Bio Mod 5 Notes Final PDF

Bio mod 5 notes final $IQ: How does reproduction ensure the continuity of a species? explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to:...

Bio mod 5 notes final $IQ: How does reproduction ensure the continuity of a species? explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: – Animals: advantages of external and internal fertilisation Internal Fertilisation External Fertilisation Internal fertilisation involves the fusion of External fertilisation involves the fusion of male and female gametes within a parent’s male and female gametes outside a parent’s body. Internal fertilisation tends to occur body. External fertilisation tends to occur between terrestrial animals. between aquatic animals. E.g., reptiles, mammals, and birds. E.g., algae, fish, and amphibians. Definition Definition Internal: Inside the parent's body, sperm External: Outside parent’s body, sperm fuses fuses with the egg to form a zygote & mostly with the egg to form a zygote & mostly mammals and plants. aquatic species Advantages Advantages - Increased possibility of the union of - Generally, a large number of offspring gametes (due to contained come out of this environment) - More genetic variation - Higher birth rate as the baby grows - Easier to fertilise as they don’t need to inside mate - More selective of mates (internally) Disadvantages - Fusion of gametes may not occur - Disadvantages Has to occur in water - Time must be spent trying to attain a mate - Decreased chance of - Increased energy must be used to fuse fertilisation/survival due to the gametes possibility of them dying  – Plants: asexual and sexual reproduction Parts of a plant Male reproductive part (Stamen) Female reproductive part (pistil) Anther – where pollen grains are formed Stigma – sticky top surface to which pollen sticks. Filament – stalk that carries the anther. The Style – joins stigma to ovary length determines whether the anthers are contained inside the petals for insect pollination Ovary – where ovules are formed or outside for wind pollination. Steps to Sexual reproduction 1. Pollen is transferred to the stigma of a flower. Its dispersal from an anther to a stigma may be aided by a pollinator, e.g bees, or it may occur through wind or water dispersal. 2. The pollen’s tube cell creates a pollen tube from the stigma towards the ovary. The pollen’s generative cell travels down this tube and divides to form two sperm cells. 3. The two sperm cells enter one of the ovules within the plant’s ovary 4. Inside the ovule, one sperm cell fertilises the egg. The other sperm cell combines with the polar nuclei to form the endosperm that helps provide nourishment for the zygote. 5. After fertilisation, an ovule matures into a seed. The seed contains the fertilised egg (zygote) and the endosperm. 6. The fertilised egg (zygote) develops into an embryo, which will grow into a new plant by cell division (mitosis) after the seed germinates Asexual Reproduction in Plants Runners - side branches with clumps of leaves and roots which grow on the ground, the roots dig down and establish the plant as its own individual plant, i.e., Strawberries, grass at beach Bulbs - bulbs are underneath certain plants which allow buds to grow from them and then flourish their own individual plant e.g., Garlic Fragmentation - branch of parent plant is cut off and planted, where it then grows roots and establishes itself as its own plant – Fungi: budding, spores Fungi reproduce asexually when conditions are good as they can reproduce quickly/ when conditions are bad they reproduce sexually Reproduction by Spores Multicellular fungi usually grow as tiny, branching filaments called hyphae that spread through the material on which the fungus feeds. Mycelium is the name of a tangled mass of hyphae. Spores are tiny sex cells that form on special hyphae. They are very light and dispersed easily through animals, water, and wind. The spore lands and forms a hyphae which develops into mycelium. Asexual – The hyphae that produces spores is haploid , in which the spores develop through mitosis resulting in haploid spores being produced and being identical to the parent. (E.g., Penicillium species) - Use spores to launch them to different parts around the main body (mycelium) - Then grow spindle like fibres (hyphae) that grow back to the mycelium - Great way to grow across a large area - use hyphae to grow and then connect back Sexual – Two different hyphae from two different mycelia form a diploid zygote. The zygote goes through meiosis to create haploid spores that have genetic material from both parent cells. These spores end up on the fruiting body of the fungus, the mushroom, which releases the spores into the environment. E.g., Shiitake mushrooms - Spores from two different fungi fuse together and form a new a single new cells with characteristics from both fungi, creating genetic variation and increases the species chance of survival Reproduction by Budding Budding is a type of cell division which occurs from the formation of a bud on the side of the cell, followed by nuclear division to provide each cell with a genetically identical nucleus. After the bud is nearly as large as the parent, cytokinesis occurs. This is the separation of the cytoplasm to form two separate cells.  - Organism makes a small version of itself that continues growing and then can be disconnected and continue growing into an adult organism – Bacteria: binary fission - Bacteria replicate its DNA, grows to almost twice its size and divides into two identical daughter cells (e. coli) – Protists: binary fission, budding Example of protist is plasmodium (causes malaria) Analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals Fertilisation refers to the fusion of the egg and the sperm 1. Ovulation: ovary releases egg 2. Egg travels through the fallopian tube (oviduct) 3. Male releases semen during sex 4. Forms zygote 5. Zygote forms strong outer membrane to stop more sperm entering Implantation refers to the attachments of the fertilised egg to the uterine lining - Zygote moves into uterus - Amniotic sac - bag containing fluid which helps keep the embryo at optimal temperature and provides cushioning - Placenta - provide nutrients and removes waste Role of hormones - O: made by the placenta/stimulates ovulation/aids blood flow to offspring/ aids organ development/ stimulates p - P: released by ovaries/ stimulates thickening of uterus lining/ aids placenta function and relaxes uterus / helps mothers