# Chapter 10 Cell Growth and Division Section 10

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Chapter 10 Cell Growth and Division

Section 10 -1 Cell Growth Key Concept: What problems does growth cause for cells? I. Limits to cell growth 1. Why do cells divide rather than continue to grow indefinitely? a. The ______ the cell is the more demands are placed larger on the cell’s _____ DNA b. Its more difficult to move enough ______ and nutrients ______ across the cell membrane wastes 2. “DNA Overload”: a. DNA controls_____ ; found in nucleus of cell function eukaryotes b. DNA meets the needs of the cell when the cell is_____, small however as the cell increases in size, the DNA cannot meet its needs anymore “_______” Information crisis

3. Exchanging Materials: a. ____, _____, and _______ Food oxygen water enter a cell through its cell membrane. b. _________ leave the same Waste products way. c. Rate of this exchange depends on the surface area to volume ratio II. Surface Area to Volume Ratio 1. To obtain the ratio of surface area to volume, _____ the surface area by the volume. divide

Cell Sizes Surface Area lengthxwidthx 6 Volume Lengthxwidthxheight Ratio of surface area to volume 6 cm 2 1 cm 3 6: 1 54 cm 2 27 cm 3 8 cm 3 3: 1 2: 1

Notice that volume _______ much more increases rapidly than surface area. This causes the ___________ surface area to volume ratio to decrease _________, which is a serious problem for the cell. large As cells get _________ it makes it more too difficult to get sufficient amounts of oxygen and nutrients in and waste products out. Question: How does an organism get bigger if the cells that it is made of do not get larger? It grows more cells. Answer: ___________

III. Division of the Cell 1. Before the cell gets too large it divides into two “_______” cells daughter 2. The process is called ____ cell ________. division Cell division solves the problem of cells Increasing size getting too large by ________ while _________ (more small cells reducing volume instead of one large cell)

3. Before cell division, the cell ______, replicates or copies, its entire DNA. a. This solves the problem of information storage __________ because each daughter cell gets a complete set of _____ information genetic 4. Each cell has an increase in ratio of surface area to volume that allows for more efficient _________ with the environment. exchange of materials

10 -2 Cell Division Key Concepts: What are the main events of the cell cycle? What are the four phases of mitosis? All cell division must involve the replication of DNA before cell division so the genetic information can be transferred to the daughter cells. In Prokaryotes the rest of cell division is simply to divide the contents _________. In Eukaryotes the division is more complex it occurs in two stages: division of the nucleus a. Mitosis: ____________ b. ______: division of the cytoplasm Cytokinesis

Unicellular organisms use mitosis and cytokinesis to ________. reproduce This is a type of ________ asexual reproduction producing two identical daughter cells from ______ parent cell. one Multicellular organisms use mitosis and add new cells to the organism cytokinesis to ____________________________ for growth and development

I. Chromosomes DNA 1. Chromosomes are composed of ______ and _____ (histones) and carry the proteins genetic information in eukaryotic cells. a. Each species of organism has a _____ of chromosomes. specific number 1. Drosophila melanogaster has ___ 8 chromosomes 2. Humans have ____ chromosomes 46

b. Chromosomes are __________ not visible except during cell division. (known as chromatin ______ when not dividing) c. Replication (copying) of the DNA occurred ____________ therefore every before cell division sister chromosome is actually two identical “______” chromatids d. Each pair of chromatids is connected to each other at an area called the ______, usually located near the center centromere of the chromosome.

centromere Sister chromatids http: //www. biostudio. com/demo_freeman_dna_coiling. htm

II. The Cell Cycle 1. Cell Cycle: the series of events the cell grow and divide goes through as they ________ separated by periods of “in-between” time called ______. interphase grows 2. During the cell cycle the cell ____, prepares for _____, and divides to division form two daughter cells, each of which then begins the cycle again _____________. 3. _______ phases of the cell cycle Four

III. Events of the Cell Cycle a. G 1 phase: _____, increase in size cell growth and _______ new proteins and synthesize organelles. b. S phase: chromosome _____ replication (synthesis) c. G 2 phase: shortest of the phases, organelles and molecules required for cell division ______ are produced. d. M Phase: _____and ______ cytokinesis mitosis G 1, S, and G 2 are all taking place during ______ : the phase between divisions. interphase

G 1 M-phase s G 2

III. Mitosis a. The mitotic phase can be sub-divided into four phases _______, prophase _______, _______ and anaphase metaphase _______ (PMAT). telophase b. Mitosis is strictly _______ division. nuclear c. Mitosis is followed by cytoplasmic division, or cytokinesis ______, to complete cell division

d. Mitosis results in two “daughter cells”, identical which are ____ to each other, and is used for growth and asexual reproduction. e. The growth and synthesis phases are collectively called interphase (i. e. in between cell division). f. The only source of genetic variation in the cells is via ________. mutations

