Honors Biology Ch. 7

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HonorsBiologyCh. 7

• A View of the Cell

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CH. 7 A View of the Cell
I. The Cell Theory

• A. History
• - before 1600s - fiber/tissue thought to be
  the basic unit of life
• - spontaneous generation
• 1. Robert Hooke (1665)
• - observed cork cells

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Robert Hooke (1665)- Coined term Cell
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2. Van Leeuwenhoek (1683)

• - first to see living cells

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Von Leeuwenhoek (1683) - first to see living
cells
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3. Mathias Schleiden (1838)

• - plants made up of cells

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4. Theodor Schwann (1838)

• - animals made up of cells

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5. Rudolph Virchow (1855)

• - cells come from other cells

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B. The Cell Theory(3 parts)

• 1. All living things are made of cells.
• 2. All cells come from preexisting cells.
• 3. Cells are the basic units of structure and
  function.

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- developed over several hundred years involving
many scientists - followed the development of the
microscope
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Research Method Light Microscopy
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(No Transcript)
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Micrograph of a neuron and dendrites using
antibodies, fluorescent proteins, and confocal
microscope
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Research Method Electron Microscopy
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Everything that lives is made of cells.
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C. Two Basic Cell Types

• 1. Prokaryotes
• - no nucleus nor organelles
• - simple internal structure
• - very small, primitive, unicellular
• - bacteria

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Prokaryote
Bacteria Cell
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2. Eukaryotes

• - have a nucleus and membrane-bound organelles
• - complex internal structure
• - animals, plants, fungi, protists

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Eukaryote
Animal Cell

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Eukaryote
Plant Cell

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II. Cell Structure
- 3 main parts of cells
1. Plasma membrane
2. Nucleus

• 3. Cytoplasm

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A. Plasma membrane

• 1.Composition
• - bilayer of phospholipids embedded with
  proteins
• - fluid mosaic theory

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Plasma membrane
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Plasma membrane
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2. Function

• - holds cell together
• - regulates movement of molecules into or out of
  the cell

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3. Cell Wall

• - rigid, layered structure on the outside of
  cells that protects and supports cell
• - found on cells of plants, fungi, and bacteria
• - plant cell walls made of cellulose

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Cell Wall
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B. Nucleus

• - control center of the cell
• - contains chromatin (DNA blueprint for cells
  proteins)

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1. Nucleolus

• - makes ribosomes
• 2. Chromatin
• - active form of chromosomes
• - long threads of DNA and protein

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C. Cytoplasm

• - liquid interior of the cell
• - mostly water with dissolved substances
  (O2,CO2, sugar, etc.)

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C. Cytoplasm

• - contains Organelles
• tiny structures that carry out specialized
  functions

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D. Assembly, Storage,and Transport
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1. Ribosomes

• - where proteins are made in a cell
• - found in both prokaryotes and eukaryotes

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2. Endoplasmic Reticulum

• - produces and transports molecules

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3. Golgi Body

• - store, modify, and package proteins,
  hormones, etc.

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4. Vacuole
- stores food, waste, sugar, water, etc.
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5. Lysosome

• - digest food molecules or worn-out
  cells

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6. Leucoplasts

• - store starch (plants only)
• 7. Chromoplasts
• - contain colorful pigments (plants
  only)
• E. Energy Transformations

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1.Mitochondrion
- "power house" of cells
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1.Mitochondrion
- site of cellular respiration Glucose
Oxygen Energy CO2 H2O C6H12O6 O2
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2. Chloroplasts
- site of photosynthesis in plant cells
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2. Chloroplasts
Sunlight H2O CO2 C6H12O6 O2
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F. Support and Locomotion

• 1. Cytoskeleton
• - internal framework of cell
• a. Microtubules
• b. Microfilaments
• - contractile proteins
• - enable cells to move

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2. Centrioles

• - aid in the division of animal cells

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3. Cell Locomotion

• a. Cilia
• - short fibers, usually in large number
• b. Flagella
• - long fibers, usually single or pairs

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III. Cellular Transport

• - molecules constantly enter and leave the cell

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A. Diffusion

• - movement of molecules from high concentration
  to low conc.
• - until dynamic equilibrium reached
• - requires no cell energy (passive)

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B. Osmosis

• - diffusion of water through a selectively
  permeable membrane

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C. Effects of Osmosis

• 1. Isotonic Solution
• - concentration of solutes the same on inside
  and outside of cell

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2. Hypotonic Solution

• - solution outside of cell contains a lower conc.
  of solutes than the cell (more water)

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a) Turgor pressure

• - pressure inside plant cells

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a) Turgor pressure
Leaves and Onion Epidermis
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a) Turgor pressure
Plant Movements from Osmosis
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b) Cytolysis

• - bursting of cells due to increased osmotic
  pressure

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c) Contractile Vacuoles

• - pump water out of cells of paramecium, ameba,
  etc. living in a hypotonic solution

Paramecium
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3. Hypertonic Solution

• - solution outside of cell contains a higher
  conc. of solutes than the cell (less water)

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a) Plasmolysis
- loss of cytoplasm (shrinking of the cell)
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b) Wilting
- loss of turgor in plant cells
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D. Passive vs. Active Transport

• 1. Passive Transport
• - requires no energy
• a) Diffusion and Osmosis

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b) Facilitated Diffusion

• - transport proteins in membrane move sugar,
  amino acids, etc.
• - follows concentration gradient

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b) Facilitated Diffusion
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2. Active Transport

• - requires cell energy
• a) Carrier proteins transport molecules from low.
  conc. to high conc. using cell energy

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Active Transport
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b) Endocytosis
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b) Endocytosis

• - movement of large amounts of material into a
  cell by engulfing and enclosing within a membrane
• - forms a vacuole within cell

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b) Endocytosis
Ameba
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c) Exocytosis
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c) Exocytosis

• - expelling large amounts of material from the
  cell

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c) Exocytosis
Paramecium
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• The
• End

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Elodea Leaf Cells
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Tomato Cells
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Potato Cells
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Human Epithelial Cells
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Onion Cells- Unstained (40x)
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Onion Cells- Stained (40x)
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Bacteria Cells
Coccus
Bacillus
Spirillum
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Von Leeuwenhoek (1675)- first to see live cells