Basic Structure of a Cell
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History of Cell Theory
• mid 1600s – Anton van Leeuwenhoek
– Improved microscope, observed many living cells
• mid 1600s – Robert Hooke
– Observed many cells including cork cells
– Named the cell
• 1850 – Rudolf Virchow
– Proposed that all cells come from existing cells
• SCI.9-12.B-2.1 - [Indicator] - Recall the
three major tenets of cell theory (all living
things are composed of one or more cells;
cells are the basic units of structure and
function in living things; and all presently
existing cells arose from previously existing
cells).
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• SCI.9-12.B-2 - [Standard The
student will demonstrate an
understanding of the structure
and function of cells and their
organelles.]
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*Cell Theory
1. All organisms consist of 1 or more
cells.
2. Cell is the smallest unit of life.
3. All cells come from pre-existing
cells.
Observing Cells (4.1)
• Light microscope
– Can observe living cells in true color
– Magnification of up to ~1000x
– Resolution ~ 0.2 microns – 0.5 microns
Observing Cells (4.1)
• Electron Microscopes
– Preparation needed kills the cells
– Images are black and white – may be colorized
– Magnifcation up to ~100,000
• Transmission electron microscope (TEM)
– 2-D image
• Scanning electron microscope (SEM)
– 3-D image
SEM
TEM
*Introduction to Cells
Cells are the basic units of organisms
Cells can only be observed under
microscope
Basic types of cells:
Animal Cell
Plant Cell
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Bacterial Cell
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*Number of Cells
Organisms may be:
• Unicellular –
composed of one cell
• Multicellularcomposed of many
cells that may
organize
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*Cells May be Prokaryotic or
Eukaryotic
 Prokaryotes include bacteria &
lack a nucleus or membrane-bound
structures called organelles
Eukaryotes include most other cells
& have a nucleus and membranebound organelles (plants, fungi, &
animals)
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SCI.9-12.B-2.3 [Indicator] - Compare the
structures and organelles of
prokaryotic and eukaryotic
cells.
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*Prokaryotes
Nucleoid region
contains the DNA
•Cell membrane &
cell wall
• Contain ribosomes
(no membrane) to
make proteins in
their cytoplasm
•Only example is
bacteria
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*Eukaryotic Cell
Contain 3 basic cell
structures:
• Nucleus
• Cell Membrane
• Cytoplasm with
organelles
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Video clip about pro vs eu
• https://www.youtube.c
om/watch?v=ss19u6vJ
NNQ
copyright cmassengale
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Two Main Types of
Eukaryotic Cells
Plant Cell
Animal Cell
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Organelles
Very small size
Can only be observed under a
microscope
Have specific functions
Found throughout cytoplasm
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• SCI.9-12.B-2.2 - [Indicator] - Summarize
the structures and functions of organelles
found in a eukaryotic cell (including the
nucleus, mitochondria, chloroplasts,
lysosomes, vacuoles, ribosomes, endoplasmic
reticulum [ER], Golgi apparatus, cilia,
flagella, cell membrane, nuclear membrane,
cell wall, and cytoplasm).
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CYTOSKELETON
RIBOSOMES
Chroma
tin
MITOCHONDRIO
N
ROUGH ER
SMOOTH ER
CENTRIOLES
GOLGI BODY
LYSOSOME
PLASMA
MEMBRANE
Fig. 4-15b, p.59
Organelles Found in Cells
Examples of Organelles include:
Endoplasmic reticulum (rough & smooth) –
canals for movement
Golgi Bodies – wrap & export proteins
Nucleolus – makes ribosomes
Lysosomes – digests & gets rid of wastes
Ribosomes – makes proteins
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*Golgi
• Stacks of flattened
sacs
• Have a shipping side &
a receiving side
• Receive & modify
proteins made by ER
• Transport vesicles
with modified proteins
pinch off the ends
Bodies
Transport
vesicle
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*Lysosome
• Contain digestive
enzymes
• Break down food and
worn out cell parts for
cells
• Programmed for cell
death (lyse & release
enzymes to break down
& recycle cell parts)
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*Nucleolus
•
Cell may have 1 to 3
nucleoli
• Inside nucleus
• Disappears when cell
divides
• Makes ribosomes that
make proteins
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• SCI.9-12.B-2.2 - [Indicator] - Summarize
the structures and functions of organelles
found in a eukaryotic cell (including the
nucleus, mitochondria, chloroplasts,
lysosomes, vacuoles, ribosomes, endoplasmic
reticulum [ER], Golgi apparatus, cilia,
flagella, cell membrane, nuclear membrane,
cell wall, and cytoplasm).
