Study Guides (248,317)
Canada (121,484)
York University (10,191)
NATS 1610 (30)

NATS 1610 Final: NATS 1610 Full Course Notes

50 Pages
Unlock Document

Natural Science
NATS 1610
Barbara Czaban

LECTURE 2 ● characteristics of living things ○ take in energy and materials from the environment ○ sense and respond to stimuli ○ reproduce and grow ○ consist of one or more cells ○ maintain homeostasis ○ undergo evolution ● classification of organisms (domains) ○ bacteria ○ archaea ○ eukarya - it has 4 kingdoms ■ protists (protista) ■ plants (plantae) ■ animals (animalia) ■ fungi (fungi) ● taxonomy of humans (where do we belong) domain: EUKARYA order: PRIMATES kingdom: ANIMALIA family: HOMINIDAE phylum: VERTEBRATA genus: HOMO class: MAMMALIA species: SAPIENS ● characteristics of primates ○ grasping feet ○ forward-facing eyes ○ small litter size ○ complex social behaviour ● speciation ○ the formation of new species ○ Charles Darwin (1859) ■ modern species are descendants of ancestral species ■ evolution occurred by the process of natural selection - the descent through modification, over long periods of time ● criteria for evolution through natural selection ○ individual variation exists within a species - some variation is inherited ■ genes define traits ■ diversity is essential 1 ○ some people live longer and have more offspring than others ■ some characteristics make them better suited to their environment ■ organisms and environment are intimately associated ○ change occurs as the traits of the surviving people (those who reproduce) become more common in the population ■ less successful traits become less common ● modes of speciation (what causes new species to evolve) ○ allopatric ■ geographic separation restricts genes ○ sympatric ■ populations may be in overlapping geographical area ■ changes in gene flow ● chromosomal changes: mutations, exploitations ● behavioural changes: non-random mating - reduces gene flow LECTURE 3 ● lines of evidence ○ fossil ○ anatomical ○ biochemical ● fossil evidence ○ preserved remnants and impressions of past organisms ○ most fossils are mineralized in sedimentary rock ○ when assembled in chronological order, it shows the evolutionary changes ○ there can be non-decomposed fossils ■ when an organism dies, but doesn’t decompose because of its location ■ frozen in ice, trapped in resin, preserved in acid ● anatomical evidence ○ homologous structures suggest shared ancestry ○ resemblance early in development indicates common descent 2 ○ vestigial organs no longer serve any purpose to humans ■ a common ancestor used them - appendix, wiggling ears ● biochemical evidence ○ gene sequences that match closely were copied from a common ancestor ○ same genetic code - same cells and cellular components LECTURE 4 ● humans and environment ○ humans are dependant on it - ecology is the study of those interactions ○ things are needed to continue living ■ raw materials, oxygen, water, energy for metabolism ● macromolecules ○ LIPIDS → fat → glycerol/fatty acids ○ CARBOHYDRATES → polysaccharides → monosaccharides ○ PROTEIN → polypeptide → amino acid ○ NUCLEIC ACID → DNA/RNA → nucleotide ● photosynthesis (done by plants) ○ pathway where light energy, carbon dioxide and water are used to produce sugar ■ oxygen is a by-product 6CO 2 6H O2+ energy → C H6O12 6O 2 ● cellular respiration (done by all cells and organisms) ○ the oxygen-requiring pathway where glucose is broken down to create carbon dioxide, water and energy C6H12 6 6O →26CO + 62 O + 2nergy ● energy and raw materials ○ build and maintain molecular, cellular and body order ○ maintains ‘organization’ ○ metabolism utilizes energy to support homeostasis ● ecosystems ○ a specific geographic area ○ organisms exist in populations of individuals ■ interact among themselves and with physical environment ■ obtain energy and food ○ different populations organize into communities ■ live in the same physical conditions ● characteristics of ecosystems 3 ○ energy flow ■ energy cannot be recycled; it is used then is lost ○ chemical cycling ■ chemicals are not created or destroyed; they are reused ○ driven by photosynthesis and chemosynthesis ● trophic