Cell Organelles and their Functions Chapter 4 Section 2

1. Cell Membrane Structure A phospholipid bi- layer around the cell that contains proteins and other markers Function Separates the cell from its environment Secretes materials out of the cell A selectively (semi) permeable membrane that recognizes friendly and enemy objects and allows some materials to enter

2. Mitochondria Structure Large organelles that contain their own DNA Has a bilayer membrane: a smooth outer membrane and very folded inner membrane (cristae)

2. Mitochondria Function Releases energy in “food” into a form the cell can use which is called ATP (cellular respiration) ATP is the currency of energy that cells useReleases energy in “food” into a form the cell can use which is called ATP (cellular respiration) ATP is the currency of energy that cells use Parts of the body that use a lot of energy will have a lot of mitochondria (muscle cells)Parts of the body that use a lot of energy will have a lot of mitochondria (muscle cells) Because the mitochondria has its own DNA, it can reproduce itself.Because the mitochondria has its own DNA, it can reproduce itself.

3. Ribosomes Structure Each cell has 1000’s of ribosomes which are little spheres A ribosome contains a protein connected to some RNA. Ribosomes don’t have membranes Function Protein Synthesis What is the function of nucleic acids?What is the function of nucleic acids?

4. Endoplasmic Reticulum ER Structure A membrane system of folded sacs and tunnels When it is covered with lots of ribosomes= rough ER When it lacks ribosomes= smooth ER

4. Endoplasmic Reticulum ER Function The place where the ribosomes assembles their proteinsThe place where the ribosomes assembles their proteins Intercellular highways: where materials can move from one part of the cell to another.Intercellular highways: where materials can move from one part of the cell to another.

5. Golgi Apparatus Structure A system of flattened sacs & membranes that emerge from the ER Function Modifies the proteins made in the ER so they can be put into packages and exported from the cell

6. Vesicles Structure Little sacs that emerge from the Golgi apparatus Function The transport passage of materials within the cell

7. Lysosomes Structure A sac of very strong enzymes in a double membrane Common in animal, fungi and protist cells, but are rare in plant cells Function Used to digest food molecules and invaders of the cell Sometime used to “self destruct” cells suicide sacs

8. Nuclear Membrane or nuclear envelope Structure A double membrane Has holes called nuclear pores Function Holds the DNA safe inside the cell Controls what enters and leaves the nucleus

9. Nucleolus Structure A spherical body in the nucleus Function Makes the ribosomes

10. Chromatin Structure A fine strand of DNA coiled around proteins Function Contains all the information for making proteins Is the inherited information that is given to the offspring during reproduction

11. Chromosomes Structure Chromatin that is coiled up tightly during cell divisionChromatin that is coiled up tightly during cell divisionFunction Same as chromatin except that it is coiled up tightly so that it can be separated cleanly into the two daughter cellsSame as chromatin except that it is coiled up tightly so that it can be separated cleanly into the two daughter cells

12. Microfilaments Structure Long threads of protein called actin Function Used when the cell moves and when a muscle cell contracts

13. Microtubules Structure Long, slender tubes of protein Function Gives structure to the cell so it doesn’t collapse on itself During cell division, microtubules are used to pull apart the chromosomes into the new daughter cells

14. Cilia Structure Short, “hair-like” structures that emerge from the cell membraneShort, “hair-like” structures that emerge from the cell membrane A cell may have 1000’sA cell may have 1000’s Function The cilia beat in unison or in waves. Cilia are used to move cellsThe cilia beat in unison or in waves. Cilia are used to move cells –e.g. paramecium Cilia move mucus or fluidsCilia move mucus or fluids –e.g. over the cells of human trachea and lungs –Female reproductive system

15. Flagellum Structure A long “whip-like” structure that emerges from the cell membrane A cell has only 1-2 flagella Function Whip back and forth to move a cell through fluid (e.g. sperm or Euglena)

16. Cell Wall Structure A rigid covering of: –Cellulose in plants Function Gives the cell an internal structure so it doesn’t collapse on itself What does an animal cell have to not collapse?

17. Vacuoles Structure An empty sac is usually large in plants Function Contains one of these materials: Water, enzymes, food particles, or waste

18. Plastids (chloroplast) Structure Have a double membrane and their own DNA Some plastids have thylakoids which contain pigments Thylakoids look like stacks of pancakes Function converts it into chemical energy. “makes food”A chloroplast contains thylakoids which absorb solar energy. Then converts it into chemical energy. “makes food”

19. Centrioles Structure Pair of small cylindrical bodies located near the nucleus Function Function in cell division