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CHAPTER 1, Law of segregation, Homologous Chromosomes, Mutations can…

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        CHAPTER 6
        
        CHAPTER 7
        
        CHAPTER 8
        
        CHAPTER 9
        
        CHAPTER 10
        
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        Mendel's laws
        
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        Variations on Mendel's Laws
        
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        The chromosomal basis of inheritance
        
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        Sex chromosomes and sex linked genes
        
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        Cell division and reproduction
        
        cell division plays many important roles in the lives of organisms: cell division is at the heart of the reproduction of cells and organisms because cells originate only from preexisting cells.some organisms reproduce through asexual reproduction, and in such instances their offspring are all genetic copies of the parent and identical to each other (clones). other organisms reproduce through sexual reproduction, creating a variety of offspring
        
        prokaryotes reproduce by binary fission: prokaryotic cells reproduce asexually by cell division. as the cell replicates its single chromosome, the copies move apart; the growing membrane then divides the cell
        
        The Eukaryotic cell cycle and mitosis
        
        the large, complex chromosomes of eukaryotes duplicate with each cell division: a eukaryotic cells has many more genes than a prokaryotic cell, and they are grouped into multiple chromosomes in the nucleus. each chromosomes contains one long DNA molecule. individual chromosomes are visible under a light microscope only when the cell is in the process of dividing; otherwise, chromosomes are thin, loosely packed chromatin fibers too small to be seen. before a cell starts dividing, the chromosomes duplicate, producing sister chromatids (containing identical DNA) that are joined together along their lengths. cell division involved the separation of sister chromatids and results in two daughter cells, each containing a complete and identical set of chromosomes
        
        the cell includes growth and division phases
        
        cell division is a continuum of dynamic changes: mitosis distributes duplicated chromosomes into two daughter nuclei. after the chromosomes are coiled up, a mitotic spindle made of microtubules moves the chromosomes to he middle of the cell. the sister chromatids then separate and move to opposite poles of the cell, at which point two new nuclei form
        
        cytokinesis differs for plant and animal cells: cytokinesis, in which the cell divides in two, overlaps the end of mitosis. in animals, cytokinesis occurs when a cell constricts, forming a cleavage furrow. in plants, a membranous cell plate forms and then splits the cell in two
        
        the rate of a cell division is affected by environmental factors: in laboratory cultures, most normal cells divide only when attached to a surface. the cultured cells continue dividing until the can touch one another. most animal cells divide only when stimulated by growth factors, and some do not divide at all. growth factors stimulate cells to divide.
        
        growth factors signal the cell cycle control system: a set of proteins within the cell controls the cell cycle. signals affecting critical checkpoints in the cell cycle determine whether a cell will go through the complete cycle and divide. the binding growth factors to specific receptors on the plasma membrane is usually necessary for cell division
        
        growing out of control, cancer cells produce malignant tumors: cancer cells divide excessively to form masses called tumors. malignant tumors can invade other tissues. radiation and chemotherapy are effective as cancer treatments because they interfere with cell division
        
        the best cancer treatment may vary by individual: mortality rates from cancer vary by age of diagnosis, race, and other factors. taking such data into account may improve outcomes of cancer treatment
        
        Meiosis and crossing over
        
        chromosomes are matched in homologous pairs: the somatic (body) cells of each species contain a specific number of chromosomes; for example, human cells have 46, consisting of 23 pairs of homologous chromosomes. the chromosomes of a homologous pair of autosomes carry genes for the same characteristics at the same place, or locus
        
        gametes have a single set of chromosomes: cells with two sets of homologous chromosomes are diploid. gametes-- eggs and sperm-- are haploid cells with a single set of chromosomes. sexual life cycles involve the alteration of haploid stages
        
        meiosis reduces the chromosome number from diploid to haploid: meiosis, like mitosis, is preceded by chromosome duplication, but in meiosis, the cell divides twice to form four daughter cells. the first division, meiosis I, starts with the pairing of homologous chromosomes. in crossing over, homologous chromosomes exchange corresponding segments. meiosis I separates the members of each homologous pair and produces two daughter cells, each with one set of chromosomes. meiosis II is essentially the same as mitosis: in each of the cells, the sister chromatids of each chromosome separate. the result is a total of four haploid cells
        
