Cytoplasm and its Organelles l Cytoplasm Membrane enclosed

Cytoplasm and its Organelles l. Cytoplasm *Membrane enclosed structures in the cytoplasm that serve specific functions and gives cell a division of labor. l Protoplasmic material between plasma membrane and nucleus. Contains thickened gellike 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 highenergy 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. l Found a lot in muscle cells (muscle cells need high energy)

2. Endoplasmic Reticulum · Branching 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. l 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. ·Has 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 l Detoxify various molecules like fatty acids.

Cytoskeleton ·Not an organelle. ·Does not have selectively permeable membrane. l 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 74 -104 ?

Nucleus: “Kernel” l l ·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. l 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 l 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 105 -130 Wkst on the anatomy of the cell. Followed by quiz on organelles and nucleus.