60 Questions
What is the result of mitosis in eukaryotic cells?
Production of genetically identical daughter cells
What type of cell division leads to the production of gametes?
Meiosis
What is the function of mitosis and cytokinesis in multicellular eukaryotes?
Growth, wound repair, and asexual reproduction
How does meiosis differ from mitosis?
Daughter cells have half the genetic material of the parent cell
What is the result of cytokinesis in cell division?
The cytoplasm of the cell divides into two distinct daughter cells
What may uncontrolled cell division lead to in multicellular organisms?
Cancer
What is the main outcome of the cell cycle in eukaryotic cells?
Production of genetically identical daughter cells
What is the purpose of meiosis in eukaryotic organisms?
Production of gametes with half the genetic material of the parent cell
What leads to the division of preexisting cells in eukaryotic organisms?
Cell division
What is the role of mitosis in wound repair in multicellular eukaryotes?
Regeneration of damaged tissue
During which phase of the cell cycle are chromosomes replicated?
S phase
What is the structure formed by DNA and histone proteins in eukaryotic cells?
Nucleosome
Which phase of mitosis involves the condensation of chromosomes and breakdown of the nuclear envelope?
Prophase
What is the process of distributing chromosomes to daughter cells during cell division called?
Mitosis
What marks the end of mitosis?
Telophase
In which phase of mitosis do the chromosomes line up in the middle of the cell?
Metaphase
What is the term for the division of the cytoplasm to form two daughter cells?
Cytokinesis
Which phase involves the splitting of centromeres and movement of sister chromatids to opposite poles of the cell?
Anaphase
What is the term for the continuous process with five subphases in mitosis?
Mitotic phase
What is the structure that joins two chromatids of a chromosome?
Centromere
What initiates cytokinesis in animals, fungi, and slime molds?
A ring of actin and myosin filaments
How does bacteria division differ from animal cytokinesis?
It does not involve cytokinesis
What causes the chromosome to move to one end of the mitotic spindle during anaphase?
Shortening of kinetochore microtubules
What is responsible for the variation in the length of the cell cycle among cell types?
Variation in the length of G1 phase
What is Mitosis-promoting factor (MPF) composed of?
A protein kinase and a cyclin subunit
When is MPF active?
When bound to the cyclin subunit
What renders MPF's Cdk subunit inactive?
Phosphorylation at two sites
What triggers the condensation of chromosomes and formation of the mitotic spindle apparatus?
MPF
What prevents the division of damaged cells and ensures proper chromosome separation?
G1, G2, and metaphase checkpoints
What is the function of the p53 protein?
Pauses the cell cycle or initiates apoptosis if the DNA is damaged
What is the main function of mitosis in multicellular eukaryotes?
Growth
What is the result of meiosis in eukaryotic organisms?
Production of gametes with half the genetic material
What is the consequence of uncontrolled cell division in multicellular organisms?
Cancer
What is the role of cytokinesis in cell division?
Division of the cytoplasm to form daughter cells
What is the function of mitosis in wound repair in multicellular eukaryotes?
Regeneration of damaged tissues
What is the key difference between meiosis and mitosis?
Meiosis produces gametes with half the genetic material, while mitosis produces genetically identical somatic cells
What may result from different types of defects in control over the cell cycle?
Different types of cancer
What is responsible for the regulation of progression through the cell cycle in eukaryotic cells?
Carefully regulated processes
What is the primary outcome of cell division in eukaryotic organisms?
Production of new cells
What is the result of mitosis and cytokinesis in multicellular eukaryotes?
Production of genetically identical cells
What is the structure of eukaryotic chromosomes consisting of DNA and histone proteins called?
Chromatin
What is the process that marks the end of mitosis and involves the division of the cytoplasm to form two daughter cells?
Cytokinesis
What is the term for the continuous process with five subphases in mitosis?
Prophase
What leads to the division of preexisting cells in eukaryotic organisms?
Mitosis
What is the term for the structure formed by DNA and histone proteins in eukaryotic cells?
Chromatin
What is the phase of mitosis that involves the condensation of chromosomes, breakdown of the nuclear envelope, and formation of the mitotic spindle?
Prophase
What is the process of distributing chromosomes to daughter cells during cell division called?
Mitosis
What is the result of mitosis in eukaryotic cells?
Formation of two daughter nuclei with identical chromosomes
What is the phase of mitosis that involves the splitting of centromeres and movement of sister chromatids toward opposite poles of the cell?
Anaphase
What is the phase of mitosis where the chromosomes line up in the middle of the cell on the metaphase plate?
Metaphase
What is the role of the p53 protein in the cell cycle?
Pauses the cell cycle or initiates apoptosis if the DNA is damaged
What is the composition of Mitosis-promoting factor (MPF)?
A protein kinase and a cyclin subunit
What differentiates benign tumors from malignant tumors?
