cell cycle Flashcards
(110 cards)
What happens during prophase in mitosis?
Chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibers form.
What is the role of spindle fibers during prometaphase in mitosis?
Spindle fibers attach to the kinetochores on the centromeres of chromosomes.
What happens during metaphase in mitosis?
Chromosomes align at the metaphase plate and spindle fibers attach to both sister chromatids of each chromosome.
What is the result of anaphase in mitosis?
Sister chromatids separate and are pulled towards opposite poles of the cell by spindle fibers.
What happens during telophase in mitosis?
Chromosomes reach opposite poles and begin to decondense, and nuclear envelopes start to reform.
What is cytokinesis in mitosis?
It is the division of the cytoplasm, usually beginning during telophase.
What is interphase in the cell cycle?
It is the period between mitotic divisions, where DNA replication occurs during the S phase.
What happens during the G1 phase of interphase?
The cell grows and carries out normal metabolic activities.
What happens during the S phase of interphase?
DNA replication occurs.
What happens during the G2 phase of interphase?
The cell prepares for mitosis by synthesizing proteins and organelles.
What is a checkpoint in the cell cycle?
A checkpoint is a control mechanism that ensures that a cell has completed necessary processes before progressing to the next stage of the cell cycle.
What is the purpose of the G1 checkpoint?
The G1 checkpoint ensures that the cell has enough resources and energy to begin DNA replication in the S phase.
What is the purpose of the G2 checkpoint?
The G2 checkpoint ensures that DNA replication was successful and that the cell is ready to enter mitosis.
What is the purpose of the spindle checkpoint?
The spindle checkpoint ensures that all chromosomes are properly attached to spindle fibers before the cell enters anaphase.
What happens if a cell fails the G1 checkpoint?
The cell enters a non-dividing state called G0, or undergoes apoptosis (programmed cell death).
What happens if a cell fails the G2 checkpoint?
The cell is prevented from entering mitosis, and DNA repair mechanisms are activated to fix any damage.
What happens if a cell fails the spindle checkpoint?
The cell is prevented from progressing to anaphase until all chromosomes are properly attached to spindle fibers.
How do checkpoint controls work?
Checkpoint controls involve specific proteins that detect DNA damage or incomplete processes, which then halt the cell cycle until the issues are resolved.
What is the significance of checkpoint controls in preventing cancer?
Checkpoint controls prevent damaged or mutated cells from proliferating, which can lead to the development of cancer.
What are some factors that can disrupt checkpoint controls?
Environmental toxins, radiation, and mutations in checkpoint control genes can all disrupt the normal functioning of checkpoints and increase the risk of cancer.
What are the gap phases in the cell cycle?
The gap phases are G1 and G2, which occur between DNA synthesis (S phase) and cell division (mitosis).
What happens during the G1 phase?
During G1, the cell grows and carries out normal metabolic activities, and checkpoint controls ensure that the cell has enough resources and energy to begin DNA replication in the S phase.
What is the duration of G1 phase?
The duration of G1 phase can vary depending on cell type, ranging from a few hours to several days.
What are some factors that can influence the duration of G1 phase?
Factors that can influence the duration of G1 phase include cell size, growth factors, and extracellular matrix signals.