2.3 structure & function of organelles - wikispaces · pdf filemay organize microtubule...
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2.3
Structure & function
of organelles
(a)
(b)
(c)
(e)
(g)
(h)
(d)
(f)
(i)
(j)
(k)
Controls the
cell activity…
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Only present in eukaryotic cell.
Usually one nucleus per cell.
Contains chromosome (DNA).
– Enclosed by nuclear membrane
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Controls the cellular activity and cell division.
The chromosome contains genetic codes to control synthesis of protein and enzymes.
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The most dense part
in the nucleus.
Compose of DNA, RNA & protein
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1. Starting with production of
rRNA
2. Ribosome protein imported
from the cytoplasm then
combined with rRNA in
nucloelus to form ribosomal
subunits
3. Ribosomal subunit pass
through nuclear pores to the
cytoplasm
Double membrane
Inner membrane
Outer membrane
• continuous with ER and covered with ribosome.
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Have numerous pore
(nuclear pore)
Regulates exchange
of material between
nucleoplasm and
cytoplasm.
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Abundant in metabolically active cell.
Semiautonomous organelle – grow and reproduced in cell.
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folded
Also known as cristae.
Contain enzymes involved in cellular respiration.
Smooth.
Highly
permeable to
small solutes.Enclosed by
inner membrane
of mitochondria.
Contains DNA,
ribosomes,
enzymes used
for Krebs cycle.
Narrow region.
Reflects the solutes composition in cytosol.
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Network of
membranous tubules
and flattened sacs
(cisternae)
The ER membrane
separate the internal
compartment of ER lumen (cisternal space) from cytosol.
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within the cell little net
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RER is the site for protein synthesis which are packaged up in membranous vesicles
prominent in
cells that
manufacture
proteins for
export
invloved in synthesis
of lipids, metabolism
of carbohydrate,
detoxification of
drugs and poison.
Smooth endoplasmic reticulum
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Enzymes – important for lipid synthesis.
Detoxification –especially in liver cells.
Store Ca+ ion for muscle contraction-specialized form of smooth ER known as sarcoplasmicreticulum
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Smooth endoplasmic reticulum
modifies, sorts and ships cells products …
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Single membrane organelle
Consist of stacked flattened membranous sacs - cisternae
Have two polar – cis face and trans face.
Sacs are not physically connected.
Present in all cells, but is most prominent in those that are metabolically active
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Located near endoplasmic reticulum.
Receive vesicles from ER.
Close to plasma membrane.
End of trans face, cisternaepinched off to form secretoryvesicle.
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Function: The Golgi body modifies, sorts and ships cells
products
-Collects protein & lipids made in ER
-The site of biochemicals synthesis:
- additional substances are added to the products, repackaged
into fresh vesicles
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Produce...
1. digestive enzymes of pancreatic juice
2. vesicles that contain material to form the cell plate
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Site of protein
synthesis…
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Consists of large subunit and small subunit.
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Free ribosomes : suspended in cytosol.
- site of synthesis of the protein retained within the cell
Bound ribosome : attached to the cytoplasmicsurface of RER and nuclear envelope.
- proteins subsequently secreted outside the cell
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Site of
photosynthesis…
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A type of plastids.
found in plants and algae
Have double membrane.
Responsible for
photosynthesis process.
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CHLOROPLAST … structures
outer membrane
Fluid filled space.
Contains DNA,
enzymes and
ribosomes.
inner membrane
stroma
Integranal lamella
Connects one granum to another granum.
Flattened and interconnected sacs.
Photosynthetic pigment located on the membrane.
thylakoid
granum
Stacks of thylakoids
DNA
Make the chloroplast has
ability to replicate.
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CHLOROPLAST …
Involved in photosynthesis
process.
-convert solar energy to chemical energy and synthesize new organic compounds
Thylakoid captures light
energy in light dependent
reaction.
Stroma is the site for light
independent reaction
process.
functions
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Lysosomes are cellular organelles that contain acid
hydrolase enzymes to break down waste materials
and cellular debris.
The membrane around a lysosome allows the
digestive enzymes to work at the 4.5 pH they
require.
Lysosome… STRUCTURE
Hydrolytic Enzyme
Modified Membrane
FUNCTION
Contains digestive enzymes which can be used to digest invading cells or break down worn-out organelles (Autophagy)
1. Primary lysosome fuse with food vacuoles and form secondary Lysosome
2. Lysosome dispense their enzymes into the vacuoles, and digesting the contents.
How its works!
How its works!
FUNCTION Cellular digestion
Phagocytosis
the digestion of
macromolecules from
phagocytosis
1. digest foreign protens,
bacteria and virus which
invaded the cell, or
2. Digest the foreign
particles engulf through
phagocytosis
3. Example: WBC
• cell's waste disposal system and can break up anything.
• cell's waste disposal system and can break up anything.
Autophagy
Autolysis
1. Breakdown the old or damaged
organelle, reused in the synthesis
of new organelles.
1. a process in which a cell self-
destructs.
2. lysosome ruptures in a cell, it
causes all of the cell's internal
proteins to be digested.
3. allows an organism to eliminate
worn-out cells or unwanted cell.
4. Example: the breakdown of the
tail of tadpoles
FUNCTION
CENTRIOLE
CENTRIOLE
Pair of cylindrical structures located in the centrosome of in animal cells,
composed of nine sets of triplet microtubules arranged in a ring.
Replicate during cell division.
May organize microtubule (spindle fibre) assembly during cell division, but must not be mandatory for this function since plants lack centrioles.