4-2 Parts of the Eukaryotic Cell

Part 2

Mitochondria the Site of Cellular

Respiration, or the place where energy is released from food and stored in ATP

the “Powerhouse” of the cell.

Mitochondria

have their own DNA. can reproduce themselves. may have been independent

cells at one time.

Ribosomes

contain no membranes. are made up of 2 pieces made

of protein and RNA. make or synthesize proteins.

Ribosome Locations

When Free in the cytosol….. they make proteins for use in the cytosol.

When Attached to the Endoplasmic Reticulum….. they make proteins that are exported from the cell.

Ribosomes

Endoplasmic Reticulum is often called ER. is made of stacks of flattened

sacks. is a highway system or path for

moving molecules through the cell

is involved in the production of proteins, sugars, fats, etc.

Rough ER

When ribosomes are attached to ER, we call it Rough ER

RER makes proteins for export

Smooth ER is Endoplasmic Reticulum without Ribosomes…..

is responsible for making lipids and hormones,

in muscles regulates Calcium levels,

in liver cells breaks down toxins and drugs.

Golgi ApparatusAKA Golgi bodies or Golgi Complex

Structure: parallel array of

flattened sacs arranged in a stack. (looks like a stack of Pita bread)

3 to 20 per cell. Likely an outgrowth of the ER

system.

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 Vesicles from the Golgi

apparatus that contain digestive enzymes. They breakdown food,

cellular debris and foreign invaders such as bacteria. Important in cell death.

Not present in plant cells.

Peroxisomes

Organelles that breakdown various substances. During

digestion 0xygen is produced and combines with H2O to form Hydrogen Peroxide…. a toxin. Peroxisomes break down

Hydrogen Peroxide.

Nucleus Most conspicuous organelle. usually spherical, but can be

lobed or irregular in shape.

Function of the Nucleus

Control center for the cell. Contains the genetic

instructions.

Structure of the Nucleus

Nuclear Envelope Nuclear pores Nucleolus Chromatin

Nuclear EnvelopeNuclear Envelope… the outer boundary of the nucleus

Double membrane separated by a 20-40 nm space.

Inner membrane supported by a protein matrix (braces) which gives the shape to the

nucleus.

Nuclear PoresNuclear Pores Regular “holes” through both

membranes. 100 nm in diameter.

Allows materials in/out of nucleus.

NucleolusNucleolus Dark area in the nucleus. 0 - 4 per nucleus. Storage area for ribosomes.

ChromatinChromatin Chrom: colored, tin: threads

DNA and Protein in a “loose” format (stringy form of DNA) Will

eventually form the cell’s chromosomes.

ChromosomesChromosomes Rod-shaped bodies made up of coiled DNA. The DNA is wrapped around proteins called

histones. The histones are coiled into nucleosomes

ChromatinHistone

MoleculesNucleosome

To be continued…….go to

Cell Biology Part 3

To be continued…….go to

4-2, Part 3