Cell Cycle Flashcards
It is an active phase where the cell performs normal biochemical functions and prepares for division.
Interphase
A phase in the interphase where the Cell grows and synthesizes proteins, lipids,
and carbohydrates.
G1 phase (Gap 1)
A phase in the interphase where DNA replication occurs, forming two
copies of each chromosome.
S phase (Synthesis)
A phase in the interphase where additional proteins and membranes are synthesized for cell division.
G2 phase (Gap 2):
During which cell cycle phase does a cell exit the cycle from G1, maintain its specialized functions without dividing, and have the potential to re-enter the cycle, undergo mitosis, or undergo apoptosis if DNA damage is severe?
Interphase Gap 0 (quiescent phase)
Which phase in the interphase occurs after mitosis, where the cell resumes synthesis of essential macromolecules, prepares plasma membrane components for future daughter cells and has a duration that varies by cell type?
G1 phase (Gap 1)
What is the duration variety of cell types?
Duration varies by cell type:
○ Slow-dividing cells (e.g., liver cells) may enter G0 and remain there for years.
○ Fast-dividing cells (e.g., bone marrow cells) complete G1 in 16–24 hours.
○ Embryonic cells may skip G1 entirely.
During which phase of the cell cycle in the interphase does DNA replication occur, producing two identical copies of each chromosome joined at the centromere?
S phase
In which phase in the interphase are proteins needed for mitosis, like the mitotic spindle, synthesized, and microtubules form centrioles near the nucleus?
S phase
During which phase in the interphase do centrioles and associated proteins form centrosomes that help organize the mitotic spindle, and mutations in centrosome-related genes can cause microcephaly?
S phase
In which phase of the cell cycle does DNA replication occur, but the cell prepares for mitosis by synthesizing more proteins?
G2 phase
During which phase in the interphase are plasma membrane components made in G1 stored in vesicles, which later merge with the plasma membrane to enclose daughter cells?
G2 Phase
This is the process where a
replicated cell divides into two identical
daughter cells.
Mitosis
They are the two identical strands of a replicated chromosome.
Chromatids
The _________ of a replicated
chromosome splits, allowing chromatids
to separate into individual
chromosomes.
centromere
In which phase of the cell cycle do chromosomes coil tightly, shortening and thickening?
Prophase
During which phase do spindle fibers form from tubulin in the cytoplasm?
Prophase
In which phase does the nuclear membrane break down and the nucleolus disappear?
Prophase
In which phase of the cell cycle do chromosomes align at the cell’s center (equator)?
Metaphase
During which phase do chromosomes attach to the spindle fibers at their centromeres?
Metaphase
In which phase do chromosomes appear still but are under equal tension from both sides?
Metaphase
In which phase of the cell cycle does the plasma membrane indent at the center?
Anaphase
During which phase do centromeres split, allowing chromatids to separate and move to opposite sides?
Anaphase
In which phase does the cell momentarily have twice the normal number of chromosomes?
Anaphase
During which phase do microtubules stretch the dividing cell?
Anaphase
In which phase of the cell cycle does the cell resemble a dumbbell with a set of chromosomes at each end?
Telophase
During which phase does the spindle disassemble?
Telophase
In which phase do nucleoli and nuclear membranes re-form?
Telophase
During which phase is genetic division complete?
Telophase
In which process are organelles and macromolecules distributed between two daughter cells?
Cytokinesis
During which process does a microfilament band contract like a drawstring, fully separating the new cells?
Cytokinesis
What happens when there is too little mitosis in the body and what happens if there is too much mitosis in the body?
Too little mitosis → Injuries remain unhealed.
Too much mitosis → Abnormal growth (e.g., tumors).
It ensures accurate chromosome replication and division:
Checkpoints
Pauses the cycle to repair damaged DNA.
DNA Damage Checkpoint
Ensures mitosis
occurs instead of cell death.
Apoptosis Checkpoint
Ensures proper spindle construction and
chromosome attachment.
Spindle Assembly Checkpoint
Cells follow an _________ that limits the number of divisions.
Internal Clock
TRUE OR FALSE: Most mammalian cells divide 40–60 times before stopping.
TRUE
What structures at the tips of chromosomes shorten with each cell division?
Telomeres
It maintains telomere length in certain cells.
Telomerase enzymes
signal aging and limit a cell’s lifespan.
Shortened telomeres
TRUE OR FALSE: Environmental factors (stress, obesity, high blood sugar) accelerate telomere
shortening.
TRUE
TRUE OR FALSE: Exercise may slow telomere shortening, as seen in studies on identical twins.
TRUE
– Cells stop dividing when they form a one-cell-thick layer.
○ If a gap forms, nearby cells divide to fill it, then stop.
Contact Inhibition
Travel through the bloodstream to stimulate mitosis (e.g., uterine
lining growth).
Hormones
Act locally to promote mitosis (e.g., Epidermal Growth Factor
aids wound healing).
Growth factors
TRUE OR FALSE: Some cancer drugs block growth factor receptors to stop abnormal cell
division.
TRUE
TRUE OR FALSE: Cyclins & kinases regulate mitosis by turning on necessary genes.
TRUE
Which of the following is true about cyclins and kinases?
A) Cyclin levels remain constant, while kinase levels fluctuate.
B) Cyclin levels fluctuate, while kinase levels remain constant.
C) Both cyclin and kinase levels fluctuate equally.
B) Cyclin levels fluctuate, while kinase levels remain constant.
Which of the following is true about cyclin-kinase pairs and mitosis?
A) When enough cyclin-kinase pairs accumulate, mitosis begins.
B) Mitosis begins when cyclin levels remain constant.
C) Mitosis begins when kinase levels fluctuate.
A) When enough cyclin-kinase pairs accumulate, mitosis begins.
Which of the following is true about cyclin degradation and resetting the cycle?
A) Enzymes degrade cyclins once mitosis starts, resetting the cycle for the next division.
B) Cyclins degrade enzymes once mitosis starts, resetting the cycle for the next division.
C) Cyclins remain intact after mitosis and do not affect the cycle.
A) Enzymes degrade cyclins once mitosis starts, resetting the cycle for the next division.
