Biology Textbook PDF - Chapter 1 Exploring Life

Chapter 1 Exploring Life PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Overview: Biology’s Most Exciting Era Biology – Is the scientific study o...

Chapter 1 Exploring Life PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Overview: Biology’s Most Exciting Era Biology – Is the scientific study of life Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The phenomenon we call life – Defies a simple, one-sentence definition Figure 1.1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  We recognize life – By what living things do Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some properties of life (b) Evolutionary adaptation (a) Order (c) Response to the environment (e) Energy processing (d) Regulation (f) Growth and (g) Reproduction development Figure 1.2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.1: Biologists explore life from the microscopic to the global scale The study of life – Extends from the microscope scale of molecules and cells to the global scale of the entire living planet Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A Hierarchy of Biological Organization The hierarchy of life – Extends through many levels of biological organization Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  From the biosphere to organisms 1 The biosphere Figure 1.3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  From cells to molecules 9 Organelles 1 µm Cell 8 Cells Atoms 10 µm 10 Molecules 7 Tissues 50 µm 6 Organs and organ systems Figure 1.3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A Closer Look at Ecosystems Each organism – Interacts with its environment Both organism and environment – Are affected by the interactions between them Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Ecosystem Dynamics The dynamics of any ecosystem include two major processes – Cycling of nutrients, in which materials acquired by plants eventually return to the soil – The flow of energy from sunlight to producers to consumers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Energy Conversion Activities of life – Require organisms to perform work, which depends on an energy source Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The exchange of energy between an organism and its surroundings – Often involves the transformation of one form of energy to another Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Energy flows through an ecosystem – Usually entering as sunlight and exiting as heat Sunlight Ecosystem Producers (plants and other photosynthetic organisms) Heat Chemical energy Consumers (including animals) Figure 1.4 Heat Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A Closer Look at Cells The cell – Is the lowest level of organization that can perform all activities required for life Figure 1.5 25 µm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Cell’s Heritable Information Cells contain chromosomes made partly of DNA, the substance of genes – Which program the cells’ production of proteins and transmit information from parents to offspring Sperm cell Nuclei containing DNA Fertilized egg Embyro’s cells with DNA from with copies of both parents inherited DNA Offspring with traits Egg cell inherited from Figure 1.6 both parents Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The molecular structure of DNA – Accounts for it information-rich nature Nucleus DNA Cell A C Nucleotide T A T A C C G T A G T A (a) DNA double helix. This model shows (b) Single strand of DNA. These geometric shapes and each atom in a segment of DNA.Made letters are simple symbols for the nucleotides in a up of two long chains of building small section of one chain of a DNA molecule. blocks called nucleotides, a DNA Genetic information is encoded in specific sequences molecule takes the three-dimensional of the four types of nucleotides (their names are Figure 1.7 form of a double helix. abbreviated here as A, T, C, and G). Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Two Main Forms of Cells All cells share certain characteristics – They are all enclosed by a membrane – They all use DNA as genetic information There are two main forms of cells – Eukaryotic – Prokaryotic Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Eukaryotic cells – Are subdivided by internal membranes into various membrane-enclosed organelles Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Prokaryotic cells – Lack the kinds of membrane-enclosed organelles found in eukaryotic cells EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane Membrane Cytoplasm Organelles Figure 1.8 Nucleus (contains DNA) 1 µm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.2: Biological systems are much more than the sum of their parts A system – Is a combination of components that form a more complex organization Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Emergent Properties of Systems Due to increasing complexity – New properties emerge with each step upward in the hierarchy of biological order Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Power and Limitations of Reductionism Reductionism – Involves reducing complex systems to simpler components that are more manageable to study Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The