Cell Organelles
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?- Created by: Churchy
- Created on: 16-01-13 13:24
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- Eukaryotic Cell Organelles
- Nucleus
- Largest Organelle in the cell, 10 -20um in diameter.
- Vital Role in Protein Synthesis
- Enclosed in a Nuclear membrane, which contains many pores, about 100nm in diameter.
- Pores allow communication between the nucleus and the cytoplasm
- Nucleus contains Chromosomes, thread like structures visible during nuclear division.
- contains 1 or more nucleoli, small, round, darkly staining bodies, they are the site of ribosome synthesis.
- Mitochondria
- Appears as rod shaped/ cylindrical organelles in electron micrographs
- Large organelles 1um x 10um
- Found in all cells, present in large numbers. metabolically active cells, for example muscle fibres contain thousands.
- have double membrane. inner membrane folded to form cristae.
- have their own DNA seperate from the DNA in the nucleus, you imherit mitochondrial DNA solely through the maternal line.
- They are the site of aerobic respiration.
- Ribosomes
- The site of protein synthesis.
- Minute structures, 25nm in diameter.
- Built of 2 subunits.
- Constructed of protein and RNA.
- Many types of cell contain vast numbers of Ribosomes.
- Endoplasmic Reticulum
- A network of 2 single folded membranes forming interconnected sheets, tubes or sacs.
- 2 distinct types of ER
- Rough ER has ribosomes attached to its outer surface. Vesicles are formed from swelling at the margins that become pinched off.
- Smooth ER has no ribosomes. SER is the site of synthesis of Lipids. SER also forms Vesicles.
- Lysosomes
- Small spherical vesicles bound by a single membrane. They contain a mixture of digestive enzymes produced by the GOLGI APPARATUS of the RER.
- Breakdown the contents of imported food vacuoles, e.g. harmful bacteria that has been engulfed.
- also fuse with and digest any broken down cell organelles.
- Golgi Apparatus
- Consists of a stack like collection of flattened membranous sacs.
- One side of the stack of membranes if formed by the fusion of membranes of vesicles from the ER
- At the other end of the stack, vesicles are formed from swellings at the margins that become pinched off.
- The site of synthesis of specific biochemicals, e.g. hormones which are packaged into vesicles.
- Microtubels & Centrioles
- Nucleus
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