Biology 40S Exam Review - Mrs Stovel

Biology 40S Exam ReviewThis course overview covers the majority of the information you will need to know for the exam. Youshould also consult your full version notes where indicated for more detail and to fill in gapsGenetics :F1 - first generation offspring, F2 - second generation offspring, P - parent generationGenotype - the genetic make-up - represented by letters of the alphabetPhenotype - the physical/chemical expression of the gene - words to describe the traitRecessive - applies to an allele - the effects of a recessive allele are masked by that of a dominantallele - therefore, two recessive alleles are required to show the recessive traitDominant - masks the effects of a recessive allele - both AA and Aa will show the same dominantphenotype because "a" is hiddenHomozygote - when both alleles for a certain gene are the same (AA or aa)Heterozygote - when the two alleles for a certain gene are different (Aa)Monohybrid crosses: only two possible gametes formed - R and r can be made by parent who isRr, but if parent is RR, then can only have gametes that are R (practice crosses from your notes)Dihybrid crosses...combine the 2 letters as many ways as you can.Ex. RrTt would give RT, Rt, rT, rtSolve crosses by placing all possible gametes in a punnett square or use fraction multiplicationmethod (practice monohybrid and dihybrid crosses from your notes)Autosomal crosses - do not use X and Y chromosomes for male and femaleSex-linked crosses - put allele letters on the X chromosomes. No allele letters on the Y. Female =X A X a , Male = X A Y. Practice crosses from your notesComplete dominance (true mendelian)- the dominant allele will always mask the effects of therecessive allele - the recessive trait will only appear in the homozygous individual. Aa genotypeshows the (A) trait and not the (a) traitIncomplete dominance (non-mendelian) - the dominant and the recessive allele together will makean in-between of the two. Practice crosses from your notes- ex. BB = black bb = white Bb = greyCo-dominance (non-mendelian) - the dominant and the recessive allele together will make acombination of the two, neither powering over the other, nor mixing- ex. B = black W - white BW = black and white

Structure of DNA - double helix - 2 nucleotide chains lying side by side (antiparallel) to form atwisted ladder. Nitrogen bases form the steps of the ladder while sugars and phosphates alternate toform the side walls.Complementary base pair law - A with T and G with C. Nitrogen bases are held together with weakhydrogen bonds to allow for unzippingDNA replication - occurs in 3 steps: Unwinding, unzipping, base pairing. Occurs during lateInterphase of mitosis and meiosis I. DNA polymerase is the proof-reading enzyme used to stick onenucleotide to another during the building of a new DNA moleculeProtein synthesis - Road MapsForward Road Map: DNAc=> mRNAc=c>amino acid sequenceFind the TAC. Triplet until you come to a stop (ATT, ATC or ACT). Read whole DNA chain to see ifthere is another TAC. If so, triplet again until coming to the next stop. Must use mRNA codes to readamino acid chart. Use A with T and G with C for DNA. Use A with U and G with C for RNABackward Road Map: tRNAc=S> mRNAt=>DNAProtein Synthesis steps: Building a Protein according to the gene recipeThe DNA unwinds and unzips in the section containing the gene. The mRNA comes and copies themessage from the gene. mRNA polymerase is an enzyme that helps to stick the mRNA together as itis being built. The mRNA then exits the nucleus and finds a ribosome in the cytoplasm. The mRNAattaches to the ribosome and the ribosome reads the mRNA codons. tRNA's with the matchinganticodon then bring the appropriate amino acids in the appropriate sequence to the ribosome. Theamino acids are then joined to form the protein.Transcription - when an mRNA is built by copying a DNA sequence (DNA - mRNA)Translation - when the mRNA code is read and a protein is made (mRNA - protein)DNA vs. RNA - deoxyribonucleic acid vs. ribonucleic acid - both contain a chemical message- DNA has deoxyribose sugar - RNA has ribose, DNA is double stranded - RNA is single, DNA staysin nucleus - RNA can move out, DNA has thymine - RNA has uracilOne Gene/One Protein Hypothesis - a gene codes for the sequence of amino acids in a proteinGene Mutations can occur by:substitution - letter gets replaced by anotherinsertion - add extra letterdeletion - remove letterinversion - rearrangement/flip flop of letters• can affect the type of protein being produced by altering the amino acid sequenceProtein mutations that can result after gene mutations are:missense - replaces one amino acid with another; mutated protein is same length as normal proteinnonsense - produces stop codon earlier in the chain; mutated protein is shorter

