The Cell Cycle Process
110 likes | 204 Vues
Learn about the phases of the cell cycle, DNA replication, chromosome structure, mitosis, and cytokinesis. Discover how cells grow, prepare for division, and form daughter cells.
The Cell Cycle Process
E N D
Presentation Transcript
The Cell Cycle p. 244 - 249 Q: What do you think would happen if a cell were simply to split into two, without any advance preparation?
The Cell Cycle • During the cell cycle a cell grows, prepares for division, and divides to form two daughter cells, each of which begins the cycle again (cell growth). • Two main phases of the cell cycle: • Interphase – cell growth & preparation for cell division • Cell division – the nucleus & cytoplasm divide to form two daughter cells
G1 phase M phase S phase G2 phase The Cell Cycle
Interphase • Cells spend most of their lives in interphase. • Three phases of interphase: • G1 • S • G2
Chromosomes • Consist of: • DNA – the cell’s coded genetic information • Proteins • They are usually found loosely spread out within the nucleus – chromatin • During mitosis, the chromatin condenses (coils up) into more visible chromosomes • WHY? • The cells of every organism have a specific number of chromosomes (humans have 46)
DNA Replication • Replication = making an exact copy • Occurs during S phase of interphase (before the cell divides) • Each copy is called a chromatid • Together they are called sister chromatids • The sister chromatids are attached to each other at the centromere • They are still considered one chromosome!
Nucleosome Chromosome DNA double helix Coils Supercoils Histones Chromatin vs.Visible Chromosomes
G1 phase M phase S phase G2 phase The Cell Cycle
Cell Division • Two main phases of cell division: • Mitosis – the division of the nucleus • Cytokinesis – the division of the cytoplasm & organelles • How does cytokinesis have to be different between plant & animal cells? • In plants, a cell plate forms to make the cell wall
Mitosis & Cytokinesis • Four phases of mitosis: • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
Review • Give two reasons why cells divide. • What are the 2 main parts of the cell cycle? • Name the two components of a chromosome. • What is the difference between chromatin and visible chromosomes? • How many chromosomes do humans have? • When does DNA replication occur? • Sister chromatids are attached to each other at the ________. • What is mitosis? • Name the 4 stages of mitosis (in order!). • What is cytokinesis?