Chapter 9 Cellular Reproduction Section 1: Cellular Growth Section 2: Mitosis and Cytokinesis Section 3: Cell Cycle Regulation

9.1 Cellular Growth Objectives: Explain why cells are relatively small. Summarize the primary stages of the cell cycle. Describe the stages of interphase.

9.1 Cellular Growth Main Idea – Cells grow until they reach their size limit, then they either stop growing or divide.

Ratio of Surface Area to Volume Chapter 9 Cellular Reproduction 9.1 Cellular Growth Ratio of Surface Area to Volume

Chapter 9 Cellular Reproduction 9.1 Cellular Growth As the cell grows, its volume increases much more rapidly than the surface area. The cell might have difficulty supplying nutrients and expelling enough waste products.

Transport of Substances Chapter 9 Cellular Reproduction 9.1 Cellular Growth Transport of Substances Substances move by diffusion or by motor proteins. Diffusion over large distances is slow and inefficient. Small cells maintain more efficient transport systems.

Cellular Communications Chapter 9 Cellular Reproduction 9.1 Cellular Growth Cellular Communications The need for signaling proteins to move throughout the cell also limits cell size. Cell size affects the ability of the cell to communicate instructions for cellular functions.

Cell Size Limitations ratio of surface area to volume Cells are smaller than a period (100um). Surface area refers to the plasma membrane ; L x W x number of sides (6) Volume refers to the contents of the cell; L x W x H Volume increases faster than surface area Higher ratio of surface area to volume allows cell to maximize diffusion and transport; more efficient

Transport of substances – smaller cells have more efficient transport Cellular communications – smaller size is more efficient for protein synthesis

Chapter 9 Cellular Reproduction 9.1 Cellular Growth Interphase is the stage during which the cell grows, carries out cellular functions, and replicates organelles. Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material (DNA) divide. Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.

The Stages of Interphase The first stage of interphase, G1 Chapter 9 Cellular Reproduction The Stages of Interphase The first stage of interphase, G1 The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.

The Second Stage of Interphase, S Chapter 9 Cellular Reproduction 9.1 Cellular Growth The Second Stage of Interphase, S The cell copies its DNA in preparation for cell division.

The Third Stage of Interphase, G2 Chapter 9 Cellular Reproduction 9.1 Cellular Growth The Third Stage of Interphase, G2 The cell prepares for the division of its nucleus.

The Cell Cycle - a cycle of growing and dividing in eukaryotic cells Interphase – cell grows, develops and replicates DNA, prepares for division; 3 substages: G1 (Gap 1) – cell is growing and replicating organelles S – synthesis – DNA replication occurs Chromosomes – contain genetic material Chromatin – relaxed form of DNA in nucleus G2 (Gap 2) cell prepares for mitosis

Chromosome Structure

Chromatin

Mitosis cell’s nucleus (DNA) divides (4 stages) (PMAT) Cytokinesis – cytoplasm divides; result is 2 identical daughter cells

9.1 Section Assessment (pg. 247 1-6) When the cell increases in size, transportation of substances across the membrane becomes difficult. The cell is not efficient. 2. The primary stages of the cell cycle are interphase, mitosis, and cytokinesis. 3. DNA is replicated during the S stage of interphase.

Diagram of cell cycle – see pg. 246 Interphase Longest phase Cell grows DNA replication occurs Mitosis Nucleus divides Occurs in 4 stages Cytokinesis Shortest phase Cytoplasm divides

The large cell would not be able to maintain itself because the plasma membrane-to-cell contents ratio would be too large and diffusion and transport would be inefficient. 6. surface area = 5 um x 5 um x 6 = 150 um2 volume = 5 um x 5 um x 5 um = 125 um3 Ratio is 6:5 Result inefficient transport

9.2 Mitosis and Cytokinesis Objectives: Describe the events of each stage of mitosis. Explain the process of cytokinesis. Main Idea Eukaryotic cells reproduce by mitosis, the process of nuclear division, and cytokinesis, the process of cytoplasm division.

