Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

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Mitosis and Cytokinesis Chapter 5.2

Transcript of Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Page 1: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Mitosis and Cytokinesis

Chapter 5.2

Page 2: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

KEY CONCEPT Cells divide during mitosis and cytokinesis.

Page 3: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Show biology presentation film clip mitosis 2

Page 4: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Chromosomes condense at the start of mitosis.

• DNA wraps around proteins (histones) that condense it.

DNA doublehelix

DNA andhistones

Chromatin

SupercoiledDNA

Page 5: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Overall, DNA has a negative charge. Look at the histone proteins above, what type of overall charge do you think they will have?

• Positive—negative and positive charges attract so if the histones were negatively charged they would repel DNA, instead they coil together.

DNA doublehelix

DNA andhistones

Chromatin

SupercoiledDNA

Page 6: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Vocabulary

• Chromosome—one long continuous thread of DNA• Nucleotides—DNA made of four different subunits • Histones—group of proteins associated with

chromosomes (help to compact DNA)• Chromatin—loose combination of DNA and proteins; ½

is called a chromatid• Centromere—sister chromatids held together at their

center; a region of condensed chromosome that looks pinched.

• Telomeres—don’t form genes—end of chromatin

Page 7: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• DNA plus proteins is called chromatin.• One half of a duplicated chromosome is a

chromatid.• Sister chromatids are held together at the

centromere.• Telomeres protect DNA and do not include genes.

Condensed, duplicated chromosome

chromatid

telomere

centromere

telomere

Page 8: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• What is the relationship between a molecule and DNA and a Chromosome?

• A chromosome is made of one continuous DNA molecule

Page 9: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Parent cell

centrioles

spindle fibers

centrosome

nucleus withDNA

• Interphase prepares the cell to divide.

• During interphase, the DNA is duplicated.

Mitosis and cytokinesis produce two genetically identical daughter cells.

Page 10: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Mitosis divides the cell’s nucleus in four phases.– During prophase, chromosomes condense and spindle fibers form.

Page 11: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Mitosis divides the cell’s nucleus in four phases.– During metaphase, chromosomes line up in the middle of the cell.

Page 12: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Mitosis divides the cell’s nucleus in four phases.– During anaphase, sister chromatids separate to opposite sides of the

cell.

Page 13: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Mitosis divides the cell’s nucleus in four phases.

– During telophase, the new nuclei form and chromosomes begin to uncoil.

Page 14: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

• Cytokinesis differs in animal and plant cells.– In animal cells, the membrane

pinches closed.– In plant cells, a cell plate forms.

Page 16: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Question

• How does cytokinesis differ in animal and plant cells?

Answer: in animal cells, the membrane pinches together to separate the cytoplasm. In plant cells, a cell plate forms and divides the cell, along which the cell membrane and cell wall re-form.

Page 17: Mitosis and Cytokinesis Chapter 5.2. KEY CONCEPT Cells divide during mitosis and cytokinesis.

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• Go to page 142• Read the Data Analysis box (in orange)Then answer the two questions:1. Display Data2. Apply