study of DNA structure, an example of reductionism – Has led to further study of heredity, such as the Human Genome Project Figure 1.9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Systems Biology Systems biology – Seeks to create models of the dynamic behavior of whole biological systems With such models – Scientists will be able to predict how a change in one part of a system will affect the rest of the system Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Outer membrane and cell surface CELL Cytoplasm Nucleus Figure 1.10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Systems biology – Is now taking hold in the study of life at the cellular and molecular levels – Includes three key research developments: high-throughput technology, bioinformatics, and interdisciplinary research teams Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Feedback Regulation in Biological Systems A kind of supply-and-demand economy – Applies to some of the dynamics of biological systems Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  In feedback regulation – The output, or product, of a process regulates that very process Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  In negative feedback – An accumulation of an end product slows the process that produces that product A A Negative feedback Enzyme 1 Enzyme 1 B B Enzyme 2 C C Enzyme 3 D D D D D D D D D D D Figure 1.11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  In positive feedback – The end product speeds up production W W Enzyme 4 Enzyme 4 X Positive X feedback Enzyme 5 Enzyme 5 Y Y Enzyme 6 Enzyme 6 Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Figure 1.12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.3: Biologists explore life across its great diversity of species Diversity is a hallmark of life Figure 1.13 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Grouping Species: The Basic Idea Taxonomy – Is the branch of biology that names and classifies species according to a system of broader and broader groups Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Classifying life Species Genus Family Order Class Phylum Kingdom Domain Ursus ameri- canus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Animalia Eukarya Figure 1.14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Three Domains of Life At the highest level, life is classified into three domains – Bacteria – Archaea – Eukarya Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Domain Bacteria and domain Archaea – Consist of prokaryotes Domain Eukarya, the eukaryotes – Includes the various protist kingdoms and the kingdoms Plantae, Fungi, and Animalia Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Life’s three domains Bacteria are the most diverse 4 µm Protists (multiple kingdoms) Kingdom Plantae consists of 100 µm and widespread prokaryotes are unicellular eukaryotes and multicellula eukaryotes that carry and are now divided among multiple their relatively simple multicellular out photosynthesis, the conversion kingdoms. Each of the rod-shaped relatives.Pictured here is an assortment of of light energy to food. structures in this photo is a bacterial cell. protists inhabiting pond water. Scientists are currently debating how to split the protists into several kingdoms that better represent DOMAIN ARCHAEA evolution and diversity. Many of the prokaryotes known Kindom Fungi is defined in part by the Kindom Animalia consists of 0.5 µm as archaea live in Earth‘s nutritional mode of its members, such multicellular eukaryotes that extreme environments, such as salty lakes as this mushroom, which absorb ingest other organisms. and boiling hot springs. Domain Archaea nutrientsafter decomposing organic includes multiple kingdoms. The photo material. Figure 1.15 shows a colony composed of many cells. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Unity in the Diversity of Life As diverse as life is – There is also evidence of remarkable unity 15 µm 1.0 µm Cilia of Paramecium. The cilia of Paramecium propel the cell through pond water. 5 µm Cross section of cilium, as viewed with an electron microscope Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving Figure 1.16 a film of debris-trapping mucus upward. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.4: Evolution accounts for life’s unity and diversity The history of life – Is a saga of a changing Earth billions of years old Figure 1.17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The evolutionary view of life – Came into sharp focus in 1859 when Charles Darwin published On the Origin of Species by Natural Selection Figure 1.18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Origin of Species articulated two main points – Descent with modification – Natural selection Figure 1.19 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Natural Selection Darwin proposed natural selection – As the mechanism for evolutionary adaptation of populations to their environments Population of organisms Overproduction Hereditary and struggle for variations existence Differences in reproductive success Evolution of adaptations Figure 1.20 in the population Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Natural selection is the evolutionary process that occurs – When a population’s heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others 1 Populations with varied inherited traits 2 Elimination of individuals with certain traits. 