1. Copyright © 2009 Pearson Education, Inc.. Lectures by Gregory Ahearn University of North Florida Chapter 4 Cell Structure and Function

2. Copyright © 2009 Pearson Education Inc. 4.1 What Features Are Shared By All Cells?  Cells are the smallest unit of ______.  Cells are enclosed by a ______ _________.  Cells use ____ as a hereditary blueprint.  Cells contain _____________, the material inside the plasma membrane and outside the DNA-containing nucleus. Fluid environment: H20, salts, organic molecules Metabolic activities: proteins, lipids, carbs, salts, sugars, AA and nucleotides  Cells obtain __________ and ___________ from their environment.

3. Copyright © 2009 Pearson Education Inc. 4.1 What Features Are Shared By All Cells?

4. Copyright © 2009 Pearson Education Inc. Fig. 4-1 frog embryo most eukaryotic cells mitochondrion most bacteria virus proteins diameter of DNA double helix chicken egg atoms 1 micrometer (  m) = 1/1,000,000 m 1 nanometer (nm) = 1/1,000,000,000 m 1 centimeter (cm) = 1/100 m 1 millimeter (mm) = 1/1,000 m Units of measurement: 1 meter (m) = 39.37 inches adult human tallest trees Diameter visible with unaided human eye visible with light microscope visible with conventional electron microscope visible with special electron microscopes 100 m 10 m 1 m 10 cm 1 cm 1 mm 100  m 10  m 1  m 100 nm 10 nm 1 nm 0.1 nm 4.1 What Features Are Shared By All Cells?  Relative sizes

5. Copyright © 2009 Pearson Education Inc. 4.1 What Features Are Shared By All Cells?  Cell function limits cell size. Diffusion of molecules across cell membranes limits the diameter of cells. As cells get bigger, their nutrient and waste elimination needs grow faster than the membrane area to accommodate them. The volume of cytoplasm grows faster than the plasma membrane area

6. Copyright © 2009 Pearson Education Inc. 4.1 What Features Are Shared By All Cells? Fig. 4-2

7. Copyright © 2009 Pearson Education Inc. 4.2 How Do Prokaryotic And Eukaryotic Cells Differ?  There are two kinds of cells. 1) _______________ cells Are found only in two groups of single- celled organisms: bacteria and archaea 2) _______________ cells Are structurally more complex cells Possess a membrane-enclosed nucleus Probably arose from prokaryotic cells

8. Copyright © 2009 Pearson Education Inc. 4.3 What Are The Main Features Of Eukaryotic Cells?  Eukaryotic cells possess a number of membrane-enclosed organelles that perform specific cell functions. _____________: contains DNA _____________: produce energy _____________________: synthesizes proteins and lipids _____________________: molecule sorting center _________________: digest cellular membranes or defective organelles

9. Copyright © 2009 Pearson Education Inc. 4.3 What Are The Main Features Of Eukaryotic Cells?  A generalized animal cell Fig. 4-3 mitochondrion vesicle cytoplasm flagellum lysosome centriole intermediate filaments Golgi apparatus vesicle nuclear pore nuclear envelope chromatin (DNA) nucleolus nucleus plasma membrane rough endoplasmic reticulum ribosome free ribosome smooth endoplasmic reticulum microtubules

10. Copyright © 2009 Pearson Education Inc. 4.3 What Are The Main Features Of Eukaryotic Cells?  A generalized plant cell Fig. 4-4 central vacuole mitochondrion vesicle plasmodesma cell wall plasma membrane intermediate filaments free ribosome ribosomes nucleus nucleolus nuclear pore chromatin nuclear envelope rough endoplasmic reticulum smooth endoplasmic reticulum Golgi apparatus chloroplast microtubules (part of cytoskeleton)

11. Copyright © 2009 Pearson Education Inc. 4.4 What Role Does The Nucleus Play? Nucleus: bound by a nuclear envelope, contains chromatin and nucleolus. Largest organelle. nucleus nuclear pores (b) Yeast cell nuclear envelope nuclear pores nucleolus chromatin (a) Structure of the nucleus Fig. 4-5

12. Copyright © 2009 Pearson Education Inc. 4.4 What Role Does The Nucleus Play?  The nuclear envelope is a _________ membrane. The membrane is perforated with channels called nuclear _______. Some smaller materials can move through the pores, while others, such as _______, cannot.  The nucleus contains chromosomes. DNA and protein are closely associated in the nucleus in chromatin. Chromatin can become condensed into chromosomes.

13. Copyright © 2009 Pearson Education Inc. 4.4 What Role Does The Nucleus Play? Fig. 4-6 chromatin chromosome

14. Copyright © 2009 Pearson Education Inc. 4.4 What Role Does The Nucleus Play?  Ribosomes are composed of ______ and _________, and serve as a “workbench” for the manufacture of __________.  Ribosome components are made at the ___________. A darkly staining region in the nucleus is called a nucleolus. The nucleolus contains DNA, RNA, proteins, and ribosomes in various stages of construction. Ribosome components leave the nucleus and are assembled in the cytoplasm.

15. Copyright © 2009 Pearson Education Inc. 4.5 What Roles Do Membranes Play In Eukaryotic Cells?  The plasma membrane isolates the cell, and alternately, helps it interact with its environment. The ___________ bilayer contains globular proteins that regulate the transport of molecules into and out of the cell. Plant cells also have a rigid structure outside the plasma membrane, called a _____ _____, which forms a protective coating.