Questions 1-6 Organelles 1.Cytoskeleton is a network of protein tubes that form thread that crisscross the cell. It gives the cell its shape/strength and provides a track for walking transport vesicles. It also helps separate DNA (chromosomes) during cell replication. In muscle cells, it allows the cells to contract and relax. 2.The membrane is a lipid bilayer (double layer) that surrounds the DNA. This is called the nuclear envelope and is pierced with holes called pores. These allow molecules (like RNA) to enter or leave the cell. Also inside the nucleus is the nucleolus, where the ribosomes are made.

3.The mitochondria has 2 membranes. The outer membrane is smooth while the inner membrane has folds which increase the surface area. This provides a larger surface on which cellular respiration takes place. In the mitochondria glucose is “burned” to make ATP. 4.The cell wall gives protection, shape and support to plant, algae, fungi and bacteria cells. It can stick to the wall of the next cell giving the entire organism support.

5.Mitochondria and chloroplast are both involved in energy reactions. They are both membrane bound organelles. They both have 2 membranes. The inner of the 2 is the site where the chemical reactions take place. 6.The ER, Golgi, and Mitochondria are all surrounded by or made of a lipid bilayer membrane. All three have folds and layers that greatly increase surface area.

Prokaryotic vs. Eukaryotic Cells  No membrane bound organelles— no nucleus, chloroplast, mitochondria etc.  Cyanobacteria (remember HAB’s?) can do photosynthesis but it doesn’t happen in a chloroplast!  Do cellular respiration but not in a mitochondria!  Has other non-membrane bound organelles (ribosomes)  Has BOTH cell walls and cell membranes!!  Very small  2 kingdoms of bacteria based upon cell wall structure. Has membrane bound organelles including nucleus, mitochondria, and chloroplast. Some have cell walls. All have a cell membrane. Tend to be much larger than Prokaryotic All kingdoms except bacteria

1.Read handout on the Cell Membrane 2.Read section 7-3 in Dragonfly. If you don’t finish come in for Study Hall or ETEH.