The Unity of Life
The Unity of Life BIOL 121
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This 26 page Class Notes was uploaded by Holden Parker on Tuesday October 13, 2015. The Class Notes belongs to BIOL 121 at Longwood University taught by David Buckalew in Fall. Since its upload, it has received 11 views. For similar materials see /class/222423/biol-121-longwood-university in Biology at Longwood University.
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Date Created: 10/13/15
Bio 121 Test 2 I Organelles with DNA9 circular DNA resembles bacterial DNA a Mitochondrion where much ATP is produced b Plastids i Chloroplasts ii Leucoplasts 11 Central vacuole of plant cells Cytoskeleton 0 Dynamic structure forms and disintegrates rapidly shape changescell movementsorganelle movements Composed of protein laments threadlike l Actin laments 810nm actin monomers dynamic9 cell movement cytokinesis division of cytoplasm aids in constriction of cell membrane 2 Microtubules 25nm alpha and beta tublin dynamic does all of the above AND forms spindle apparatus of mitosismeiosis 3 Intermediate laments provide structure not dynamic do not form and disintegrate rapidly intermediate because they are between sixes of actin and microtubules ll 24 nm Centrioles 0 Serve as sites for microtubule formation 0 Spindle apparatus 0 Basal body for agella and cilia o A pair of nine sets of 3 microtubules oriented right angles Membranes Composed of phospholipid bilayer with embedded proteins 0 Likened to a uid mosaic structure 0 Receptors for molecules inout 0 Binding location one cell to another 0 Chanel for molecular ow 0 Cell marker signals self vs non self antigens Cholesterol 0 Provides a small support in cell structure Proteins and protein complexes perform key functions in membranes 0 Transporters cell to cell identity adhesion o Enzymes Cell surface reception adhesion Diffusion 0 Movement of substances through a selectively permeable membrane 0 Simple diffusion requires no cell energy ATP concentration gradient 0 Facilitated diffusion requires cell energy ATP aided by receptor Tonicity of solutions o Solute solvent 0 Hypertonic higher concentration of solute lower concentration of solvent 0 Hypotonic lower concentration of solute higher concentration of solvent Active transport 0 Requires ATP to be used 0 Membrane protein receptor 1 Symport transport a Two molecules same direction 11 Antiport Chapter 5 Energy and metabolism life energy transformation Each property by which we de ne life order growth reproduction responsiveness internal regulation requires energy Deprived of a source of energy life stops Energy cycle of earth The ow of energy in living systems Thermodynamics 0 Branch of chemistry concerned with energy changes 0 Energy capacity to do work 0 Energy consists in two states 0 Kinetic energy in use 0 Potential energy stored 0 Energy takes many forms mechanical sound light electrical heat There are millions of biological examples of potentialkinetic energy Most convenient measure of energy is heat calorie Ifood calorie is a kilocalorie or 1000 calories A simple sugar glucose fructose provides about 700 kilocalories or energy per mole o Photosynthesis sugars provide the carbon skeleton to make 0 Amino acids 0 Fatty acid chains and glycerol for lipids 0 One mole of a lipid with three 16 C saturated fatty acid chains yields 2340 kcals 0 Without constant in ow of solar energy life as we know it would not exist Nuclear Winter Alvarez hypothesis Laws of thermodynamics 0 First law energy cannot be created or destroyed 0 Finite quantity in universe 0 In any energy transformation change some usable energy is lost 0 Second law of thermodynamics in any energy change usable energy is lost 0 Lost energy entropy o Entropy is always increasing in the universe 0 Gibbs free energy equation 0 Reactions in cell Anabolic chemical reaction Catabolic chemical reaction Cellular energy 0 Brought about through cellular catalysts enzymes Enzymes 0 Mostly proteins 0 Catalyze reactions in cells by binding reactants substrates for cell reactions to occur 0 Speci c for substances to which they bind 0 Lower energy of activation of reaction 0 Share not altered by reaction reusable Enzyme structure Niacin NAD 9relay electrons and hydrogen to electron transport chain Ribo avin FAD Pantothenic Acid CoA 9relay 2 carbon moleculesfood sources to Kreb s cycle Redox oxidationreduction Oxidation loss of electrons and loss of energy Reduction gain of electrons and gain of energy Enzyme regulation Three ways inhibitory processes 1 Bio feedback inhibition relates to biochemical pathways 2 Competitive inhibition one substance competes with another for active site a Sulfa drugs compete for active site on an enzyme that will change a substrate to folic acid nucleic acid magic bullet 3 Non competitive inhibition Cell Respiration CR 0 Change of food energy to cell energy 0 ATP is about 7 