiled and condense into chromosomes.
Chromosomes line up in pairs and are joined at the centromere. In the cytoplasm, the spindle
fibers begin to form and are made of microtubules.
List the 5 major phases of mitosis and describe the events characteristic of each phase. - ANS
✔✔Interphase, Prophase, Metaphase, Anaphase, Telophase. / Cell division is only complete
after cytokinesis, which takes place during anaphase and telophase.
Compare cytokinesis in animal and plant cells. - ANS ✔✔Plant Cells: Cell wall forms / Animal
Cells: Cleavage furrow forms
What are the 2 major functions of mitotic cell division in multicellular eukaryotes such as plants
and animals? - ANS ✔✔Mitosis= cell division by which the nucleus of the cell divides. / process
of cell renewal and growth in a plant, animal or fungus.
What are stem cells? What potential uses do they have? - ANS ✔✔Cells with potential to
develop into many different types of cells in the body. The serve as a repair system for the body.
What is cancer? What actually causes cancer? - ANS ✔✔Cancer is the uncontrolled growth of
abnormal cells in the body. Cancer develops when the body's normal control mechanism stops
working. Old cells do not die and instead grow out of control, forming new, abnormal cells.
