Download Cells Chp 7 BioA.1

Cells
Bio.A.1.1 - Explain the characteristics common to
all organisms
Bio.A.1.2 – Describe relationships between
structure & function at biological levels of
organization
BIO.A.1 – Basic Biological Principles
• Bio.A.1.1.1 – Describe the characteristics of life
shared by all prokaryotic and eukaryotic
organisms
• Bio.A.1.2.1 – Compare cellular structures & their
functions in prokaryotic and eukaryotic cells
• Bio.A.1.2.2 – Describe & interpret relationships
between structure & function at various levels of
biological organization
Vocabulary
Cell
Cell theory
Cell membrane
Nucleus
Eukaryote
Prokaryote
Cytoplasm
organelle
Golgi apparatus
vacuole
chloroplasts
lysosome
mitochondria
cytoskeleton
cell wall
centriole
lipid bilayer
ribosome
selectively permeable
endoplasmic reticulum
The Cell Theory
• Cells are the basic unit of life
• All living things are made of cells
– Plants, animals, bacteria, etc.
• Cells are the basic unit of structure and function
in living things
– Can you give an example from your own body?
• New cells are produced only from existing cells
Microscopes
• We use various types of microscopes to see into and study
cells
• We will use a compound light microscope
– Uses light and 2 lenses to create an image of the cell
– Can only magnify the image about 1000 times
– Not every part of a cell can be clearly seen with a light
microscope
• Electron microscopes use a beam of electrons and offer
much higher resolution – can be used to study cell
structures that are one billionth of a meter in size!
Microscopes
• There are 2 types of electron microscopes
– Transmission electron microscopes produce images
that are flat and 2 dimensional because the specimen
must be cut into ultra-thin slices
– Scanning electron microscopes produce 3 dimensional
images of the specimen’s surface
• Electron microscopes require the specimen to be
preserved & placed in a vacuum – which means
only non-living cells and tissues can be examined
What Do You Think?
• What type of microscope would you use to
examine cellular life in a drop of pond water?
Why?
• What type of microscope would you use to
examine the surface of the nucleus? Why?
• You are presented with a specimen to examine.
What are two questions you could ask to
determine the best microscope to use?
Prokaryotes and Eukaryotes
• There are a variety of cells, but all cells have a few
characteristics in common
–
–
–
–
All cells (at some point) have DNA (genetic material)
All cells have a cell membrane (flexible barrier)
All cells have cytoplasm (watery substance)
All cells have proteins and ribosomes (structure that
makes proteins)
– All cells (living things) grow, reproduce, obtain and use
materials/energy, maintain a stable internal environment
and respond to their environment
Prokaryotes
• Prokaryotes are generally smaller and simpler than
eukaryotes
• Prokaryotic cells do not separate their genetic
material into a nucleus
• They do not have specialized organelles
• ALL prokaryotes are single celled organisms
• Bacteria are prokaryotes
Typical Prokaryote
What type of
microscope do
you think would
be best to use to
examine a typical
prokaryotic cell?
Why?
Eukaryotes
• Eukaryotes are generally larger and much more
complex than prokaryotes
• Eukaryotic cells contain many highly specialized
internal structures (organelles)
• One organelle is called the nucleus – Eukaryotes
store DNA inside the nucleus.
• Some eukaryotes are single celled (amoeba) and
some are multicellular (us)
Eukaryotes
• Not all eukaryotic cells are the same but there are
many parts most or all have in common
– Nucleus – where the DNA is stored, has a nuclear
membrane with nuclear pores
• The nucleolus is inside the nucleus and is where the ribosomes
are made
Ribosomes – make proteins, also found in prokaryotes,
made of RNA and have 2 subunits
The Nucleus
Eukaryotes
– Rough Endoplasmic Reticulum – network of
membranes that modify proteins and studded with
ribosomes, connected to nucleus
• How is the rough ER’s structure related to its function?
– Smooth Endoplasmic Reticulum – network of
membranes, synthesize membrane lipids & detoxifies
drugs
• What human organ would you expect to have large amounts of
smooth ER?
Eukaryotes
– Golgi Apparatus – network of membranes that
modifies, sorts and packages proteins after they leave
the rough ER
– Vacuoles – membrane bound storage facilities for the
cell, often large & filled with water especially in plants
Eukaryotes
– Lysosomes – membrane bound and filled with enzymes,
for breaking down large molecules or older cell parts
– Centrioles – made of protein, help organize cell
division, in animal cells but not plant cells
Eukaryotes
– Cytoskeleton – helps the cell maintain its shape and
also helps control cell movement
• Microtubules – large tubes
• Intermediate filaments – middle sized tubes, for support
• Microfilaments – smallest in size
Eukaryotes
– Mitochondria – convert chemical energy stored in food
(glucose) into more useful chemical energy (ATP),
double membrane bound organelle, cell respiration
– Chloroplasts – found in plant but not animal cells,
convert light energy into chemical energy (glucose),
double membrane bound organelle, photosynthesis
Eukaryotes
– Cell membrane – all cells have a cell membrane, a
fluid-mosaic, phospholipid bilayer that is selectively
permeable, important in maintaining homeostasis
Eukaryotes
– Cell wall –provides extra rigid support and protection
for the cell, most are porous, not found in animal cells,
made of cellulose in plants
What do you think?
• The cell can be compared to a city. Can you
determine which cell part would be most like the
following parts of a city and why?
• City Hall
– nucleus
• Post Office
– golgi
• Streets & Highways
– cytoskeleton
• Recycling Center
– lysosome