frameshift - changes whole amino acid sequence after mutation; mutated protein can be any length(shorter, longer or same length) compared with normal proteinno effect - even though the gene may be changed, if the same amino acids are coded for, theprotein will still be the sameGene regulation - many cells can turn genes or protein synthesis on and off as needed.Transcriptional regulation is the most commonly used type. There are others (see your notes)Some genes also have on/off switches (regulatory regions) (See notes on Lac Operon)rDNA (recombinant DNA) - plasmid (ring of DNA from a bacteria) containing a human gene. Manyuses (see your notes)Restriction enzyme - molecular scissors - cuts DNA at a precise point. Some types can createsticky ends - pieces with complementary bases that can stick togetherDNA Ligase - molecular glue - enzyme that can attach DNA nucleotides togetherElectrophoresis - used to do DNA fingerprinting - separates small DNA pieces/fragments accordingto different lengths, using an electric current. DNA is negative and will be pulled to the positive pole.Longer/heavier pieces move slowest and will be left nearest the origin at the negative pole. Seeassignment called DNA Fingerprinting to review how to plot DNA pieces onto a "paper gel-Cloning a gene - cut desired gene out of a DNA strand using a restriction enzyme• remove plasmid from a bacteria and cut plasmid with same restriction enzyme as above• sticky ends of plasmid and gene will match and will be drawn together• add DNA ligase to complete the seal• create more copies by letting plasmid re-enter a new bacteria and let bacteria reproduce• multiple copies of the original gene will be made by the bacteria. SEE your notes on "How to clone a gene" and "Redesigning Bacteria" for more detailsPros and Cons (Benefits and Risks) of Genetic Engineering -Research this on your own. Two good articles are:http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-3.pdfhttp://www.buzzle.com/articles/pros-and-cons-of-qenetic-enqineering.htmlSee also Promises and Problems of Recombinant DNA Research - Chapter 11 of your textBiodiversity:Classification Heirarchy- Kingdom, Phylum, Class, Order, Family Genus, SpeciesSpecies - the most specific group - interbreeding individuals that produce fertile offspringBinomial nomenclature - scientific name using genus(capitalize) and species(no caps) names5 kingdoms - (most advanced to least advanced) - see notes for criteria (eukaryotic etc)1. animalia2. plantae3. fungi4. protista (eukaryotic single celled)5. monera (prokaryotic bacteria)

Dichotomous Key - tool used to identify organisms/give them a name. Uses process of elimination.Subdivides by 2, See notes and Shark assignment. Be able to use a key and be able to design onePlants;Bryophytes - non-vascular plants - evolutionary dead ends• gametophyte is the dominant version of the alternation of generations• have waxy waterproof coating• have portholes in their leaves for gas exchange• tissues did not have rigid support & could only support vertical growth of a few cms.• did not have true roots but had rhizoids to act as anchors but not absorb and transport waterand nutrients throughout their bodies• water had to reach entire plant by diffusion from cell to cell• sperm needs abundant water to be able to swim to egg - have to live in wet habitatsTracheophytes - Lower vascular plants - Ferns• sporophyte is the dominant version of the alternation of generations• have waxy coating to prevent dessication• have portholes for gas exchange• sporophyte has vascular tissue - they can grow tall because they have a "skeleton" andbecause their roots can absorb large quantities of water• sperm still needs water for sperm to swim to egg, but not as much water as the gametophyteforms a "cup" shape to help trap waterMoss and Fern life cycles - (SEE 43 MOSSES AND LIVERWORTS and 44 FERNS booklet fordiagrams. Know that archegonia makes eggs and antheridia make sperm)Vascular Tissue - xylem and phloem - doubles as a transport and a skeletal systemxylem - carries water upwards from root to leaves2 kinds: tracheids & vessel membersphloem - carries food downwards from leaves to root2 kinds: sieve tube members & companion cellsAngiosperms and Gymnosperms - higher vascular seed plantsgymnosperms : cone bearing plants (including evergreens)- have "naked" seeds because there is no ovary to protect the ovule or embryo- not much food supply to nourish the embryoangiosperms : flowering plants- have "enclosed" seeds because there is an ovary to protect both the ovule and later the embryo- have flowers to attract insect and animal pollinators and increase chances of fertilization- flowers form fruits which help to further protect the ovary and also end up aiding in seed dispersalwhen animals eat the fruits and deposit seed away from parent plant- more successful than the gymnosperms because of the above- 2 kinds monocots and dicots