        mitosis and meiosis have important similarities and differences: both mitosis and meiosis begin with diploid parent cells that have chromosomes duplicated during the previous interphase. mitosis produces two genetically identical diploid somatic daughter cells, whereas meiosis produces four genetically unique haploid gametes
        
        independent orientation of chromosomes in meiosis and random fertilization lead to varied offspring: each chromosome of a homologous pair differs at many points from the other member of the pair. random arrangements of chromosome pairs at metaphase I of meiosis lead to many different combinations of chromosomes in eggs and sperm. random fertilization of eggs by sperm greatly increases this variation
        
        homologous chromosomes may carry different versions of genes: the differences between homologous chromosomes come from the fact that they can bear different versions of genes at corresponding loci
        
        crossing over further increases genetic variability: genetic recombination, which results from crossing over during prophase I of meiosis, increases variation still further
        
        Alterations of chromosome number and structure
        
        accidents during meiosis can alter chromosome number: an abnormal chromosome count is the result of nondisjunction, which can result from the failure of a pair of homologous chromosomes to separate during meiosis I or from the failure of sister chromatids to separate during meiosis II
        
        a karyotype is a photographic inventory of an individual's chromosomes: to prepare a karyotype, white blood cells are isolated, stimulated to grow, arrest at metaphase, and photographed under a microscope. the chromosomes are arranged into ordered pairs so that any chromosomal abnormalities can be detected
        
        an extra copy of chromosome 21 causes Down Syndrome: trisomy 21, the most common chromosome number abnormality, results in a condition called Down Syndrome
        
        abnormal numbers of sex chromosomes do not usually affect survival: nondisjunction of the sex chromosomes during meiosis can result in individuals with a missing or extra X or Y chromosome. In cases (such as XXY), leads to syndromes that can affect the health of the individual; in other cases (such as XXX), the body is normal
        
        new species can arise from errors in cell division: nondisjunction can produce polyploid organisms, organisms with extra sets of chromosomes. such errors in cell division can be important in the evolution of new species
        
        alterations of chromosome structure can cause birth defects and cancer: chromosomes breakage can lead to rearrangements--deletions, duplications, inversions, and translocation--that can produce genetic disorders or, if the changes occur in the somatic cells, cancer
        
        An introduction to photosynthesis
        
        photosynthesis fuels the biosphere: plants, algae, and some photosynthetic protists and bacteria are autotrophs, the producers of food consumed by virtually all heterotrophic organisms
        
        photosynthesis occurs in chloroplasts in plant cells: chloroplasts are surrounded by a double membrane and contain stacks of thylakoids and a thick fluid called stroma
        
        scientists traced the process of photosynthesis using isotopes:experiments using both heavy and radioactive isotopes helped determine the details of the process of photosynthesis
        
        photosynthesis is a redox process, as is cellular respiration: in photosynthesis H2O is oxidized and CO2 is reduced
        
        photosynthesis occurs in two stages, which are linked by ATP and NADPH: the light reactions occur in the thylakoids, producing ATP and NADPH for the Calvin Cycle, which takes place in the stroma
        
        The light reactions: converting solar energy to chemical energy
        
        visible radiation absorbed by pigments drives the light reactions: certain wavelengths of visible light are absorbed by chlorophyll and other pigments. carotenoids also function in photo-protection form excessive light
        
        photosystems capture solar energy: thylakoid membranes contain photosystems, each consisting of light-harvesting complexes and a reaction-center complex. a primary electron acceptor receives photo-excited electrons from reaction-center chlorophyll
        
        two photosystems connected by an electron transport chain convert light energy to the chemical energy of ATP and NADPH: electrons shuttle from photosystem II to photosystem I, providing energy to make ATP, and then reduce NADP+ to NADPH. photosystem II regains electrons as water is split and O2 released
        
        the light reactions take place within the thylakoid membranes: in photophosphorylation, the electron transport chain pumps H+ into the thylakoid space. the concentration gradient drives H+ back through ATP synthase, powering the synthesis of ATP
        
