Download Basic Structure of a Cell - Appoquinimink High School

Basic Structure of a Cell
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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
Bacterial Cell
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What is used to view cells?
• Compound microscopes
– Anton van Leeuwenhoek inventor
– a microscope which uses multiple lenses to collect
light from the sample and then a separate set of
lenses to focus the light into the eye.
Electron microscopes
– Developed in the 1930’s
• Scanning electron microscopes (SEM)
–Scan surface of cells
Electron microscopes
• Transfer electron microscopes (TEM)
–Study structures combined with cells
Scanning Tunneling Microscope
– is an instrument for imaging surfaces at the
atomic level.
Xenon on Nickel (110)
Cell theory
• All organisms are
comprised of one or more
cells
• The Cell is the basic unit of
life
• All cells come from
preexisting cells
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
membrane-bound organelles
(plants, fungi, & animals)
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Prokaryotes
Nucleoid region
contains the DNA
•Cell membrane &
cell wall
• Contain
ribosomes (no
membrane) to
make proteins in
their cytoplasm
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Eukaryotic Cell
Contain 3 basic cell
structures:
• Nucleus
• Cell Membrane
• Cytoplasm with
organelles
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Two Main Types of Eukaryotic
Cells
Plant Cell
Animal Cell
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Cell Structures = Organelles
Very small size
Can only be observed under a
microscope
Have specific functions
Found throughout cytoplasm
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Organelles Found in Cells
Cell membrane
Lies immediately against the
cell wall in plant cells
Made of protein and
phospholipids
Selectively permeable
Living layer
Controls the movement of
materials into and out of
the cell
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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
Bound 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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Smooth & Rough Endoplasmic
Reticulum
Smooth ER lacks ribosomes
& makes proteins USED In
the cell. Also makes lipids.
Rough ER has ribosomes on
its surface & makes proteins
to EXPORT
Located close to nucleus.
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Golgi Bodies
• Stacks of flattened
sacs (pancakes)
• Have a shipping side &
a receiving side
• Receive & modify
proteins made by ER
• Transport vesicles
with modified proteins
pinch off the ends
Transport vesicle
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Ribosomes
Comprised of protein and
RNA molecules
Scattered throughout
cytoplasm and on the rough
ER.
Provide structural support for
RNA and aid in making proteins
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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)
• Are found in blood
cells- can destroy
bacteria.
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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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Cell Powerhouse
Mitochondria
Rod shape
Site of Cellular
respiration
Produces ATP
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Warm UP
• What is the function of the cell membrane,
mitochondria, ribosome and nucleus?
Plant Cell Organelles
Chloroplast
Contain the green
pigment chlorophyll
Traps sunlight to make
sugars (food)
Process called
photosynthesis
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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
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
Contains cell sap
Sugars, proteins, minerals,
wastes, water, and pigments
Animal cells have one it is just
not as large
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Animal Cell Organelles
• Near the nucleus
• Paired structures
• Help cell divide
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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
Nucleus at the center
Nucleus near cell wall
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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
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Levels of Organization
Atoms
Molecules
CELLS (muscle cells,nerve cells)
TISSUES (muscle, epithelium)
ORGANS (heart, lungs,
stomach)
SYSTEMS (circulatory system)
ORGANISM (human)
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Levels of Organization (con’t)
Population
Community
Ecosystem
Biome
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Centriole