Chapter 3 Cell Structure Section 1: Looking at Cells Section 2: Cell Features Section 3: : Cell Organelles

Section 1 Looking at Cells Objectives: Describe how scientists measure the length of objects. Relate magnification and resolution in the use of microscopes. Analyze how light microscopes function. Compare light microscopes with electron microscopes. Describe the scanning tunneling microscope.

Section 1 Looking at Cells Cells Under the Microscope Measuring Cell Structures Scientists use the metric system to measure the sizes of objects viewed under a microscope.

Characteristics of Microscopes Microscopes enable biologists to examine the details of cell structure and to understand how organisms function. two quantitative characteristics of microscopes Magnification : making object larger Resolution: making object clearer

Section 1 Types of Microscopes Compound Light Microscope low magnification can be used to examine living cells. Electron Microscopes high magnification cannot be used to examine living cells. Scanning Tunneling Microscope uses a computer to generate a three- dimensional image of the object. DNA Stoma plant cell Plant cell

Parts of a microscope

Section 2 Cell Features Objectives: List the three parts of the cell theory. Determine why cells must be relatively small. Compare the structure of prokaryotic cells with that of eukaryotic cells. Describe the structure of cell membranes.

Section 2 1.Cell features A. The Cell Theory 1.All living things are composed of cells 2. Cells are the basic units of structure & function in organisms 3. All cells arise from other cells.

-Small cells function more efficiently than large cells because small cells have a higher surface-area-to-volume ratio than large cells -Substances do not have to travel as far to reach the center or outside of the cell. B. Cell Size

C. Common Features of Cells All cells have a cell membrane, cytoplasm, ribosomes, and DNA.

Section 2 2. Prokaryotes Earliest life forms on earth Smallest simplest cells cells lack a nucleus and other internal compartments. Carries DNA in single circular molecule Modern Bacteria e. Colianthrax bacillus

Characteristics of Prokaryotes Grow very rapidly Can live aerobically(O 2 ) or anaerobically ( no O 2 ) surrounded by a cell wall cell organelles and DNA moving freely within the cytoplasm. Usually has flagella or tail for movement Some have sticky capsules

Section 2 3. Eukaryotic Cells (plant & animal) First cells organized with internal compartments DNA is within a nucleus Contains organelles to allow specific functions.

1.The Cytoplasm (both) Cells have cytoplasm that includes everything inside the cell and outside the nucleus Jelly like substance that allows all cell functions to take place 2.The Cytoskeleton ( both) made of microscopic protein fibers that provide the structural framework for the cell and its organelles. - microtubules and microfilaments fibers.

Section 2 The Cell Membrane (both) 3. The Cell Membrane is a Barrier The cells gate keeper Controls what goes in & out of cell. The lipid bilayer is made up of a double layer of phospholipid molecules and protiens. The selective permeability of the cell membrane is mainly due to the way phospholipids interact in water.

Not an individual structure, part of membrane Membrane Proteins 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 Organelles 4. The Nucleus (both) directs the cell's activities and stores DNA. Control center of cell Directs synthesis of proteins Located inside it’s own membrane within the cytoplasm 5. Nucleolus (both) Nucleus inside nucleus where RNA is synthesized and stored

6. Nuclear membrane/nuclear envelope (both) membrane that surrounds the nuclear material. membrane that surrounds the nuclear material. The nuclear gate keeper The nuclear gate keeper Controls what goes in and out of the nucleus through pores Controls what goes in and out of the nucleus through pores 7.Nucleoplasm (both) Fluid like substance Fluid like substance inside the nucleus inside the nucleus Allows for support of Allows for support of genetic material and genetic material and transportation of material transportation of material in and out of nucleus in and out of nucleus

Section 3 8. Ribosomes (both) Found inside the cytoplasm or attached to rough endoplasmic reticulum (rER). Production of Proteins (protein synthesis) Work benches of the cell

9. Endoplasmic Reticulum (both) Found inside the cytoplasm Can be rough (w/ ribosomes) or smooth Cell transport system Moves proteins and other substances throughout the cell.

10. Golgi Body/Golgi Apparatus (both) Located in the cytoplasm Package and Distribute Proteins made by ribosomes vesicles carry proteins from the rough ER to Golgi Golgi Modifies the proteins and they are either released from the Golgi by vesicles outside the cell or remain in the cell.

Section 3 Cell Organelles 11. Lysosomes (Both) Located in the cytoplasm Some protein containing vesicles remain in the cell and become lysosomes. Lysosomes contain digestive enzymes (lysozymes) that digest and recycle a cell's used components. Work with Golgi & ER

Section Mitochondria (both) Found in the cytoplasm Control cellular respiration by harvesting energy from organic compounds to ATP. (breaks down food to energy) Considered power house of cell Mitochondria have their own DNA and this allows them to make some of their own proteins.

13. Vacuole (both) Found in the cytoplasm Found in the cytoplasm Store house for water and waste products Store house for water and waste products Very large and pigmented in plant cell Very large and pigmented in plant cell Called central vacuoleCalled central vacuole Animal cell is very small, looks like small bubble Animal cell is very small, looks like small bubble

14. Flagella (animal-bacteria) Attached to cell membrane and used for movement 15. Cilia (animal) Short hair like structures on the outside of the cell Movement of substances (lungs-mucus) Movement of animal 16. Microvilli (animal) Fingerlike projections found within the cell membrane. Increase surface area of cell Digestive tract

Section Cell wall( plant) Outside the cell membrane of the cell. Made of cellulose (carbohydrates) and proteins Provides rigid support and protection for the plant Connects cells to adjacent cells Does not interfere with movement of substances across cell membrane

 18. Chloroplasts (plant) Located inside the cell Located inside the cell Contains pigment chlorophyll that is responsible for green color & photosynthesis Contains pigment chlorophyll that is responsible for green color & photosynthesis Converts sunlight into food Converts sunlight into food Have their own DNA and thought to be descendants of ancient prokaryotes. Have their own DNA and thought to be descendants of ancient prokaryotes.

 19.Plastid (plant) Found inside the plant cell Found inside the plant cell Store nutrients and pigments Store nutrients and pigments Vitamin A

 20.Centrosome ( animal) Protein fibers that help move the chromosomes Protein fibers that help move the chromosomes Contains centrioles that are small bodies involved in cellular reproduction: mitosis Contains centrioles that are small bodies involved in cellular reproduction: mitosis

 21.Peroxisome ( animal) Vacuole smaller than lysosome in the cytoplasm Vacuole smaller than lysosome in the cytoplasm Toxic compounds are neutralized Toxic compounds are neutralized Contains enzymes like catalse that break down hydrogen peroxideContains enzymes like catalse that break down hydrogen peroxide Helps synthesize bile & cholesterol Helps synthesize bile & cholesterol