levels ○ feeding relationships within an ecosystem ○ follow transformation of energy ○ map movements of chemicals ○ two kinds ■ autotrophs - make their own food from inorganic substances (producers) ■ heterotrophs - cannot make own food; must consume to stay alive (consumers) ● producers ○ perform photosynthesis and chemosynthesis ○ fuel for cellular respiration and building blocks for growth ○ plants, algae, photosynthetic prokaryotes/protozoans, bacteria ○ chemosynthesis - uses energy from chemical reactions to make organic molecules, doesn’t use any light ■ hydrothermal vents - areas where hot, mineral-rich water enters seawater from the deep ocean floor ● some archaebacteria live here; they are chemoautotrophs ● they are the primary producers for organisms living here ● consumers ○ primary ■ organisms that consume producers (herbivores) ○ secondary ■ organisms that consume herbivores (carnivores) ○ tertiary ■ organisms that consume carnivores (omnivores) ● decomposers ○ they are consumers ○ get energy from non-living organic material ■ absorbs nutrients from dead organisms and decompose organic material ○ detritivores ■ animals that eat remains of dead animals; crabs, vultures, earthworms 4 ● energy ○ about 10% of the energy is passed on to the next trophic level - energy is lost because of cellular respiration and other energy-consuming processes ○ only the energy that is converted to biomass is available ■ biomass - dry weight of the organism; weight without water ○ ⅔ of the 10% of energy is used for cellular respiration LECTURE 5 ● biogeochemical cycles ○ nutrients are moved from the environment to organisms, then back to the environment ○ there are reservoirs of the nutrients in the environment ● water cycle ○ cycling of water molecules ○ between bodies of water to the atmosphere, then back to Earth, where the water is available to organisms 5 ● carbon cycle ○ movement of carbon-containing molecules from organisms and the Earth’s crust to the atmosphere and oceans, then back into organisms ● phosphorus cycle ○ phosphorus moves through rocks and living organisms ● nitrogen cycle 6 ○ movement of nitrogen from atmosphere, through nitrogen-fixing organisms in the soil and water, into plants and then to consumers; then back into the atmosphere ● disruption from human activity ○ human population growth ○ increased activities and technologies ■ causes global warming and climate change - greenhouse gases ● global warming ○ long term rise in Earth’s surface temperature; correlates with the rapid accumulation of greenhouse gases in the atmosphere ● renewable energy sources ○ can replace the use of greenhouse gases; better for the environment ■ solar energy, wind power, alcohol, hydrogen, methane LECTURE 6 ● defining life ○ condition that distinguishes organisms from inorganic objects and dead things ○ growing with metabolism, reproduction and adaptation ○ follows the characteristics of life ● characteristics of life ○ organism needs to have ALL of these, at some point during existence ■ order + organization ■ acquiring/using energy ■ metabolism ■ regulation ■ sensing/responding to stimuli ■ cells 7 ■ motion ■ growth/reproduction ■ ability to evolve ● chemistry of carbon compounds (what are organisms made of) ○ carbohydrates, lipids, nucleic acids, protein ● are viruses alive? ○ they are inert mixtures of protein and genetic material ○ not affected by antibiotics ○ tobacco mosaic virus, adenovirus, influenza virus, bacteriophage T4 ● viruses are ‘clever’ ○ they increase their numbers and evolve into new forms ○ use host cells ‘to do the work’ - LYTIC AND LYSOGENIC CYCLES ■ viral genetic material is released from virus ■ host cell processes the viral genetic material ■ produces more viral nucleic acid/ proteins, which makes more virus cells 8 ● RNA ○ some viruses have RNA as their genetic material; retroviruses, HIV ○ RNA must be copied into DNA, using an enzyme - reverse transcriptase ■ makes many mistakes and viruses readily mutate ● prions ○ infectious self-reproducing protein structures with no nucleic acid ○ they are a misfolded form of a protein that is normally present of the surface of nerve and