Cell Cycle Overview

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Questions and Answers

Which phase of the cell cycle is responsible for synthesizing DNA?

S Phase (correct)

G1 Phase

G2 Phase

M Phase

What is primarily occurring during the G1 phase of the cell cycle?

Cell growth and metabolism (correct)

DNA replication

Cell division

Chromosome alignment

What is the primary function of the G2 phase in the cell cycle?

Preparation for mitosis (correct)

DNA repair

Protein degradation

Apoptosis initiation

Which phase follows the M phase in the cell cycle?

G1 Phase Signup and view all the answers

During which phase of the cell cycle does the actual cell division occur?

M Phase Signup and view all the answers

What is a critical checkpoint in the cell cycle that assesses DNA integrity prior to entering mitosis?

G2 Checkpoint Signup and view all the answers

What is the main role of checkpoints in the cell cycle?

To prevent mutations and maintain genomic integrity Signup and view all the answers

Which of the following is not true about the interphase of the cell cycle?

It is the phase of active mitosis Signup and view all the answers

What is the primary function of the G1 phase in the cell cycle?

Cell growth and normal metabolic roles take place. Signup and view all the answers

Which of the following statements is true regarding the M phase?

It is the phase where cell division actually occurs. Signup and view all the answers

What occurs during the first checkpoint of the cell cycle?

The cell commits to cell division. Signup and view all the answers

During which phase of the cell cycle does DNA replication occur?

S phase Signup and view all the answers

Nerve cells are typically found in which stage of the cell cycle?

G0 phase Signup and view all the answers

What happens during the G2 phase of the cell cycle?

Cell growth and preparation for mitosis. Signup and view all the answers

What criteria are evaluated during the checkpoints in the cell cycle?

Cell size, DNA replication, and DNA damage. Signup and view all the answers

Which type of cell stops division after a certain stage, as mentioned?

Heart cells Signup and view all the answers

What is the primary function of the G1 checkpoint in the cell cycle?

It checks for DNA damage before entering S phase. Signup and view all the answers

During which phase does the cell prepare for mitosis?

G2 Phase Signup and view all the answers

What is the role of cyclin proteins during the cell cycle?

They promote the transition between different cell cycle phases. Signup and view all the answers

What is the end product of mitosis?

Two genetically identical daughter cells. Signup and view all the answers

Which statement correctly describes the G2 checkpoint?

It primarily checks the integrity of DNA before mitosis. Signup and view all the answers

How many chromosomes are present after mitosis in a human somatic cell?

46 chromosomes Signup and view all the answers

What characteristic best describes equational division?

It produces two identical daughter cells. Signup and view all the answers

What occurs during the M phase of the cell cycle?

Cell divides into two daughter cells. Signup and view all the answers

Study Notes

Cell Cycle

The cell cycle is a series of events that take place in a cell leading to its growth and division.
The cycle has two phases: Interphase (Growth phase) and M-phase (Division phase).
The cell cycle is regulated by cyclin proteins and cyclin-dependent kinases (CDK) enzymes.
Checkpoints are control mechanisms within the cell cycle ensuring that the cell progresses through each stage appropriately.
The cell cycle is divided into four main phases: G1 (gap 1), S (synthesis), G2 (gap 2), and M (mitosis).
The G1 phase is the first gap phase, where the cell grows and prepares for DNA replication.
The G1/S checkpoint is a critical checkpoint, deciding if the cell is ready to proceed to S-phase.
The S-phase is the synthesis phase where DNA replicates, leading to the duplication of chromosomes.
The G2 phase is the second gap phase, where the cell continues to grow and prepares for mitosis.
The G2/M checkpoint ensures that the cell has replicated its DNA correctly before entering M-phase.
The M-phase encompasses the processes of karyokinesis (nuclear division) and cytokinesis (cytoplasmic division).
The M-phase is divided into two stages: mitosis and cytokinesis.
Mitosis is the process of nuclear division, where chromosomes are equally segregated into two daughter nuclei.
Cytokinesis is the division of the cytoplasm, resulting in two daughter cells.

DNA and Chromosome Changes

The amount of DNA in a cell during the cell cycle is measured in picograms (pg).
The DNA content of a cell doubles during the S-phase of the cell cycle.
The chromosome number (n) remains constant throughout the cell cycle.
In mitosis, daughter cells have the same DNA content and chromosome number as the parent cell.

Duration of the Cell Cycle

The duration of the cell cycle varies significantly across different organisms and cell types.
Bacterial cells have a cell cycle duration of 20-30 minutes.
Yeast cells have a cell cycle duration of 1-5 hours.
Human skin cells complete the cell cycle in approximately 24 hours.

G1 Phase and its Relevance to the Cell Cycle

Cell growth and metabolic activity occur in the G1 phase.
The G1 phase is a significant portion of the cell cycle, often lasting 23 hours in human cells.
Cells can enter a resting stage (G0) from the G1 phase, exiting the cell cycle.
Nervous cells (neurons) are non-dividing cells and remain permanently in the G1 phase.

Important Note

Cells in the G1 phase are actively engaged in metabolic activities and protein synthesis.
The G1/S checkpoint allows progression into the S-phase only if the cell meets specific requirements, ensuring DNA replication occurs under appropriate conditions.

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Description

Explore the essential phases of the cell cycle, including Interphase and M-phase. Test your knowledge on the role of cyclins, CDKs, and key checkpoints that regulate cell division. Understand how the G1, S, G2, and M phases contribute to cell growth and replication.