2.3 structure & function of organelles - wikispaces · pdf filemay organize microtubule...

2.3

Structure & function

of organelles

(a)

(b)

(c)

(e)

(g)

(h)

(d)

(f)

(i)

(j)

(k)

Controls the

cell activity…

3

Only present in eukaryotic cell.

Usually one nucleus per cell.

Contains chromosome (DNA).

– Enclosed by nuclear membrane

4

5

Controls the cellular activity and cell division.

The chromosome contains genetic codes to control synthesis of protein and enzymes.

6

The most dense part

in the nucleus.

Compose of DNA, RNA & protein

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8

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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11

Abundant in metabolically active cell.

Semiautonomous organelle – grow and reproduced in cell.

12

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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15

16

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.