Benign tumors are noninvasive and noncancerous, while malignant tumors are invasive and can spread throughout the body
What is the function of cytokinesis in cell division?
Divides the cytoplasm to form two daughter cells
What is the result of uncontrolled cell division in multicellular organisms?
Cancerous cells with defects in cell-cycle checkpoints
What causes the chromosome to move to one end of the mitotic spindle during anaphase?
Kinetochore microtubules shorten due to loss of tubulin subunits
What is the role of the G2 cell-cycle checkpoint?
Allows enzymes to activate MPF
What is the process initiated by a ring of actin and myosin filaments during cytokinesis?
Causing the cell membrane to pinch inward in a cleavage furrow
What is the function of the metaphase cell-cycle checkpoint?
Ensures proper chromosome separation
What is the result of MPF being active only when bound to the cyclin subunit?
Induces mitosis in all eukaryotes
Study Notes
Understanding Cell Division and Cancer
- Cytokinesis in animals, fungi, and slime molds is initiated by a ring of actin and myosin filaments causing the cell membrane to pinch inward in a cleavage furrow.
- Bacteria divide via fission, which is similar to animal cytokinesis but does not involve cytokinesis.
- During anaphase, kinetochore microtubules shorten due to loss of tubulin subunits from their plus ends at the kinetochore, pulling the chromosome to one end of the mitotic spindle.
- The length of the cell cycle can vary greatly among cell types, with variation in the length of G1 phase being responsible for these differences.
- Mitosis-promoting factor (MPF) induces mitosis in all eukaryotes and is composed of a protein kinase and a cyclin subunit.
- Cyclin concentration regulates the concentration of MPF, with MPF being active only when bound to the cyclin subunit.
- MPF's Cdk subunit is rendered inactive when phosphorylated at two sites, but late in G2 phase, enzymes cause one phosphate group to drop off, activating MPF.
- MPF triggers a chain of events culminating in the condensation of chromosomes and formation of the mitotic spindle apparatus, but is deactivated during anaphase by an enzyme complex that degrades its cyclin subunit.
- There are three distinct cell-cycle checkpoints: G1, G2, and metaphase, which prevent the division of damaged cells and ensure proper chromosome separation.
- The p53 protein pauses the cell cycle or initiates apoptosis if the DNA is damaged, and is an example of a tumor suppressor.
- Cancer is caused by cells with uncontrolled growth, invasion of nearby tissues, and spread to other sites in the body, arising from cells in which cell-cycle checkpoints have failed.
- Cancerous cells have defects that make proteins required for cell growth active when they should not be, and defects that prevent tumor suppressor genes from shutting down the cell cycle.
- Benign tumors are noninvasive and noncancerous, while malignant tumors are invasive and can spread throughout the body, a process known as metastasis.
Understanding Cell Division and Cancer
- Cytokinesis in animals, fungi, and slime molds is initiated by a ring of actin and myosin filaments causing the cell membrane to pinch inward in a cleavage furrow.
- Bacteria divide via fission, which is similar to animal cytokinesis but does not involve cytokinesis.
- During anaphase, kinetochore microtubules shorten due to loss of tubulin subunits from their plus ends at the kinetochore, pulling the chromosome to one end of the mitotic spindle.
- The length of the cell cycle can vary greatly among cell types, with variation in the length of G1 phase being responsible for these differences.
- Mitosis-promoting factor (MPF) induces mitosis in all eukaryotes and is composed of a protein kinase and a cyclin subunit.
- Cyclin concentration regulates the concentration of MPF, with MPF being active only when bound to the cyclin subunit.
- MPF's Cdk subunit is rendered inactive when phosphorylated at two sites, but late in G2 phase, enzymes cause one phosphate group to drop off, activating MPF.
- MPF triggers a chain of events culminating in the condensation of chromosomes and formation of the mitotic spindle apparatus, but is deactivated during anaphase by an enzyme complex that degrades its cyclin subunit.
- There are three distinct cell-cycle checkpoints: G1, G2, and metaphase, which prevent the division of damaged cells and ensure proper chromosome separation.
- The p53 protein pauses the cell cycle or initiates apoptosis if the DNA is damaged, and is an example of a tumor suppressor.
- Cancer is caused by cells with uncontrolled growth, invasion of nearby tissues, and spread to other sites in the body, arising from cells in which cell-cycle checkpoints have failed.
- Cancerous cells have defects that make proteins required for cell growth active when they should not be, and defects that prevent tumor suppressor genes from shutting down the cell cycle.
- Benign tumors are noninvasive and noncancerous, while malignant tumors are invasive and can spread throughout the body, a process known as metastasis.
Test your knowledge of cell division and cancer with this quiz covering topics such as cytokinesis, mitosis, cell-cycle checkpoints, tumor suppressor genes, and the characteristics of cancerous cells. Sharpen your understanding of these fundamental biological processes and their implications in health and disease.
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