4-2 Parts of the Eukaryotic Cell Part 2

Mitochondria u the Site of Cellular Respiration, or the place where energy is released from food and stored in ATP u the “Powerhouse” of the cell.

Mitochondria u have their own DNA. u can reproduce themselves. u may have been independent cells at one time.

Ribosomes u contain no membranes. u are made up of 2 pieces made of protein and RNA. u make or synthesize proteins.

Ribosome Locations u When Free in the cytosol….. they make proteins for use in the cytosol. u When Attached to the Endoplasmic Reticulum….. they make proteins that are exported from the cell.

Ribosomes

Endoplasmic Reticulum u is often called ER. u is made of stacks of flattened sacks. u is a highway system or path for moving molecules through the cell u is involved in the production of proteins, sugars, fats, etc.

Rough ER u When ribosomes are attached to ER, we call it Rough ER u RER makes proteins for export

Smooth ER u is Endoplasmic Reticulum without Ribosomes….. u is responsible for making lipids and hormones, u in muscles regulates Calcium levels, u in liver cells breaks down toxins and drugs.

Golgi Apparatus AKA Golgi bodies or Golgi Complex u Structure: parallel array of flattened sacs arranged in a stack. (looks like a stack of Pita bread) u 3 to 20 per cell. u Likely an outgrowth of the ER system.

u The Golgi Apparatus package and modify proteins and lipids into vesicles (small, spherical shaped sacs that bud form the Golgi apparatus). The vesicles often merge and merge with the plasma membrane to release contents to the outside of the cell.

Lysosome u Vesicles from the Golgi apparatus that contain digestive enzymes. They breakdown food, cellular debris and foreign invaders such as bacteria. u Important in cell death. u Not present in plant cells.

Peroxisomes u Organelles that breakdown various substances. During digestion 0xygen is produced and combines with H 2 O to form Hydrogen Peroxide…. a toxin. u Peroxisomes break down Hydrogen Peroxide.

Nucleus u Most conspicuous organelle. u usually spherical, but can be lobed or irregular in shape.

Function of the Nucleus u Control center for the cell. u Contains the genetic instructions.

Structure of the Nucleus u Nuclear Envelope u Nuclear pores u Nucleolus u Chromatin

Nuclear Envelope Nuclear Envelope … the outer boundary of the nucleus u Double membrane separated by a nm space. u Inner membrane supported by a protein matrix (braces) which gives the shape to the nucleus.

Nuclear Pores u Regular “holes” through both membranes. u 100 nm in diameter. u Allows materials in/out of nucleus.

Nucleolus u Dark area in the nucleus. u per nucleus. u Storage area for ribosomes.

Chromatin u Chrom: colored, tin: threads u DNA and Protein in a “loose” format (stringy form of DNA) Will eventually form the cell’s chromosomes.

Chromosomes u Rod-shaped bodies made up of coiled DNA. u The DNA is wrapped around proteins called histones. u The histones are coiled into nucleosomes Chromatin Histone Molecules Nucleosome

To be continued……. go to Cell Biology Part 3

To be continued……. go to 4-2, Part 3