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IB Higher Level Biology Image Review Fig. 3-UN3 – Hydrogen bond + H + – O – + H + – Fig. 4-UN5 Reacts with H2O P P P Adenosine ATP Pi P Inorganic phosphate P Adenosine ADP Energy Fig. 5-2 HO 1 2 3 H Short polymer HO Unlinked monomer Dehydration removes a water molecule, forming a new bond HO 2 1 H 3 H2O 4 H Longer polymer (a) Dehydration reaction in the synthesis of a polymer HO 1 2 3 4 Hydrolysis adds a water molecule, breaking a bond HO 1 2 3 (b) Hydrolysis of a polymer H H H2O HO H Fig. 5-21f Hydrophobic interactions and van der Waals interactions Polypeptide backbone Hydrogen bond Disulfide bridge Ionic bond 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 Microvilli Golgi apparatus Peroxisome Mitochondrion Lysosome Fig. 6-9b NUCLEUS Nuclear envelope Nucleolus Chromatin Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments Microtubules Mitochondrion Peroxisome Chloroplast Plasma membrane Cell wall Plasmodesmata Wall of adjacent cell CYTOSKELETON Fig. 7-7 Fibers of extracellular matrix (ECM) Glycoprotein Carbohydrate Glycolipid EXTRACELLULAR SIDE OF MEMBRANE Cholesterol Microfilaments of cytoskeleton Peripheral proteins Integral protein CYTOPLASMIC SIDE OF MEMBRANE Fig. 8-15 Course of reaction without enzyme EA without enzyme EA with enzyme is lower Reactants Course of reaction with enzyme ∆G is unaffected by enzyme Products Progress of the reaction Fig. 8-17 1 Substrates enter active site; enzyme changes shape such that its active site enfolds the substrates (induced fit). 2 Substrates held in active site by weak interactions, such as hydrogen bonds and ionic bonds. Substrates Enzyme-substrate complex 6 Active site is available for two new substrate molecules. Enzyme 5 Products are released. 4 Substrates are converted to products. Products 3 Active site can lower EA and speed up a reaction. Fig. 9-17 Electron shuttles span membrane CYTOSOL 2 NADH Glycolysis Glucose 2 Pyruvate MITOCHONDRION 2 NADH or 2 FADH2 6 NADH 2 NADH 2 Acetyl CoA + 2 ATP Citric acid cycle + 2 ATP Maximum per glucose: About 36 or 38 ATP 2 FADH2 Oxidative phosphorylation: electron transport and chemiosmosis + about 32 or 34 ATP Fig. 9-16 H+ H+ H+ H+ Protein complex of electron carriers Cyt c V Q ATP synthase FADH2 NADH 2 H+ + 1/2O2 H2O FAD NAD+ ADP + P i (carrying electrons from food) ATP H+ 1 Electron transport chain Oxidative phosphorylation 2 Chemiosmosis Fig. 10-21 H2O CO2 Light NADP+ ADP + P i Light Reactions: Photosystem II Electron transport chain Photosystem I Electron transport chain RuBP ATP NADPH 3-Phosphoglycerate Calvin Cycle G3P Starch (storage) Chloroplast O2 Sucrose (export) Fig. 11-8-5 Hormone (testosterone) EXTRACELLULAR FLUID Plasma membrane Receptor protein Hormonereceptor complex DNA mRNA NUCLEUS CYTOPLASM New protein Fig. 12-6 G2 of Interphase Centrosomes Chromatin (with centriole (duplicated) pairs) Prophase Early mitotic Aster Centromere spindle Nucleolus Nuclear Plasma envelope membrane Chromosome, consisting of two sister chromatids Metaphase Prometaphase Fragments Nonkinetochore of nuclear microtubules envelope Kinetochore Kinetochore microtubule Anaphase Cleavage furrow Metaphase plate Spindle Centrosome at one spindle pole Telophase and Cytokinesis Daughter chromosomes Nuclear envelope forming Nucleolus forming Fig. 13-8 Metaphase I Prophase I Centrosome (with centriole pair) Sister chromatids Chiasmata Spindle Prophase II Metaphase II Anaphase II Telophase II and Cytokinesis Sister chromatids remain attached Centromere (with kinetochore) Metaphase plate Homologous chromosomes separate Homologous chromosomes Fragments of nuclear