Feature Monocots Dicots# of embryos 1 cotyledon 2 cotyledons# of seed leaves 1 seed leaf 2 seed leavesRootstype usually fibrous usually taprootstissues presentepidermis, cortex,endodermis, pericycle,xylem, phloem, pithep, cor, endo, peri, x, p,vascular cambiumxylem arrangement ring starphloem arrangement inside pericycle inside arms of starStemsvascular bundlearrangementtissues present in wholestemtissues present in vascularbundleability to undergo secondarygrowthLeaves- vein arrangementscatteredcuticle, epidermis, cortex,vascular bundlesxylem, phloemnoparallelringcuticle, epidermis, cortex,vascular bundlesxylem, phloem, vascularcambiumyesnet-likeFlowers- petal arrangementmultiples of 3 multiples of 4 or 5Examples orchids, grass, lilies trees, peanuts and mostother plantsPlant tissues -ROOTS:root cap - the part of the root that protects the growing root tip as it pushes through the soilregion of elongation - one of the parts of the root that contributes to the growing length of the rootregion of differentiation - the part of the root that matures into the different tissues that performdifferent tasks for the rootapical meristem - the part of the plant that adds new cells to the root and therefore also contributesto growth in length of the rootpericycle - the part of the root that produces branch roots

endodermis - the part of the root that ensures that water is forced into the xylem (inner ring)casparian strip - allows water to enter endodermis but does not allow it to escapeepidermis - the outer 'skin' of the root that absorbs water from the soilvascular cambium - the part of the root (also stem and leaf) that produces new xylem and phloemand contributes to growth in diameterroot hair - the part of the root that increases the absorptive capacity of the rootstarch plastid - the part of the root that stores food made by the leaves during photosynthesiscortex - the part of the root that helps to structurally support the root and also can store food such asstarchSTEMS:pith cells - stores energy and water for the plantvascular bundles - contain the xylem and phloem of the stemtrichome - protects the plant from predators and prevents water loss (like hair) (dead air space)cuticle - waxy outer layer that prevents desiccationLEAVES:Midrib - bulge created by the main veinvein - contains xylem and phloem in leavesstomata - tiny opening/pores that admit C02 for photosynthesis and release H20 vapour and 02guard cells - control the opening and closing of the stomatapalisade cells - located just beneath the upper epidermis, smaller than spongy cellsspongy cells - rounder and larger than palisade cells, lots of air spaces between themepidermis - there is an upper and lower layer in leaves, the lower having more stomata , the upperbeing thickerChoroplasts - where photosynthesis occurs. Green in color. Found in palisade, spongy and guardcells. Highest amount found in palisade cellsPlant adaptations to life on land -PROBLEMDessication (drying out)Gas ExchangeSupport body without waterReproduce sexually without waterAbsorb water/nutrients from soilSOLUTIONWaxy waterproof layerPores/portholes in the waxy layerVascular TissuePollen/Pollen tubes/SeedsRoots containing vascular tissue (suction)Plant Diagram Labelling - SEE Root, Stem and Leaf labs and "Plant Architecture & Function" notesAnimals: - 2 subdivisions of animal kingdom - Invertebrates and Chordates/VertebratesInvertebrate phylums -- porifora - sponges- cnideria/coelenturata - jellyfish- Platyhelminthes - flatworms- Nematode - round worms- Mollusca - snails, clams and squids- Annelids - earthworms and leeches- Arthropoda - insects, crustaceans and barnacles- Echinodermata - starfish, sea urchins and sea cucumbers

Evolutionary trends of invertebrates -1. bilateral symmetry2. cephalization3. elongated body with a two ended gut tube4. coelom5. segmentationVertebrate/Chordate classes - also see notes for innovations possessed by each class- mammals- birds- reptiles- amphibians- fishEvolutionary trends of vertebrates - all vertebrates have all 5 invertebrate characteristics plus :1. spinal cord2. notochord or backbone3. tail (at some stage of life cycle)4. muscle blocks5. gill slits (at some stage of the life cycle)Invertebrate Characteristics:The following list is more easily memorized with thePorifora:not bilaterally symmetrical(asymmetrical)no cephalizationno gut tube (filter feeder)no coelomno segmentationCnideria:not bilaterally symmetricalno cephalizationno two ended gut tube (has stomach)no coelomno segmentationPlatyhelminthes:bilateral symmetrycephalizedno two ended gut tubeno coelomno segmentationNematoda:bilateral symmetrycephalizedtwo ended gut tubepseudocoelom (not real coelom)no segmentationiart from your textbook (on your invert review)Mollusca:bilateral symmetrycephalizedtwo ended gut tubecoelomno segmentationAnnelida:bilateral symmetrycephalizedtwo ended gut tubecoelomsegmentationArthropoda:bilateral symmetrycephalizedtwo ended gut tubecoelomsegmentationEchinodermata:no bilateral symmetry in adults(bilateral symmetry in larvae)not cephalized (adults)two ended gut tubecoelomno segmentation