3 Reproduction of survivors. 4 Increasing frequency of traits that enhance Figure 1.21 survival and reproductive success. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The products of natural selection – Are often exquisite adaptations of organisms to the special circumstances of their way of life and their environment Figure 1.22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Tree of Life Many related organisms – Have very similar anatomical features, adapted for their specific ways of life Such examples of kinship – Connect life’s “unity in diversity” to Darwin’s concept of “descent with modification” Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Darwin proposed that natural selection – Could enable an ancestral species to “split” into two or more descendant species, resulting in a “tree of life” Large ground finch Small Large ground tree finch Large cactus ground finch finch Geospiza Camarhynchus Green Gray Geospiza magnirostris psitacula warbler warbler Sharp-beaked fuliginosa Woodpecker Medium Geospiza Medium tree finch finch finch ground finch ground finch conirostris finch Certhidea Certhidea GeospizaCactus Cactospiza Camarhynchus difficilis ground finch pauper olivacea fusca pallida Geospiza Mangrove Small tree finch fortis finch Geospiza Camarhynchus scandens Cactospiza parvulus heliobates Seed eater Cactus flower Seed eater Vegetarian eater finch Platyspiza crassirostris Insect eaters Bud eater Ground finches Tree finches Warbler finches Common ancestor from Figure 1.23 South American mainland Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Each species is on twig of a branching tree of life – Extending back in time through ancestral species more and more remote All of life – Is connected through its long evolutionary history Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.5: Biologists use various forms of inquiry to explore life At the heart of science is inquiry – A search for information and explanation, often focusing on specific questions Biology blends two main processes of scientific inquiry – Discovery science – Hypothesis-based science Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Discovery Science Discovery science – Describes natural structures and processes as accurately as possible through careful observation and analysis of data Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Types of Data Data – Are recorded observations – Can be quantitative or qualitative Figure 1.24 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Induction in Discovery Science In inductive reasoning – Scientists derive generalizations based on a large number of specific observations Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Hypothesis-Based Science In science, inquiry that asks specific questions – Usually involves the proposing and testing of hypothetical explanations, or hypotheses Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Role of Hypotheses in Inquiry In science, a hypothesis – Is a tentative answer to a well-framed question, an explanation on trial – Makes predictions that can be tested Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  We all use hypotheses in solving everyday problems Observations Questions Hypothesis # 1: Hypothesis # 2: Dead batteries Burnt-out bulb Prediction: Prediction: Replacing batteries Replacing bulb will fix problem will fix problem Test prediction Test prediction Figure 1.25 Test falsifies hypothesis Test does not falsify hypothesis Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Deduction: The “If…then” Logic of Hypothesis-Based Science In deductive reasoning – The logic flows from the general to the specific If a hypothesis is correct – Then we can expect a particular outcome Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A Closer Look at Hypotheses in Scientific Inquiry A scientific hypothesis must have two important qualities – It must be testable – It must be falsifiable Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Myth of the Scientific Method The scientific method – Is an idealized process of inquiry Very few scientific inquiries – Adhere to the “textbook” scientific method Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations In mimicry – A harmless species resembles a harmful species Flower fly (non-stinging) Honeybee (stinging) Figure 1.26 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  In this case study – Mimicry in king snakes is examined – The hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present Scarlet king snake Key Range of scarlet king snake Range of eastern color snake North Carolina South Carolina Eastern coral snake Figure 1.27 Scarlet king snake Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Field Experiments with Artificial Snakes To test this mimicry hypothesis – Researchers made hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes (a) Artificial king snake Figure 1.28 (b) Brown artificial snake that has been attacked Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  After a given period of time – The researchers collected data that fit a key prediction