envelope Telophase I and Cytokinesis Anaphase I Microtubule attached to kinetochore Cleavage furrow Sister chromatids separate Haploid daughter cells forming Fig. 13-9 MITOSIS MEIOSIS Parent cell Chromosome replication Prophase Chiasma Chromosome replication Prophase I Homologous chromosome pair 2n = 6 Replicated chromosome MEIOSIS I Metaphase Metaphase I Anaphase Telophase Anaphase I Telophase I Haploid n=3 Daughter cells of meiosis I 2n MEIOSIS II 2n Daughter cells of mitosis n n n n Daughter cells of meiosis II SUMMARY Property Mitosis Meiosis DNA replication Occurs during interphase before mitosis begins Occurs during interphase before meiosis I begins Number of divisions One, including prophase, metaphase, anahase, and telophase Two, each including prophase, metaphase, anaphase, and telophase Synapsis of homologous chromosomes Does not occur Occurs during prophase I along with crossing over between nonsister chromatids; resulting chiasmata hold pairs together due to sister chromatid cohesion Number of daughter cells and genetic composition Two, each diploid (2n) and genetically identical to the parent cell Four, each haploid (n), containing half as many chromosomes as the parent cell; genetically different from the parent cell and from each other Role in the animal body Enables multicellular adult to arise from zygote; produces cells for growth, repair, and, in some species, asexual reproduction Produces gametes; reduces number of chromosomes by half and introduces genetic variability amoung the gametes Fig. 14-8a EXPERIMENT YYRR P Generation Gametes YR yyrr F1 Generation YyRr Hypothesis of independent assortment Hypothesis of dependent assortment Predictions Predicted offspring of F2 generation yr Sperm or 1/ 4 Sperm 1/ 1/ 2 YR 2 yr 1/ 4 1/ 2 1/ 4 1/ 4 Yr yR 1/ 4 yr YR YYRR YYRr YyRR YyRr YYRr YYrr YyRr Yyrr YyRR YyRr yyRR yyRr YyRr Yyrr yyRr yyrr YR YYRR Eggs 1/ 2 YR YyRr 1/ 4 Yr Eggs yr yyrr YyRr 3/ 4 1/ 4 yR 1/ 4 Phenotypic ratio 3:1 1/ 4 yr 9/ 16 3/ 16 3/ 16 1/ 16 Phenotypic ratio 9:3:3:1 Fig. 14-UN2 Degree of dominance Complete dominance of one allele Example Description Heterozygous phenotype PP same as that of homozygous dominant Pp Incomplete dominance Heterozygous phenotype intermediate between of either allele the two homozygous phenotypes CRCR Codominance Heterozygotes: Both phenotypes expressed CRCW CWCW IAIB Multiple alleles In the whole population, ABO blood group alleles some genes have more IA , IB , i than two alleles Pleiotropy One gene is able to affect multiple phenotypic characters Sickle-cell disease Fig. 14-UN3 Relationship among genes Epistasis Example Description One gene affects the expression of another BbCc BbCc BC bC Bc bc BC bC Bc bc 9 Polygenic inheritance A single phenotypic AaBbCc character is affected by two or more genes :3 :4 AaBbCc Fig. 15-2b All F1 plants produce yellow-round seeds (YyRr) 0.5 mm F1 Generation R R y r Y LAW OF SEGREGATION The two alleles for each gene separate during gamete formation. y r Y LAW OF INDEPENDENT ASSORTMENT Alleles of genes on nonhomologous chromosomes assort independently during gamete formation. Meiosis r R Y y r R Metaphase I Y y 1 1 r R r R Y y Anaphase I Y y r R Metaphase II R r 2 2 Gametes y Y Y R R 1 4 YR r 1 3 4 yr Y Y y r y Y y Y r r 14 Yr y y R R 14 yR 3 Fig. 15-13-3 Meiosis I Nondisjunction Meiosis II Nondisjunction Gametes n+1 n+1 n–1 n–1 n+1 n–1 n Number of chromosomes (a) Nondisjunction of homologous chromosomes in meiosis I (b) Nondisjunction of sister chromatids in meiosis II n Fig. 15-16b Fig. 15-11 RESULTS Recombination frequencies 9% Chromosome 9.5% 17% b cn vg Fig. 16-7 5 end Hydrogen bond 3 