Unit 2 Notes

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Unit 2 Notes

• Cellular Transportation And The Cell Cycle

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Cell Transportation 2 main types

• 1. Passive transport Does not require energy
  from the cell
• Moves downhill, with the concentration gradient

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Cellular Transportation Type 2

• 2. Active Transport Requires energy to occur.
• Moves uphill, against the concentration gradient.

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Passive Transport(No energy required)

• 3-Types

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1st Type Passive Transport

• Simple Diffusion Movement of any substance
  from areas of higher to lower concentrations
• diffusion animation

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2nd Type Passive Transport

• Osmosis Movement of water from areas of
  higher to lower concentrations

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3rd Type Passive Transport

• Facilitated diffusion Movement of substances
  from higher to lower concentration with help from
  a protein molecule
• Animation How Facilitated Diffusion Works

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2-Types of Active Transport (Energy Required)

• 1. Exocytosis The expulsion of particles from
  the cell.
• 2. Endocytosis surrounding and engulfing
  particles.
• Pinocytosis Cell drinking the cell takes in
  liquids.
• Phagocytosis Surrounding and taking in of large
  particles.

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Phagocytosis

• Animation Phagocytosis

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Solute vs Solvent

• Solute The dissolved substance in a liquid.
• Solvent The liquid that the solute is dissolved
  in Usually water

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Types of solutionsIsotonic solution

• Concentrations of solute are equal in the cell
  and the solution. (cellsolution)
• Water moves back and forth at the same rate.
• Water in Water Out

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Hyp-O-tonic solution(Hyp-Ohh no Im
swelling-tonic)

• HypOtonic Concentrations of solute are higher
  in the cell than in the solution (cell-higher,
  solution-lower)
• Water moves into the cell.
• The cell swells and can burst.

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Hypertonic Solution

• Concentrations of solute are lower in the cell
  than in the solution (cell-lower,
  solution-higher)
• Water moves out of the cell.
• The cell shrinks.

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Limits to cell size

• A cells size is limited, so organisms grow by
  cellular division.
• The cells of a baby are the same size as the
  cells of an adult.

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So Why Cant cells just grow larger???
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Three factors that limit the growth of cells

• 1. Diffusion across cell surface.
• 2. Shortage of DNA.
• 3. Surface to volume ratio.

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Diffusion

• Diffusion is efficient over short distances, but
  becomes inefficient and slow over large
  distances.
• Socells that are large have a more difficult
  time getting nutrients into the cell and waste
  products out of the cell.

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DNA

• A cell cannot survive without sufficient amounts
  of DNA to make necessary proteins
• Unusually large cells must have multiple nuclei
  in order to supply needed DNA

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Surface Area to Volume Ratio

• As a cells size increases, its volume increases
  faster than its surface area

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Cell Reproduction

• Mitosis Asexual reproduction (Cell Cycle)
• The process by which one cell divides into two
  cells, both identical to the original parent cell

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The Dreaded C Words!

• Chromatin
• Chromosomes
• Chromatid
• Centromeres
• Centrioles

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Chromatin

• Relaxed DNA.

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Chromosomes

• Condensed DNA.
• DNA that is preparing to undergo cellular
  division
• Can now be seen with a microscope.

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Chromatids and Centromeres

• Sister Chromatids Halves of a duplicated parent
  chromosome.
• Centromeres The structure that joints two
  sister chromatids.

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Chromatin and Chromosome
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Centrioles- Produce the spindle and aid in
replication
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The Cell Cycle

• The process of asexual reproduction (mitosis) of
  the cell
• Contains three major parts
• 1. Interphase 2. Mitosis 3. Cytokinesis

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The Cell Cycle
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Part One of the Cell CycleInterphase

• The cell spends the majority of its life in
  interphase.
• A time in which the cell is preparing for
  division.

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Interphase3-Parts

• G-1 Maturation.
• S-Phase DNA replicates - makes a duplicate copy
  of itself.
• G-2 Organelles replicate and final preparations
  for division.

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Mitosis

• Division of the nucleus
• 4-phases
• Prophase
• Metaphase
• Anaphase
• Telophase
• PMAT

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Parts of MitosisProphase

• The chromatin condense to form visible
  chromosomes
• The nuclear envelope begins to dissolve
• The centrioles divide and begin to migrate to
  opposite sides of the cell

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Parts of Mitosis ContMetaphase

• Centrioles have moved to opposite sides of the
  cell
• The spindle has formed
• Chromosomes are lined up in the middle of the
  cell across the equator

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Parts of Mitosis ContAnaphase

• The centromeres split and the spindles pull the
  sister chromatids apart toward opposite sides of
  the cell

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Parts of Mitosis ContTelophase

• The chromosomes move to opposite sides of the
  cell.
• The nuclear envelope begins to reform around each
  set of chromosomes at opposite sides of the cell.

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Cytokinesis

• Division of the cytoplasm
• Begins to occur during telophase
• Different in plants and animal cells

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Cytokinesis Cont

• Animal cells the plasma membrane pinches in to
  form two separate cells
• Plant cells A rigid cell plate begins to form
  between the two new cells, dividing them and
  becoming a cell wall.

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mitosis animation
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Control of the Cell Cycle

• The cell cycle is controlled by proteins and
  enzymes
• Contact with other cells causes cell to stop
  dividing.
• Cell stop dividing when they lose contact with
  other cells

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Cancer

• Uncontrolled cell growth resulting in tumors
• Metastasis Cells break lose and travel through
  the circulatory system spreading throughout the
  body.

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Causes of Cancer

• Environmental factors that damage genes.
• Ex Cigarette smoke, UV rays from the sun, air
  and water pollution, viruses