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An organelle is a body contained in a cell.
Largest organelle in cell - 10µm
Double phospholipid membrane
Has `pores' in the nuclear membrane
o Small enough so that DNA doesnt get out
o Large enough for ribosomes and RNA to get out to the cytoplasm.
Nucleolus produces ribosomes (protein makers)
Chromatin is genetic material wrapped up with `histones'
Endoplasmic Reticulum (ER)
2 types smooth (SER) and rough (RER)
Both types consist of a series of tubes and sheets. Double membrane structures produce
fluid-filled sacs called cisternae.
They are continuous with the nuclear membrane and the cell membrane.
Rough Endoplasmic Reticulum (RER)
o Has ribosomes on the membrane to make proteins
o Proteins produced pass in to the cisternae
o They are moved to the end of the RER where they are packaged into `vesicles'
(bubbles of membranes containing the proteins)
o These vesicles move to the Golgi body
o The ribosomes are dense and give the RER a dotty appearance.
Smooth Endoplasmic Reticulum
o No ribosomes hence smooth
o Membranes are tube-like
o It has a double membrane
o Synthesizes lipids, steroids
o Its other function is detoxification
A series of flattened tubes
At the ends are vesicles. These are at differing stages of formation.
These vesicles contain proteins which have been produced by the RER
The golgi body repackages and labels the proteins by adding `glycoproteins' and sends
them to their destination.
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Dark spherical bodies
Surrounded by a single membrane
Contains digestive enzymes that break down chemicals (enzymes made in RER and then
repackages in the GB)
o Break down material taken in by the cell (endocytosis)
o Destroy old or worn out organelles
o Destroy entire cells
Bound by a double membrane
The inner layer is folded to form cristae
The space between is a watery matrix which contains enzymes, DNA, ribosomes, calcium
They are 1-2µm long
o To produce energy from…read more