end 1 nm 3.4 nm 3 end 0.34 nm (a) Key features of DNA structure (b) Partial chemical structure 5 end (c) Space-filling model Fig. 16-17 Overview Origin of replication Lagging strand Leading strand Leading strand Lagging strand Overall directions of replication Single-strand binding protein Helicase 5 Leading strand 3 DNA pol III 3 Parental DNA Primer 5 Primase 3 DNA pol III Lagging strand 5 4 DNA pol I 3 5 3 2 DNA ligase 1 3 5 Fig. 16-UN3 DNA pol III synthesizes leading strand continuously Parental DNA 3 5 DNA pol III starts DNA synthesis at 3 end of primer, continues in 5 3 direction 5 3 5 Primase synthesizes a short RNA primer Lagging strand synthesized in short Okazaki fragments, later joined by DNA ligase 3 5 Fig. 17-3b-3 Nuclear envelope DNA TRANSCRIPTION Pre-mRNA RNA PROCESSING mRNA TRANSLATION Ribosome Polypeptide (b) Eukaryotic cell Fig. 17-7 Promoter Transcription unit 5 3 Start point RNA polymerase 3 5 DNA 1 Initiation 5 3 RNA transcript RNA polymerase Template strand of DNA 3 2 Elongation Rewound DNA 5 3 RNA nucleotides 3 5 Unwound DNA 3 5 5 5 Direction of transcription (“downstream”) 3 Termination 3 5 5 3 5 3 end 5 3 RNA transcript Nontemplate strand of DNA Elongation Completed RNA transcript 3 Newly made RNA Template strand of DNA Fig. 17-16b P site (Peptidyl-tRNA binding site) E site (Exit site) A site (AminoacyltRNA binding site) E P A mRNA binding site Large subunit Small subunit (b) Schematic model showing binding sites Growing polypeptide Amino end Next amino acid to be added to polypeptide chain E tRNA 3 mRNA 5 Codons (c) Schematic model with mRNA and tRNA Fig. 18-6 Signal NUCLEUS Chromatin Chromatin modification DNA Gene available for transcription Gene Transcription RNA Exon Primary transcript Intron RNA processing Tail Cap mRNA in nucleus Transport to cytoplasm CYTOPLASM mRNA in cytoplasm Degradation of mRNA Translatio n Polypeptide Protein processing Active protein Degradation of protein Transport to cellular destination Cellular function Fig. 18-UN4 Chromatin modification • Genes in highly compacted chromatin are generally not transcribed. • Histone acetylation seems to loosen chromatin structure, enhancing transcription. • DNA methylation generally reduces transcription. Transcription • Regulation of transcription initiation: DNA control elements bind specific transcription factors. Bending of the DNA enables activators to contact proteins at the promoter, initiating transcription. • Coordinate regulation: Enhancer for liver-specific genes Enhancer for lens-specific genes Chromatin modification Transcription RNA processing RNA processing • Alternative RNA splicing: Primary RNA transcript mRNA degradation Translation mRNA or Protein processing and degradation Translation • Initiation of translation can be controlled via regulation of initiation factors. mRNA degradation • Each mRNA has a characteristic life span, determined in part by sequences in the 5 and 3 UTRs. Protein processing and degradation • Protein processing and degradation by proteasomes are subject to regulation. Fig. 19-8a Glycoprotein Viral envelope Capsid Reverse transcriptase RNA (two identical strands) HOST CELL HIV Reverse transcriptase Viral RNA RNA-DNA hybrid DNA NUCLEUS Provirus Chromosomal DNA RNA genome for the next viral generation New virus mRNA Fig. 20-2 Cell containing gene of interest Bacterium 1 Gene inserted into plasmid Bacterial Plasmid chromosome Recombinant DNA (plasmid) Gene of interest DNA of chromosome 2 Plasmid put into bacterial cell Recombinant bacterium 3 Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest Gene of Interest Protein expressed by gene of interest Copies