The cell’s chromatin tightens. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis The Stages of Mitosis Prophase The cell’s chromatin tightens. Sister chromatids are attached at the centromere. Spindle fibers form in the cytoplasm.

The nuclear envelope seems to disappear. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis The nuclear envelope seems to disappear. Spindle fibers attach to the sister chromatids. Prometaphase

They line up in the middle of the cell. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Metaphase Sister chromatids are pulled along the spindle apparatus toward the center of the cell. They line up in the middle of the cell.

The microtubules of the spindle apparatus begin to shorten. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Anaphase The microtubules of the spindle apparatus begin to shorten. The sister chromatids separate. The chromosomes move toward the poles of the cell.

The chromosomes arrive at the poles and begin to relax. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Telophase The chromosomes arrive at the poles and begin to relax. Two new nuclear membranes begin to form and the nucleoli reappear. The spindle apparatus disassembles.

The 4 Stages of Mitosis http://www.johnkyrk.com/mitosis.html Prophase – “poles form” (centrioles) “poof” chromosomes condense; spindle forms Metaphase – “meet in the middle” chromosomes line up at the equator Anaphase – “pull apart” chromosomes move to opposite poles Telophase – “pinch together” “two new” nuclear envelope forms; chromosomes decondense

Mitosis

In animal cells, microfilaments constrict, or pinch, the cytoplasm. Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Cytokinesis In animal cells, microfilaments constrict, or pinch, the cytoplasm. In plant cells, a new structure, called a cell plate, forms. Visualizing the Cell Cycle

Plant Cell Division

Remember the Stages of Cell Division I Interphase Probably Prophase Make Metaphase A Anaphase Teacher Telophase Crazy Cytokinesis http://www.johnkyrk.com/mitosis.html

Prokaryotic cells undergo binary fission- cell divides into 2 genetically identical cells WHY? Prokaryotic cells do not have a nucleus. Mitosis is division of the nucleus.

Binary Fission - lhs.lps.org

Bacterial Cell: Binary Fission student.nu.ac.th

9.2 Section Assessment (pg. 252 1-7) To complete the cell cycle, a cell must undergo cytokinesis to produce two daughter cells.

2. Mitosis Prophase Nuclear membrane disintegrates; chromosomes condense Metaphase Chromosomes attach to spindle and line up at the equator of cell Anaphase Chromosomes move apart to opposite poles Telophase Cell pinches together; Chromosomes relax

A cell spends the most time in prophase of mitosis. 3. chromosome in prophase sister chromatid centromere A cell spends the most time in prophase of mitosis. Cytokinesis in plant cells involves forming a cell plate between the two cells. 6. 7. In a week, 128 cells would be produced. (2, 4, 8, 16, 32, 64, 128 = 7 days)

9.3 Cell Cycle Regulation Objectives: 1. Summarize the role of cyclin proteins in controlling the cell cycle. 2. Explain how cancer relates to the cell cycle. 3. Describe the role of apoptosis. 4. Summarize the two types of stem cells and their potential uses. Main Idea - The normal cell cycle is regulated by cyclin proteins.

9.3 Cell Cycle Regulation Normal Cell Cycle Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Normal Cell Cycle Different cyclin/CDK combinations signal other activities, including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.

Quality Control Checkpoints Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Quality Control Checkpoints The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong. Spindle checkpoints also have been identified in mitosis.

Normal Cell Cycle http://cellsalive.com/cell_cycle.htm cell division rate varies with type of cell 2. substances that signal cell reproduction cyclins – proteins that regulate (start and stop) cell cycle cyclin-dependent kinases – enzyme that binds with cyclins during interphase and mitosis to start stages or cell cycle, DNA replication 3. quality control checkpoints monitor cell cycle; can stop it if error occurs

Abnormal Cell Cycle: Cancer Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Abnormal Cell Cycle: Cancer Cancer is the uncontrolled growth and division of cells. Cancer cells can kill an organism by crowding out normal cells, resulting in the loss of tissue function.

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Causes of Cancer The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations. Various environmental factors can affect the occurrence of cancer cells.

