Cell Theory and Cell Structure

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Cell Theory and Cell Structure
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Cell Theory

• The term cell was coined in 1665 by
• Robert Hooke
• He looked at a slice of dried cork bark
• All living things are comprised of cells.
• Cells are the smallest living unit in an
  organism.
• Cells come from previously existing cells.

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Cell Diversity
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A Typical Cell
A typical cell combines features that many
different cells possess.
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Organization of the Cell

• Smallest living unit
• Plasma (cell) membrane
• Cytoplasm
• Cytosol
• Organelles

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1. Plasma (Cell) Membrane

• Outer boundary
• Physical
• Chemical
• Comprised of
• two layers of lipid (fat) called outer and inner
  layersall cells have this feature
• Proteins proteins give the cell its unique
  personalitydifferent cells have different
  proteins.and therefore different functions

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1. Plasma (Cell) Membrane
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Specific Functions of Plasma Membrane Proteins

• Transport (see Cystic Fibrosis p. 33)
• Adhesion
• Enzymes
• Cell recognition
• Receptors

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2. Cytoplasm

• Consists of cytosol (liquid)
• Organelles

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Cytosol

• The viscous, liquid inside of the cell
• Contains water, ions (Na, K, Ca, Cl), nutrients,
  proteins, carbohydrates, lipids.etc.
• Organelles little organs that either float
  around in the cytosol or are held in place within
  the cytosol

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Organelles

• Endoplasmic Reticulum (ER)
• A network of
• membrane
• bound tunnels
• within the cytoplasm
• Two types
• based on
• appearances

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Endoplasmic Reticulum
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Two Types of ER

• Rough endoplasmic reticulum (rER)
• Smooth endoplasmic reticulum (sER)
• Names based on appearance

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Endoplasmic Reticulum (ER)
Rough ER (rER) Smooth ER (sER)
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Rough Endoplasmic Reticulum (rER)

• Particles attached to
• outside of membrane
• are ribosomes.
• Ribosomes are the site
• of protein sysnthesis
• within the cell.

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Smooth Endoplasmic Reticulum (sER)

• No ribosomes attached
• to membrane
• Continuous with rER
• Synthesis of lipids (fats)
• Synthesis of
• carbohydrates
• Detoxifies drugs,
• alcohol and poisons

sER
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Golgi Apparatus

• Stack of membranes
• Modifies, packages and sorts proteins and lipids
  to be secreted from the cell.

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Golgi Apparatus

• Proteins and lipids made in ER get passed to
  Golgi to become modified.
• Golgi packages these products and secretes them.

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Mitochondria

• Double membrane (outer and inner)
• Bean shaped
• Inner membrane
• enzymes produce
• high-energy ATP
• Adenosine triphosphate
• Sole source of energy
• for the cell

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Nucleus

• Largest organelle in cell
• Control center of cells activities
• Repository of inherited traits
• Inherited traits are in the form of genes
• Genes are comprised of DNA
• Deoxyribonucleic acid
• DNA coils tightly to form chromosomes when cell
  is about ready to divide.
• Mature red blood cells do not have a nucleus

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Nucleus