Animal adaptations to life on land -lungs: allow animals to acquire oxygen from air (lobe-finned lung fish = first to be able to live on land)legs: (eventually tucked underneath body): allow movement on landeggs/placenta to protect embryo: higher success rate for reproduction; can happen on landmore chambered heart (3+): better separation of oxygenated and de-oxygenated blood; blood withhigher oxygen content = higher energy production - more energy is needed to move on landmethods of preventing desiccation: fur, hair or feathershomeothermy: (mammals and birds) - ability to keep internal temperature stable (not affected bysurrounding temperature) - allowing for stable rate of cellular activity - more energy - movementskeleton (see notes on the benefits of different skeletons) - supports tissues/withstands gravityEvidences for evolution -Fossils - best evidence - no disputing that organisms have changed over timeFrom plants and animals - living examples whose changes over time have been observed anddocumented (peppered moths, antibiotic resistant bacteria, pesticide resistant pests, horses,humans)Vestigial structures - structures in organisms that have no function but indicate an evolutionary linkto other organisms that possess that same structure. Ex. snakes may have evolved from lizard-likecreatures as they have "stumpy vestiges", of what might have been legs, remaining on theirskeletons. Humans have a tail bone, suggesting that the humans likely evolved from an organismthat has a tail.Embryology - similarities in the very early development of vertebrate embryos suggests a commonancestryBehaviour.Biochemistry and DNA seguencing - similiarities suggest common ancestryGeographical distribution - ex. flightless birds found on completely different pieces of land (separatedby water)- flightless, so only could have evolved when continents were once togetherDomestication - shows that in only a few generations, humans can change the physical features ofan animal - if human selection can do it, surely natural selection can tooHomologous Structures - same structure, different function. Ex. Whale flipper, bird wing and humanarm have exactly the same bones - suggests common ancestorAnalogous Structures - different structure, same function . Ex. Bird and Butterfly wings - builtdifferent which suggests non-common ancestry, but same function which suggests that shapes ofstructures are molded by natural selection - only certain shapes of wings will allow for flight.Darwin's theory -• all life descended from a common ancestor• organisms, even of the same species, are all different and that those which happen to havevariations that help them to survive in their environments, get to reproduce and have moreoffspring. Darwin called this Natural Selection• the offspring are born with their parents' helpful traits and as they reproduce, individuals withthat trait will make up more of the population and other individuals that are not so well adapteddie off. Darwin called this Natural Selection• Darwin's theory can be divided into five parts:1. overproduction - organisms produce more offspring than actually survive2. struggle for existence (competition) - every organism must struggle to survive by competingagainst other organisms for resources3. variation - there is variation within a species (if all were the same none would be better suitedthan any other and selection would not occur). Variation is the raw material that NaturalSelection acts on

4. survival of the fittest - some variations allow members of a species to survive and reproducebetter than others (differential reproductive success - if an organisms has a trait that helps itsurvive or reproduce, it is more likely to survive and be able to reproduce).Fitness=reproductive success. The more reproduction - the more fit an organism is.5. origin of new species by inheritance of successful variations - organisms that survive andreproduce pass their traits to their offspring, and the helpful traits gradually appear in moreand more of the populationSee notes for differences between Darwin's and Lamark's theoryAgents of evolution -1 .Natural Selection - the changing of allele frequencies in the population gene pool by differentialreproductive success - the organisms who are fit for/well adapted to the environment are ableto produce more offspring, leaving more of those advantageous alleles in the gene pool(survival of the fittest - the environment is choosing which traits are beneficial). Artificialselection is similar but humans choose the traits, not nature/the environment3 types of natural selection:1 .stabilizing - the individuals who show the average or intermediate trait are selected for2. directional - one variations is favoured, causing the bell curve distribution to shift3. disruptive - both of the "extremes" are selected for, the "average" is not selected2. Mutation (as well as other types of genetic variation - exon shuffling)these can produce new beneficial adaptations and are considered to be the raw material fornatural selection to act on3. Gene Flow - when individuals of a population migrate and take their genes with themif individuals who have migrated mate with members of the different population, differentalleles may enter the gene pool that were not there before4. Non Random Mating (AKA sexual selection) - if individuals of a certain genotype tend only to matewith others of the same genotype, then the result can be a change in the genotypic frequencies ofthat populationaka - individuals mating with individuals because of physical or behavioral characteristicsex. short males w/ short females5. Genetic Drift - when the allele frequency of a population changes unexpectedly and unpredictablyoccurs when the size of a population becomes smaller and when this smaller populationremains isolatedthe isolated members must only have a small sample of the overall variation that was presentin the original gene pool2 types:a) Population bottleneck- caused by something like natural disaster or disease - rapid decrease in population size- only a few organisms survive - likely because their genes/adaptations allowed them to survive-the now smaller gene pool will re-establish the population with less variation

