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The Cell Cycle & Mitosis. Chapter 5. 5.1 – The Cell Cycle. Key Concept: Cells have distinct phases of growth, reproduction, and normal functions. When a living thing grows, what happens to its cells?.

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5 1 the cell cycle
5.1 – The Cell Cycle
  • Key Concept:
    • Cells have distinct phases of growth, reproduction, and normal functions.
when a living thing grows what happens to its cells
When a living thing grows, what happens to its cells?
  • Does an animal get larger because each cell increases in size or because it produces more of them?
  • What are some things that all cells in your body must have?
the cell cycle has 4 main stages
The cell cycle has 4 main stages.
  • The cell cycle is a regular pattern of growth, DNA replication, and cell division.
the main stages of the cell cycle are gap 1 synthesis gap 2 mitosis
The main stages of the cell cycle are: Gap 1, Synthesis, Gap 2, & Mitosis.
  • Gap 1 (G1): cell growth and normal functions, copy organelles (most cells spend most of their time here)
    • Only proceed to S if the cell has enough nutrition, adequate size, undamaged DNA
  • Synthesis (S): copies DNA
  • Gap 2 (G2): additional growth
  • Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis)
    • Mitosis occurs only if the cell is large enough and the DNA undamaged.
cells divide at different rates
Cells divide at different rates.
  • The rate of cell division varies with the need for that type of cell.
  • Some cells are unlikely to divide
    • Example: neurons – stay in G0
cell size is limited
Cell size is limited.
  • Cell volume increases faster than surface area.
    • Cells need to stay small to allow diffusion and osmosis to work efficiently.
slide10

Surface area must allow for adequate exchange of materials.

    • Cells that must be large have unique shapes (i.e. neurons)
5 2 mitosis cytokinesis
5.2 – Mitosis & Cytokinesis
  • Key Concept:
    • Cells divide during mitosis and cytokinesisinto two new daughter cells.
chromosomes condense at the start of mitosis
Chromosomes condense at the start of mitosis.
  • Chromosomes: carry genetic information (DNA) that is passed from one generation of cells to the next.
  • DNA wraps around proteins (histones) that condense it.
slide13

DNA plus proteins (histones) is called chromatin.

  • Each chromosome is composed of two chromatids
  • Sister chromatids are held together at the centromere.
  • Telomeresprotect DNA and do not include genes(like the caps on shoelaces)
mitosis and cytokinesis produce two genetically identical daughter cells
Mitosis and cytokinesis produce two genetically identical daughter cells.
  • Interphase prepares the cell to divide.
  • DNA is duplicated.
mitosis divides the cell s nucleus in four phases pmat
Mitosis divides the cell’s nucleus in four phases - PMAT
  • Prophase – first & longest
    • Chromosomes condense, spindle fibers form, and the nuclear membrane disappears.
mitosis divides the cell s nucleus in four phases
Mitosis divides the cell’s nucleus in four phases.
  • Metaphase
    • Chromosomes line up across the middle of the cell.
mitosis divides the cell s nucleus in four phases1
Mitosis divides the cell’s nucleus in four phases.
  • Anaphase
    • Sister chromatids are pulled apart to opposite sides of the cell.
mitosis divides the cell s nucleus in four phases2
Mitosis divides the cell’s nucleus in four phases.
  • Telophase
    • Two nuclei form at opposite ends of the cell, the nuclear membranes reform, and the chromosomes uncoil back into chromatin
cytokinesis differs in animal and plant cells
Cytokinesis differs in animal and plant cells.
  • Cytokinesis is when the cytoplasm separates
    • Animal cells: membrane pinches the

two new cells apart

    • Plant cells: a cell plate (new cell wall) separates the two new cells
slide24

http://schoolworkhelper.net/wp-content/uploads/2011/02/onion-mitosis-3-lab.jpghttp://schoolworkhelper.net/wp-content/uploads/2011/02/onion-mitosis-3-lab.jpg

5 3 regulation of the cell cycle
5.3 – Regulation of the Cell Cycle
  • Key Concept:
    • Cell cycle regulation is necessary for healthy growth.
internal and external factors regulate cell division
Internal and external factors regulate cell division.

External Factors: come from outside cell

Internal Factors: come from inside cell

Kinases and cyclins

Kinases: enzymes in cells

Cyclins: proteins

Both help to advance a cell to different parts of the cell cycle

May be triggered by external factors

  • Include physical and chemical signals
    • Cell to cell contact: when one cell touches another, they stop growing
    • Growth factors: chemical signals released by cells that tell other cells to grow
  • Trigger internal factors, which affect the cell cycle
cell division is uncontrolled in cancer
Cell division is uncontrolled in cancer.
  • Cancer cells form disorganized clumps called tumors.
    • Benign tumors remain clustered and can be removed.
    • Malignant tumors metastasize, or break away, and can form more tumors.
apoptosis is programmed cell death
Apoptosis is programmed cell death.
  • Apoptosis is the process of programmed cell death.
    • Normal feature in healthy organisms
    • Caused by a cell’s production of self-destructive enzymes
    • Example of apoptosis in healthy organisms: Occurs during fetal development(responsible for

separation of fingers and toes)

slide30

Cancer cells do not carry out normal cell functions(this is part of why they’re so bad!)

  • Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.
  • Carcinogens are substances known to cause cancer (they damage those genes)
    • Chemicals, tobacco smoke, X-rays, UV rays, HPV
  • Cancer can also be caused by genetics (i.e. BRCA1)
  • Standard cancer treatments typically kill both cancerous and normal, healthy cells.
5 4 asexual reproduction
5.4 – Asexual Reproduction
  • Key Concept:
    • Many organisms reproduce by cell division.
binary fission is similar to mitosis
Binary fission is similar to mitosis.
  • Asexual reproduction is the creation of offspring from a single parent – leads to genetically identical offspring.
    • Binary fission produces two daughter cells genetically identical to the parent cells.
    • Binary fission occurs in prokaryotes.
environment determines which form of reproduction is most advantageous
Environment determines which form of reproduction is most advantageous
  • Asexual reproduction is an advantage in consistently favorable conditions.
  • Sexual reproduction is an advantage in changing conditions.
some eukaryotes reproduce by mitosis
Some eukaryotes reproduce by mitosis.
  • Budding forms a new organism from a small projection growing on the surface of the parent.
  • Fragmentation is the splitting of the parent into pieces that each grow into a new organism.
  • Vegetative reproduction forms a new plant from the modification of a stem or underground structure on the parent plant.
5 5 multicellular life
5.5 – Multicellular Life
  • Key Concept:
    • Cells work together to carry out complex functions.
multicellular organisms depend on interactions among different cell types
Multicellular organisms depend on interactions among different cell types.
  • Tissues are groups of cells that perform a similar function.
  • Organs are groups of tissues that perform a specific or related function.
  • Organ systems are groups of organs that carry out similar functions.
specialized cells perform specific functions
Specialized cells perform specific functions.
  • Cells develop into their mature forms through the process of cell differentiation.
  • Cells differ because different combinations of genes are expressed.
  • A cell’s location in an embryo helps determine how it will differentiate.