AP Biology - Cell Cycle/Mitosis

Cells divide to…?

allow growth, repair, maintain efficiency, preserve genetic continuity, and reproduction of organisms

what happens in G1?

During G1, the cell grows, synthesizes proteins, and prepares for DNA replication. It also carries out normal metabolic functions and produces organelles. Cells increase in size and produce RNA and proteins.

what does G1 check for?

cell size, DNA damage, growth factors, ATP availability, environmental factors and nutrients

what happens in S phase?

DNA replication occurs, producing sister chromatids, centrosomes are also duplicated

what happens in G2?

During G2, the cell continues to grow and prepares for mitosis. It checks for DNA damage, verifies accuracy/completion of DNA. The cell also produces organelles and structures needed for mitosis, such as microtubules.

what does G2 check for?

DNA damage, proper replication, and cell size.

what happens in prophase?

Chromatin condenses into chromosomes, the nuclear envelope breaks down, and spindle fibers begin to form.

what are the components of a spindle fiber?

astral microtubules which anchor the spindle to the membrane, polar microtubules that span between poles which keep them apart, and kinetochore microtubules which attach to centromeres

what happens in metaphase?

chromosomes align at the equator, known as the metaphase plate, spindle fibers attach to the centromeres of the chromosomes

what happens in the metaphase checkpoint?

checks for proper chromosome alignment at the metaphase plate and ensures all spindle fibers are correctly attached to the centromeres before proceeding to anaphase

what happens in anaphase?

sister chromatids separate and are pulled toward opposite poles of the cell, the separated chromatids are now considered individual chromosomes, moving away from each other as the spindle fibers shorten

what happens in telophase?

chromosomes arrive at the poles and begin to de-condense, nuclear envelopes reform around each set of chromosomes, resulting in two distinct nuclei in the cell

what happens in cytokinesis?

the cytoplasm divides, leading to the formation of two separate daughter cells, each with its own nucleus and organelles.

what happens in cytokinesis for ANIMAL cells?

the cell membrane pinches inwards due to the contractile ring which is made up of actin filaments and myosin motor proteins, forming a cleavage furrow that ultimately divides the cell into two daughter cells.

what happens in cytokinesis for PLANT cells?

the cell forms a cell plate at the center, which develops into a new cell wall, ultimately separating the two daughter cells.