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*Smooth & Rough Endoplasmic
Reticulum
Smooth ER lacks
ribosomes & makes
lipids also
detoxifies poisons
from medicine and
alcohol
Rough ER has
ribosomes on its
surface & makes
proteins to EXPORT
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Cell Powerhouse
*Mitochondrion
(mitochondria )
Rod shape
*Site of Cellular
respiration
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*
Mitochondria
Active cells like
muscles have more
mitochondria
*Burn sugars to
produce energy ATP
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*Surrounding the Cell
Cell membrane
Lies immediately
against the cell wall
in plant cells
Made of protein and
phospholipids
Selectively permeable
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• SCI.9-12.B-2.2 - [Indicator] - Summarize
the structures and functions of organelles
found in a eukaryotic cell (including the
nucleus, mitochondria, chloroplasts,
lysosomes, vacuoles, ribosomes, endoplasmic
reticulum [ER], Golgi apparatus, cilia,
flagella, cell membrane, nuclear membrane,
cell wall, and cytoplasm).
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*Cell or Plasma Membrane
Cell membrane
Living layer
Controls the
movement of
materials into and
out of the cell
Selectively
permeable
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Read this!
Proteins and carbohydrates on the outside
of cells give cells their “identity.” This
lets the immune system know that the
cells belong in that body.
Transplanted organs are often rejected
by the body because the immune system
recognized the proteins and carbs as
not belonging to that person’s body.
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• SCI.9-12.B-2.2 - [Indicator] - Summarize
the structures and functions of organelles
found in a eukaryotic cell (including the
nucleus, mitochondria, chloroplasts,
lysosomes, vacuoles, ribosomes, endoplasmic
reticulum [ER], Golgi apparatus, cilia,
flagella, cell membrane, nuclear membrane,
cell wall, and cytoplasm).
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Cytoplasm of a Cell
Cytoplasm
Jelly-like substance
enclosed by cell
membrane
Provides a medium
for chemical
reactions to take
place
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*More on Cytoplasm
Cytoplasm
Contains organelles
to carry out
specific jobs
Examples:
chloroplast &
mitochondrion
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*Control Organelle
Nucleus
Controls the normal
activities of the cell
Contain the DNA
Bounded by a
nuclear membrane
Contains chromosomes
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More on the Nucleus
Nucleus
Each cell has fixed
number of
chromosomes that
carry genes
Genes control cell
characteristics
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Plant Cell Organelles
Chloroplast
Contain the green
pigment chlorophyll
Traps sunlight to
make to make
sugars (food)
Process called
photosynthesis
37
• SCI.9-12.B-2.2 - [Indicator] - Summarize
the structures and functions of organelles
found in a eukaryotic cell (including the
nucleus, mitochondria, chloroplasts,
lysosomes, vacuoles, ribosomes, endoplasmic
reticulum [ER], Golgi apparatus, cilia,
flagella, cell membrane, nuclear membrane,
cell wall, and cytoplasm).
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Chromoplast – gives plants
colors other than green.