kcal 0 Two forms of cellular respiration o Aerobic oxygen serves as terminal electron acceptor TEA o Fermentation organic molecule serves as TEA pyruvic acid or derivative Aerobic CR 0 Occurs in 4 steps l Glycolysis 6 C sugar 9 two 3C pyruVic acid or pyruvate 2 Transition reaction two pyruvates lose 2 C02 to become two 2 C acetyl groups 3 Krebs Cycle two 2C become 4 CO2 which is released 4 Electron Transport chain NADH2FADH2 relay energy to ATP majority of ATP Glycolysis 6 C9 2X3C Transition occurs between cytoplasm and mitochondrion Kreb s cycle 0 Electron Transport Chain ATP synthase uses energy From H to synthesize 3ADP That will bond with 3 P to 3 ATP Chapter 8 Photosynthesis importance 1 billion years ago photosynthesis began created 03 layer ozone 400 million years to produce land plants photosynthesis produces 20 of oxygen Created an oxygenated atmosphere Aerobic CR yields 36 ATP 6C sugars allowing for larger organisms 02903 upper stratosphere blocks much of UV radiation hitting earth Allowed for land colonization Photosynthesis plant Li mass energy food for r to heterotrophs r Photosynthesis requires two steps 1 Light dependent reactions 2 Light independent reactions Photosynthesis as a process takes place in chloroplasts of mesophyll cells Light dependent Reaction Light independent Reaction Occurs in matrix or stroma All reactions occur within one cell within chloroplasts C02 and RuBP PGA 3C Cool season plants Reactions occur within mesophyll and bundle sheath cells C02 and PEP9 Oxaloactetate 4 C 0 Warm season plants 0 First xation of C02 that happens in matrix of chloroplasts in mesophyll CAM Photosynthesis o Crassulacean acid metabolism 0 Cacti succulents stone crops 0 Tough leaf surface 0 Light dependent reactions in day 0 First C02 xation occurs at night stomates open night to take in C02 Chemiosmosis movement of chemicals by water from high concentration to low concentration down concentration gradient generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration Photorespiration is the process by which RuBP a sugar has oxygen added to it by the main enzyme involved in photosynthesis rubisco instead of carbon dioxide as happens during photosynthesis Rubisco favours carbon dioxide to oxygen Even when stomates are open 20 of RuBP Chapter 1 Biology is defined as the study of life Characteristics of living things Cellular organization Order Sensitivity Growth development reproduction Energy utilization Evolutionary adaptation Homeostatis J Cells surrounded by cell membrane all cells come from preexisting cells cell theory 2 Order membranes 9 organelles mitochondria energy generationendoplasmic reticulum protein and fat synthesis fuel energy for the cell Organs make organ systems which regulate the activity of the cell 3 Sensitivity reacting to environment can lead to adaptation 4 Growth Development reproduction guidance of DNA9 inheritance coordination of mitosis and meiosis 5 Energy utilization energy usage begins cell level a Autotrophs b Heterotrophs carbohydrates other carbon sources proteins lipids nucleic acids 9 ATP 6 Evolutionary adaptation producers dictate consumers 7 Homeostasis maintenance of a stable internal environment tonicity concentration ph HZO9 proteinenzyme function Heirarchy of Life biosphere a Cellular level atoms molecules macromolecules organelles b organism level cells tissue organs organ systems organism c I I 39 level level I 39 species 39 all plants amp animals biotic and abiotic ecosystems Relative to life on Earth the entire planet can be viewed can viewed as one large ecosystem called the biosphere The biosphere is approximately 25 miles thick Approximately 19 miles into the air and 6 miles below the ocean s surface diameter of earth at equator 792641 miles only about 50 miles contains life At each level of hierarchy emergent properties emerge Interactions hierarchy emergent properties emerge Interactions between molecules cells organisms etc result in a system beyond the sum of its parts This makes the process of life difficult to define Science Latin for llto know Charles Darwin sought natural rather than supernatural causes for the unitydiversity of nature and in doing so revolutionized biology Published the then controversial book on the origin of species etc in 1859 Aeolian Charles Lyell 1830 geology Darwin traveled 5yrs on the EgLe 1830 s South America Australia Galapagos islands The Process of Science Science seeks answers to natural phenomena 0 Activities that can be observed and measure 0 Activities that can verified through testing Ex Cell theory molecular theory DNA9 RNA9 Protein evolutionary theory Science uses two ways to approach problem solving Inductive reasoning generalization that summarizes many observations Deductive reasoning hypothesis testing and ifthen logicquot9 reasoning flows from general to specific Does spontaneous generation occur Sg belief that some life forms usually