18 Questions
What is the primary function of cyclin proteins in the cell cycle?
To regulate the cell cycle by binding to CDK
At which stage of the cell cycle does the binding of cyclin to CDK initiate protein synthesis?
G2 phase
What is the purpose of checkpoints in the cell cycle?
To monitor the cell cycle for errors
What is the result of uncontrolled cell growth and division?
Cancer
What is a characteristic of cancer cells compared to normal cells?
They spend less time in interphase
What can cause the occurrence of cancer cells?
Environmental factors
What is the consequence of unregulated cell growth and division?
Tissue function is lost
What is the role of CDK in the cell cycle?
To regulate the cell cycle by binding to cyclin
What is the primary mechanism that ensures the regulation of the normal cell cycle?
binding between cyclin and CDK proteins
During which stage of the cell cycle does the binding of cyclin to CDK signal the initiation of DNA replication?
S phase
What is the consequence of a failure in the regulation of the cell cycle?
cancer
What is the primary difference between cancer cells and normal cells in terms of their cell cycle?
cancer cells have a shorter interphase
What is the purpose of the checkpoint at the end of the G1 phase?
to monitor DNA damage
What is the result of cancer cells crowding out normal cells?
tissue atrophy
What is the primary characteristic of cancer cells in terms of their growth and division?
they grow and divide as long as they are supplied with nutrients
What is the role of environmental factors in the occurrence of cancer cells?
they can affect the occurrence of cancer cells
What is the primary mechanism that ensures the quality of DNA replication during the cell cycle?
quality control checkpoints
What is the consequence of a failure in the quality control checkpoints during the cell cycle?
unregulated cell growth and division
Study Notes
Cell Cycle Regulation
- Cell division rate varies depending on cell type
- Proteins and enzymes control the cell cycle
- Cyclin proteins regulate the normal cell cycle in eukaryotic cells
Cyclin and CDK in Cell Cycle
- Cyclin and cyclin-dependent kinase (CDK) control the cell cycle in eukaryotic cells
- Binding of cyclin to CDK triggers cell cycle activities:
- G1 stage: signals cell cycle start
- S phase: signals DNA replication
- G2 phase: initiates protein synthesis for mitosis
- Mitosis: signals nuclear division activities
Quality Control Checkpoints
- Checkpoints in the cell cycle monitor and regulate the cycle
- Checkpoints at:
- End of G1: monitors DNA damage
- End of S phase: monitors DNA replication
- End of G2 phase: monitors protein synthesis and DNA structure
- End of mitosis: monitors chromosome separation
Cancer and Cell Cycle
- Cancer is uncontrolled growth and division of cells due to failure in cell cycle regulation
- Cancer cells:
- Spend less time in interphase
- Grow and divide continuously with nutrients
- Can cause tissue function loss and death
Causes of Cancer
- Environmental factors can cause cancer
- Carcinogens: substances or agents that cause cancer
- Examples of carcinogens: smoking, UV light, X-ray, and asbestos
Apoptosis (Programmed Cell Death)
- Apoptosis regulates cell number in multicellular organisms
- Cells die through an intracellular death program when no longer needed
- Characteristics of apoptosis:
- Cells shrink or shrivel in a controlled process
- 50-70 billion cells die daily in an average human adult
- 20-30 billion cells die daily in an average child aged 8-14
Cell Cycle Regulation
- Cell division rate varies depending on cell type
- Proteins and enzymes control the cell cycle
- Cyclin proteins regulate the normal cell cycle in eukaryotic cells
Cyclin and CDK in Cell Cycle
- Cyclin and cyclin-dependent kinase (CDK) control the cell cycle in eukaryotic cells
- Binding of cyclin to CDK triggers cell cycle activities:
- G1 stage: signals cell cycle start
- S phase: signals DNA replication
- G2 phase: initiates protein synthesis for mitosis
- Mitosis: signals nuclear division activities
Quality Control Checkpoints
- Checkpoints in the cell cycle monitor and regulate the cycle
- Checkpoints at:
- End of G1: monitors DNA damage
- End of S phase: monitors DNA replication
- End of G2 phase: monitors protein synthesis and DNA structure
- End of mitosis: monitors chromosome separation
Cancer and Cell Cycle
- Cancer is uncontrolled growth and division of cells due to failure in cell cycle regulation
- Cancer cells:
- Spend less time in interphase
- Grow and divide continuously with nutrients
- Can cause tissue function loss and death
Causes of Cancer
- Environmental factors can cause cancer
- Carcinogens: substances or agents that cause cancer
- Examples of carcinogens: smoking, UV light, X-ray, and asbestos
Apoptosis (Programmed Cell Death)
- Apoptosis regulates cell number in multicellular organisms
- Cells die through an intracellular death program when no longer needed
- Characteristics of apoptosis:
- Cells shrink or shrivel in a controlled process
- 50-70 billion cells die daily in an average human adult
- 20-30 billion cells die daily in an average child aged 8-14
Learn about the normal cell cycle, its regulation, and the role of cyclin proteins and enzymes in controlling the process. Discover how cyclin-dependent kinases bind to start cell cycle activities.
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