Abnormal Cell Cycle: Cancer cancer – uncontrolled growth and division of cells – cell cycle fails cancer cells crowd out normal cells cancer cells spend less time in interphase, so they divide fast caused by mutations in DNA and environmental factors carcinogens – substances that cause cancer (asbestos, tobacco, secondhand smoke, UV radiation, X rays) 6. cancer genetics – requires many changes in DNA; risk increases with age, can run in families

Comparison of Normal and Cancerous Stomach Cells

Cancerous Stomach Cells Normal Stomach Cells Interphase 120 min. Prophase 60 min. Metaphase 10 min. Anaphase 3 min. Telophase 12 min. Cancerous Stomach Cells Interphase 16 min. Prophase 15 min. Metaphase 2 min. Anaphase 1 min. Telophase 3 min.

Apoptosis Programmed cell death Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Apoptosis Programmed cell death Cells going through apoptosis actually shrink and shrivel in a controlled process.

apoptosis - programmed cell death; can help protect against cancerous growths

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Stem Cells Unspecialized cells that can develop into specialized cells when under the right conditions

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Embryonic Stem Cells After fertilization, the resulting mass of cells divides repeatedly until there are about 100–150 cells. These cells have not become specialized.

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Adult Stem Cells Found in various tissues in the body and might be used to maintain and repair the same kind of tissue Less controversial because the adult stem cells can be obtained with the consent of their donor Cellular Reproduction

stem cells -unspecialized cells that can develop into specialized cells embryonic stem cells – found in embryos; controversial due to source adult stem cells – found in various tissues of body including newborns; less controversial because adult can give consent for removal

9.3 Section Assessment pg. 257 (1-7) Certain cyclin proteins and cyclin-dependent enzymes regulate mitosis and the cell cycle. The cancer cell cycle is shorter. Cancer cells divide in an uncontrolled way. Three carcinogens are cigarette smoke, UV radiation, and asbestos.

In apoptosis a cell undergoes programmed cell death; cancer cells divide unrestrained as long as they are supplied with essential nutrients. Stem cells may be used to treat medical conditions and genetic defects.

Embryonic stem cells, found in developing embryos, can develop into many kinds of cells. Adult stem cells are found in developed tissues and might be used to maintain and repair the same kind of tissue in which they are found.

If apoptosis did not occur to cells with significant DNA damage people would probably have higher rates of cancer and genetic diseases.

Chapter Resource Menu Chapter Diagnostic Questions Cellular Reproduction Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding lesson.

1. Which is the first phase of mitosis? Chapter 9 Cellular Reproduction Chapter Diagnostic Questions 1. Which is the first phase of mitosis? interphase prophase metaphase telophase

During what phase do the sister Chapter 9 Cellular Reproduction Chapter Diagnostic Questions During what phase do the sister chromatids line up in the middle of the cell? interphase metaphase anaphase telophase

3. Which is not a phase of the cell cycle? Chapter 9 Cellular Reproduction Chapter Diagnostic Questions 3. Which is not a phase of the cell cycle? cytokinesis interphase apoptosis mitosis

1. Which can more efficiently supply nutrients and Chapter 9 Cellular Reproduction 9.1 Formative Questions 1. Which can more efficiently supply nutrients and expel waste products? larger cells smaller cells cells with lower surface area to volume ratio cells shaped like a cube

2. At what stage does a cell spend most of its life? Chapter 9 Cellular Reproduction 9.1 Formative Questions 2. At what stage does a cell spend most of its life? cytokinesis interphase mitosis synthesis

3. What happens in the cell during cytokinesis? Chapter 9 Cellular Reproduction 9.1 Formative Questions 3. What happens in the cell during cytokinesis? The cell grows and carries out normal functions. The cell copies its DNA and forms chromosomes. The cell’s nucleus and nuclear material divide. The cell’s cytoplasm divides.

4. In what stage of the cell cycle does the Chapter 9 Cellular Reproduction 9.2 Formative Questions 4. In what stage of the cell cycle does the cell’s replicated genetic material separate? cytokinesis interphase mitosis prophase

5. Which diagram shows anaphase? Chapter 9 Cellular Reproduction 9.2 Formative Questions 5. Which diagram shows anaphase?