lower life forms could arise spontaneously from nonliving matter ex toads snakes and mice come from soil and old rags Larvae after you because you are sweaty Evidence Pro and Con 1668 Redi disapproved SG 1745 Neeham proved SG 1760 Spallanzani disproved SG 1858 Rudolf Virchow suggested bio genesis 1860 Pasteur settled controversy Hypothesis quoteducated guess library research Usually asks a question and can be answered with a yes or no Unifying themes of Science Cell theory Robert Hook 1665 to Anton Van Leeuwenhoek 1700 to Schleiden and Schwann 1839 All living organisms are made of cells and all living things come from preexisting other living cells Later it was proposed that all cells came from preexisting cells Molecular theory llCentral Dogma of molecular biology DNA is molecule of inheritance DNA encodes genes which make up and control living organisms DNA9RNA9 Protein Evolutionary Change Over time lifeforms have evolved varying characteristics to adapt to varied environment Evolutionary Conservation Some characteristics of earlier organisms are preserved and passed on to future generations Fossil evidence for evolution geochronology Eons of biological change shown in successive layers of rack strata Earliest organisms found in preCambrian rock Simplest life form fossils at lowest depth and more advanced forms in shallower depths Fossil evidence for evolution similar life in similar habitats Similarity in cell components Plant cells and animal cells Exemplifies extreme conservation of cellular components across biotic realm although heterotrophy autotrophy is biologically ancient Animal cells have golgi plants have dictyosomes Homology among vertebrate limbs Similarities due to common ancestors or genetic lineage Molecular evidence for evolution Rhesus monkey being primates and closely related to humans have fewer differences in the amino acid sequence of hemoglobin protein than more distantly related species Non mammalian vertebrates differ to a greater extent Chain ofamino acids in hemoglobin quotpolypeptidequot 300AA s bond between amino acids are peptide bonds CHAPTER 2 Water an absolute necessity for life Approximately three quarters of the planet is covered by water Life existed in water two billion years prior to adapting to land 60 percent of human weight is from water 83 percent of human blood composition Where water exists life may be found Water is critical to cell biochemistry Water is critical for photosynthesis Water is the lluniversal solvent Water s structure Covalent molecule that shows polarity positive side negative side Simple molecular structure with oxygen bound to two hydrogen atoms by single covalent bonds Electro negativity of 0 is much greater that H so the bonds between these atoms are quotpolarquot H20 molecules covalent bonds Polarity of molecule Properties of H20 Cohesion binds or coheres to other H20 molecules by hydrogen bonds to itself Adhesion binds or adheres to other substances by hydrogen bonds not itself Cohesion and adhesion work together to perform capillary action transpiration of plants imbibitions High specific heat serves as a sink for heat High heat of vaporization serves to release heat Solid water ice is less dense than the liquid hydrogen bonds go static at 0 degrees C liquid water at 34 degrees C is denser than regular water Universal solvent water surrounds other polar substances hydrophilic hydrophobic sugar protein nucleic acid polar Not lipids non polar H2O dissociates splits pH measure of free H ions in solution pH power of hydrogen pH logH More negatively charged ions solution becomes caustic base More positively charged ions solution becomes caustic acid Proteins change in shape or denature as solution becomes caustic Major buffer in body is carbonic acid For every one number change in pH difference of 10 Polymers 4 Categories proteins lipids carbohydrates nucleic acids carbon is the central element of biomolecules Valence relates to the of unpaired electrons in outermost energy shell All biomolecules contain a carbon chain or ring quotskeletonquot Carbon s bonding capacity is high valence of 4 and forms covalent bonds A lot of energy in covalent bonds when covalent bonds are broken some energy is trapped between ADPP yielding ATP Carbon linkages singlechains rings carbon bonds to more than just hydrogen 0H9 hydroxyl group tends to be polar Amino Acid NH2 amine COOH carboxyl carbon hydrogen and R Group Carbon binds to OH groups in sugars NHZ groups in amino acids H2PO4 groups in nucleotides of DNA RNA ATP Functional groups Hydroxyl Carbonyl Carboxyl Amine Sulfhydryl Phosphate Methyl Isomers have the same molecular formulas but different structures Structural isomer difference in the C skeleton structure Stereoisomers difference in location of functional groups 0 Enantiomers mirror images of each other llright hand llleft hand C bounded to 4 different atoms is called a chiral