of gene Basic Protein harvested 4 Basic research and various applications research on gene Gene for pest resistance inserted into plants Gene used to alter bacteria for cleaning up toxic waste Protein dissolves blood clots in heart attack therapy Basic research on protein Human growth hormone treats stunted growth Fig. 20-20 Embryonic stem cells Adult stem cells Early human embryo at blastocyst stage (mammalian equivalent of blastula) From bone marrow in this example Cells generating all embryonic cell types Cells generating some cell types Cultured stem cells Different culture conditions Different types of differentiated cells Liver cells Nerve cells Blood cells Fig. 22-UN1 Observations Individuals in a population vary in their heritable characteristics. Organisms produce more offspring than the environment can support. Inferences Individuals that are well suited to their environment tend to leave more offspring than other individuals and Over time, favorable traits accumulate in the population. Fig. 23-13 Original population Original Evolved population population (a) Directional selection Phenotypes (fur color) (b) Disruptive selection (c) Stabilizing selection Fig. 24-14-4 Isolated population diverges Possible outcomes: Hybrid zone Reinforcement OR Fusion Gene flow Hybrid Population (five individuals are shown) OR Barrier to gene flow Stability Table 40-1 Fig. 40-17 External environment Animal body Organic molecules in food Digestion and absorption Heat Energy lost in feces Nutrient molecules in body cells Carbon skeletons Cellular respiration Energy lost in nitrogenous waste Heat ATP Biosynthesis Cellular work Heat Heat Fig. 41-10 Tongue Sphincter Salivary glands Oral cavity Salivary glands Mouth Pharynx Esophagus Esophagus Sphincter Liver Stomach Ascending portion of large intestine Gallbladder Gallbladder Duodenum of small intestine Pancreas Liver Small intestine Small intestine Large intestine Rectum Anus Appendix Cecum Pancreas Stomach Small intestine Large intestine Rectum Anus A schematic diagram of the human digestive system Fig. 41-13 Carbohydrate digestion Oral cavity, pharynx, esophagus Protein digestion Nucleic acid digestion Fat digestion Polysaccharides Disaccharides (starch, glycogen) (sucrose, lactose) Salivary amylase Smaller polysaccharides, maltose Stomach Proteins Pepsin Small polypeptides Lumen of small intestine Polysaccharides Pancreatic amylases Polypeptides Pancreatic trypsin and chymotrypsin DNA, RNA Fat globules Pancreatic nucleases Bile salts Maltose and other disaccharides Nucleotides Fat droplets Smaller polypeptides Pancreatic lipase Pancreatic carboxypeptidase Glycerol, fatty acids, monoglycerides Amino acids Epithelium of small intestine (brush border) Small peptides Disaccharidases Monosaccharides Nucleotidases Nucleosides Dipeptidases, carboxypeptidase, and aminopeptidase Amino acids Nucleosidases and phosphatases Nitrogenous bases, sugars, phosphates Fig. 42-UN2 Inhaled air Alveolar epithelial cells Pulmonary arteries Exhaled air Alveolar spaces CO2 O2 Alveolar capillaries of lung Systemic veins Pulmonary veins Systemic arteries Heart Systemic capillaries CO2 O2 Body tissue Fig. 42-6 Superior vena cava Capillaries of head and forelimbs 7 Pulmonary artery Pulmonary artery Capillaries of right lung Aorta 9 3 Capillaries of left lung 3 2 4 11 Pulmonary vein Right atrium 1 Pulmonary vein 5 Left atrium 10 Right ventricle Left ventricle Inferior vena cava Aorta 8 Capillaries of abdominal organs and hind limbs Fig. 42-7 Pulmonary artery Aorta Pulmonary artery Right atrium Left atrium Semilunar valve Semilunar valve Atrioventricular valve Atrioventricular