Cell Structure and Function (Ch 7.2)

Cell Organization Two parts to a cell: Nucleus and Cytoplasm Nucleus: everything in the nucleus Nucleolus and DNA Cytoplasm: Everything outside of the nucleus Includes the organelles  “little organs” Each one differentiates to perform a particular function

Nucleus Nucleus = main office This is the control center of the cell Contains DNA or coded instructions for making protein and other important cells Structure Outside Nucleus Nuclear envelope  has pores so RNA and protein can enter and leave nucleus Inside Nucleus Chromosomes: carry the cell’s genetic information  mostly found as chromatin (DNA bound to protein) Nucleolus: assembly of ribosomes begin

Vacuoles / Vesicles Vacuoles = Storage Vacuoles: large places to store things like water, salt, sugar, and protein plants have a large center vacuole → helps with strength Vesicles: smaller vacuoles in animal cells that transport materials

Lysosomes Lysosomes = clean-up crew Lysosomes: small cells with enzymes that help break down large molecules into small molecules, and they break down cells that are no longer useful RARE in plant cells

Cytoskeleton Cytoskeleton = frame of structure Cytoskeleton: a tight web of proteins that make up the structure of the cell Some parts transfer things throughout a cell and some help the cell move Two types of filaments: microfilaments: threadlike structure made of actin (protein) allows for movement in the cell microtubules: made up of tubulin (protein) that makes up the structure of the cell gives the cell its shape helps with cell division →  mitotic spindle fibers to separate DNA → forms centrioles in animals cells to help with division

Ribosomes Ribosomes = Factory workers Ribosomes: units of RNA and protein that are found in the cytoplasm or on the rough endoplasmic reticulum (rough ER) they are coded to follow specific directions that come from the boss (DNA)

Endoplasmic Reticulum Endoplasmic Reticulum (ER): membrane system where lipids are put together → proteins and other materials are shipped here to be put together as well Two types of ER: Rough ER: proteins are made here by the ribosomes and shipped out to the cell Smooth ER: has specialized enzymes that  make membrane lipids and get rid of toxins What organ will contain smooth ER?

Golgi Apparatus Golgi Apparatus = Shipping Station Golgi Apparatus: stack of flat membrane sacs that stores or ships the proteins out of the cell ER → reads “address tags” or codes on protein and packages them into vesicles to send them to the golgi apparatus Golgi Apparatus →changes and packages the protein to either store it or ship it outside the cell

Chloroplasts Chloroplasts = Solar Power Plant they take energy from the sun and make food through photosynthesis ONLY found in plant cells has two outer membranes and is filled with the green pigment chlorophyll Chlorophyll absorbs the energy from the light to make food

Mitochondria Mitochondria = Power Plant found in both cells changes the chemical energy in cells to usable forms of energy large contributor to respiration in animal cells two membranes → inner membrane is larger than outer membrane ***Both chloroplasts and mitochondria have their own DNA (genetic information)

Cell Wall Cell Wall = Wall or Roof Cell Wall: used for support, shape, and protection Animal cells do NOT have cell walls Plant cells DO have cells walls → helps plants stand up straight (cellulose)

Cell Membrane Cell Membrane = Insulation inside of the wall both cells have an outer cell membrane surrounding the outside (lipid bilayer) creates a strong and flexible outer layer that controls what enter and leaves the cell Lipid Bilayer = Lipids: molecules made of carbon and hydrogen that makes up the lipid bilayer two part → head and tail hydrophilic head → water loving → on the outside hydrophobic tail → water hating → on the inside (made of oil) the tails stick together like a sandwich with the heads on the outside