        The Calvin Cycle: Reducing CO2 to Sugar
        
        ATP and NADPH power sugar synthesis in the Calvin cycle: the steps of the Calvin cycle include carbon fixation, reduction, release of G3P, and regeneration of RuBP. using carbon from CO2, electrons from NADPH, and energy from ATP, the cycle constructs G3P, which is used to build glucose and other organic molecules
        
        other methods of carbon fixation have evolved in hot, dry climates: in C3 plants, a drop in CO2 and rise in O2 when stomata close divert the calving cycle to photorespiration. C4 plants to CAM plants first fix CO2 into four-carbon compounds that provide CO2 to the Calvin cycle even when stomata close on hot, dry days
        
        The global significance of photosynthesis
        
        photosynthesis provides food and O2 for almost all living organisms
        
        rising atmospheric levels of carbon dioxide may affect plants in various ways: scientists study the effects of rising CO2 levels using laboratory growth chambers and field studies. long-term field projects enable scientists to asses the effects of CO2 levels on natural ecosystems
        
        reducing both fossil fuel use and deforestation may moderate climate change: CO2 and other gases in the atmosphere create the greenhouse effect. an international agreement reached at the Paris climate conference of 2015 seeks to reduce greenhouse gas emissions and limit global warming
        
        Cellular respiration: Aerobic harvesting of energy
        
        photosynthesis and cellular respiration provide energy for life: photosynthesis uses solar energy to produce organic molecules and O2 from CO2 and H2O. in cellular respiration, O2 is consumed during the breakdown of organic molecules to CO2 and H2O, and energy is released
        
        breathing supplies O2 for use in cellular respiration and removes CO2
        
        cellular respiration banks energy in ATP molecules
        
        the human body uses energy from ATP for all its activities
        
        cells capture energy from electrons "falling" from organic fuels to oxygen: electrons removed from fuel molecules (oxidation) are transferred to NAD+ (reduction). NADH passes electrons to an electron transport chain. as electrons "fall" from carrier to carrier and finally to O2, energy is released.
        
        Stages of cellular respiration
        
        glycolysis harvests chemical energy by oxidizing glucose to pyruvate: ATP is used to prime a glucose molecule, which is split in two. these three-carbon intermediates are oxidized to two molecules of pyruvate, yielding a net of 2 ATP and 2 NADH. ATP is formed by substrate-level phosphorylation, in which a phosphate group is transferred from an organic molecule to ADP
        
        after pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules: the oxidation of pyruvate yields acetyl CoA, CO2, and NADH. for each turn of the citric acid cycle, two carbons from acetyl CoA are added, 2 CO2 are released, and 3 NADH and 1 FADH2 are produced
        
        most ATP production occurs by oxidative phosphorylation: in mitochondria, electrons from NADH and FADH2 are passed down the electron transport chain to O2, which picks up H+ to form water. energy released by these redox reactions is used to pump H+ into the inter membrane space. in chemiosmosis, the H+ gradient drives H+ back through ATP synthase complexes in the inner membrane, synthesizing ATP
        
        scientists have discovered heat-producing, calorie burning brown fat in adults
        
        review: each molecule of glucose yields many molecules of ATP: substrate-level phosphorylation and oxidative phosphorylation produce up to 32 ATP molecules for every glucose molecule oxidized in cellular respiration
        
        Fermentation: Anaerobic harvesting of energy
        
        fermentation enables cells to produce ATP without oxygen: under anaerobic conditions, muscle cells, yeasts, and certain bacteria produce ATP by glycolysis. NAD+ is recycled from NADH as pyruvate is reduced to lactate (lactic acid fermentation) or alcohol and CO2 (alcohol fermentation)
        
        glycolysis evolved early in the history of life on earth: glycolysis occurs in the cytosol of the cells nearly all organisms and is thought to have evolved in ancient prokaryotes
        
        Connections between metabolic pathways
        
        cells use many kinds of organic molecules as fuel for cellular respiration
        
        organic molecules from food provide raw materials for biosynthesis: cells use intermediates from cellular respiration and ATP for biosynthesis of other organic molecules. metabolic pathways are often regulated by feedback inhibition
        
