Transcript Eukaryotic Cell Substructure

Eukaryotic Cell Substructure
Plant and Animal Cells
ANIMAL CELL
Mitochondria
Structure - composed of
modified double unit
membrane (protein, lipid)
- inner membrane infolded
to form cristae
- Function - site of cellular
respiration ie. the release
of chemical energy from
food
Glucose + Oxygen ------> Carbon Dioxide +
Water + Energy (ATP)
DNA
Inter-membrane space
Cytoskeletal structures
Cells contain elaborate
arrays of protein fibers
that serve such functions
as:
• Establishing cell shape
• Providing mechanical
strength
• Locomotion (cilia,
flagella)
• Chromosome separation
in mitosis and meiosis
• Intracellular transport of
organelles
Major components of cytoskeletal
system
• Intermediate Filaments
• Microtubules
• Actin filaments
www.cytochemistry.net/Cell-biology/filam.htm
Centrioles
• a pair of cylinder-like
structures.
• function in cell division.
• made up of nine
bundles of microtubules
• found only in animal
cells.
www.quantumconsciousness.org/.../cambrian.html
Rough and Smooth
Endoplasmic Reticulum
•Endo means within
•Plamic refers to the
cytoplasm
•Reticulum means a network.
Thus the endoplasmic
reticulum is a series of
interconnected,
intracytoplasmic, membrane
bounded sacs.
Rough endoplasmic reticulum (RER)
• appear rough due to presence of ribosomes
•involved in protein synthesis.
Smooth endoplasmic reticulum (SER)
•has no ribosomes
•The SER is involved in
•cholesterol metabolism,
•membrane synthesis, (Lipids)
•Detoxification,
•Ca++ storage along with other cellular processes.
Vesicles
Membrane bound intracellular sacs
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transport vesicles
endocytotic vesicles
exocytotic vesicles
lysosomal vesicle
secretory vesicle
adipose vesicles
Golgi Apparatus/Body
• Proteins are
transported from the
RER to the golgi
apparatus and from the
golgi apparatus to the
plasma membrane in
transport vesicles.
Lysosmes
A primary lysosome contains
many enzymes
• synthesized in the RER and
sorted in the golgi.
Peroxisomes/Micorbodies
• Organelles that contain enzymes to degrade
fatty acids and amino acids.
– A biproduct of this degradation is H2O2 hydrogen
peroxide – highly toxic to proteins
• Also contain the enzyme catalase which
destroys H2O2
• The enzymes are synthesized on the RER and
are sorted/refined into the peroxisomes in the
golgi apparatus
PLANT CELL
How Plant and Animal Cells Differ
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PLANT CELLS
Cell walls present
Plastids occur in
cytoplasm
Lysosomes not usually
evident
Centrioles present only in
cells of lower plant forms
• Large vacuoles filled with
cell sap
ANIMAL CELLS
• No cell walls
• No plastids are found
• Lysosomes occur in
cytoplasm
• Centrioles always present
• Vacuoles, if present, are
small and contractile or
temporary vesicles
Cell Wall
• Cell walls are made of
specialized sugars called
cellulose.
• Cellulose is called a
structural carbohydrate
(complex sugar)
because it is used in
protection and support.
Cell Wall
• Function
• help a plant keep its
shape
• protect the cells
• allow plants to grow to
great heights
• For smaller plants, cell
walls are slightly elastic
Plastids
• Large cytoplasmic
organelles found in the cells
of most plants
• There are three plastid
categories– Leucoplasts (white or
colorless plastids that store
starch granules) ,
– Chromoplasts (colored
plastids that store pigment
molecules like cartenoids
which store yellow and
orange pigment)
– Chloroplasts which are
essential in the
photosynthetic process
Leukoplasts
• non-pigmentous, 2x5
µm, variable shaped
plastids for storage
• 3 types: AMYLOPLASTS
(starch), ALEUROPLAST
(protein), ELAIOPLASTS
(oils)
Chromoplasts
• Chromoplast are derived
from chloroplast.
• Synthesize carotenoid
pigments such as carotene
or lycopene.
• Found in flowers, fruit, and
leaves in stress or
senescence.
• In flowers, carotenoid
pigment enables the
forming of different color,
which can attract insects
and other pollinators.
Chloroplasts
• Site of photosynthesis.
• 500,000 chloroplasts per
square millimeter of leave
surface
• Contain chlorophyll, the green
pigment that absorbs energy
from sunlight
• Sunlight captured by
chlorophyll enables carbon
dioxide from the air to unite
with water and minerals from
the soil and create food.
• Chlorophyll gives plants their
characteristic green color.
DNA
Questions
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6.
What are the similarities and
differences between plant and
animal cells?
Explain what is meant by the
statement "The cell is the
functional unit of life.”
_______ are known as the
'sites of intracellular digestion'.
_______ consist of enzymes,
which help in digestion.
_______ are known as the
'power-houses of the cell'.
Ribosomes are found attached
on the _______.
7.
Why don't animal cells need cell
walls?
8. The green color of leaves is due
to the presence of the _______
pigment.
9. The network of convoluted
tubules is called the _______.
10. Secretory granules are formed
by the _______ of the animal
cell.
11. _______ are known as the
'sites of protein synthesis in the
cell'.
12. Cell organelle that imparts
colour to flowers ________
Task
Use your textbook to write descriptions of the
following:
• Cytoplasm
• Cilia
• Flagella