Warm up Sep. 5 What happens in G1 What happens during S phase? What happens during the cell cycle?

Warm Up Sep. 11 Two differences between plant an animal cells. Why are plant cells Eukaryotic? What are two phases of mitosis?

Bell Work Sep. 8 What is happening in Prophase? In Metaphase? What are the other 2 phases?

Cell Growth and Division Chapter 10: page

Cell Division

Vocabulary Cell division Chromosomes Chromatid Cell Cycle Interphase

Cell division Results in 2 cells that are identical to the parent cell Occurs in two main stages: – Mitosis: division of the cell nucleus – Cytokinesis: division of the cytoplasm

Chromosomes chroma = colored ; soma = body Chromosomes – structures which contain DNA

Chromosomes (continued) Each chromosome consists of two identical sister chromatids The chromatids are attached to each other by an area known as the centromere.

Essential Questions What is a chromosome? What is produced during cell division? What happens during cytokinesis?

Cell Cycle Three things occur during the cell cycle: – Growth – Preparation to divide – Divides to form two daughter cells

Events of the Cell Cycle Interphase – G1 – S – G2 Mitosis (PMAT) – Prophase – Metaphase – Anaphase – Telophase Cytokinesis

Interphase Majority of the cell’s life Cell is growing and preparing for mitosis Absence of visible chromosomes – chromatin

Phases of Interphase G1 – Cell growth (in size) S – DNA is synthesized Replicated G2 – Prepare for mitosis – “mother cell” G0 – Cells are not dividing

Mitosis Pg

Vocabulary Mitosis Prophase Metaphase Anaphase Telophase

Characteristics of Mitosis Process of growth Asexual reproduction Results in 2 identical cells

Phases of Mitosis Prophase Metaphase Anaphase Telophase PMAT

Prophase First and longest phase of mitosis Chromatin condense into chromosomes Nuclear membrane and nucleolus disappear Spindles form – Fanlike structures that help separate the chromosomes

Metaphase Short, second phase Chromosomes line up at the metaphase plate

Warm up What happens in Metaphase? What happens in Prophase? What happens in G1 of interphase?

Anaphase Third phase Sister chromatids are pulled toward the poles

Telophase Final phase of mitosis Reversal of prophase – Nuclear membrane and nucleolus reappear – Chromosomes unwrap into (chromatin) A new double membrane begins to form between the 2 new nuclei

Warm up What happens during Anaphase? Telophase? Cytokinesis?

Cytokinesis pp

Cytokinesis in Animal Cells The plasma membrane pinches in along the equator – Cleavage furrow 2 new cells are separated

Cytokinesis in Plant Cell Plasma membrane does not pinch off Cell plate is laid down across the equator Cell membrane is formed around each cell A new cell wall forms on each side of the cell plate

10-3 Regulating the Cell Cycle pp

Warm UP Sep. 9 What happens in anaphase? What happens in telophase? What happens in S of interphase?

Controls on Cell Division – Cell Cycle Regulators Cells will divide as long as there is space available. Cyclins regulate the timing of the cell cycle in eukaryotic cells.

Controls on Cell Division – Cell Cycle Regulators (continued) External Regulators – Proteins that respond to event outside the cell – i.e., speed up or slow down the cell cycle (growth regulators)

Checkpoints control the cell cycle G1 checkpoint – Checks cell size and suitable environment G2 checkpoint – Checks replicated DNA, if the cell is large enough, suitable environment Metaphase checkpoint – Checks if chromosomes are aligned on spindles

Cancer: Uncontrolled Cell Growth

Characteristics of Cancer Occurs when cells do not respond to the signals that regulate growth Form masses of tissue called tumors that deprive normal cells of nutrients 2 nd leading cause of death in the USA

Causes of Cancer Environmental factors – Geographic location, cigarette smoke, air and water pollution, and exposure of UV light – Viral infections – Damaged genes p53

Cancer prevention Diets low in fat and high in fiber – Diets high in fat are linked to colon, breast, and prostate cancers Vitamins and minerals – Carotenoids – Vitamin A, C, E – Calcium Daily exercise Not using tobacco products

Cell Cycle Web Links