Essay on Topic 3 Cells

Submitted By Ellie369
Words: 338
Pages: 2
A description of the following cell organelles present in animal cells: nucleus, nucleolus, ribosomes, rough and smooth endoplasmic reticulum mitochondria, centrioles, lysosomes, and Golgi apparatus with images.

Mitochondrion (plural mitochondria): the inner of its two membranes is folded to form finger-like projections called cristae. The mitochondria are the site of the later stages of aerobic respiration. Nucleus: enclosed by an envelope composed of two membranes perforated by pores. Contains chromosomes and a nucleolus. The DNA in chromosomes contains genes that control the synthesis of proteins.

Nucleolus: a dense body within the nucleus where ribosomes are made.

Rough endoplasmic reticulum (rER): a system of interconnected membrane-bound, flatted sacs. Ribosomes are attached to the outer surface. Proteins made by these ribosomes are transported through the ER to other parts of the cell.

Ribosomes: made of RNA and protein, these small organelles are found free in the cytoplasm or attached to endoplasmic reticulum. They are the site of protein synthesis.

Cell surface membrane (plasma membrane): phospholipid bilayer containing proteins and other molecules forming a partially permeable barrier.
Smooth endoplasmic reticulum (sER): like rough ER, but does not have any attached ribosomes, smooth ER makes lipids and steroids. (E.g. reproductive hormones).