brain cells ■ scrapie - disease in sheep ■ kuru - found in cannibals who eat brains ■ BSE (bovine spongiform encephalopathy) - mad cow disease ■ creutzfeldt-jacob disease - human version of BSE ○ create sponge-like holes in the brain, causing death ○ there is no treatment for any of the diseases ● how prions ‘reproduce’ ○ it converts the normal forms of the proteins into the prion versions LECTURE 7 9 ● chronology of life development ● theories on the origins of life ○ life was created by the action of one or more gods ■ natural phenomenon; not testable ○ life originated from non-living matter on Earth ■ spontaneous generation ■ chemical evolution ■ hydrothermal vents ○ life came from some other place in the universe ■ this causes other problems ● spontaneous generation theory ○ idea that life forms could arise from inanimate objects, instead of seeds or eggs ■ fleas from dust, maggots from dead fish ○ it was made obsolete by the work of Louis Pasteur ● Pasteur’s findings ○ 1859 experiment to see if living matter can spontaneously generate from nonliving matter ○ first showed that air is full of microorganisms ■ they can be killed with heat ○ second showed that spontaneous generation does not occur ■ conditions were very different many years ago 10 ● conditions of primitive Earth - 4.5 bya ○ 700 million years of meteor bombardment ○ intense lightening and UV radiation ○ Earth’s crust is hot and volcanic ○ too hot and hostile for life ● conditions of primitive Earth - 3.8 bya o ○ Earth cooled down (90-100 ) ○ less intense, but still strong energy sources (UV radiation, thermal energy) ○ little or no atmosphere oxygen (free O ) 2 ○ atmosphere gases mainly from volcanic eruptions (outgassing) - NH3, NH2, 2 , CO ,2CO, CH ,4H O2 ● chemical evolution ○ the chemical and physical processes in Earth’s primordial environment may have eventually produced simple cells ■ suggests that life evolved from chemicals ■ chemical complexity increased over 300 million years ● four stages in the formation of life 1. the abiotic synthesis of small organic molecules ■ abiont - synthesis outside the body of an organism 2. joining these small molecules (monomers) into polymers and macromolecules 3. origin of self-replicating molecules - genetic material 4. packaging these newly formed organic molecules into protobionts ■ protobionts - evolutionary precursors of the first prokaryotic cells 11 ● stage one ○ 1920’s: the idea of the ‘primordial soup’ - Oparin/Haldane ■ suggested that conditions of primordial Earth would have enabled life to first come into existence on early Earth ○ 1953: Stanley Miller/Harold Urey ■ tested Oparin/Haldane hypothesis with proposed conditions of early Earth ■ produced amino acids and other organic molecules ■ concluded that organic molecules can be synthesized abiotically ● another possible source is from space ● stage two ○ abiotic origin hypothesis predicts that monomers link to form polymers ○ similar conditions likely on Earth when dilute solutions of monomers splashed onto fresh lava or shores of oceans/lakes (also maybe in hydrothermal vents) ○ spontaneous assembly of molecules in these areas ● stage three ○ RNA world hypothesis ■ RNA was first genetic material that could replicate itself; DNA came later ○ DNA world - DNA replication - structure enables duplication ■ double stranded, making it more stable ■ complementary binding - A/T, C/G ■ passed on to new generations ○ RNA can also replicate and evolve ■ single stranded, making it less stable ■ complementary binding - A/U, C/G ■ occasional copying errors create mutations - this is what causes evolution ● stage four ○ formation of protobionts ○ single membraned sacs ■ they do form spontaneously LECTURE 8 ● chemicals ○ matter makes up everything that is of this world ■ made of chemical elements ○ we are made of more than 90 elements ■ they cannot be broken apart by normal means ■ typical human was worth $3.57-$4.50 (Sept. 2013) ■ 90% is carbon (18%), nitrogen (3%), oxygen (65%) and hydrogen (10%) ● atoms ○ in 2 areas 12 ■ central nucleus ■ pathways around nucleus (shells) - they orbit around ○ 3 types of particles ■ positive (protons) - in