Chapter 3
Cell Structure
Looking at Cells
• Scientist use
microscopes to look at
cells
• Light/electron scopes
• Micrograph- image as
seen through scope
• Magnification 100X
• Resolution-clarity of
microscopic image
Types of Microscopes
• Compound light
microscope has 2
lenses (multiply
#’s)
– one = eye piece,
– one = objective lense
• Electron Microscopes
• Uses an electron beam
inside a vacuum
chamber
• Stain specimen w/
metal ions
• Can magnify up to
200,000X
Cell Features
•
•
•
•
Cell size (small cells have a
greater surface area/volume
ratio)
Prokaryotes -lacks a nucleus
and other internal
compartments
Eukaryotes- have nucleus
Cell theory
– All living things made of
cells
– Cells are basic units of
structure and function
– All cells arise from existing
cells
Eukaryotic Cells
• Nucleus houses the
cells’ DNA
• Organelle-structure that
carries out a specfic cell
activity
• Cytoskeleton- provides
the interior framework
of animal cell - anchors
organelles to the
cytoplasm
Cell Membrane
• Lipids form barrier b/w
inside and outside of
cell
• Cell membrane only
allows certain
substances to enter/exit
(permeable)
• See diagrams on pages
60-61
Cell Organelles
• Nucleus- controls most cell functions
• Ribosomes- make proteins
• ER - extensive system of internal membranes that
move proteins and other substances through cell
• Rough ER - ER that has ribosomes attached
• Smooth ER- makes lipids and break down toxic
substances
• ER, Golgi apparatus, and lysosomes work together in
the production, packaging and distribution of proteins
(Figure 15 page 64)
Cell Organelles Continued
• Mitochondriaorganelle that
makes energy from
organic compounds
(makes ATP)
• Mitochondria also
has DNA and
ribosomes
• Plant cell organelles
– Cell wall is composed of
proteins and
carbohydrates
– Chloroplasts use light
energy to make
carbohydrates
– Central vacuole stores
water and helps to
control cell pressure