10-1 Cell Growth

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10-1 Cell Growth

• Complete Guided Reading Workbook 10-1 and 10-2

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By the end of today you will be able to

• Explain the problems that growth causes for
  cells.
• Describe how cell division solves the problems of
  cell growth.
• Name and describe the main events of the cell
  cycle.

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Lets do some math!!!!
                  

• Calculate the surface area of each sphere.
• Calculate the volume of each sphere.
• Then, calculate the surface area to volume ratio.
  Round s up or down to make it easier.

S.A. 4 (pi) r 2
Radius 2cm S.A. ________ V __________ Ratio
SAV ________
Radius 2cm S.A. ___50cm2__ V
__33cm3____ Ratio SAV 5033_or 1.511
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Radius 1cm S.A. _____ V ______ Ratio SAV
___
Radius 2cm S.A. ___50cm2__ V
__33cm3____ Ratio SAV 5033_or 1.511
Radius 1cm S.A. __13cm2___ V __4cm3____ Ratio
SAV _134 or 3.251__
Radius 3cm S.A. _____ V ______ Ratio SAV
___
Radius 3cm S.A. __113cm2_ V
___113cm3___ Ratio SAV _113113 or 11__
S.A. 4 (pi) r 2

1. As the spheres get larger what happens to the
   SAV ratio?

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1st problem Cell size and material exchange

• The larger a cell grows the more trouble it has
• moving enough nutrients in
• Moving all the waste materials out

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2nd problem DNA overload
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Checkpoint!!!!

• What are two problems that cell growth causes for
  cells?
• The larger a cell becomes, the more demands the
  cell places on its _____ and the more trouble the
  cell has moving enough _________and _________
  across the cell membrane.
• What is viable solution for cells solve these
  problems?
• Cell Division A larger cell splits into two
  smaller daughter cells.

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The Cell Cycle and Mitosis

• Chapter 10-2
• Homework 10-2-3 in guided reading

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The Cell Cycle - series of events that cells go
through as they grow and divide

• The cell cycle is divided into two halfs
• Interphase - period of the cell cycle between
  cell divisions
• M phase period of time when mitosis and cell
  division occurs

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Parts of Interphase

• G1 Phase
• Growing
• Synthesize new proteins and organelles
• Doing their jobs
• Longest phase of cell cycle
• S Phase
• Chromosomes(DNA) are replicated
• Key proteins associated with replication are made
  (centromeres)
• G2 Phase
• Shortest of the 3 phases of interphase
• Organelles and molecules for cell division are
  produced (centrioles)
• Check-up phase before mitosis

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Chromatin and Chromosomes

• Chromatin - A complex of DNA and proteins in the
  cell nucleus that condenses to form chromosomes
  during cell division.
• Chromosomes Condensed Chromatin
• They are the same stuff, just in different forms

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Chromatin condenses in chomosomes before mitosis
begins

• Chromatin

• Chromosomes

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Chromosomes

• Different organisms have different s of
  chromosomes
• Humans cells 46
• Fruit Fly cells 8
• Carrot cells 18
• King Crab cells - 208

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Chromosomes Replication

• During the cell cycle (before cell division can
  take place) chromosomes are replicated to form an
  identical copy of itself.
• Two identical copies of a chromosome are called
  sister chromatids (one of two identical
  sister parts of a duplicated chromosome)
• Centromere - area where the chromatids of a
  chromosome are attached

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M Phase, Cell Division and Mitosis
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Mitosis

• Prophase
• Metaphase
• Anaphase
• Telophase

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Cytokinesis
-Cytoplasmic division and other changes exclusive
of nuclear division that are a part of mitosis or
meiosis.
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In plant cells, a cell plate forms. The cell
plate is synthesized by the fusion of multiple
membrane-bounded vesicles. Their fusion supplies
new plasma membrane for each of the two daughter
cells. Synthesis of a new cell wall between the
daughter cells then occurs at the cell plate.
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10-3 cell cycle regulation

• Homework 10-3 guided reading workbook

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Checkpoint

• 1. The break down of a cells entire life is the
  _______ ________.
• 2. The phase of the cell cycle when the cell is
  growing, replicating DNA and getting ready for
  mitosis is _____________.
• 3-6. What are the four phases of Mitosis?
• 7. The process of a cell actually splitting in
  two is called _______________.

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Controls on Cell Division
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How do cells know when to divide and when not to?

• Internal regulators are proteins that respond
  to events inside the cell.
• Some proteins make sure cells do not enter
  mitosis until all of the chromosomes have been
  replicated.
• What stage of the cell cycle do you think these
  proteins work?
• G2 phase
• Cyclins (internal regulator) one of a family of
  closely related proteins that regulate the cell
  cycle in eukaryotic cells

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Cyclins
Protein that periodically rises and falls in
concentration in step with the eukaryotic cell
cycle. Cyclins activate crucial protein kinases
(called cyclin-dependent protein kinases, or CDK)
and thereby help control the progression from one
stage of the cell cycle to the next. Cascade of
events!!
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Cyclins
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External Regulators

• External regulators - Proteins that respond to
  events outside the cell are called external
  regulators.
• External regulators direct cells to speed up or
  slow down the cell cycle.
• Growth factors are among the most important
  external regulators, which tell cells to speed up
  division. When is this important?
• Molecules found on the surfaces of neighboring
  cells often have an opposite effect, causing
  cells to slow down or stop their cell cycles.

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Uncontrolled Cell Growth

• Cancer cell
• Various forms of cancer have many causes
• Smoking
• Radiation
• Viral infections
• The common thread in all cancers is that control
  over the cell cycle has broken down.
• Over 50 of cancer cells have a defect in the p53
  gene.

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Quiz on ThursdayHO due wednesday
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p53 antioncogene

• p53 is a tumor suppressor gene found mutated in
  about half of human cancers.
• It encodes a gene regulatory protein that is
  activated by damaged DNA and is involved in
  blocking further progression of the cell cycle.

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Oncogenes SRC, proto-oncogene tyrosine-protein
kinase