Section 2

Chemistry of CellsProkaryotes

•Prokaryotic Cells Prokaryotic cells lack a nucleus and other internal compartments.

•Characteristics of Prokaryotes Prokaryotic cells are surrounded by a cell wall and they have cell organelles and DNA moving freely within the cytoplasm.

Section 2

Chemistry of CellsEukaryotic Cells

•Eukaryote Cells Eukaryote cells have a nucleus and other organelles.

•The Cytoskeleton Eukaryote cells have a cytoskeleton of microscopic protein fibers that provide the structural framework for the cell and its organelles. There are three different kinds of cytoskeleton fibers: actin fibers, microtubules, and intermediate fibers.

Section 2

Chemistry of CellsThe Cell Membrane

•The Cell Membrane as a Barrier The lipid bilayer of a cell membrane is made up of a double layer of phospholipid molecules. The selective permeability of the cell membrane is mainly due to the way phospholipids interact in water.

•Membrane Proteins Proteins in cell membranes include enzymes, receptor proteins, transport proteins, and cell-surface markers.

Section 3

Cell Organelles Objectives:

•Describe the role of the nucleus in cell activities.

•Analyze the role of internal membranes in protein production.

•Summarize the importance of mitochondria in eukaryotic cells.

•Identify three structures in plant cells that are absent from animal cells.

Section 3

Cell OrganellesThe Nucleus

•Function of Nucleus The nucleus of a eukaryotic cell directs the cell's activities and stores DNA.

Section 3

Cell OrganellesRibosomes and the Endoplasmic Reticulum•Production of Proteins In eukaroytic cells, proteins are manufactured at ribosomes found within the cytoplasm and found on an internal membrane system called the rough endoplasmic reticulum (ER).

•Packaging and Distribution of Proteins In eukaroytic cells, vesicles carry proteins from the rough ER to an internal membrane system, called the Golgi apparatus, to be processed. Modified proteins are either released from vesicles outside the cell or remain in the cell.

Section 3

Cell OrganellesRibosomes and the Endoplasmic Reticulum continued

•Lysosomes Some protein containing vesicles remain in the cell and become lysosomes. Lysosomes digest and recycle a cell's used components.

Section 3

Cell OrganellesMitochondria

•Function of Mitochondria Mitochondria harvest energy from organic compounds to ATP.

•Mitochondrial DNA Mitochondria have their own DNA and this allows them to make some of their own proteins.

Section 3

Cell OrganellesStructure of Plant Cells

•Unique Features of Plant Cells Plant cells have three structures that animal cells lack: a cell wall, chloroplasts, and a central vacuole.

Can Organelles Get Sick?

Tay-Sachs Disease