Amyloplast – stores starch in
plants- found in potatoes
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Plant Cell
Cell wall
Dead layer
Large empty spaces
present between
cellulose fibers
Freely permeable
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Plant Cell
Cell wall
Made of cellulose
which forms very
thin fibers
Strong and rigid
Found in plant cells
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*Plant Cell
Cell wall
Protect and support
the enclosed
substances
(protoplasm)
Resist entry of
excess water into
the cell
Give shape to the cell
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*Plant Cell Organelles
Vacuole
Have a large central
vacuole
Surrounded by tonoplast
Contains cell sap
Sugars, proteins,
minerals, wastes, &
pigments
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Different kinds of plant
cells
Onion Epidermal Cells
Guard Cells
root hair
Root Hair Cell
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vacuole
cytoplasm
nucleus
mitochondrion
glycogen
granule
Animal cell
No cell wall or
chloroplast
Stores glycogen
in the
cytoplasm for
food energy
cell
membrane
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Animal Cell Organelles
•
•
•
•
Near the nucleus
Paired structures
Help cell divide
Not found in plant cells
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Different kinds of animal
cells
white blood cell
Amoeba
red blood cell
muscle cell
cheek cells
sperm
nerve cell
Paramecium
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*Similarities between plant
cells and animal cells
Both have a cell membrane
surrounding the cytoplasm
Both have a nucleus
Both contain mitochondria
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*Differences between plant
cells and animal cells
Animal cells
Plant cells
Relatively
smaller in size
Relatively
larger in size
Irregular shape
Regular shape
No cell wall
Cell wall present
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*Differences between Plant
Cells and Animal Cells
Animal cells
Plant cells
Vacuole small or
absent
Large central
vacuole
Glycogen as food
storage
Starch as food
storage
Nucleus at the
center
Nucleus near cell
wall
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Levels of Organization
CELLS
(muscle cells,nerve cells)
TISSUES (muscle, epithelium)
ORGANS (heart, lungs,
stomach)
ORGAN SYSTEMS (circulatory
system)
ORGANISM (human)
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The cell is the Basic Unit
of Life
• Cell is the smallest unit of living organisms
• Unicellular organisms are made of one cell
only
• The cells of multicellular organisms are
specialized to perform different functions
– e.g. mesophyll cells for photosynthesis
and root hair cells for water absorption
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Levels of organization
• Cells are
grouped
together and
work as a
whole to
perform special
functions
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Tissue
• A group of similar cells to
perform a particular function
– Animals : epithelial tissue,
muscular tissue
– Plants : vascular tissue,
mesophyll
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Organ
• Different tissues group together
to carry out specialized functions
– Heart : consists of muscles,
nervous tissue and blood
vessels
– Leaf : consists of epidermis,
mesophyll and vascular tissue
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The Structures of a Leaf
(Plant Organ)
Chloroplast
Palisade
Mesophyll Cell
Spongy Mesophyll
Cell
Air Space
Stoma
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The Structures of a Heart
(Animal Organ)
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System
• Several organs and tissues work together
to carry out a particular set of functions in a
co-ordinated way
– Human : digestive, respiratory, excretory,
circulatory and reproductive systems
– Plant : root and shoot systems
copyright cmassengale
60
Human Body Systems
Examples of systems :
 Digestive System
 Respiratory System
 Circulatory System
 Nervous System
 Reproductive System
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Examples of a Human Body System
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Examples of a Human Body System
The Respiratory System
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Examples of a Human Body System
Circulatory System
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Examples of a Human Body System
Nervous System
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It’s You!
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Terms for your test
Ribosomes
Chloroplast
*Photosynthesis
Mitochondria
*Prokaryotic
*Eukaryotic
Smooth ER
Rough ER
*Amyloplasts
*Chromoplasts
Cell membrane
Golgi bodies
Chromatin
Centrioles in centrosome
Chromosomes
Nucleolus
Vacuoles
*Difference b/w
prokaryotic/eukaryotic
smooth/rough ER
plant/animal cell
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*Cells May be Prokaryotic or
Eukaryotic
 Prokaryotes include bacteria &
lack a nucleus or membrane-bound
structures called organelles
Eukaryotes include most other cells
& have a nucleus and membranebound organelles (plants, fungi, &
animals)
68