Presentation on theme: "Name 2 limitations to cell growth. How does DNA limit cell growth?"— Presentation transcript:
1 Name 2 limitations to cell growth. How does DNA limit cell growth? 10.1 Pre-Read QuestionsName 2 limitations to cell growth.How does DNA limit cell growth?Why is the ratio of surface area to volume important?Describe the process of cell division.
3 Does not continue to grow bigger CellsDoes not continue to grow biggerCells just continue to produce more cells
4 Limits to Cell Growth2 main reasonsLarger a cell becomes, the more demands the cell places on its DNALarger cells -- harder time processing information, harder time getting rid of wastes
5 Limits to Cell Growth2 main reasons2. Cell has more trouble moving enough nutrients and wastes in and out of cell
6 Reason #1 DNA “overload” DNA = information that controls a cell’s functionif cells grow, DNA does not make extra copiesDNA would not be able to serve the needs of the cellMore people in a city, not enough police officers -- more crimes can occur without much control
7 Reason #2: Exchanging Materials how fast materials leave or enter the cell depends on surface areafood and oxygen depend on cell volume
8 Ratio of Surface Area to Volume as surface area increases, its volume increases at a faster rate
9 Ratio of Surface Area to Volume Consequence = cells have a more difficult time to move needed materials in and waste products out
10 one cell divides into 2 new cells Cell Divisionhow cells reproduceone cell divides into 2 new cellsdaughter cells
11 before cell division - cell copies DNA Each daughter cell gets own copy of DNA
23 G1 Phasecell growingincrease in size and synthesize new proteins and organelles
24 S Phasechromosome replicationproteins synthesized
25 G2 PhaseDNA replication complete at beginningshortest phase
26 prepare for cell division G2 Phaseorganelles producedprepare for cell division
27 10.2 Post Read QuestionsDescribe the 2 stages of cell division.Draw a chromosome and label and describe its parts.What are the different phases of interphase? Describe each one.What is the cell cycle?
30 Interphase In between periods of cell division Cell growth and DNA replication occur
31 Prophase first and longest phase (50%-60%) chromosome becomes visible centrioles take position on opposite sides of nucleus at the centrosome
32 Prophase Centrioles lie in centrosome so they can organize the spindle Spindle = fanlike microtubule structure that helps separate the chromosomes
33 Prophaseend = chromosomes coil and nuclear envelope break down
34 Metaphase lasts only a few minutes chromosomes line up across the center of the cell
35 Metaphase (cont)microtubules connect the centromere of each chromosome to the two poles of the spindle
36 Anaphasecentromeres that join the sister chromatids split into individual chromosomes and are moved apart to opposite poles
37 Telophase chromosomes become dense material spindle breaks apart nucleolus appears
38 Cytokinesis Division of cytoplasm usually occurs the same time as telophaseAnimal Cell = cell membrane draw inward and pinched offPlant cell = cell plate forms midway between the 2 nuclei; cell wall appears
42 Ch 10 Review Questions (Cont) What is cytokinesis? When does it occur?Compare how cytokinesis works between animal and plant cells.Describe metaphase.Describe anaphase.If you were to look at a picture of telophase and anaphase, how can you distinguish the difference between the two?
50 proteins that respond to events inside the cell Internal Regulatorsproteins that respond to events inside the cellsignals cell cycle to continue ONLY WHEN OTHER THINGS ARE COMPLETEThere are proteins that tell cells when ALL the chromosomes are complete and its ready to go onto the next step
51 External Regulator proteins that respond to events outside the cell direct cells to speed up or slow down the cell cycleexample: growth regulatorsGrowth regulators control how a scab is form … tells it where to go and how much to put on
52 Uncontrolled Cell Growth Cancerbody loses ability to control growthdoes not respond to the regulator proteinsresult = large masses of cells
53 Tumors masses of cells damages the surrounding tissues cells break off and spread throughout the body
54 Cause of cancer brought on by smoking tobacco radiation exposure viral infectionetc
55 10.3 Review QuestionsWhy is it important for cells to have regulated cell growth?What is the purpose of the protein cyclin?Compare and contrast internal regulators and external regulators.What is cancer? What causes cancer?