2 Living organisms have life cycles. Life cycles begin with organism’s formation, followed by growth and development and end in death.
3 Individual cells have life cycles. Some cells constantly complete the cycle, others take hours or longer.Cell cycle is broken down into sections
4 Interphase The longest part of a cell’s life cycle Several major things occur during Interphase;The cell grows, develops.Organelles are duplicated.The DNA is copied (chromosomes duplicated)The cell prepares for cell division.Interphase is NOT part of mitosis.
6 In Interphase, chromatids are duplicated. When the nucleus is ready to divide, each duplicated chromosome coils into two thickened strands called chromatids.
7 MitosisMitosis: process in which the nucleus divides to form two identical nuclei.Steps of Mitosis: Prophase, Metaphase, Anaphase, and Telophase. (PMAT)
8 Prophase (Prepare) First step of mitosis Chromatids are fully visible under a microscopeNucleolus and nuclear membrane disintegrateTwo organelles called centrioles move to opposite ends in the cell.Between the centrioles, (only in animal cells) thin threadlike structures called spindle fibers begin to stretch across the cell.
9 Metaphase (Middle)The chromosomes line up across the midline of the cell.The centromere of each chromosome becomes attached to the spindle fibers.
10 Anaphase (Apart)The centromere, in the center of each pair of chromatids, splits in half.The spindle fibers shorten, pulling the pair of chromatids apart.Each pair of chromatids separate, and move to opposite ends of the cell.
11 Telophase (Two nuclei form) Spindle fibers disappear.Nuclear membrane reappears.Chromosomes begin to uncoil and a new nucleus forms.
12 Cytokinesis Division of the cytoplasm In animal cells – the cell membrane pinches in the middle.In plant cells – a cell plate forms followed by the formation of new cell walls .Then cells enter into Interphase to repeat the cell cycle again.
13 CytokinesisAnimal CellWhy doesn’t a plant cell pinch in at the sides like an animal cell?Plant Cell