Cells Overview Chapter 3 for Anatomy Chapter 7 for Biology

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Cells OverviewChapter 3 for Anatomy Chapter 7
for Biology
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Life is Cellular

• A cluster of neural cells were derived from human
  embryonic stem cells in the lab. The motor
  neurons are shown in red neural fibers appear
  green and the blue specks indicate DNA in cell
  nuclei.

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Microscopes

• Mid 1600s
• 1665 Robert Hooke
• 1st Compound Microscope
• After looking at Cork
• Saw cambers called Cells
• Anton Van Leeuwenhoek
• Pond water (animalcules)

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Cork Cells / Microscopic Animals

• Cork Cells at 100X Magnification / Plankton have
  limited powers of locomotion

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Scanning Electron Microscope

• SEM is a type of electron microscope that images
  the samples surface by scanning it with a
  high-energy beam of electrons.

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Transmission Electron Microscope

• TEM uses a beam of highly energetic electrons to
  examine objects very closely, on a fine scale. A
  TEM shines a beam of electrons through an object.

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Scanning Probe Microscope

• SPM is a branch of microscopy that forms images
  of surfaces using a physical probe that scans the
  specimen.

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Cell theory

• All organisms are comprised of more than one cell
• Cell is the basic unit of life
• All cells come from preexisting cells

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What is an organelle?

• Membrane bound structures with particular
  functions within eukaryotic cells

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Types of Organelles

• Nucleus
• Cell membrane
• Ribosomes
• Endoplasmic reticulum
• Golgi Apparatus
• Lysosomes
• Vacuoles
• Mitochondria
• Chloroplast Plants only
• Cell wall plants only
• Cytoskeleton

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Bacteria cell
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Cell Wall

• The rigid cell wall of plants is made of fibrils
  of cellulose embedded in a matrix of several
  other kinds of polymers
• Bacteria cell wall is made up of polysaccharides
  and protein.

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Chloroplast

• Captures light energy in plants and produces ATP
  and reduce NADP to NADPH through a complex set of
  processes called photosynthesis.

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Endoplasmic Reticulum

• Synthesis of protein and lipids
• Rough ER protein synthesis can exsist in
  cytoplasm
• Smooth ER lipid synthesis

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Ribosomes

• Sites of protein synthesis
• Scattered throughout cytoplasm
• Comprised of protein and RNA molecules
• Provide structural support for RNA during protein
  synthesis from amino acids

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Golgi Bodies

• Composed of six flattened membranous sacs
• Packages and delivers proteins synthesized by
  ribosomes
• Proteins arrive at this spot in vesicles, where
  glycoproteins are to be received

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Golgi Bodies

• They pass through one end and continue to pass
  over the sac until the protein is chemically
  processed
• When the altered glycoprotein reaches outermost
  layer, then bubblelike structures form and move
  throughout the cell membrane exocytosis

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Mitochondria

• Elongated fluid filled sacs
• Move slowly through cytoplasm and reproduce by
  dividing
• Has inner and outer layers

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Mitochondria

• Inner layer has cristae that control some
  chemical reactions, through enzymatic processes
• Chemical reactions release energy
• Major site of ATP production energy for the cell

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Lysosome

• garbage men of the cell
• Membranous sacs
• Powerful enzymes that breakdown nutrient
  molecules or foreign particles
• In blood cells can destroy bacteria
• In cells in general can breakdown dead cell
  parts

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Microfilaments

• Tiny rods of actin protein that form meshwork or
  bundles
• Provide cell mobility
• In muscle cells they aggregate to form
  myofybrils, which help the cells to contract

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Microtubules

• Long slender tubes with diameter two to three
  times that of microfilaments
• Composed of globular tubulin proteins 92 array
  (9 outside, 2 inside)

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Centrosome

• Structure near Golgi Apparatus and nucleus
• Consists of two hollow cylinders called
  centrioles
• Lie at right angles and distribute chromosomes
  evenly to new cells during mitosis.

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Cilia

• Motile extensions from certain cells
• Comprised of microtubules in 92 array
• Tiny hairlike structures
• Move to and fro, in succession, so that there is
  a wavelike motion

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Flagella

• Motile extensions from certain cells
• Comprised of microtubules in 92 array
• A cell will only normally have one flagellum
• Swim motion

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Vesicles

• Or vacuoles
• Membranous sacs formed by part of the cell
  membrane folding inward and pinching off
• Material outside the cell is now inside and in
  the cytoplasm

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Cell Nucleus

• Houses genetic material
• Enclosed in a double layer nuclear envelope
  inner and outer lipid bilayer membranes
• Protein-lined channels called nuclear pores that
  allow for certain molecules to exit

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Nucleolus

• Small dense body composed largely of RNA and
  protein
• No surrounding membrane
• Forms in specialized regions of certain
  chromosomes
• Ribosomes form in the nucleolus and move through
  nuclear pores to the cytoplasm

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Chromatin

• Loosely coiled fibers of DNA and proteins
  chromosomes
• DNA information for protein synthesis
• Beginning of cell division chromatin coil
  tightly and individual chromosomes become visible

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Cell Membrane Structure

• A phospholipid consists of a
• polar portion, called the head,
• two longer fatty acids, called the tail.

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Cell Membrane Structure
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fault.htm

• When mixed with water, the heads are attracted to
  the polar water molecules.
• The nonpolar tails move as far from water as
  possible, and a double layer of phospholipids
  with tails to the interior results.

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Phospholipid bi-layer of a cell membrane