1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Human Biology Sylvia S. Mader Michael Windelspecht Chapter 3 Cell Structure and Function Lecture Outline Part 2

2 What are the 2 major types of cells in all living organisms? Prokaryotic cells –Thought to be the first cells to evolve –Lack a ________ –Represented by bacteria and archaea Eukaryotic cells –Have a _________ that houses _____ –Many membrane-bound organelles 3.2 How Cells are Organized

3 What do prokaryotic and eukaryotic cells have in common? A ___________________ that surrounds and delineates the cell A ____________: the semi-fluid substance inside the cell that contains organelles DNA 3.2 How Cells are Organized

4 What do eukaryotic cells look like? 3.2 How Cells are Organized Figure 3.4 The structure of a typical eukaryotic cell. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. 2.5 µm Plasma membrane: outer surface that regulates entrance and exit of molecules protein phospholipid CYTOSKELETON: maintains cell shape and assists movement of cell parts: Microtubules: cylinders of protein molecules present in cytoplasm, centrioles, cilia, and flagella Intermediate filaments: protein fibers that provide support and strength Actin filaments: protein fibers that play a role in movement of cell and organelles Centioles: short, cylinders of microtubules Vesicle: membrane-bounded sac that stores and transports substances b. Cytoplasm: semifluid matrix outside nucleus that contains organelles Centrosome: microtubules organizing center that contains a pair of centroles Lysosome: vesicle that digests macromolecules and even cell parts Golgi apparatus: processes, packages, and secretes modified cell products Polyribosome: string of ribosomes simultaneously synthesizing same protein Mitochondrion: organelle that carries out cellular respiration, producing ATP molecules Ribosomes: particles that carry out protein synthesis Smooth ER: lacks ribosomes, synthesizes lipid molecules Rough ER: studded with ribosomes, processes proteins ENDOPLASMIC RETICULUM: Nucleolus: region that produces subunits of ribosomes Chromatin: diffuse threads containing DNA and protein Nuclear envelope: double membrane with nuclear pores that encloses nucleus NUCLEUS: mitochondrion chromatin nucleolus nuclear envelope endoplasmic reticulum © Dennis Kunkel/Visuals Unlimited

5 Where did eukaryotic cells come from? 3.2 How Cells are Organized Figure 3.5 The evolution of eukaryotic cells. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DNA 1. Cell gains a nucleus by the plasma membrane invaginating and surrounding the DNA with a double membrane. Nucleus allows specific functions to be assigned, freeing up cellular resources for other work. 2. Cell gains an endomembrane system by proliferation of membrane. Increased surface area allows higher rate of transport of materials within a cell. 3. Cell gains mitochondria. Ability to metabolize sugars in the presence of oxygen enables greater function and success. 4. Cell gains chloroplasts. Ability to produce sugars from sunlight enables greater function and success. chloroplast Plant cell has both mitochondria cnd chloroplasts. Animal cell has mitochondria, but not chloroplasts. mitochondrion aerobic bacterium photosynthetic bacterium Original prokaryotic cell

6 What are some characteristics of the plasma membrane? It is a ____________ bilayer. It is embedded with proteins that move in space. It contains ____________ for support. It contains carbohydrates on proteins and lipids. It is _____________________. 3.3 The Plasma Membrane and How Substances Cross It

7 Figure 3.6 Organization of the plasma membrane. 3.3 The Plasma Membrane and How Substances Cross It Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Outside hydrophilic heads carbohydrate chain glycoprotein cholesterol integral protein filaments of cytoskeleton phospholipid bilayer hydrophobic tails Inside peripheral protein plasma membrane extracellular matrix (ECM) glycolipid

8 What does selectively permeable mean? The membrane allows some things __ while keeping other substances ____. 3.3 The Plasma Membrane and How Substances Cross It + – phospholipid molecule protein macromolecule aquaporin noncharged molecules H2OH2O charged molecules and ions – + Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.7 Selective permeability of the plasma membrane.

9 How do things move across the plasma membrane? 1. Diffusion 2. Osmosis 3. Facilitated transport 4. Active transport 5. Endocytosis and exocytosis 3.3 The Plasma Membrane and How Substances Cross It

10 What are diffusion and osmosis? 1.___________ is the random movement of molecules from a ________ concentration to a __________ concentration. 2.Osmosis is the __________ of water molecules. 3.3 The Plasma Membrane and How Substances Cross It

The Plasma Membrane and How Substances Cross It Figure 3.8 Diffusion across the plasma membrane. What are diffusion and osmosis? Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. particle plasma membrane water cell time a. Initial conditionsb. Equilibrium conditions