Organelles and other such bits. (:

Organelles are the bits that make the cell more efficient and designed for it's purpose.

Epithelial cells, which we are focusing on, are speificated to secrete and absorb in the small intestine. They line the small intestine in an epithelial layer, about 1mm in thickness. They have microvilli (little flappy hair type bits on the top, a bit like the tassley bits on the end of a scarf, I guess?) are there top increase surface area, so more can be absorbed.

Part of the cell...

Nucleus; They control activity in the cell, direct protein synthesis, contain cromatin (which is DNA and proteins, diffused together.) Cromatin condenses and becomes thicker into the usual chromosome shape.

It also makes RNA, which makes ribosomes.

Nuclear Envelope; Is a double membrane with little gaps along it called nuclear pores, these allow the nucleus to communicate with the cytoplasm.

Endo-plasmic Reticulum; Comes in two varieties, Rough and Smooth. Rough is named so becuase it has ribosomes attached on it. It transports material throughout the cell. Used for the synthesis of proteins and can be used as a passway for proteins after.

There are no ribosomes on the smooth endoplasmic reticulum. They transport, produce and store lipids, and some carbohydrates. In the liver the smooth endoplasmic reticulum aids with detoxification.

Boths need to produce enzymes and absorb, in relation the an epithelial cell, that is, as it's purpose is the absorb and produce.

Ribosomes; Can exist on their own or in chains (polyribosome) in the cytoplasm. Made by nucleolous. Made my two units, RNA & Protein, in a cottage loaf type shape.

In relation the the epithelial cells, they have 80's ribosomes, they are bigger and sediment faster.

Golgi Apparatus; Have vesicles on the end, ready to bud off. Made of flattened sacs, called cisternae. It collects the products of the cell, which I believe are lysosomes, not 100% sure, someone correct me if I'm wrong, repackages them into vesicles to transport around & out of the cell. Modifies proteins produced by the endoplasmic reticulum. Collection, Modification, Packaging & Distribution. (:

Lysosome; A lot of enzymes in them. One membrane thick, can contain up to 50 different enzymes. Used for breaking other things down, like other cells and worn down organelles. Releasesthe content to the outsidde of the cell by fusing with it. Phagocites (they engulf and digest bad bacteria) can help them along.

Mitochondrion; 1-10mm in length, double membrane. Space between membrane is the inner membrane space, forms folds, folds are called Cristae. These are the site of ATP production, enzyemes that form it are situated there, in aerobic respiriation. Inbetween the folds is a called the matrix. This is the site of the krebs cycles. Has it's on DNA & ribosomes, /can/ produce own protein. Epithelial need lots of them as they use lots of ATP which is stored in mitochondria. More christae = more ATP. ATP = Energy ^_^