Download CELLS

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History of the cell:
The development and refinement of
magnifying lenses and light microscopes
made the observation and description of
microscopic organisms and living cells
possible.
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*Leeuwenhoek –
developed and
improved simple
microscopes; he saw
small living things in
a drop of pond
water and called
them “animalcules”.
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*He studied cork
with a microscope
and described the
small boxes he
decided to call
cells after rooms
in monasteries.
*He named the cell
a “cell”.
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*A German
botanist who
concluded that
all plants are
made of cells.
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*A German
zoologist who
concluded that
all animals are
made of cells.
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* All living things are made of cells.
* The cell is the basic unit of structure and function in all
living things.
* All cells come from pre-existing cells.
* MODERN CELL THEORY ADDS:
* Energy flow occurs within cells.
* Cells contain hereditary information that is passed from
cell to cell during cell division.
* All cells are basically the same in chemical composition
in organisms of similar species.
* Continued advancements in microscopy
allowed the observation of cell organelles and
internal structure.
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* Two types were developed in the mid 1900’s.
* The scanning electron microscope (SEM) uses a beam of
electrons to scan the surface of a cell.
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* Prokaryotes are cells that do not contain
a nucleus or other membrane-bound
organelles.
* They are much smaller that eukaryotes.
* Bacteria are prokaryotes.
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*Organelles are membrane-bound
structures in a eukaryotic cell.
*Each organelle has a specific
function for cell survival.
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• All cells, prokaryotic
and eukaryotic, have a
plasma membrane.
• It is a phospholipid
bilayer.
• It is selectively
permeable as it
regulates what goes in
and out of the cell.
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*The nucleus controls all cellular
functions.
*It contains chromatin which is made up
of DNA and proteins.
*DNA is the blueprint for all cellular
activity.
• The nucleolus is found in the nucleus.
• It produces ribosomes.
• It is the dark, dense regions of the
nucleus.
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* Ribosomes are where proteins are made.
* Some are free in the cytoplasm and some are
bound to the endoplasmic reticulum.
* Ribosomes are NOT membrane-bound and are
found in both eukaryotes and prokaryotes.
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* The cytoplasm is all cellular contents outside
the nucleus in eukaryotic cells.
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* The ER is a series of membranous canals for the transport
of materials.
* They are the sites of chemical reactions.
* Rough ER – ribosomes are attached that are producing
proteins
* Smooth ER – no ribosomes attached; involved in production
and storage of lipids
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*Also called the Golgi bodies or Golgi complex
*It receives proteins from the ER.
*It modifies, packages, and ships the proteins.
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*Vacuoles are membrane-bound sacs
for temporary storage.
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*They are the cell’s recyclers.
*Lysosomes contain digestive enzymes
to digest worn out organelles, food
particles, or viruses.
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*These are the sites for
photosynthesis.
*They capture light energy and
convert it to chemical energy.
*The chemical energy is stored in
food molecules.
* These are the sites for cellular respiration.
* They are called the “powerhouse of the cell”.
* They break down food molecules and release
energy.
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*This support structure in the
cytoplasm is composed of
microtubules and microfilaments.
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*Centrioles are involved in cell
division. They are found only in
animal cells.
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*These are short, numerous hair-like
projections on the cell surface for
locomotion or feeding.
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*Flagella are longer projections on
the cell surface that move with a
whip-like motion.
*They are primarily used for
locomotion.
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*The cell wall is an inflexible barrier
that protects the cell and gives it
support.
*They are found in prokaryotes,
fungi, plants, and in plant-like
protists.
*Plant cells have a cell wall as well as
a plasma membrane.
*Animal cells only have a plasma
membrane.
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*Plant cells have chloroplasts and
mitochondria.
*Animal cells only have mitochondria.
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*Plant cells have a large central
vacuole for water storage.
*Animal cells only have small,
temporary vacuoles.
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*Animal cells have centrioles.
cells do not.
Plant