General Biology - Cell Cycle

(10-15-2025)

Reproduction

One of the functions of the cell is ____________.

Cellular Reproduction

The only way a living organism can grow is by ________ ____________.

Wound Healing

_____ ________ js an example of cell reproduction

Nucleus

The ________ is the control center of the cell.

Chromatin

The relaxed form of DNA in the cell’s nucleus; uncoiled DNA

Prokaryotes

Reproduce by a process known as binary fission.

Eukaryotes

Reproduce by cell division.

Cell Cycle

Process of cellular reproduction; a cycle of growing and dividing

Interphase, Mitosis, and Cytokinesis

Three (3) stages of the cell cycle:

Interphase

-growth; further divided into G1, S, and G2.

-The stage during which cell grows, carries out cellular functions, and replicates

Mitosis

Nuclear Division

Cytokinesis

-Cytoplasm division

-the stage where cytoplasm divides, creating a new cell.

G1, S, and G2

Three (3) substages of Interphase:

G1 or Gap 1

____ _ Substage is where the cell grows and performs its normal functions.

S or Synthesis

_______ substage where DNA is replicated

G2 or Gap 2

____ _ is where the cell prepares for mitosis or division of the nucleus.

Replication

________ is the process of making copies of its DNA in preparation for the next stage of the cell cycle.

Mitosis

Stage of the cell cycle during which the cell’s nucleus and nuclear material divides.

Sister Chromatids

_____ _______ are structures that contain identical DNA copies and are formed during DNA replication.

Prophase, Metaphase, Anaphase, and Telophase

Four (4) stages of mitosis:

Cell Plate

In plant cells, the cells divide at the structure call the ____ ______.

Cell ring

In animal, when the cell divides at the structure is called ____ ____.

12-24 hours

The most normal actively dividing animal cells complete the cycle in _____ _____

Prophase

Sets the stage for DNA segregation, Cell's chromatin condenses, becoming more and more compact and are shaped condensing into visible chromosomes. Chromosomes like an X; at the end of prophase, nuclear membrane disintegrates; nucleolus disappear; microtubules called spindle fibers form in the cytoplasm; centrosomes mov to opposite poles.

Metaphase

Chromosomes attach to the spindle apparatus and align along the equator of the cell.

Anaphase

Microtubules shorten, moving chromosomes to apposite poles The paired sister chromatids separate, and the new daughter chromosomes begin to move toward the poles

Telophase

Chromosomes reach poles of cell; nuclear envelope re forms; nucleolus reappears; chromosomes decondense.

Spindle Apparatus

______ ________ in animal cells consist of spindle fiber, centriole, and aster fibers.

It forms during prophase and prometaphase when the nuclear envelope starts to disappears or break down.

Polar, Astral, and Kinetochore microtubules

Three (3) types of microtubules:

Polar Microtubule

overlap in the middle region of the cell and keep the two poles apart.

Astral Microtubule

Interact with proteins attached to the cell membrane and assist in keeping the poles apart.

Kinetochore Microtubules

Attach to the kinetochores on the chromosomes.

Centromere

Structure at the center of the chromosomes where sister chromatids are attached.

It ensures that a complete copy of replicated DNA will become part of cells at the end of the cycle.

Centrosome

An organelle in the cytoplasm near the nucleus. Consists of a pair of centrioles, each one a hollow tube formed by nine triplets of microtubules.

Genetic Consistency

Mitosis results in ________ _________.

Genetic Diversity

Meiosis results in ________ _________.

Restriction point

Checkpoints that act as built-in stop signals that halt the cell.

Go-ahead

If it receives ________, the cell will complete a cell division.

no go-ahead

If __ _______ signal is received, the cell will exit the cell cycle and become a non dividing cell.

Go zero phase

These non dividing cells are arrested in the __ ____ _____.

G1 to S transition

__ __ _ ________ marks a key decision point for the cell.

cyclin and protein kinase

Two (2) kinds of molecules that control the timing of the cell cycle:

Cyclin

a regulatory protein whose levels fluctuate cyclically in a cell, related to the timing of the division.

Protein kinase

catalyze the phosphorylation of target proteins that regulate the cell cycle

Cyclin-dependent kinase

the kind of protein kinase involved in the timing of the cell cycle

Cell cycle checkpoints

points where where signaling pathways regulate the progress of the cell cycle.

G1 and G2, S, and M checkpoint

Three (3) checkpoints during interphase and one during mitosis:

G1 checkpoint and G2 checkpoint

Both triggered by DNA damage

S Checkpoint

triggered by incomplete replication or DNA damage

M checkpoint

triggered by a chromosome that fails to attach to the spindle