) Founder effect- caused when a small group of individuals migrate together and establish their own new populationelsewhere- the new group of "founders" have only a fraction of the alleles the original population had- group likely migrates away because they differ from the original population slightly, causingthese "different" alleles to be highly concentrated within the new populationHardy-Weinberg Equilibrium-principle states that no evolution will occur as long as there is no natural selection, no mutation orother factor that can create new genetic variation, no gene flow, no sexual selection/non-randommating, and no small population sizes-ie - predicts that if all factors remain constant, the gene pool will also remain constant or have thesame composition generation after generation, thus creating genetic equilibrium- can use the equation R 2 + 2Rr + r 2 (P 2 + 2PQ + Q 2 ) to calculate gene/allele frequenciesIsolation - causes gene frequencies to change because mutations and exon shuffling can createnew variations in populations. If there is no gene flow or mating between members of the isolatedpopulations, then the new characteristics won't be shared. Speciation will occur if the newcharacteristics prevent the mating or production of fertile offspring - that is - the separatedpopulations become different speciesgeographical: (extrinsic)- populations of the same species are separated by geography (distance, mountains, rivers)- genetic changes/mutations happen randomly and differently in the separated populations and thrunatural selection will accumulate in the separated populationsreproductive: (intrinsic)- when different populations of the same species either do not interbreed, or if they do, no fertileoffspring are produced- can occur either before or after zygote formation- examples of RIMs: mechanical, behavioral, seasonal (see your notes for further examples andexplanations)Coevolution - occurs when two or more organisms evolve together in order to maintain arelationship- build a "partnership" with the other organisms- three different types are:-predator-prey relationships-symbiotic relationships-parasitic relationshipsAdaptive radiation - a type of divergent evolution- instead of two new species evolving from a single ancestor, more than two new species evolve- the number of new species depends on how many new habitats the ancestral group of organismsmoved into and were successful at adapting to- separate species are formed when they cannot produce fertile offspringPhyletic Gradualism vs Punctuated Equilibrium - see your notes

Origin of life - thought to have occurred around 3.8 billion years ago. Biologists today believe thatlife originated from molecular aggregates/compounds in the sea/tide pools.The first living things werethought to have been heterotrophic prokaryotes (bacteria) - see notes on heterotroph hypothesisMethanogens - bacteria that produce methane (and hydrogen sulfide gas)- chemoautotrophs : make own food by synthesizing organic compounds from inorganic precursors- trap heat energy from other chemical reactions to power their own synthetic reactions- were probably one of the first types of autotrophs, but did not give rise to today's life formsOrigin of the earth & atmosphere- at first the earth was a huge barren ball of ice and rock with a radioactive centre- the center was heated until the rock melted- this molten rock erupted through the surface and with it, clouds of gases from the interior werereleased - creating the 1st atmosphere (no oxygen)Origin/evolution of Organic Compounds and first cells - see your notes - including the"Evolution - unit in a nutshell" pageConnections Section:1. See Exam Video Questions worksheet2. "What is the connection between Genetic Engineering and Evolution?" (research on your own)Exam Format• Approximately equal marks from the Biodiversity and Genetics units• Approximately 100 multiple choice (—100 marks)• Approximately 10 short answer questions including video questions (—60 marks)• Short answer questions will vary from 4 to 8 marks per question• There will be a small degree of choice in the short answer section. Choose carefully and donot answer more than the required number of questions. If you know all questions equallywell, choose the ones worth more marks as this will help dilute mistakes made in the multiplechoice section of the exam