Ch 7: Cell Structure and Functions AP Biology
The Cell Theory 1. All living things are made of cells. 2. New cells come from existing cells. 3. Cells are the basic units of structure and function of living things.
Cell types to know: Prokaryotic Eukaryotic
Types of Cells animal cells plant cells bacteria cells Prokaryote -No organelles -No nucleus -Have ribosomes Eukaryotes - Have membrane bound organelles, a true nucleus and ribosomes What differences can you see between these cells?
Cell size comparison Animal cell Bacterial cell most bacteria 1-10 microns eukaryotic cells 10-100 microns Viruses are smaller than bacteria and they are NOT ALIVE! micron = micrometer = 1/1,000,000 meter diameter of human hair = ~20 microns
Prokaryotic Cells Smaller than eukaryotic Less complex than eukaryotic No nucleus, mitochondria, vacuoles, or chloroplasts Have Ribosomes Have DNA and RNA Circular DNA strands called plasmids
Eukaryotic Cells Larger More complex Have nucleus, mitochondria, vacuoles, or chloroplasts Have Ribosomes Have DNA and RNA
Now we are going to look at the parts of the eukaryotic cell
Cell parts (organelles) to know: Nucleus Ribosomes Vacuole Mitochondria Chloroplast Plasma or cell membrane Cell wall
Model Animal Cell Organelles = membrane bound structures inside a cell that perform specific functions required by the cell.
If they each perform specific functions, will they all have the same structure?
Cytoplasm = jelly-like filling that holds organelles Surface Area: Volume Lab http://www.biologyjunction.com/cell_size.htm
Nucleus Function control center of cell contains most of the DNA instructions for building proteins Structure Surrounded by nuclear membrane that contains nuclear pores that allows particles to pass in and out of the nucleus Where is the nucleus in a bacterial cell?
Ribosomes Function Site of protein synthesis Where instructions are read to build proteins from DNA Structure 2 subunits some free in cytoplasm some attached to ER Ribosomes on ER large subunit small subunit
Ribosomes get their protein directions from the DNA sequence DNA RNA Proteins Specific Traits Bacteria have a few thousand ribosomes Human cells have a million ribosomes The more protein a cell needs to make = the more ribosomes it will have
Vacuoles storage structures food vacuoles central vacuole protist plant cells contractile vacuoles
Vacuoles storage structures Stores water, salts, proteins, and carbohydrates in a cell Plant cells have a single, large vacuole to store water Keeps the plant upright; provides support without water = plant will wilt Many small vacuoles are found in some animal cells
Mitochondria Powerhouse of the cell Structure double membrane Function make ATP energy cellular or aerobic respiration glucose + O 2 water + CO 2 + ATP fuels the work of life ATP
Mitochondria Inner fold increases the surface area so that the mitochondria can produce more energy in less space In humans, nearly all inherited come from the egg (contains their own maternal DNA) The more energy a certain cell type needs = the more mitochondria it will have
Chloroplast Plant Cells Only Chloroplasts where photosynthesis occurs Uses sunlight to make glucose (sugar) Converts light energy chemical energy H 2 O + CO 2 Glucose + O 2 Sugar (glucose) = stored energy build leaves & roots & fruit out of the sugars sugar
Mitochondria are in both cells! Chloroplasts are only in plant cells. animal cells plant cells mitochondria Chloroplast
Organelles work together to get the jobs of the cell done Examples in plants: chloroplast make glucose for the cell; mitochondria use glucose to make energy that cell can use
Another Example: DNA codes for proteins which are assembled by the ribosomes and used as enzymes for energy production at the mitochondria
Homeostasis and the Cell Membrane Video
Cell MEMBRANE Structure phosphate head thin, flexible membrane around all cells double layer of fat phospholipid bilayer (water tolerant end so that it can function with water on the inside and outside of the cell) Proteins transport molecules lipid tail
Do oil and water mix?
Cell MEMBRANE (cont.) FUNCTIONS of the Cell Membrane: 1.Separates the inside of the cell from the outside environment. 2.Control what enters and leaves the cell (selectively permeable) 3.Carbohydrates act like chemical identification cards, allowing individual cells to identify one another.
Cell Wall- Structure: Strong, supporting layer Found in plants, algae, fungi, and many prokaryotes (NOT found in animal cells) Found outside of the cell/plasma membrane Made of carbohydrates (cellulose in plants) Function: Provides protection and support Porous allows water, O 2, CO 2, and other substances to pass through easily Not selective (doesn t regulate what goes in and out)
cytoplasm jelly-like material holding organelles in place 1 vacuole storage 2 nucleus protects DNA controls cell 6 mitochondria 3 make ATP energy from sugar + O 2 cell membrane cell boundary controls movement of materials in & out 4 ribosomes 5 builds proteins
Which two structures ONLY occur in plant cells?
Animal Cell
Plant Cell
1. What type of cell is shown below? (Plant or Animal)
2. What type of cell is shown below? (Eukaryote or Prokaryote)
3. What type of cell is shown below? (Plant, Animal or Bacteria)
Microscopes used to see cells Types: Light Scanning Electron: more detail Electron Transmission: more detail
Total Magnification Objective x Eyepiece
Prokaryotic vs Eukaryotic Cells https://www.youtube.com/watch?v=rubahiij4ea AP Biology