Key Key % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes 17% In areas where coral snakes were absent, most attacks 83% were on artificial king snakes X North X X X XXX Carolina South XX Carolina X X X XX 16% 84% In areas where coral snakes were present, most attacks were on Figure 1.29 artificial king snakes Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Designing Controlled Experiments Experiments must be designed to test – The effect of one variable by testing control groups and experimental groups in a way that cancels the effects of unwanted variables Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Limitations of Science Science cannot address supernatural phenomena – Because hypotheses must be testable and falsifiable and experimental results must be repeatable Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Theories in Science A scientific theory – Is broad in scope – Generates new hypotheses – Is supported by a large body of evidence Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Model Building in Science Models of ideas, structures, and processes – Help us understand scientific phenomena and make predictions From From body lungs Right Right artium artium Right Right ventricle ventricle Figure 1.30 To lungs To body Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Culture of Science Science is a social activity – Characterized by both cooperation and competition Figure 1.31 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Science, Technology, and Society Technology – Applies scientific knowledge for some specific purpose Figure 1.32 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 1.6: A set of themes connects the concepts of biology Underlying themes – Provide a framework for understanding biology Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Eleven themes that unify biology Table 1.1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 4 Carbon and the Molecular Diversity of Life PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Overview: Carbon—The Backbone of Biological Molecules All living organisms – Are made up of chemicals based mostly on the element carbon Figure 4.1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 4.1: Organic chemistry is the study of carbon compounds Organic compounds – Range from simple molecules to colossal ones Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The concept of vitalism – Is the idea that organic compounds arise only within living organisms – Was disproved when chemists synthesized the compounds in the laboratory In 1953, Stanley Miller simulated what were thought to be environmental EXPERIMENT conditions on the lifeless, primordial Earth. As shown in this recreation, Miller used electrical discharges (simulated lightning) to trigger reactions in a primitive “atmosphere” of H2O, H2, NH3 (ammonia), and CH4 (methane)—some of the gases released by volcanoes. A variety of organic compounds that play key roles in living cells were RESULTS synthesized in Miller’s apparatus. Organic compounds may have been synthesized abiotically on the CONCLUSION early Earth, setting the stage for the origin of life. (We will explore Figure 4.2 this hypothesis in more detail in Chapter 26.) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 4.2: Carbon atoms can form diverse molecules by bonding to four other atoms Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Formation of Bonds with Carbon Carbon has four valence electrons This allows it to form four covalent bonds with a variety of atoms Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The bonding versatility of carbon – Allows it to form many diverse molecules, including carbon skeletons Name and Molecular Structural Ball-and- Space- Comments Formula Formula Stick Model Filling Model H (a) Methane CH4 H C H H H H (b) Ethane C2H H C C H 6 H H (c) Ethene H H C2H4 C C Figure 4.3 A-C (ethylene) H H Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The electron configuration of carbon – Gives it covalent compatibility with many different elements Hydrogen Oxygen Nitrogen Carbon (valence = 1) (valence = 2) (valence = 3) (valence = 4) H O N C Figure 4.4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Molecular Diversity Arising from Carbon Skeleton Variation Carbon chains – Form the skeletons of most organic molecules – Vary in length and shape H H H H H (a) Length H C C C H H C C H H H H H H Ethane Propane H H C H H H H H H H (b) Branching H C C C C H H C C C H H H H H H H H Butane 2-methylpropane (commonly called isobutane) H H H H H H H H (c) Double bonds H C C C C H H C C C C H H H H H 1-Butene 2-Butene H H H H C H H (d) Rings H C C H C C H H C H C H C H C C C Figure 4.5 A-D Cyclohexane Benzene Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Hydrocarbons Hydrocarbons – Are molecules consisting of only carbon and hydrogen Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Hydrocarbons – Are found in many of a cell’s organic molecules Fat droplets (stained red) 100 µm Figure 4.6 A, B (a) A fat molecule (b) Mammalian adipose cells Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Isomers Isomers – Are molecules with the same molecular formula but different structures and properties Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Three