valve Right ventricle Left ventricle Fig. 42-24 Branch of pulmonary vein (oxygen-rich blood) Branch of pulmonary artery (oxygen-poor blood) Terminal bronchiole Nasal cavity Pharynx Larynx Alveoli (Esophagus) Left lung Trachea Right lung Bronchus Bronchiole Diaphragm Heart SEM 50 µm Colorized SEM 50 µm Fig. 42-25 Rib cage expands as rib muscles contract Air inhaled Rib cage gets smaller as rib muscles relax Air exhaled Lung Diaphragm INHALATION Diaphragm contracts (moves down) EXHALATION Diaphragm relaxes (moves up) Fig. 42-27 Cerebrospinal fluid Pons Breathing control centers Medulla oblongata Carotid arteries Aorta Diaphragm Rib muscles Fig. 43-2 Pathogens (microorganisms and viruses) INNATE IMMUNITY • Recognition of traits shared by broad ranges of pathogens, using a small set of receptors • Rapid response ACQUIRED IMMUNITY • Recognition of traits specific to particular pathogens, using a vast array of receptors • Slower response Barrier defenses: Skin Mucous membranes Secretions Internal defenses: Phagocytic cells Antimicrobial proteins Inflammatory response Natural killer cells Humoral response: Antibodies defend against infection in body fluids. Cell-mediated response: Cytotoxic lymphocytes defend against infection in body cells. Fig. 43-8-3 Pathogen Splinter Chemical Macrophage signals Mast cell Capillary Red blood cells Phagocytic cell Fluid Phagocytosis Fig. 43-15 Antibody concentration (arbitrary units) Primary immune response to antigen A produces antibodies to A. Secondary immune response to antigen A produces antibodies to A; primary immune response to antigen B produces antibodies to B. 104 103 Antibodies to A 102 Antibodies to B 101 100 0 7 Exposure to antigen A 14 21 28 35 42 Exposure to antigens A and B Time (days) 49 56 Fig. 43-16 Humoral (antibody-mediated) immune response Cell-mediated immune response Key Antigen (1st exposure) + Engulfed by Gives rise to Antigenpresenting cell + Stimulates + + B cell Helper T cell + Cytotoxic T cell + Memory Helper T cells + + + Antigen (2nd exposure) Plasma cells Memory B cells + Memory Cytotoxic T cells Active Cytotoxic T cells Secreted antibodies Defend against extracellular pathogens by binding to antigens, thereby neutralizing pathogens or making them better targets for phagocytes and complement proteins. Defend against intracellular pathogens and cancer by binding to and lysing the infected cells or cancer cells. Fig. 44-14c Juxtamedullary nephron Cortical nephron Renal cortex Collecting duct To renal pelvis (c) Nephron types Renal medulla Fig. 44-14d 10 µm Afferent arteriole from renal artery SEM Glomerulus Bowman’s capsule Proximal tubule Peritubular capillaries Efferent arteriole from glomerulus Distal tubule Branch of renal vein Collecting duct Descending limb Loop of Henle (d) Filtrate and blood flow Ascending limb Vasa recta Fig. 40-16 Sweat glands secrete sweat, which evaporates, cooling the body. Body temperature decreases; thermostat shuts off cooling mechanisms. Thermostat in hypothalamus activates cooling mechanisms. Blood vessels in skin dilate: capillaries fill; heat radiates from skin. Increased body temperature Homeostasis: Internal temperature of 36–38°C Body temperature increases; thermostat shuts off warming mechanisms. Decreased body temperature Blood vessels in skin constrict, reducing heat loss. Skeletal muscles contract; shivering generates heat. Thermostat in hypothalamus activates warming mechanisms. Fig. 46-10 Oviduct Ovary Uterus (Urinary bladder) (Pubic bone) (Rectum) Cervix Urethra Shaft Glans Prepuce Vagina Labia minora Labia majora Vaginal opening Ovaries Clitoris Oviduct Follicles Uterus Corpus luteum