        Membrane structure and function
        
        membranes are fluid mosaics of lipids and proteins with many functions: the proteins embedded in a membrane's phospholipid bilayer perform various functions
        
        the spontaneous formation of membranes was a critical step in the origin of life
        
        passive transportation is diffusion across a membrane with no energy investment: solutes diffuse across membranes down their concentration gradients
        
        osmosis is the diffusion of water across a membrane
        
        water balance between cells and their surroundings is crucial to organisms: cells shrink in a hypertonic solution and swell in a hypertonic solution. in isotonic solutions, animal cells are normal, but plant cells are flaccid
        
        transport proteins can facilitate diffusion across membranes
        
        research on another membrane protein led to the discovery of aquaporins
        
        cells expand energy in the active transport of a solute
        
        exocytosis and endocytosis transport large molecules across membranes: a vesicle may fuse with the membrane and expel its contents, or the membrane may fold inward, enclosing material from outside the cell
        
        Energy and cell
        
        cells transform energy and matter as they perform work: kinetic energy is the energy of motion. potential energy is energy stored in the location or structure of matter and includes chemical energy. according to the laws of thermodynamics, energy can change from but cannot be destroyed, and energy transfers or transformations increase disorder, or entropy, with some energy being lost as heat
        
        chemical reactions either release or store energy: exergonic reactions release energy. endergonic reactions require energy and yield products rich in potential energy. metabolism encompasses all of a cell's chemical reactions
        
        ATP drives cellular work by coupling examples exergonic and endergonic reactions: the hydrolysis of ATP and, often, the transfer of a phosphate group is involved in chemical, transport, and mechanical work
        
        How enzymes function
        
        enzymes speed up the cell's chemical reactions by lowering energy barriers: enzymes are catalysts (usually proteins) that decrease the activation energy needed to begin a reaction
        
        a specific enzyme catalyzes each cellular reaction: an enzyme's substrate fits specifically in its active site
        
        enzyme inhibition can regulate enzyme activity in a cell: inhibitors can be either competitive or noncompetitive. feedback inhabitation helps regulate metabolism
        
        many drugs, pesticides, and poisons are enzyme inhibitors
      - CELL
        
        microscopes reveal the world of the cell: the light microscope can display living cells. the greater magnification and resolution of the scanning and transmission electron microscopes reveal the ultrastructure of cells
        
        the small size of cells relates to the need to exchange materials across the plasma membrane: the microscopic size of most cells provides a large surface-to-volume ratio. the plasma membrane is a phospholipid bilayer with embedded proteins
        
        prokaryotic cells are structurally simpler than eukaryotic cells: all cells have a plasma membrane, DNA, ribosomes, and cytosol. prokaryotic cells lack organelles
      - NUCLEUS AND RIBOSME
        
        the nucleus contains the cell's genetic instructions: the nucleus houses the cell's DNA, which directs protein synthesis via messenger RNA. subunits of ribosomes are assembled in the nucleolus
        
        ribosomes make proteins for use in the cell and for export: composed of ribosomal RNA and proteins, ribosomes synthesize proteins according to directions from DNA
      - ENDOMEMBRANE SYSTEM
        
        many organelles are connected in the endomembrane system
        
        the endoplasmic reticulum is a biosynthetic workshop: the ER is a membranous network of tubes and sacs. smooth ER synthesizes lipids and processes toxins. rough ER produces membranes, and ribosomes on its surface make membrane and secretory proteins
        
        the golgi apparatus modifies, sorts, and ships cell products: the golgi apparatus consists of stacks of sacs in which products of the ER are processed and then sent to other organelles or to the cell surface
        
        lysosomes are digestive compartments within a cell: lysosomes house enzymes that break down ingested substances and damaged organelles
        
        vacuoles function in. the general maintenance of the cell: some protists have contractile vacuoles. plant cells contain a large central vacuole that stores molecules and wastes and facilitates growth
        
        a review of the structures involved in manufacturing and breakdown: the organelles of the endomembrane system are interconnected structurally and functionally
      - ENERGY-CONVERTING ORGANELLES
        
        mitochondria harvest chemical energy from food
        
        chloroplasts convert solar energy to chemical energy
        
        mitochondria and chloroplasts evolved by endosymbiosis: these organelles originated from prokaryotic cells that became residents in a host cell
      - CYTOSKELETON AND CELL SURFACES
        
