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Questions and Answers
What does the G1 phase primarily involve?
What does the G1 phase primarily involve?
The S phase is when DNA replication occurs.
The S phase is when DNA replication occurs.
True
What is the G0 phase also known as?
What is the G0 phase also known as?
State of quiescence
The __________ is the structure that helps in dividing the DNA during M phase.
The __________ is the structure that helps in dividing the DNA during M phase.
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Match the cell cycle phase with its description:
Match the cell cycle phase with its description:
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Which phase comes after the S phase?
Which phase comes after the S phase?
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The centriole does not duplicate during interphase.
The centriole does not duplicate during interphase.
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What is the function of the G1 checkpoint?
What is the function of the G1 checkpoint?
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What is the primary purpose of the cell cycle?
What is the primary purpose of the cell cycle?
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The interphase is the shortest phase of the cell cycle.
The interphase is the shortest phase of the cell cycle.
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What are the two main phases of the cell cycle?
What are the two main phases of the cell cycle?
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During the interphase, the cell produces a copy of its genetic material (DNA) during the ______ phase.
During the interphase, the cell produces a copy of its genetic material (DNA) during the ______ phase.
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Match the cell cycle phases with their corresponding descriptions:
Match the cell cycle phases with their corresponding descriptions:
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Which of the following statements about mitosis is true?
Which of the following statements about mitosis is true?
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Cells in the G0 phase are actively dividing.
Cells in the G0 phase are actively dividing.
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Name one significance of mitosis.
Name one significance of mitosis.
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Which cyclin-CDK complex is primarily responsible for the G1/S transition in the cell cycle?
Which cyclin-CDK complex is primarily responsible for the G1/S transition in the cell cycle?
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The Anaphase Promoting Complex/Cyclosome (APC/C) marks securin for degradation in order to promote the transition from metaphase to anaphase.
The Anaphase Promoting Complex/Cyclosome (APC/C) marks securin for degradation in order to promote the transition from metaphase to anaphase.
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What role does the mTOR pathway play in cell division?
What role does the mTOR pathway play in cell division?
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Cyclin B/CDK1 drives the cell into __________.
Cyclin B/CDK1 drives the cell into __________.
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Match the growth factors with their role in the cell cycle:
Match the growth factors with their role in the cell cycle:
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What is the primary function of mitotic kinases during mitosis?
What is the primary function of mitotic kinases during mitosis?
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Growth factors directly cause DNA replication to occur in cells.
Growth factors directly cause DNA replication to occur in cells.
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Upon the degradation of __________, separase is activated to cleave cohesin proteins.
Upon the degradation of __________, separase is activated to cleave cohesin proteins.
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Study Notes
Cell Cycle and Mitosis
- Cell cycle (cell division cycle) is an ordered sequence of events in a cell, resulting in growth and DNA replication, forming two daughter cells.
- Cell cycle promotes renewal and regeneration of hair, blood cells, skin, and specific internal organs.
Stages of the Cell Cycle
- Interphase (I) is the longest phase, including G1, S, and G2 phases.
- G0 Phase: A resting period where cells temporarily stop dividing.
- G1 Phase: First gap phase, cell growth, and organelle copy.
- S Phase: Synthesis phase, DNA replication occurs.
- G2 Phase: Second gap phase, cell growth, protein production, and preparation for mitosis.
- Mitotic (M) Phase: Mitosis, the actual cell division process.
- Mitosis has four sub-stages: prophase, metaphase, anaphase, and telophase.
- Karyokinesis: division of the nucleus.
- Cytokinesis: division of the cytoplasm, forming two separate daughter cells.
Duration of the Cell Cycle
- Cell cycle duration varies among cell types.
- A typical human cell cycle lasts 24-90 hours.
- Specific phases within a typical cycle, like G1 (11 hours), S (8 hours), and G2 (4 hours) and M (1 hour).
- Some cells, like yeast, complete a full cycle in 90 minutes.
Significance of Mitosis
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Maintains chromosome count. Daughter cells receive a precise chromosome number.
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Crucial for growth and development of multicellular organisms. Organisms develop from a single fertilized egg to a complex structure through successive divisions.
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Maintains genetic consistency across tissues.
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Tissue repair - Damaged cells replaced, facilitates healing.
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Repairs damaged tissues. Crucial role in wound healing and tissue regeneration.
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Maintains proper cell size.
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Essential for normal tissue growth and maintenance.
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Important for growth, maintenance & survival of multicellular organisms.
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Important to maintain cellular homeostasis.
Mitotic Blockage
- Factors that can interrupt cell division.
- Anti-microtubule drugs (e.g., Paclitaxel): inhibit spindle formation.
- DNA damage-induced mitotic block: cell cycle checkpoints detect and respond to damage.
- Targeting cell cycle proteins (e.g., CDK, Cdc25): inhibition leads to mitotic blockage.
- Nutrient/ Cellular stress: can trigger cell cycle arrest to prevents mitotic progression if conditions are unfavorable,
- Aneuploidy-causing agents (e.g., Nocodazole): disrupting microtubules, affecting chromosome segregation.
Stimulation of Cell Division
- Cyclins & Cyclin-dependent kinases (CDKs) regulate cell division through the cell cycle.
- Multiple checkpoints ensure proper division.
- Growth factors stimulate cells to enter the cell cycle.
- Nutritional status and energy sensing: cells need nutrients and energy to divide.
- mTOR and AMPK pathways play roles.
- Anaphase Promoting Complex (APC/C): ensures cell cycle progression.
- Proper spindle formation (essential for accurate chromosome segregation).
Mitotic Checkpoints
- Spindle Assembly Checkpoint (SAC): ensuring chromosomes are correctly attached to spindle fibers.
Cytokinesis
- Division of cytoplasm into two daughter cells.
- Animal cells: cleavage furrow, contractile ring.
- Plant cells: cell plate formation by Golgi vesicles.
Cancer and Mitosis
- Uncontrolled cell division and tumor formation.
- Cancer cells bypass normal cell cycle controls.
- Mitosis is a key research area for cancer therapies.
Homeostasis and Replacement of Senescent Cells
- Maintaining tissue homeostasis (balancing cell death and division).
- Replacing senescent (aged) cells with new, healthy cells to maintain tissue integrity and function.
Mitosis and Immune Response
- White blood cells (e.g., T and B cells) proliferate rapidly through mitosis during immune responses.
- Clonal expansion is necessary for mounting a defense against pathogens.
Summary of Mitosis
- Mitosis enables growth, repair, and asexual reproduction.
- Crucial processes for the normal functioning of multicellular organisms.
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Description
Test your knowledge of the cell cycle and mitosis with this quiz! Explore the different phases, including interphase, G1, S, G2, and the mitotic phase. Understand the importance of these processes in growth and regeneration.