Uterine wall Endometrium Cervix Vagina Fig. 46-11 Seminal vesicle (behind bladder) (Urinary bladder) Prostate gland Urethra Scrotum Bulbourethral gland Erectile tissue of penis Vas deferens Epididymis Testis (Urinary bladder) (Urinary duct) Seminal vesicle (Rectum) Vas deferens (Pubic bone) Ejaculatory duct Erectile tissue Prostate gland Urethra Penis Bulbourethral gland Vas deferens Epididymis Testis Scrotum Glans Prepuce Fig. 46-12a Epididymis Seminiferous tubule Testis Cross section of seminiferous tubule Primordial germ cell in embryo Mitotic divisions Sertoli cell nucleus Spermatogonial stem cell 2n Mitotic divisions Spermatogonium 2n Mitotic divisions Primary spermatocyte 2n Meiosis I Lumen of seminiferous tubule Secondary spermatocyte n n Meiosis II Neck Tail Midpiece Head Spermatids (at two stages of differentiation) Early spermatid n n n n n n Differentiation (Sertoli cells provide nutrients) Plasma membrane Mitochondria Sperm Nucleus Acrosome n n Fig. 46-12e Ovary Primary oocyte within follicle In embryo Growing follicle Primordial germ cell Mitotic divisions 2n Oogonium Mitotic divisions Primary oocyte (present at birth), arrested in prophase of meiosis I 2n Completion of meiosis I and onset of meiosis II First polar n body n Secondary oocyte, arrested at metaphase of meiosis II Mature follicle Ruptured follicle Ovulated secondary oocyte Ovulation, sperm entry Completion of meiosis II Second polar n body Corpus luteum n Fertilized egg Degenerating corpus luteum Fig. 46-16 Maternal arteries Maternal veins Placenta Maternal portion of placenta Umbilical cord Chorionic villus, containing fetal capillaries Maternal blood pools Uterus Fetal arteriole Fetal venule Umbilical cord Fetal portion of placenta (chorion) Umbilical arteries Umbilical vein Fig. 46-18 from ovaries Oxytocin + from fetus and mother’s posterior pituitary Positive feedback Estradiol Induces oxytocin receptors on uterus Stimulates uterus to contract Stimulates placenta to make Prostaglandins Stimulate more contractions of uterus + Fig. 48-3 Sensory input Integration Sensor Motor output Effector Peripheral nervous system (PNS) Central nervous system (CNS) Fig. 48-10-5 Key Na+ K+ 3 4 Rising phase of the action potential Falling phase of the action potential Membrane potential (mV) +50 Action potential –50 2 2 4 Threshold 1 1 5 Resting potential Depolarization Extracellular fluid 3 0 –100 Sodium channel Time Potassium channel Plasma membrane Cytosol Inactivation loop 5 1 Resting state Undershoot Fig. 48-15 5 Synaptic vesicles containing neurotransmitter Voltage-gated Ca2+ channel Postsynaptic membrane 1 Ca2+ 4 2 Synaptic cleft Presynaptic membrane 3 Ligand-gated ion channels 6 K+ Na+ Fig. 49-3 Quadriceps muscle Cell body of sensory neuron in dorsal root ganglion Gray matter White matter Hamstring muscle Spinal cord (cross section) Sensory neuron Motor neuron Interneuron Fig. 50-27-4 Thick filament Thin filaments Thin filament Myosin head (lowenergy configuration ATP ATP Thick filament Thin filament moves toward center of sarcomere. Actin ADP Myosin head (lowenergy configuration ADP + Pi Pi ADP Pi Cross-bridge Myosin binding sites Myosin head (highenergy configuration Fig. 55-4 Tertiary consumers Microorganisms and other detritivores Detritus Secondary consumers Primary consumers Primary producers Heat Key Chemical cycling Energy flow Sun Fig. 55-10 Tertiary consumers Secondary consumers 10 J 100 J Primary consumers 1,000 J Primary producers 10,000 J 1,000,000 J of sunlight Fig. 55-14a Transport over land Solar energy Net movement of water vapor by wind Precipitation Evaporation over ocean from ocean Precipitation over