UNIT 4 BIOLOGY REVISION Red: Need to study/finish notes Yellow: memorizing/consolidating 1. OPEN BOOK/OPEN TIME 2. CLOSED BOOK/OPEN TIME 3. CLOSED BOOK/CLOSED TIME Green : confident/practicing Qs Pending/WIP/Done KEY TOPIC TYPE OF ACTION STATUS PLASMA MEMBRANE Factors : Allele frequency Notes/memorise/practice The incidence of an allele within a gene pool The sum of total genes and their alleles in a gene pool Change one base in the DNA code Change in a nucleotide that results in a different codon that codes for a diff amino acid, changing protein structure Change in one nucleotide that codes for premature stop codon Base addition or deletion that changes reading frame of sequence, resulting in structural changes in protein produced Altering the structure of a chromosome by inserting deleting or swapping a cluster of nucleotides, potentially involving many genes A part of a chromosome is copied resulting in that chromosome having two or more copies of that section. A segment of a chromosome is removed than replaced in reverse order A portion of a chromosome is removed Part of two chromosomes swapped Part of one chromosome is added to a diff chromosome Mutations, random mating, large population, less selective pressure, A factor that impacts an organism’s ability to survive thus selecting for the fitest individual Phenotypes that confer selective advantage (ability to camouflage) to a selection pressure such as a predator Done Done Done Done Done Gene pool POINT Missense Nonsense Frame Shift BLOCK Duplication Inversion Deletion Translocation Insertion Causes of variation (new alleles) Selective agent Selection Pressure on PHENOTYPES Factors affecting Allele freq Gene flow Genetic Drift Founder effect mutation, gene flow, genetic drift, and natural selection. The flow of alleles in and out of a population dur to migration of individuals Change in population’s allele frequencies due to random occurrence reducing genetic variation in a population When a small group of individuals colonise a new population. The founding group’s gene pool is small so the genetic diversity of the new founder population is also small Done Done Done Done Done Done Done Done Done Done Done Bottle neck Selective Breeding Causes that increase/decrease GENETIC DIVERSITY DATING Fossil Record Stratigraphy Relative Absolute TYPES OF FOSSILS Mould Cast Imprint Trace Transitional fossil Index fossil STEPS fossilisation When a large portion of a population is wiped out by a random event, the loss of so many individuals mean many unique alleles are lost, occurs when new popu has lower genetic diversity than pre-disaster population The alteration of a poulation’s gene pool due to human intervention usually selecting for a desired trait. Involves breeding individuals both of whom share the desired trait over generations Genetic drift, geneflow, natural selection, mutations, Documentation of fossils across time and space. Is evidence that life on earth has changed over time. Stratigraphy is the study of the relative positions of the rock strata, some of which contain fossils. The law of superposition states that the lowest stratum is the oldest and the upper strata are progressively younger. The age is estimated relative to the known age of the strata above and below the layer in which the fossil is found Method of determining the relative age of an object in relation to a stratum of rock or a fossil. Absolute dating is based on the decay of certain radioactive elements – the rates at which they decay at are known. Formed when an organism is trapped in sediment decomposing and leaving a cavity in the rock When the cavity becomes filled with other material forming a 3D model of the organism Imprint fossils are formed from an organism moving in some way, leaving behind a trace or track. An impriminting or otherwise fragment of a fossil, usually a print. Provides evidence of activity A fossil that shows an intermediate form of an ancestral group and descendants A fossil of known age, typically very old and can be used to compare the relative age of other fossils Conditions: 1. Lived for a short period of time 2. abundant fossil 3. widely geographically distributed 4. easily identified 1. Sinking to bottom of water body and covered with sediment 2. Rapidly covered 3. Low oxygen 4. Organism is undisturbed DEVELOPMENTAL BIOLOGY Structural morphology Homologous Analogous Vestigial MOLECULAR HOMOLOGY DNA AMINO ACID SEQUENCES PHYLOGENETIC TREE Common ancestor Cladogram PRIMATES HOMINOIDS HOMININS Structural 5. Pressure of more sediment layers can result in sediments turning to rock 6. Hard body parts preserved The comparison of embryo development across species The comparison of phenotypical structures across different species Homologous structures may serve different functions, but are fundamentally and morphologically similar, indicating that the species shared a common ancestor different function, but same structure Analogous structures carry out similar functions that evolved in species that don’t necessarily share a common ancestor, (evolved independently) due to facing similar selection pressures – same function but different structure Vestigial structures are structures remaining in an organism which had a role in the ancestral species but are now functionally useless. Determines shared ancestry between a pair of structures or genes in different taxa. Involves looking at DNA sequences of genes that are common to the species analysed Analysing diff and sims in amino acid sequences between the species to determine relatednesss A branching diagram that depicts the evolutionary relationships between different groups of organisms An ancestor that two or more descendants have in common Organises groups based on similarity without consideration of time or extinction Members of the order primates, that share the features of prehensile hands, opposabale thumbs/toe, binocular 3D vision and social behaviour. Superfamily including grater apes, lesser apes, share characteristics of broad rib cage, no tail, y5 shaped molar teeth, and large cranium Members of taxonomic tribe, includes Humans and bipedal ancestors and relatives Skull: Body: Cranial capacity: increases Spine C Shaped>Shaped Face shape: flater Rib cage: funnel>Barrel Brow ridge: smaller Pelvis long, narrow>short&bowl Teeth: U shape -> V shape Arm leg ratio>decreases Foramen Magnum-> more central Functional Cognitive HOMO NEANDERTHALENSIS Homo erectus Homo Denisovan HOMO SAPIENS OUT OF AFRICA MULTI REGIONAL Heel increase in size Hands: Tools, hunting Lodging Carrying