types of isomers are – Structural – Geometric – Enantiomers H H C H H C H H H H H H H H (a) Structural isomers H C C C C C H H C C C H H H H H H H H H X X H X (b) Geometric isomers C C C C H H X H CO2H CO2H (c) Enantiomers C C H NH2NH2 H CH3 CH3 Figure 4.7 A-C Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Enantiomers – Are important in the pharmaceutical industry L-Dopa D-Dopa (effective against (biologically Figure 4.8 Parkinson’s disease) inactive) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 4.3: Functional groups are the parts of molecules involved in chemical reactions Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Functional Groups Most Important in the Chemistry of Life Functional groups – Are the chemically reactive groups of atoms within an organic molecule Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  – Give organic molecules distinctive chemical properties OH CH3 Estradiol HO Female lion OH CH3 CH3 O Testosterone Figure 4.9 Male lion Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Six functional groups are important in the chemistry of life – Hydroxyl – Carbonyl – Carboxyl – Amino – Sulfhydryl – Phosphate Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds FUNCTIONAL HYDROXYL CARBONYL CARBOXYL GROUP O O OH C C (may be written HO ) OH STRUCTURE In a hydroxyl group (—OH), The carbonyl group When an oxygen atom is double- a hydrogen atom is bonded to an oxygen atom, which in > ( CO) consists of a carbon atom joined to bonded to a carbon atom that is also bonded to a hydroxyl group, turn is bonded to the carbon an oxygen atom by a the entire assembly of atoms is skeleton of the organic double bond. called a carboxyl group (— molecule. (Do not confuse COOH). this functional group with the – Figure 4.10 hydroxide ion, OH.) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds Ketones if the carbonyl group is NAME OF Alcohols (their specific Carboxylic acids, or organic within a carbon skeleton COMPOUNDS names usually end in -ol) acids Aldehydes if the carbonyl group is at the end of the carbon skeleton EXAMPLE H H H O H O H C C OH H C C H C C H OH H H H C H Ethanol, the alcohol H present in alcoholic H Acetic acid, which gives vinegar beverages Acetone, the simplest ketone its sour tatste H H O H C C C H H H Figure 4.10 Propanal, an aldehyde Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds FUNCTIONAL Is polar as a result of the A ketone and an Has acidic properties because PROPERTIES electronegative oxygen atom aldehyde may be it is a source of hydrogen ions. drawing electrons toward structural isomers with The covalent bond between different properties, as oxygen and hydrogen is so polar itself. that hydrogen ions (H+) tend to is the case for acetone Attracts water molecules, and propanal. dissociate reversibly; for helping dissolve organic example, compounds such as sugars (see Figure 5.3). H O H O H C C H C C + H+ H OH H O- In cells, found in the ionic form, which is called a Figure 4.10 carboxylate group. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds AMINO SULFHYDRYL PHOSPHATE H SH O N (may be written HS ) O P OH H OH The amino group (—NH2) The sulfhydryl group In a phosphate group, a consists of a nitrogen atom consists of a sulfur atom phosphorus atom is bonded to four bonded to two hydrogen bonded to an atom of oxygen atoms; one oxygen is atoms and to the carbon hydrogen; resembles a bonded to the carbon skeleton; two skeleton. hydroxyl group in shape. oxygens carry negative charges; abbreviated P. The phosphate group (—OPO32–) is an ionized form of a phosphoric acid group (— OPO3H2; note the two hydrogens). Figure 4.10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds H H H H OH OH H O O C C N H C C SH H C C C O P O- HO H H H H H O- H H Glycine Ethanethiol Glycerol phosphate Because it also has a carboxyl group, glycine is both an amine and a carboxylic acid; compounds with both groups Figure 4.10 are called amino acids. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Some important functional groups of organic compounds Two sulfhydryl groups can Makes the molecule of which Acts as a base; can pick interact to help stabilize it is a part an anion (negatively up a proton from the protein structure (see charged ion). surrounding solution: Figure 5.20). Can transfer energy between organic molecules. H H N +N H H H (nonionized) (ionized) Ionized, with a charge of 1+, under cellular Figure 4.10 conditions. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Chemical Elements of Life: A Review The versatility of carbon – Makes possible the great diversity of organic molecules Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 5 The Structure and Function of Macromolecules PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Overview: The Molecules of Life – Another level in the hierarchy of biological organization is reached when small organic molecules are joined together Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Macromolecules – Are large molecules composed of smaller molecules – Are complex in their structures Figure 5.1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 5.1: Most macromolecules are polymers, built from monomers Three of the classes of life’s organic molecules are polymers – Carbohydrates – Proteins – Nucleic acids Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  A polymer – Is a long molecule consisting of many similar building blocks called monomers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Synthesis and Breakdown of Polymers Monomers form larger molecules by condensation reactions called dehydration reactions HO 1 2 3 H HO H Short polymer Unlinked monomer Dehydration removes a water H2O molecule, forming a new bond HO 1 2 3 4 H Longer polymer Figure 5.2A (a) Dehydration reaction in the synthesis of a polymer Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Polymers can disassemble by – Hydrolysis HO 1 2 3 4 H Hydrolysis adds a water H2O molecule, breaking a bond HO 1 2 3 H HO H Figure 5.2B (b) Hydrolysis of a polymer Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The Diversity of Polymers Each class of polymer – Is formed from a specific set of monomers 1 2 3 H HO Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Although organisms share the same limited number of monomer types, each organism is unique based on the arrangement of monomers into polymers An immense variety of polymers can be built from a small set of monomers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 5.2: Carbohydrates serve as fuel and building material Carbohydrates – Include both sugars and their polymers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Sugars Monosaccharides – Are the simplest sugars – Can be used for fuel – Can be converted into other organic molecules – Can be combined into polymers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Examples of monosaccharides Triose sugars Pentose sugars Hexose sugars (C3H6O3) (C5H10O5) (C6H12O6) H O H O H O H O C C C C H C OH H C OH H C OH H C OH Aldoses H C OH H C OH HO C H HO C H H H C OH H C OH HO C H H C OH H C OH H C OH Glyceraldehyde H H C OH H C OH Ribose H H Glucose Galactose H H H H C OH H C OH H C OH C O C O C O HO C H Ketoses H C OH H C OH H H C OH H C OH Dihydroxyacetone H C OH H C OH H H C OH Ribulose H Figure 5.3 Fructose Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Monosaccharides – May be linear – Can form rings H O 1C 6CH OH 2 6CH OH 2 2 CH2OH H C OH 5C O H 5C O 6 3 H H H H H O HO C H 5 H 4C H 1C 4C H 1C H 4 4 1 OH H OH H OH H C OH O HO 3 2 OH OH 2C OH OH H 5 C OH 3 C 3C 2C H OH 6 H OH H OH H C OH H Figure 5.4 (a) Linear and ring forms. Chemical equilibrium between the linear and ring structures greatly favors the formation of rings. To form the glucose ring, carbon 1 bonds to the oxygen attached to carbon 5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Disaccharides – Consist of two monosaccharides – Are joined by a glycosidic linkage Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Examples of disaccharides (a) Dehydration reaction in the synthesis of maltose. The bonding CH2OH CH2OH CH2OH CH2OH of two glucose units O O O O forms maltose. The H H H H H H 1–4 H H H H H 1 glycosidic 4 H glycosidic link joins OH H OH H OH H linkage OH H OHOH the number 1 carbon OH HO of one glucose to the HO HO O OH number 4 carbon of the second glucose. H OH H OH H OH H OH Joining the glucose H2O monomers in a Glucose Maltose Glucose different way would result in a different disaccharide. CH2OH CH2OH CH2OH CH2OH H O O H O H 1–2 O H H H H H 1 glycosidic 2 (b) Dehydration reaction OH H H HO OH H linkage H HO OH HO in the synthesis of HO CH2OH HO O CH2OH sucrose. Sucrose is a disaccharide formed H OH OH H H OH OH H from glucose and fructose. Notice that fructose, H2O though a hexose like Glucose Fructose Sucrose glucose, forms a five-sided ring. Figure 5.5 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Polysaccharides Polysaccharides – Are polymers of sugars – Serve many roles in organisms Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Storage Polysaccharides Starch – Is a polymer consisting entirely of glucose monomers Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  – Is the major storage form of glucose in plants Chloroplast Starch 1 µm Amylose Amylopectin Figure 5.6 (a) Starch: a plant polysaccharide Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Glycogen – Consists of glucose monomers – Is the major storage form of glucose in animals Mitochondria Giycogen granules 0.5 µm Glycogen Figure 5.6 (b) Glycogen: an animal polysaccharide Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Structural Polysaccharides Cellulose – Is a polymer of glucose Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  – Has different glycosidic linkages than starch H O CH2O C CH2O H H O H C OH H O OH H H H H 4 OH H HO C H 4 1 OH H HO OH HO H H C OH H OH C H OH H OH a glucose H C OH b glucose (a) a and b glucose ring structures CH2O CH2O CH2O CH2O H H H H O O O O 1 4 1 4 1 4 1 OH OH O OH O OH O HO O OH OH OH OH (b) Starch: 1– 4 linkage of a glucose monomers CH2O CH2O OH OH H H O O O OH O OH OH 1 4 O OH HO OH O O CH2O CH2O OH OH H H (c) Cellulose: 1– 4 linkage of b glucose monomers Figure 5.7 A–C Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  – Is a major component of the tough walls that enclose plant cells About 80 cellulose Cellulose microfibrils molecules associate in a plant cell wall Microfibril to form a microfibril, the Cell walls main architectural unit of the plant