Cell Features

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Cell Features

• Chapter 3 Section 2

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Robert Hooke

• 1665
• Observed cork little boxes called cells
• Crude microscope

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Anton van Leeuwenhoek

• 1675
• Observed pond water
• Living creatures
• Animalcules

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Mattias Schleiden

• 1838
• Concluded cells make up every part of a plant

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Theodor Schwann

• 1839
• Claimed that animals are made up of cells

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Rudolph Virchow

• 1858
• Determined cells come only from other cells

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The Cell Theory

• 1. All living things are made of One or more
  cells.
• 2. Cells are the basic units of structure and
  function in organisms.
• 3. All cells arise from existing cells.

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Why must cells be small?

• 100 trillion cells in the body
• Cells surface-area to volume ratio must be high
• Small cells can exchange substances easier

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Side Length Surface Area l x W x 6 ( 6 sides) Volume L x W x H Surface Area/Volume Ratio S.A. Volume
1 mm 1 x 1 x 6
2 mm 2 x 2 x 6
4 mm 4 x 4 x 6
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Side Length Surface Area l x W x 6 ( 6 sides) Volume L x W x H Surface Area/Volume Ratio S.A. Volume
1 mm 1 x 1 x 6 6 mm2 1 x 1 x 1 1 mm3 6 1
2 mm 2 x 2 x 6 24mm2 2 x 2 x 2 8 mm3 3 1
4 mm 4 x 4 x 6 96 mm2 4 x 4 x 4 64 mm3 3 2
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Common cell features to ALL cells (5 total)

• 1. Cell membrane (Plasma membrane)
• Regulates what enters and leaves the cell (gases,
  nutrients, wastes)

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Plasma Membrane
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Common Features

• 2. Cytoplasm
• Houses the contents of the cell

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Cytoplasm
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Common Features

• 3. Cytoskeleton
• Microscopic fibers that give the cell shape

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Cytoskeleton
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Common Features

• 4. Ribosomes
• Where proteins are made in the cell

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Ribosomes
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Common Features

• 5. DNA
• Regulates all cellular activities

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DNA
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Prokaryotes

• Single celled organism
• No nucleus, no internal compartments

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Prokaryotes

• Early prokaryotes lived 3.5 billion years ago
• Modern prokaryotes are bacteria

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Bacteria cell parts
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Bacteria Cell parts

• Cell wall (composed of polysaccharides Amino
  Acids)
• Plasma Membrane
• Flagella - enables movement
• DNA - in circular ring
• Capsule - enables it to cling to almost anything
• Draw prokaryotic cell in your notes

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Eukaryotes

• Includes all plant and animal cells
• Can be single celled organism or multicellular
  made up of many cells

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Eukaryotes

• Some have Flagella or cilia for movement
• Has a nucleus and internal compartments called
  organelles
• Organelle little organs carry out specific
  activities

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Organelle groups

• Organelles for making Proteins
• Organelles for supporting the cell
• Organelles for Producing energy for the cell
• Organelles for breaking down and storing wastes

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Organelles for making proteins include

• Nucleus - brain directs all activities
• ER - smooth Rough - Membrane system that move
  proteins
• Ribosomes - proteins are made on these
• Golgi Apparatus - packaging distribution post
  office

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Nucleus, ER, Ribosomes and Golgi
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Organelles for supporting the cell

• Cell Membrane - Outer boundary of the cell
• Microtubules - support highway system
• Microfilaments - support highway system
• Cell Wall (plant cell) - surround cell membrane
  in plant cells

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Cell Membrane, microtubules, microfilaments, cell
wall
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Organelles that produce energy

• Mitochondria - Provides the energy the cell needs
  powerhouse
• Chloroplast (plant cell) - Site of photosynthesis

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Mitochondria and Chloroplast
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Organelles that breakdown Store

• Lysosomes - Digest waste products Garbage
  collectors
• Vesicles - vehicles of the cell carry
  substances
• Central Vacuole (plant cell) - storage site for
  water

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Lysosomes, Vesicles, Central Vacuole
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Cell Membrane

• Selectively permeable
• Made up of phospholipids (2 fatty acids bonded to
  a phosphate)
• Draw Phospholipid

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Lipid Bilayer

• Form a lipid bilayer
• Polar heads that are hydrophilic (interact with
  water)
• Nonpolar tails that are hydrophobic (repel water)
• Draw the lipid bilayer

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• Because of this some molecules are able to pass
  directly through the cell membrane and others
  need to travel through a protein embedded in the
  membrane.

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Protein function

• Proteins embedded in the membrane have different
  functions
• Cell surface markers
• Receptor proteins
• Enzymes
• Transport proteins

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Cell Surface Markers

• Cell-surface marker (carbohydrates proteins) -
  help other cells recognize their cell types

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Receptor Proteins

• Receptor protein - recognize and bind specific
  substances the cell needs

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Enzymes

• Enzymes - involved in important reactions in the
  cell

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Transport Proteins

• Transport Proteins Aid the movement of
  substances into and out of the cell that cant go
  directly through the cell membrane