Interphase Stage between division This is when the cell is not dividing, but is carrying out its normal cellular functions __________. is not Chromatin _____ visible _____, histones and DNA centrioles all replicated Replication of _______ like cell organelles mitochondria, occurs in the cytoplasm. G 1, S and G 2 phases are occurring

condense chromosomes ______ visible Prophase Beginning of mitosis (nuclear division) and become ______. Due to DNA replication during interphase, each chromosome consists of two identical sister chromatids _______ connected at centromere the ______ opposite centrioles move to _____ poles of cell (in animal cells) disappears Nucleolus _______ Spindle fibers begin to form and attach ______ to chromosomes near the centromere Phase ends with the breakdown of the _________ nuclear membrane

Metaphase (middle) Spindle fibers connect centrioles _______ to chromosomes Chromosomes align along equator ______of cell. Anaphase chromosome separate Centromeres _______, split allowing sister chromatids separate to ________ Chromatids move towards opposite _____ poles, centromeres first, creating a “V” shape

Telophase New nuclei form Spindle fibers disperse ______ Nuclear membranes ________ form around each set of chromatids Nucleoli ______ reform End of nuclear division

Animal Cell Division in White Fish Blastula

Centrioles Centromere Nuclear envelope Daughter Cells Chromatin Centrioles Chromosomes ________ (paired chromatids) Spindle Centrioles Individual Chromosomes Nuclear envelope reforms http: //highered. mcgraw-hill. com/sites/0072437316/student_view 0/chapter 11/animations. html#

Onion Root Tip

For Use with Lab: Plant Cell Growth as seen in Onion Root Tip

Cytokinesis Cytoplasmic division New daughter cells form In animal cells a ________ forms, cleavage furrow which splits the cell in two. In plant cells vesicles move to the equator, line up and fuse to form two membranes called the _____. A new cell plate _____ is laid down cell wall between the membranes, which fuses with the existing cell wall.

V. Cytokinesis: a. Division of the ________ cytoplasm b. End of the _________ cell cycle c. Production of two _______ daughter cells identical plants d. Different in _____ and _____ cells animals Cell plate forming Wall of parent cell Daughter nucleus Cleavage furrow Contracting ring of microfilaments Daughter cells Cell wall Vesicles containing cell wall material New cell wall Cell plate Daughter cells

10 -3 Regulating the Cell Cycle Key Concepts: How is the cell cycle regulated? How are cancer cells different from other cells? Multicellular _______ organisms control cell growth and division very carefully (way to increase number of cells and size of organism) replacement This provides the ________ of cells wear out or are broken down that ____________.

I. Controls on Cell Division: 1. Cells in a ________ will continue to divide petri dish until they come into ______ with other cells. contact 2. Then the cells _____________. stop dividing 3. Cells are _______ from the center of the removed dish. 4. Then the cells ________ the open space bordering will begin dividing 5. until they have _______ the empty space. filled 6. The controls for cell growth and division can be __________. turned on and off 7. We can see the same thing happen in our _________. own bodies

3. 1. 5. 2. 4. Question: What happens when you cut your finger or break your bone? Answer: The cells bordering the injury will begin dividing to fill in the gap in the tissues that have been torn or broken. This is the process known as healing.

II. Cell Cycle Regulators 1. Scientists wondered what ______cell controlled division. 2. Tim Hunt and Mark Kirschner discovered that cells in mitosis contained a protein that when injected into a cell would cause the formation of spindle fibers. 3. Protein group known as ______ cyclins regulates the cell cycle. 4. They rise and fall in time with the ____. cell cycle

regulate 5. Cyclins _______ the timing of the eukaryotic cell cycle in _____cells. Two main groups of protein regulators: 1. Internal Regulators: respond to events _________. inside the cell Ex. Make sure cell doesn’t enter mitosis until chromosomes have all replicated 2. External Regulators: respond to events _____________. outside the cell Ex. Embryonic growth and healing

III. Uncontrolled Cell Growth A. Cancer 1. Cell Growth is so controlled because when it is not controlled things go very, very______. wrong 2. _____ is a disorder in which some of Cancer the body’s own cells lose the ability to control growth.

3. Cancer cells do not respond to the _______that regulate the growth of signals most cells. 4. When cells divide __________ uncontrollably they form masses of cells called _____ tumors that can damage the surrounding tissue. 5. Cancer cells can break off and _______ throughout the body spread disrupting normal activities and causing serious medical problems or even death.

B. Causes of Cancer 1. Smoking ______ tobacco 2. _______ exposure Radiation Viral Infection 3. _______ 4. ______ defect Genetic C. Cancer is a disease of the _____. cell cycle http: //www. gardasil. com/

Breast Cancer Cell