young Scanning for predators Evolution of higher cognitive processes such as: planning, speech and abstract thinking. Relatives of Homo sapiens. They differed from Homo sapiens in a variety of ways including – they had large faces with angled cheek bones, large noses for coping with cold, dry air, and chunkier, shorter builds suited to colder climates. It is thought that they had complex social structures and were possibly the first humans to have language. Homo erectus was the earliest Homo species to expand out of Africa. They had similar body proportions and behaviours to Homo sapiens. were discovered in Siberia, Russia. Analysis of the mtDNA from the fossils reveal that they were closely related to both Neanderthals and Homo sapiens, but genetically distinct. Therefore, the evidence suggests that Homo denisovans interbred with both Homo neanderthalensis and Homo sapiens. Modern Humans. Homo sapiens can generally be characterised by a leaner, more agile bipedal build than our predecessors. Homo erectus migrated in first wave of migration becoming Neanderthals and Denisovans The second migration involved homo sapiens migrating from Africa and interbreeding with them eventually outcompeting them. Homo sapiens evolved in multiple regions around the world at the same time with gene flow occurring between the different groups. DNA MANIPULATION Endonuclease Ligase an enzyme which cleaves a polynucleotide chain by separating nucleotides at specific recognition sites that are complementary to the enzyme’s active site An enzyme that joins the ends of two fragments ligating them together by catalysing the formation of covalent bonds btw nucleotides. Polymerase (RNA/DNA) PCR – Steps & Temperature Primer Nucleotides Taq Polymerase Gel Electrophoresis Uses DNA ladder Gene of interest Vectors -features (3) Recombinant Plasmids Antibiotic resistance gene Transformation - Define - How it occurs Identifying success Gene Cloning Invitro Vs Invivo An enzyme that catalyses the synthesis of a complementary strand of RNA to a DNA template strand using free nucleotides A process that amplifies a specific segment of genetic material so it can be analysed Short nucleic acid sequences that are complementary to DNA template strand which act as a starting point for the Taq polymerase, initiating transcription. Monomer of nucleic acid polymers such as RNA and DNA, building blocks of genetic material Heat tolerant DNA polymerase that synthesises complementary strand of DNA A process of separating DNA fragments based on size in base pairs. It is helpful in gene identification, identifying individuals from DNA samples and determining the size of a gene in base pairs. Uses agarose gel and electric field. It is helpful in gene identification, identifying individuals from DNA samples and determining the size of a gene in base pairs Crime investigations Contains a sample of DNA fragments of known lengths that act as a baseline that allow size approximations of the unknown fragments. Desired/investigated gene Plasmid in which gene of interest is inserted into Self-replicating, multiple copies. Replication origin site. Cloning site. Selectable marker gene. Contains many recognition sites Plasmids that have the gene of interest and antibiotic resistant gene Gene that confers resistance to antibiotics in the bacteria Insertion of the recombinant plasmid into the bacteria either through electroporation or heat shock when the bacteria are cultured on an antibiotic e.g. tetracycline, only those with the successfully introduced plasmid with the antibiotic resistance will survive and form colonies, with untransformed ones dying Making many copies of a specific gene of interest Invivo: research or modification done within the organism Uses/EG of cloning products IMPLICATION Social Ethical GMO Transgenic Eg. Recombinant DNA technology Invitro: technique of performance conducted in a controlled environment outside a living organism (cultured in lab) Eg. PCR --> treatment of genetic disorders --> produces large samples for research purposes --> create transgenic organisms Will there be equity of access? Overpopulation -ve impacts on population’s fitness +ves: Increase population size may benefit economy ~Treating diseases may reduce pressure on hospitals +VES: may save life and increase life expectancies More ethical than non bacterial sources such as animals Facilitates production of proteins like insulin without the need of animals -ves: Considered playing God Which gene therapies should be researched? Genetically Modified Organisms: Genes of an organism altered for a desirable characteristics using gene engineering tech Organisms with from another gene from another species inserted in them GMO in crops productivity CROPS resistance to insect, predation and/or disease IMPLICATION BIOLOGICAL SOCIAL CANOLA: Herbicide resistant Savoury flavour: Tomatoes that live longer without rotting Bt cotton: herbicide and insect resistance Golden rice: Vitamin A +ves: Requires less pesticide use Higher crop yields -ves: Safety of consuming GMOs Cross pollination b/w GM plants and wild plants Cross pollination b/w GM and non-GM crops +ves: Increased food supply, nutritional content and food quality cheapness -ves: Labelling and consumer choice Patents and pricing Large companies could take over as they have more money to buy GMO ETHICAL STRATEGIES Epidemics Pandemics IDENTIFY pathogen Physical Molecular Immunological TYPES of treatment Disinfectant Antiseptic Sterilization Quarantine/Isolation Antibiotics Antiviral Playing God Charging poor countries for GM seeds Cross pollination and honesty issues Rapid spread of disease within a geographical area Refers to worldwide spread of disease with a significant amount of cases Visualising pathogen via electron microscope to determine structure Whole genome sequencing: provides info about pathogen including pertaining to is resistance PCR: used to amplify segments of DNA specific to pathogen. ELISA: exposing blood sample to antigens. If patient has been exposed to pathogen, they will have antibodies that bind to antigen, scientists will be able to determine this via a colour change test. Disinfectants are chemical agents designed to inactivate or destroy microorganisms on inert surfaces Substance used to inhibit spread of microbials on skin medicinal purposes Isolating infected or potentially infected individuals from the rest of the healthy population. Antibiotic directly destroy bacteria by inhibiting biochemical pathway Inhibit Virus’s insertion replication or release from cells