        the cell's internal skeleton helps organize its structure and activities: the cytoskeleton includes microfilaments, intermediate filaments, and microtubules. their functions include maintenance of cell shape, anchorage and movement of organelles, amoeboid movement, and muscle contraction
        
        scientists discovered the cytoskeleton using the tools of biochemistry and microscopy
        
        cilia and flagella move when microtubules bend: eukaryotic cilia and flagella are locomotor appendages made of microtubules in a 9" + 2" arrangement
        
        the extracellular matrix of animal cells functions in support and regulation: the ECM consists mainly of glycoproteins, which bind tissue cells together, support the plasma membrane, and communicate with the cytoskeleton
        
        three types of cell junctions are found in animal tissues: tight junctions bind cells to form leakproof sheets. anchoring junctions rivet cells into strong tissues. gap junctions allow ions and small molecules to flow from cell to cell
        
        cell walls enclose and support plant cells: plant cell walls are made largely of cellulose. plasmodesmata are connecting channels between cells
        
        review: eukaryotic cell structures can be grouped on the basis of four main functions:these functions are (1) genetic control; (2) manufacturing distribution, and breakdown; (3) energy processing; and (4) structural support, movement, and communication between cells
    - - life's molecular diversity is based on the properties of carbon: carbon's ability to bond with four other atoms is the basis for building large and diverse organic compounds. hydrocarbons are composed of only carbon and hydrogen. isomers have the same molecular formula but different structures
      - a few chemical groups are key to the functioning of biological molecules: hydrophilic functional groups give organic molecules specific chemical properties
      - cells make large molecules from a limited set of small molecules : short monomer + monomer -> dehydration -> longer polymer
        short monomer + monomer <-hydrolysis <- longer polymer
    - - monosaccharides are the simplest carbohydrates: a monosaccharide has a formula that is a multiple of CH2O and contains hydroxyl groups and a carbonyl group
      - two monosaccharides are linked to form a disaccharide
      - are we eating too much sugar: the FDA recommends that only 10% of daily calories come from added sugar. research supports the correlation between high sugar intake and adverse health effects
    - - fats are lipids that are mostly energy-storage molecules: lipids are diverse, hydrophobic compounds composed largely of carbon and hydrogen. fats (triglycerides) consist of glycerol linked to three fatty acids. saturated fatty acids are found in animal fats; unsaturated fatty acids are typical of plant oils
      - scientific studies document the health risks of trans fats
      - phospholipids and steroids are important lipids with a variety of functions: phospholipids are components of cell membranes. steroids include cholesterol and some hormones
      - anabolic steroids pose health risks
    - - proteins have a wide range of functions and structures: proteins are involved in almost all of a cell's activities; as enzymes, they regulate chemical reactions
      - proteins are made from amino acids linked by peptide bonds: protein diversity is based on different sequences of amino acids, monomers that contain an amino group, a carboxyl group, H atom, and an R group, all attached to a central carbon. the R groups distinguish 20 amino acids, each with specific properties
      - a protein's functional shape results from four levels of structure: a protein's primary structure is the sequence of amino acids in its polypeptide chain. its secondary structure is the coiling or folding of the chain, stabilized by hydrogen bonds. the tertiary structure is the overall three-dimensional shape of a polypeptide, resulting from interactions among R groups. proteins made of more than one polypeptide have quaternary structure.
    - - the nucleic acids in DNA and RNA are information-rich polymers of nucleotides: nucleotides are composed of a sugar, a phosphate group, and a nitrogenous base. DNA is a double helix; RNA is a single polynucleotide chain. DNA and RNA serve as the blueprints for proteins and thus control the life of a cell. DNA is the molecule of inheritance
      - lactose tolerance is a recent event in human evolution: different mutations in DNA have led ti lactose tolerance in several human groups whose ancestors raised dairy cattle
  - - - liquid water: hydrogen bonds constantly break and re-form
      - ice: stable hydrogen bonds hold molecules apart
- - - - bacteria
    - - archaea
    - - prolists
      - kingdom plantae
      - kingdom fungi
      - kingdom animalia