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

Looking at Cells Objectives: 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. 2

Looking at Cells Cells Under the 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. Magnification and resolution are two quantitative characteristics of microscopes. 3

Looking at Cells Types of Microscopes Section 1 Looking at Cells Types of Microscopes Compound Light Microscope Light microscopes have a low magnification and can be used to examine living cells. Electron Microscopes Electron microscopes have a high magnification but cannot be used to examine living cells. Scanning Tunneling Microscope The scanning tunneling microscope uses a computer to generate a three-dimensional image of the object. 4

Cell Features Objectives: List the three parts of the cell theory. 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. 5

Chemistry of Cells The Cell Theory Section 2 Chemistry of Cells The Cell Theory Cell Theory The cell theory has three parts. Cell Size Small cells function more efficiently than large cells because small cells have a higher surface-area-to-volume ratio than large cells. Common Features of Cells All cells have a cell membrane, cytoplasm, ribosomes, and DNA. 6

Chemistry of Cells Prokaryotes Section 2 Chemistry of Cells Prokaryotes Prokaryotic Cells Prokaryotic cells lack a nucleus and other internal compartments. Characteristics of Prokaryotes Prokaryotic cells are surrounded by a cell wall and they have cell organelles and DNA moving freely within the cytoplasm. 7

Chemistry of Cells Eukaryotic Cells Section 2 Chemistry of Cells Eukaryotic Cells Eukaryote Cells Eukaryote cells have a nucleus and other organelles. The Cytoskeleton Eukaryote cells have a cytoskeleton of microscopic protein fibers that provide the structural framework for the cell and its organelles. There are three different kinds of cytoskeleton fibers: actin fibers, microtubules, and intermediate fibers. 8

Chemistry of Cells The Cell Membrane Section 2 Chemistry of Cells The Cell Membrane The Cell Membrane as a Barrier The lipid bilayer of a cell membrane is made up of a double layer of phospholipid molecules. The selective permeability of the cell membrane is mainly due to the way phospholipids interact in water. Membrane Proteins Proteins in cell membranes include enzymes, receptor proteins, transport proteins, and cell-surface markers. 9

Cell Organelles Objectives: 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. 10

Cell Organelles The Nucleus Section 3 Cell Organelles The Nucleus Function of Nucleus The nucleus of a eukaryotic cell directs the cell's activities and stores DNA. 11

Cell Organelles Ribosomes and the Endoplasmic Reticulum Section 3 Cell Organelles Ribosomes and the Endoplasmic Reticulum Production of Proteins In eukaroytic cells, proteins are manufactured at ribosomes found within the cytoplasm and found on an internal membrane system called the rough endoplasmic reticulum (ER). Packaging and Distribution of Proteins In eukaroytic cells, vesicles carry proteins from the rough ER to an internal membrane system, called the Golgi apparatus, to be processed. Modified proteins are either released from vesicles outside the cell or remain in the cell. 12

Cell Organelles Ribosomes and the Endoplasmic Reticulum continued Section 3 Cell Organelles Ribosomes and the Endoplasmic Reticulum continued Lysozymes Some protein containing vesicles remain in the cell and become lysozymes. Lysozymes digest and recycle a cell's used components. 13

Cell Organelles Mitochondria Section 3 Cell Organelles Mitochondria Function of Mitochondria Mitochondria harvest energy from organic compounds to ATP. Mitochondrial DNA Mitochondria have their own DNA and this allows them to make some of their own proteins. 14

Cell Organelles Structure of Plant Cells Section 3 Cell Organelles Structure of Plant Cells Unique Features of Plant Cells Plant cells have three structures that animal cells lack: a cell wall, chloroplasts, and a central vacuole. 15