At the end of mitosis the nuclear material is Chapter 9 Cellular Reproduction 9.2 Formative Questions 6. True or False At the end of mitosis the nuclear material is divided and two new cells have formed.

What are the “key and ignition” that start Chapter 9 Cellular Reproduction 9.3 Formative Questions What are the “key and ignition” that start the various activities in the cell cycle? chromatin and chromosomes cyclin and CDKs microtubules and spindle fibers protein and ribosomes

8. Which of these cancer-causing substances Chapter 9 Cellular Reproduction 9.3 Formative Questions 8. Which of these cancer-causing substances or agents is impossible to avoid completely? chemicals such as asbestos food and drinks that the FDA warns may contain carcinogens tobacco and second-hand smoke ultraviolet radiation from the Sun

What is the term for the programmed Chapter 9 Cellular Reproduction 9.3 Formative Questions What is the term for the programmed death of cells that are damaged beyond repair or have harmful changes in their DNA? apoptosis carcinogens cytokinesis mitosis

Which cells are not locked into becoming Chapter 9 Cellular Reproduction 9.3 Formative Questions Which cells are not locked into becoming one particular kind of cell and are capable of developing into specialized tissues? apoptotic cells cancer cells prokaryotic cells stem cells

11. This cell has completed what stage of mitosis? Chapter 9 Cellular Reproduction Chapter Assessment Questions 11. This cell has completed what stage of mitosis? anaphase interphase metaphase telophase

What term is used to describe programmed cell death? Chapter 9 Cellular Reproduction Chapter Assessment Questions What term is used to describe programmed cell death? apoptosis anaphase necrosis cyclins

13. What is the role of cyclins in a cell? Chapter 9 Cellular Reproduction Chapter Assessment Questions 13. What is the role of cyclins in a cell? to control the movement of microtubules to signal for the cell to divide to stimulate the breakdown of the nuclear membrane to cause the nucleolus to disappear

C B A 14. Which cell has the lowest ratio of surface area to volume? Chapter 9 Cellular Reproduction Standardized Test Practice 14. Which cell has the lowest ratio of surface area to volume? C B A

15. At what stage of interphase does the cell take Chapter 9 Cellular Reproduction Standardized Test Practice 15. At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus? G1 S G2 M

Which occurs in plant cells but not animal Chapter 9 Cellular Reproduction Standardized Test Practice Which occurs in plant cells but not animal cells during the cell cycle? formation of a cell plate formation of microtubules formation of a cleavage furrow at the equator of the cell movement of chromosomes to the poles of the cell

17. Multiple changes in DNA are required to Chapter 9 Cellular Reproduction Standardized Test Practice True or False 17. Multiple changes in DNA are required to change an abnormal cell into a cancer cell.

18. Which is not a condition that can result in cancer? Chapter 9 Cellular Reproduction Standardized Test Practice 18. Which is not a condition that can result in cancer? a failure in the control mechanisms that regulate the cell cycle a failure in the repair systems that fix changes or damage to DNA a failure of the spindle fibers to move chromosomes during mitosis mutations or changes in segments of DNA that control protein production

Glencoe Biology Transparencies Chapter 9 Cellular Reproduction Glencoe Biology Transparencies

Chapter 9 Cellular Reproduction Image Bank

Section 1 Vocabulary cell cycle interphase mitosis cytokinesis Chapter 9 Cellular Reproduction Vocabulary Section 1 cell cycle interphase mitosis cytokinesis chromosome chromatin

Section 2 Vocabulary prophase sister chromatid centromere Chapter 9 Cellular Reproduction Vocabulary Section 2 prophase sister chromatid centromere spindle apparatus metaphase anaphase telophase

Section 3 Vocabulary cyclin cyclin-dependent kinase cancer carcinogen Chapter 9 Cellular Reproduction Vocabulary Section 3 cyclin cyclin-dependent kinase cancer carcinogen apoptosis stem cell

Visualizing the Cell Cycle Chapter 9 Cellular Reproduction Animation Visualizing the Cell Cycle