nucleus ■ neutral (neutrons) - in nucleus ■ negative (electrons) - orbit around ● atomic number ○ number of protons in nucleus ○ written as subscript to lower left of the symbol ● atomic weight ○ number of protons + neutrons ○ written as superscript to upper left of symbol ● electrically neutral atoms ○ they have the same number of protons and electrons ● electrons and their shells ○ electrons orbit around the atom nucleus in the shells ○ atoms try to lose, gain or share electrons until they have a full valence (octet rule) ○ 1st shell → holds up to 2 electrons ○ 2nd shell → holds up to 8 electrons ○ 3rd shell → holds up to 8 electrons (but can hold more, depending on atom) ● valence shell ○ outermost shell of an atom and it has valence electrons ○ atom is most stable when this shell is filled ○ not having a full valence shell makes the atom more reactive 13 ● isotopes ○ variations of an atom that have the same number of protons but different neutrons ■ they have a different weight ○ some isotopes are unstable - radioactive isotopes ■ they spontaneously decay, giving off different energy / subatomic particles ■ can be used as a dating tracer ■ radiation kills healthy cells and cancerous cells ● atoms reacting with other elements to form.. ○ molecules ■ groups of 2+ atoms, held together in a stable association ■ some molecules are made of only 1 element (oxygen 2 O ) ○ compounds ■ molecules containing 1+ type of element (water - 2H, 1O) ○ chemical bonds ■ hold atoms together in molecules or compounds ● chemical bookkeeping ○ chemical equation shows reaction: reactants → products ○ atoms are rearranged but never lost ■ accounted on both sides of equation; it is balanced ○ use symbols for elements when writing formulas ● what determines an interaction ○ the number and arrangement of the electrons ○ electron vacancies ■ unfilled valence shells make atoms likely to react ○ valence shell ■ an atom with a full valence shell will not bond (ex: noble gases) ● chemical bonds ○ the union between the electrons of neighbouring atoms ○ form in attempt to stabilize the outer shell of the interacting atoms ○ 3 types 14 ■ ionic bonds ■ covalent bonds ■ hydrogen bonds ● ionic bonds ○ formed by the attraction of oppositely charged ions 1. one atom loses an electron and becomes a positively charged ion 2. the other atom gains the electron and becomes a negatively charged ion 3. charge differences attract the 2 ions to each other ● covalent bonds ○ very stable bonds ○ forms when atoms share a pair of valence electrons ○ each atom’s attractive forces ‘pulls’ on the other atom’s unpaired electron ■ causes the 2 electrons to occupy a shared orbital LECTURE 9 ● basic information about water ○ 70% of total body weight is water - THE REST IS CARBON COMPOUNDS ○ life originated in water ○ its physical and chemical properties make life possible ■ capacity to dissolve or repel substances ■ cohesion and adhesion ■ temperature-stabilizing effects ■ liquid form over a range of temperatures (0-100 C) 15 ● polar covalent bonds ○ form when atoms don’t share electrons equally ○ in water, the oxygen atom’s nucleus has more protons, make it more positive ■ the compound still has the same amount of positive and negative charges, but the distribution makes it slightly more positive or negative ● hydrogen bonds ○ relatively weak bond ○ form by the attraction of a positively charged hydrogen end of a polar molecule to the negatively charged end of another polar molecule ○ can occur between different molecules or within the same molecule ● liquid water vs. ice liquid water ice molecules held together loosely molecules held together tightly water flows water is solid no spaces between molecules spaces between molecules ● cohesion ○ water molecules ‘cling’ to each other ○ polarity of water results in hydrogen bonding between molecules ○ surface tension ■ clinging at air-water interface ○ water flows as a unit because of this clinging ○ BROWNIAN MOTION 16 ● properties of water ○ liquid at room and body temperatures ■ other materials are gaseous at these temperatures ■ can be used to travel and carry materials ○ solvent for other polar molecules ■ permits chemical reactions because of its polar nature ■ ‘spheres of hydration’ ● layer of water around an ion ■ hydrophilic ● water loving; binds with water ■ hydrophobic ● water hating; repels water ○ cohesive and adhesive ■ when the same molecules stick to each other (cohesion) ● ‘pull’ on each other ■ when different molecules stick to each other (adhesion) ● ‘stick’ to structures ■ good for transporting nutrients in trees ● xylem (water) and phloem (food) ○ temperature rises and falls slowly ■ high heat capacity ● a lot of heat is needed to raise the temperature ■ protects organisms from rapid temperature changes ● maintains homeostasis ■ water in blood helps to distribute heat throughout the body ○ high heat of vapourization ■ a lot of heat is needed to vapourize the liquid ■ prevents overheating ■ water evaporating from a surface carries away heat, cooling the surface ○ frozen water is less dense than liquid water ■ hydrogen bonds are rigid; frozen water expands ■ ice floats, liquid water does not ● allows life to exist underneath ● water, acids, bases, pH and buffers ○ water molecules can dissolve (breakdown) to form hydrogen ions (H ) and - hydroxyl ions (OH ) ■ then they can re-bind to form water - it’s a cycle ● acids ○ pH: 0-6 ○ anything that can donate hydrogen ions (H ) 17 ○ increase H concentration in solution ● bases ○ pH: 8-14 + ○ anything that can accept hydrogen ions (H ) ○ decrease H concentration in solution ● pH scale + ○ measures the concentration of H in a solution and indicates how acidic/basic it is ● buffers ○ helps keep the pH within normal limits + ■ taking up excess H when concentrations increase ■ adding H when concentrations decrease ○ various buffer systems in the body maintain the correct pH level ● carbonic acid-bicarbonate buffering system ○ keep the pH of blood at 7.4 (fairly neutral) ○ if H level decrease, carbonic acid will dissociate to release H into blood (↑H ) + ○ if H level increase, it combines with bicarbonate ions, making carbonic acid (↓H ) LECTURE 10 ● shapes of molecules ○ carbon can form covalent bonds with 4 other atoms ■ tetrahedron shape ○ 2 carbon atoms can be joined with a double bond ■ flat structure tetrahedron flat 18 ● variation in carbon skeletons ○ shape changes because of the diversity of organic molecules ■ the skeletons vary in length ■ may be straight, branched or arranged in closed rings ■ skeleton may include double bonds ● hydrocarbons ○ hydrogen atoms attached to a carbon backbone ○ non-polar and do not dissolve in water (hydrophobic) ● functional groups ○ single or cluster of atoms, covalently bonded to the carbon backbone ○ replace one or more hydrogen atoms of the hydrocarbon skeleton ○ the number and arrangement of functional groups give each molecule its own unique properties ○ increase solubility in water ■ they are hydrophilic ○ they can act as acids or bases ● most common functional groups ○ hydroxyl (OH) ○ carbonyl (COH) ○ carboxyl (COOH) ○ amine (NH2) ○ sulfhydryl (SH) ○ phosphate (PO4) 19 ● carbon rings ○ carbons are numbered to identify them LECTURE 11 ● macromolecules ○ cells join smaller organic molecules to form larger molecules ○ 4 major classes ■ carbohydrates (monosaccharide) ■ fat (glycerol/fatty acids) ■ protein (amino acids) ■ nucleic acid (nucleotides) ○ the chemical mechanisms that cells use to make and break polymers are similar for all classes of macromolecules ● polymers ○ consist of many similar or identical building blocks, linked by covalent bonds ○ form chains of repeating subunits (monomers) ■ lipids do not form chains though ● condensation reaction (dehydration reaction) ○ process that joins monomers by covalent bonds ○ one monomer provides a hydroxyl (OH), the other provides hydrogen (H) 20 ■ these form water as a by-product (H O) 2 ○ aided by enzymes ■ synthetases ○ CREATING LONGER CHAINS BY GETTING RID OF WATER ● hydrolysis reaction ○ process that degrades polymers when covalent bonds connecting the monomers are disassembled ○ a hydrogen atom and a hydroxyl group from a split water molecule attach to where the covalent bond used to be ○ this reaction dominates the digestion process ○ aided by enzymes ■ hydrolases ○ USING WATER TO BREAK UP CHAINS LECTURE 12 ● carbohydrates ○ simple sugars and polymers (chains) of sugars ○ most names end in -ose ○ monosaccharide (GLUCOSE) ■ major fuel source for cellular work ■ energy is stored in chemical bonds between carbon and other atoms ○ disaccharide (MALTOSE) ○ polysaccharide (STARCH) ■ polymers of monosaccharides ■ fuel storage and structural roles 21 ● monosaccharide (one sugar) ○ classified by the number of carbons in the backbone ■ 6 carbons → hexose (C 6 12)6 ■ 5 carbons → pentose (C5H 10)5 ■ 3 carbons → triose (3 6 O3) ○ minor structural changes result in different sugars or formation of ring structure ■ ex: glucose and galactose (look at picture below) ○ aldoses ■ double bond is at the end of the chain ○ ketoses ■ double bond is somewhere in the middle of the chain ● disaccharide (two sugars) ○ sugars joined by condensation reactions ○ maltose → glucose + glucose ■ broken down by maltase ○ sucrose → glucose + fructose ■ broken down by sucrase ■ not synthesized in animals ■ water soluble, easily transported ■ cane sugar, beet sugar, pineapple ○ lactose → glucose + galactose ■ sugar in milk/dairy ■ broken down by lactase 22 ■ lactose intolerance is when people do not have lactase in their body, so they cannot break down dairy products ● polysaccharide (three or more sugars) ○ structure depends on kinds of sugar and the way they are joined ○ starch, glycogen, cellulose ■ they are all made of glucose, but linked differently ○ functions are energy storage and other polysaccharides serve as building materials for a cell or organism ● starch vs. glycogen starch glycogen storage form of glucose in plants storage form of glucose in animals (liver/muscle) long chains of glucose long chains of glucose many branching side chains more, but shorter, branches than starch ● cellulose ○ most abundant polysaccharide and organic material ○ in plant cell wall ○ unbranched ■ it is long, rigid fibrils, which are held together in ‘sheets’ ○ not digestible by humans ■ need enzyme, cellulase, to digest ○ ‘roughage’ or ‘fibre’ ■ helps food move through the intestines/colon LECTURE 13 ● structure of eukaryotic cells ○ cell membrane, nucleus, cytoplasm ○ cytoplasm is divided into cytosol and organelles ■ cytosol: gel-like fluid portion ■ organelles: solid pieces in the cell; with or without membrane 23 ● cellular metabolism ○ intracellular chemical reactions ■ degradation, synthesis, transformation of small organic molecules ■ linear or cyclic reactions ○ enzymes play a big role ■ they speed up reactions ■ mostly proteins, catalytic ■ keep optimum pH and temperature ■ interact with substrate at the active site ○ coenzymes ■ they help the enzymes ■ molecules that move hydrogen atoms and electrons to the sites of chemical reactions in cells ■ ex: NAD , FAD ● how enzymes and substrates fit together ○ at the active site, substrate molecules bind briefly and form a product ○ active site brings the molecules close enough so they interact and form a product ■ enzyme’s shape may change ○ once the product is released, the enzyme goes back to previous shape ● metabolic pathways 24 ○ anabolic ■ favour the synthesis of molecules to build organs and tissues ■ often condensation/dehydration reaction ○ catabolic ■ favours the breakdown of complex molecules into simpler ones ■ often hydrolysis reaction ● energy ○ energy source for the body is the chemical energy in the carbon bonds of ingested food ■ must be converted into a useable form of energy ■ ATP (adenosine triphosphate) ● the cell’s energy currency ■ the high energy phosphate bonds of ATP store energy ● ATP/ADP cycle ○ provides energy for cell activities ■ cells use ATP constantly, so it must always be replenished ● cellular respiration ○ three chemical pathways ■ glycolysis (anaerobic respiration) ■ kreb’s cycle (aerobic respiration) ■ electron transport chain (aerobic respiration) ● mitochondria ○ ATP is formed in its inner compartment ○ enclosed by a double membrane ■ inner and outer ■ allows for stockpiling of hydrogen ions and formation
More Less

Related notes for NATS 1610

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.