molecule Chiral molecules rotate polarized light to the right d form or to the left L form Monomers are made into polymers via dehydration reactions Polymers are broken down into monomers via hydrolysis reactions Carbohydrates sugars Most abundant biomolecules on earth Simple sugars double sugars or chains of sugars Exist in a ring structure within the solution of the cell sugar monomers Carbons are counted in ring structure starting from right and moving clockwise Double sugars disaccharides Two six C chains or rings bonded together Glucose fructose sucrose table sugar Alpha bond shows the covalent bond below the plain of the sugars easy to break down Beta bond9 shows the covalent bond above the plain of the sugars very very hard to break cant be broken by any human enzymes Complex Carbohydrates polysaccharides Starch amylose Cellulose Glycogen Chitin in cell wall of some fungi and exoskeleton of insects Proteins polypeptides Composed of chains polymers of amino acids 20 amino acids exist Amino acids contain 0 Central carbon Amine group Carboxyl group 000 R group The twenty amino acids all differ with respect to their R group Genetic Code 3x3 combinations of AUGC important for translation of protein synthesis Code for 20 amino acids 64 possible combinations Peptide Bonds Occur between amino acids The COOH group of one amino acid binds to the NH2 group of another amino acid This forms a peptide bond There are at least seven functions of proteins Enzyme catalyst specific for 1 reaction Defense antibody proteins other proteins Transport hemoglobin myoglobin transferrins etc Support keratin fibrin collagen Motion9 actinmyosin cytoskeletal fibers Regulation9 some hormones regulatory proteins on DNA cell receptors Storage Ca and Fe attached to storage proteins There are four levels of proteins structure Primary sequence of amino acids alpha helix Secondary forms pleated sheet helix or coil beta pleated sheeth Tertiary entire length of amino acid folded into shape Quaternary several amino acid sequences linked together The chain polymer of amino acids form a variety of loops coils and folded sheets from an assortment of bonds Nucleic acids DNA deoxyribonucleic acid DNA is a double polymer 2 chains lldouble helix Each chain is made of nucleotides The 2 chains bond together to form a helix Each nucleotide contains 3 parts 1 5 carbon sugar deoxyribose 2 Phosphate group 3 Nitrogen Base AGCT Antiparallelism9 affects DNA replication protein synthesis and cell division DNA RNA polymerase9 reads DNA from 3 to 5 direction but only replicates in the 5 to 3 direction RNA single chain of polymers and neucleotides RNA has ribose 1 oxygen added AUGC 3 forms of RNA Messenger RNA mRNA Transfer RNA tRNA Ribosomal RNA rRNA Lipids Large energy storing compounds Contain a core molecule of glycerol 3 carbon sugar Fatty acids bind to OH groups creating triglycerides Fatty acid chain has 1420 carbons Saturated fats carbon to carbon bonds are single convalent and each carbon has the maximum of hydrogens binding to it or quotsaturatingquot it Higher melting point solids at room temperature Unsaturated fats less of hydrogens per each carbon at least one double covalent bond between each carbon Lower melting point liquids at room temp mobile in blood llhealthier fatsquot Trans fats hard to move in the body Omega three fatty acids in walnuts almonds salmon Water is released in bond between triglycerides and fatty acid chains Phospholipids Plipids make up P lipid bilayer of cell membranes cell membrane nuclear envelope Endoplasmic reticulum Golgi apparatus mitochondria plastids Chapter 4 Lipids synthesize in ER Endomembrane vacuome Cell structure A hyposthesis originally proposed that all organisms are composed of cells Over time the concept has with stood scientific confirmation to now encompass 3 principles in cell theory 0 All organisms are composed of one or more cells and the life process of metabolism and heredity occur within those cells 0 Cells are the basic units of organization of all life 0 Cells arise by the division of preexisting cells Relative Size Ranges Pro beforekaryotic cells bacteria no nucleus Eutruekaryotic cells plants animals algae fungi Karyon kernel or nucleus Prokaryotic cells are about 110 um in length 1 millionth meter Eukaryotic cells are about 10100 um in length Most cells are microscopic although vertebrate egg cells are large enough to be seen with the naked eye Limitation to cell size9 limited by surface area 100um is about the limit PRO No nucleus 1 chromosome haploid Circular chromosome No organelles quotsmall ribosomes 70 S EU Nucleus membrane bound At least two chromosomes diploid Linear chromosomes Organelles organs of cells quotlarge ribosomes 80 S S Svedberg how quickly they sediment or spin out in a centrifuge Eukaryotic cell structures 1 Nucleus 2 Ribosomes 3 Endoplasmic reticulum
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