land Evapotranspiration from land Percolation through soil Runoff and groundwater Fig. 55-14b CO2 in atmosphere Photosynthesis Photosynthesis Cellular respiration Burning of fossil fuels Phytoand wood plankton Higher-level consumers Primary consumers Carbon compounds in water Detritus Decomposition Fig. 55-14c N2 in atmosphere Assimilation NO3– Nitrogen-fixing bacteria Decomposers Ammonification NH3 Nitrogen-fixing soil bacteria Nitrification NH4+ NO2– Nitrifying bacteria Denitrifying bacteria Nitrifying bacteria Fig. 55-14d Precipitation Geologic uplift Weathering of rocks Runoff Consumption Decomposition Plant uptake of PO43– Plankton Dissolved PO43– Uptake Sedimentation Soil Leaching Fig. 55-UN2 Organic materials available as nutrients Organic materials unavailable as nutrients Fossilization Living organisms, detritus Assimilation, photosynthesis Coal, oil, peat Respiration, decomposition, excretion Inorganic materials available as nutrients Atmosphere, soil, water Burning of fossil fuels Weathering, erosion Formation of sedimentary rock Inorganic materials unavailable as nutrients Minerals in rocks Fig. 56-UN1 Genetic diversity: source of variations that enable populations to adapt to environmental changes Species diversity: important in maintaining structure of communities and food webs Ecosystem diversity: Provide life-sustaining services such as nutrient cycling and waste decomposition Fig. 35-2 Reproductive shoot (flower) Apical bud Node Internode Apical bud Vegetative shoot Leaf Shoot system Blade Petiole Axillary bud Stem Taproot Lateral branch roots Root system Fig. 35-14a2 (a) Root with xylem and phloem in the center (typical of eudicots) Endodermis Key to labels Pericycle Dermal Ground Vascular Xylem Phloem 50 µm Fig. 36-2-3 CO2 O2 Light H 2O Sugar O2 H2O and minerals CO2 Fig. 36-20 Vessel (xylem) Sieve tube Source cell (phloem) (leaf) H2O 1 Loading of sugar Sucrose 1 H2O Bulk flow by negative pressure Bulk flow by positive pressure 2 2 Uptake of water 3 Unloading of sugar Sink cell (storage root) 4 Water recycled 3 4 H2O Sucrose Fig. 38-2 Germinated pollen grain (n) (male gametophyte) Anther Stamen Anther Stigma Carpel Style Filament Ovary Pollen tube Ovary Ovule Embryo sac (n) (female gametophyte) FERTILIZATION Sepal Petal Egg (n) Sperm (n) Receptacle (a) Structure of an idealized flower Key Zygote (2n) Mature sporophyte plant (2n) Haploid (n) Diploid (2n) Seed Germinating seed Seed Embryo (2n) (sporophyte) (b) Simplified angiosperm life cycle Simple fruit Fig. 38-2b Germinated pollen grain (n) (male gametophyte) Anther Ovary Pollen tube Ovule Embryo sac (n) (female gametophyte) FERTILIZATION Egg (n) Sperm (n) Key Zygote (2n) Mature sporophyte plant (2n) Haploid (n) Diploid (2n) Germinating seed Seed Seed Embryo (2n) (sporophyte) (b) Simplified angiosperm life cycle Simple fruit Fig. 39-3 CELL WALL 1 Reception CYTOPLASM 2 Transduction Relay proteins and second messengers Receptor Hormone or environmental stimulus Plasma membrane 3 Response Activation of cellular responses Fig. 39-4-3 1 Reception 2 Transduction 3 Response Transcription factor 1 CYTOPLASM Plasma membrane cGMP Second messenger produced Specific protein kinase 1 activated NUCLEUS P Transcription factor 2 Phytochrome activated by light P Cell wall Specific protein kinase 2 activated Transcription Light Translation Ca2+ channel opened Ca2+ De-etiolation (greening) response proteins Table 39-1 Fig. 39-11 1 Gibberellins (GA) 2 Aleurone secretes send signal to aleurone. -amylase and other enzymes. 3 Sugars and other nutrients are consumed. Aleurone Endosperm -amylase GA GA Water Scutellum (cotyledon) Radicle Sugar