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Cells and Organelles
End of Course Review
The Cell Theory
1. All living things are made of cells
2. Cells are the basic unit of life
3. All cells come from other cells
Prokaryotes
• Prokaryotes do NOT have a
nucleus.
• Prokaryotes do NOT have
membrane-bound
organelles
• Prokaryotes DO have DNA
and ribosomes
• Bacteria cells are
prokaryotes.
• Bacteria are unicellular or
made of just one cell.
• The first cells were probably
prokaryotes
Eukaryotes
• Eukaryotes have DNA in a
nucleus
• Eukaryotes have membrane
bound organelles such as
– Mitochondria
– Golgi Bodies
– Endoplasmic Reticulum
• Everything except bacteria
are eukaryotes
• Most eukaryotes like plants
and animals are
multicellular or made of
more than one cell
Cell Membrane
• The cell membrane is like the
skin of the cell
• It controls what goes into and
out of the cell
• The cell membrane may also be
called the plasma membrane
• It has two layers of lipids with
proteins floating through it
Cell Wall
• The cell wall is outside
the plasma membrane
• It is in plant cells, but
not animal cells
• It provides plants cells
extra support and
protection
Nucleus
• The nucleus holds the cell’s DNA
• DNA can either be in loose
stands called chromatin or
tightly wound into
chromosomes
• The nucleus controls the activity
of the cell through the DNA
• The nucleus has a membrane
around it called the nuclear
envelope
• It has little openings or pores
• Inside the nucleus there is a
dense region called the
nucleolus
• The nucleolus is where
ribosomes are made
Cytoplasm
• The cytoplasm is the fluid
that fills up the cell.
• It is mostly water
• All the organelles and
other cell contents float
around in the cytoplasm
Endoplasmic Reticulum (E.R.)
• The E.R. surrounds the nucleus
• Parts of the cell membrane are made here
• Proteins, like those in the cell membrane, are made and modified here.
• E.R. can be smooth or rough
– Rough E.R. has ribosomes on it
– Smooth E.R. does not.
Ribosomes
• Ribosomes read the
messages from DNA and
turn them into proteins
• Proteins are made up of
smaller units called amino
acids
Golgi Bodies
• Can also be called Golgi Complex or Golgi Apparatus
• Proteins from the E.R. are packaged and sent to their final
destination, sometimes outside of the cell.
• The packages are surrounded by a membrane and are called vesicles
Lysosomes
• Lysosomes are filled with
enzymes that break down
food, wastes, and other
things inside the cell.
• Enzymes are a special
kind of protein that speed
up chemical reactions
• Enzymes are an important
part of digestion
• Plant cells do NOT have
lysosomes
Vacuoles
• Vacuoles store water and other materials the cell needs.
• The vacuole in plant cells are very large and take up most of
the cell
• In animal cells, they are much smaller or even not there
Chloroplasts
• This is where light from the
sun is used to make food in
the form of sugar
• Chloroplasts take in water
and carbon dioxide and
produce sugar and oxygen
• This process is called
photosynthesis
• Animals do NOT have
chloroplast
• Chloroplasts make plants
green because they have
the pigment chlorophyll
carbon
dioxide
oxygen
water
sugar
photosynthesis
chloroplast
Mitochondria
• Mitochondria make energy
for the cell
• The energy comes from the
sugar and oxygen produced
in the chloroplasts
• The sugar and oxygen is
turned into water, carbon
dioxide, and ATP
• ATP carries the energy that
powers the cell
• The process that creates
energy is called cellular
respiration
Cytoskeleton
• The shape of the cell is supported by the cytoskeleton
• It contains a network of microfilaments and microtubules
• The cytoskeleton can also allow the cell to move
Centrioles
•
•
•
•
Centrioles work with the cytoskeleton
They are important when cells divide
They attach to chromosomes and separate them into two copies
Plant cells do NOT have centrioles
Dividing Cell
chromosomes
Animal Cell
Animal Cells vs. Plant Cells
Cells and Organelles
End of Course Review