Chapter 7 A Tour of the Cell (1).ppt

Chapter 7 A Tour of the Cell PowerPoint® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.1 The Fu...

Chapter 7 A Tour of the Cell PowerPoint® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.1 The Fundamental Units of Life • The cell is the simplest collection of matter that can live • Cell structure is correlated to cellular function Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.2 Microscopy • Scientists use microscopes to visualize cells • In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the image Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.2 Microscopy • The quality of an image depends on – Magnification, the ratio of an object’s image size to its real size – Resolution: the minimum distance of two distinguishable points on a specimen – Contrast, the difference in light intensity between the image and the adjacent background Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 10 m Human height Length of some nerve and muscle cells 0.1 m Chicken egg 1 cm 100 µm Most plant and animal cells 10 µm Nucleus Most bacteria 1 µm 100 nm 10 nm Mitochondrion Smallest bacteria Viruses Ribosomes Proteins Lipids 1 nm 0.1 nm Small molecules Atoms Electron microscope 1 mm Frog egg Light microscope 1m Unaided eye Fig. 6-2 7.2 Microscopy Electron Microscopy •Scanning Electron Microscope (SEM) focus a beam of electrons onto the surface of a specimen, providing images that look 3-D. SEM shows surfaces. •Transmission Electron Microscope (TEM) focus a beam of electrons through a specimen •TEMs are used mainly to study the internal structure of cells. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 6-4 TECHNIQUE (a) Scanning electron microscopy (SEM) RESULTS Cilia 1 µm (b) Transmission electron Longitudinal Cross section section of of cilium microscopy (TEM) 1 µm cilium 7.3 Cell Types • There are two types of cells: prokaryotic or eukaryotic • Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells • Domain Eukarya: Protists, fungi, animals, and plants all consist of eukaryotic cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.3 Cell Types • Basic features of all cells: – Plasma membrane – Semifluid substance called cytosol – Chromosomes (carry genes) – Ribosomes (make proteins) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.3 Cell Types • Prokaryotic cells are characterized by having – No nucleus – DNA in an unbound region called the nucleoid – No membrane-bound organelles – Cytoplasm bounded by the plasma membrane Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 6-6 Fimbriae Nucleoid Ribosomes Plasma membrane Bacterial chromosome Cell wall Capsule 0.5 µm (a) A typical rod-shaped bacterium Flagella (b) A thin section through the bacterium Bacillus coagulans (TEM) 7.3 Eukaryotic Cells • Eukaryotic cells are characterized by having – DNA in a nucleus that is bounded by a membranous nuclear envelope – Membrane-bound organelles – Cytoplasm in the region between the plasma membrane and nucleus • Eukaryotic cells are generally much larger than prokaryotic cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.3 Eukaryotic Cells • A eukaryotic cell has internal membranes that partition the cell into organelles BioFlix: Tour Of An Animal Cell BioFlix: Tour Of A Plant Cell Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 6-9a Nuclear envelope ENDOPLASMIC RETICULUM (ER) Flagellum Rough ER NUCLEUS Nucleolus Smooth ER Chromatin Centrosome Plasma membrane CYTOSKELETON: Microfilaments Intermediate filaments Microtubules Ribosomes Golgi apparatus Mitochondrion 7.4 Organelles’ Functions Organelle Function Nuclear Envelope A membrane that encloses the nucleus Nucleolus Make ribosomal RNA and combine it with protein Chromatin Package DNA into a small volume Golgi Apparatus Intracellular Transport and Packaging of proteins Ribosomes Make Protein Mitochondrion Production of Energy Cytoskeleton A network of protein fibers that give the cell its shape and facilitate movement Endoplasmic Reticulum Folding and Transport of Proteins Fig. 6-9b NUCLEUS Nuclear envelope Nucleolus Chromatin Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments Microtubules Mitochondrion Chloroplast Plasma membrane Cell wall Plasmodesmata Wall of adjacent cell CYTOSKELETON 7.5: Mitochondria and Chloroplasts & Peroxisomes • Mitochondria are the sites of cellular respiration to generate ATP. • Chloroplasts, found in plants and algae, are the sites of photosynthesis • Peroxisomes contain enzymes that oxidize certain molecules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.6 Mitochondria • Mitochondria are in nearly all eukaryotic cells • They have a smooth outer membrane and an inner membrane folded into cristae • The inner membrane creates two compartments: intermembrane space and mitochondrial matrix • Cristae present a large surface area for enzymes that synthesize ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 6-17 Intermembrane space Outer membrane Free ribosomes in the mitochondrial matrix Inner membrane Cristae Matrix 0.1 µm 7.7 Respiration • Respiration is the process that uses oxygen to break down large, organic molecules into smaller inorganic molecules (releases energy organisms can use). – Glucose + oxygen produces carbon dioxide + water + energy – C6H12O6 + 6O2  6CO2 + 6H2O + energy 7.7 Respiration • There are two types of respiration: Aerobic- with Oxygen Glucose + Oxygen -> Carbon Dioxide + Water +ENERGY Anaerobic (Muscle cells in humans, Plants and Microorganisms) -without Oxygen Glucose -> Carbon Dioxide + Alcohol +ENERGY 7.8 Chloroplasts • The chloroplast is a member of a family of organelles called plastids • Chloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis • Chloroplasts are found in leaves and other green organs of plants and in algae Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7.8 Chloroplasts • Chloroplast structure includes: – Thylakoids: Tiny compartments found inside the chloroplast and their role is to help absorb sunlight in order for Photosynthesis to occur. – Granum: Stacks of Thylakoids make the coinshaped Granum and it is the site of light reactions of photosynthesis. – Stroma, the internal fluid of the chloroplast where starch is produced. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 6-18 Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm 7.9 Photosynthesis What is needed for photosynthesis? From soil? From air? From the sun? 2) How is the light energy absorbed? Light Energy Chloroplast CO2 + H2O Sugars + O2 6H2O + 6CO2 ----------> C6H12O6+ 6O2 Go to Section: