Cytoplasm and its Organelles Organelles *Membrane enclosed structures in the cytoplasm that serve specific functions and gives cell a division of labor. Cytoplasm Protoplasmic material between plasma membrane and nucleus. Contains thickened gel- like fluid called cytosol which contains water, proteins, and small amounts of fats, carbohydrates and electrolytes.

5 Major Organelles Found in Cytoplasm 1. Mitochondria 2. Endoplasmic reticulum 3. Golgi apparatus 4. Lysosomes 5. Peroxisomes

1. Mitochondria “Energy powerhouse”  Spherical or sausage shape  2 layers of lipid bilayer membrane. Only organelle to have double bilayer *Inner layer is folded into cristae to increase surface area so that metabolic enzymes can occur along their surface, outer layer is selectively permeable *Can self duplicate during times of high- energy need.

Mitochondria  Break down process is called cellular respiration which produces ATP, has enzyme which breaks down nutrient molecules.  In addition to enzymes, it has a concentration of DNA to help synthesize protein. Found a lot in muscle cells (muscle cells need high energy)

2. Endoplasmic Reticulum  ranching and rejoining hollow tubes.  Serves as transportation network for newly synthesized molecules.  Contains 2 types: rough and smooth. *rough is abundant in WBC. It contains ribosomes and works in protein synthesis *smooth is abundant in liver cells. It does not have ribosomes and it is used in lipid synthesis.

3. Golgi Apparatus  Found near nucleus  Composed of flattened disc shape sacks called cisternae. As molecules are ready to be secreted, a portion of the golgi apparatus pinches off to form a secretory vesicle. This then fuses with plasma membrane to release packaged material to outside.

4. Lysosomes  Spherical structures.  Recycles other organelles.  as hydrolytic enzyme.  Since these can destroy the cell itself, they are called “self destructive bags” or “suicide packets”.   Releases enzymes by exocytosis to break down material outside the cell. *An impairment of the lysosomes is called Tay-Sachs disease.

Lysosomes

5. Peroxisomes  Spherical Detoxify various molecules like fatty acids.

Cytoskeleton  ot an organelle.  Does not have selectively permeable membrane. Made of 2 types of proteins which give structural framework of cell. 1. Microtubules *long hollow tubes *maintain shape of cell 2. Microfilaments *thin and thread-like and arranged in bundles *provide cellular movement *called myofilaments in muscles.

Questions ?

Nucleus: “Kernel”   Control center of cell   Largest thing in cell  Primary function is protein synthesis  Contains DNA and RNA  Spherical  Located near center

A. Nuclear Membrane   Surrounds nucleus   Selectively permeable   Double lipid bilayer *Contains pores which allows movement of molecules produced during protein synthesis to pass between nucleoplasm and cytoplasm

B. Nucleoplasm   Gel-like sap in nuclear membrane. Contains nucleoli (site of ribosome synthesis) and chromatin.

C. Nucleolus   Site of RNA synthesis  Small and spherical  Prominent during interphase but not during cell division Composed of protein and RNA

D. Chromatin   In interphase, it appears as tiny granules.   During cell division, it starts to organize into chromosomes which are composed of a single DNA molecule. Genes are segments of DNA molecules.  DNA and its genes control the regulation of protein synthesis.

Questions Wkst on the anatomy of the cell. Followed by quiz on organelles and nucleus.