cell wall. 0.5 µm Plant cells CH2OH OH CH2OH OH O O O O OH OH OH OH O O O O O O CH OH OH CH2OH H 2 Cellulose CH2OH OH CH2OH OH molecules O O O O OH OH OH OH Parallel cellulose molecules are O O O O O O CH OH OH CH held together by hydrogen 2 2OH H bonds between hydroxyl CH2OH OH CH2OH OH O O O O groups attached to carbon OH OH O OH O O OH O atoms 3 and 6. O CH OH O A cellulose molecule OH CH2OH H 2 is an unbranched b Figure 5.8 b Glucose glucose polymer. monomer Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Cellulose is difficult to digest – Cows have microbes in their stomachs to facilitate this process Figure 5.9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Chitin, another important structural polysaccharide – Is found in the exoskeleton of arthropods – Can be used as surgical thread CH2O H H O OH H OH H OH H H NH C O CH3 (a) The structure of the (b) Chitin forms the exoskeleton (c) Chitin is used to make a chitin monomer. of arthropods. This cicada strong and flexible surgical is molting, shedding its old thread that decomposes after exoskeleton and emerging the wound or incision heals. Figure 5.10 A–C in adult form. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 5.3: Lipids are a diverse group of hydrophobic molecules Lipids – Are the one class of large biological molecules that do not consist of polymers – Share the common trait of being hydrophobic Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Fats Fats – Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids H O H H H H H H H H H H H H H H H H C OH C C C C C C C C H C C C C C C C C HO H H H H H H H H H H H H H H H H C OH Fatty acid H C OH (palmitic acid) H Glycerol (a) Dehydration reaction in the synthesis of a fat Ester linkage H O H H H H H H H H H H H H H H H H C O C C C C C C C C H C C C C C C C C H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H H H C O C C C C C C C C H C C C C C C C C H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H H H C O C C C C C C C C H C C C C C C C C H H H H H H H H H H H H H H H H Figure 5.11 (b) Fat molecule (triacylglycerol) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Fatty acids – Vary in the length and number and locations of double bonds they contain Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Saturated fatty acids – Have the maximum number of hydrogen atoms possible – Have no double bonds Stearic acid Figure 5.12 (a) Saturated fat and fatty acid Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Unsaturated fatty acids – Have one or more double bonds Oleic acid cis double bond Figure 5.12 (b) Unsaturated fat and fatty acid causes bending Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Phospholipids Phospholipids – Have only two fatty acids – Have a phosphate group instead of a third fatty acid Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Phospholipid structure – Consists of a hydrophilic “head” and hydrophobic “tails” CH2 + N(CH ) 3 3 Choline CH2 O O P O– Phosphate O CH2 CH CH2 Glycerol O O C O C O Fatty acids Hydrophilic head Hydrophobic tails (c) Phospholipid (a) Structural formula (b) Space-filling model Figure 5.13 symbol Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  The structure of phospholipids – Results in a bilayer arrangement found in cell membranes WATER Hydrophilic head WATER Hydrophobic tail Figure 5.14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Steroids Steroids – Are lipids characterized by a carbon skeleton consisting of four fused rings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  One steroid, cholesterol – Is found in cell membranes – Is a precursor for some hormones H3C CH3 CH3 CH3 CH3 Figure 5.15 HO Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Concept 5.4: Proteins have many structures, resulting in a wide range of functions – Proteins Have many roles inside the cell Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  An overview of protein functions Table 5.1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Enzymes – Are a type of protein that acts as a catalyst, speeding up chemical reactions 1 Active site is available for 2 Substrate binds to a molecule of substrate, the enzyme. Substrate reactant on which the enzyme acts. (sucrose) Glucose Enzyme OH (sucrase) H2O Fructose H O 4 Products are released. 3 Substrate is converted Figure 5.16 to products. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Polypeptides Polypeptides – Are polymers of amino acids A protein – Consists of one or more polypeptides Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  Amino Acid Monomers Amino acids – Are organic molecules possessing both carboxyl and amino groups – Differ in their properties due to differing side chains, called R groups Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  20 different amino acids make up proteins CH3 CH3 CH3 CH3 CH3 CH CH2 H CH3 CH3 CH2 H3 C CH O O O O O H3 N+ C C H3 N+ C C H3 N+ C C H3 N+ C C H3 N+ C C O– O– O– O– O– H H H H H Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Nonpolar CH3 CH2 S H2 C CH2 NH O CH2 H2 N C C CH2 O CH2 CH2 O– O O H H3 N+ C C H3 N+ C C H3 N+ C C O– O– O– H H H Methionine (Met) Phenylalanine (Phe) Tryptophan (Trp) Proline (Pro) Figure 5.17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings  OH NH2 O NH2 O C