immune system tolerate infant - Oxy ; triggers uterine contractions - HCG: maintains the corpus luteum, which allows progesterone to continue secreting First trimester - HCG hormone rises rapidly as it maintains the corpus luteum, which allows it to continue secreting progesterone (ensures lining remains receptive to embryo) - P and O released by corpus luteum interact with hypothalamus and pituitary gland and decrease production of other period hormones, which prevents menstruation and ovulation - High levels of P also stimulate changes in mothers body (enlargements of uterus, formation of mucus plug to seal the cervix and breast growth) Second trimester - High levels of P and O are vital to continue pregnancy, however HCG and corpus luteum decline as placenta takes over producing P and O End of third trimester - Increased O is released to induce receptors to form on uterine wall that can bind to oxytocin - Oxytocin triggers labour/increased production during labour (created by mothers and babies pituitary gland) - Oxytocin causes muscle contractions of uterus, which push the baby towards the cervix - Feedback loop is caused  Evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture What is agriculture - The growth of crops and animals for human needs Manipulation in agriculture - Selective breeding refers to the creation of organism with certain desirable characteristics (eg chickens, corn) - Types: - natural breeding: (putting male and female in close environment and waiting for them to breed) - artificial insemination: (taking sperm from a male and inserting it into a desirable female) - artificial pollination: ( taking pollen from one flower and inserting it into another flower using a small brush) - cloning: (reproduce by creating a genetically identical copy of an organism using genetic engineering techniques How does it impact Positive Negative - Increased sales (increase in - When used excessively, reduced production, improved quality/pay biodiversity (gene pool becomes more) smaller as “undesirable” traits are - More resistant to pests and disease bred out and variation in a species (farmers save money on pesticides decreases/ more likely to suffer from and less environmental changes in the environment) contamination) Impact is huge and positive, so long as the threat of reduce biodiversity is managed Cell Replication $IQ: How important is it for genetic material to be replicated exactly? model the processes involved in cell replication, including but not limited to: – mitosis and meiosis Mitosis Parent cell 1. DNA replicates 2. Chromatin shortens and thickens to form chromosomes 3. Chromosomes line up individually 4. Spindle fibres attach to chromosomes 5. Spindle fibres shorten, centromeres break and chromatids move apart 6. Cytoplasm separates, cell and nuclear membrane form, chromosomes uncoil Two identical daughter cells Interphase - chromosomes duplicate P- chromosomes condense M - middle/ chromosomes line up in the middle / nucleus gone A - away/ chromosomes move away from the middle to the poles (spindles pull them away) T - two/ two new nuclei form around the chromosomes on either side Meiosis - PMAT twice Meiosis 1 Interphase - chromatids (chromosomes) duplicate to have 2 chromatids (still chromosomes) P1 - chromosomes condense and nucleus breaks down/ homologous chromosomes (same size) pair up Crossing over occurs between homologous chromosomes - segments of chromosome swap at the same spot to create new allele combinations. This is possible because homologous chromosomes carry the same genes at the same spot, in the same order. M1 - chromosomes line up in homologous pairs in the middle of the cell/ cells can line up in random order though, this is random segregation A1 - spindle fibres attach, shorten, and chromosome pairs are split in half T1 - new nucleuses form Cytokinesis 1 - cells split in 2 with 23 duplicated chromosomes Meiosis 2 P- chromosomes condense M - middle/ chromosomes line up in the middle / nucleus gone A - away/ chromosomes move away from the middle to the poles (spindles attach to centromeres and pull them away) T - two/ two new nuclei form around the chromosomes on either side = 4 new daughter cells that are all different (gametes) – DNA replication using the Watson and Crick DNA model, including nucleotide composition, pairing and bonding Structure of DNA - DNA is double stranded, each with a sugar-phosphate backbone as well as nitrogenous bases. The shape is described as a double helix. - The nitrogenous bases bond with the opposite strand base via hydrogen bonds. The bonding occurs with Adenine going with Thymine and Cytosine going with Guanine. - A nucleotide is the basic building block of a DNA molecule. Each DNA consists of a phosphate, a nitrogenous base and a deoxyribose sugar. There are 4 different nucleotides for 4 different nitrogenous bases. Nucleotide orientation is different on either strand (flipped): - One strand is in the 5’ prime→3’ prime orientation - One strand is in the 3’ prime→5’ prime orientation This is based on the carbons that make up the sugar in the DNA and as the strand is flipped, one goes 5’ 3’ while the other goes 3’ 5’. Nucleotide (Deoxyribose sugar) DNA pairing C - G ( 3 dotted lines) A - T (U w/ RNA) (2 dotted lines) Semi conservative model (watson and crick) - When dna is produced, one of the strands in each new dna molecule comes from the old dna (reduced the chance of copying a strand incorrectly DNA replication 1. The enzyme dna helicase unzips the strands by breaking the hydrogen bonds between the bases (quite weak bonds makes replication easy) 2. Each exposed strand acts as a template 3. Dna polymerase (enzyme) helps bind nucleotides in the cell nucleus to the single strand (pairs them up) 4. DNA polymerase stitches the newly joined nucleotides together so the sugar phosphate backbone is formed (which is a polymer) Assess the effect of the cell replication processes on the continuity of species Helps in formation of haploid gametes for carrying out sexual reproduction. Plays a vital role in maintaining the ideal number of chromosomes in organisms. Introduces new characteristics in organisms as a result of recombination due to crossing over.  $ IQ: Why is polypeptide synthesis important? construct appropriate representations to model and compare the forms in which DNA exists in eukaryotes and prokaryotes Feature Prokaryotic (bacteria) Eukaryotic DNA shape Single circular chromosome Many linear chromosomes Bound or unbound Unbound Bound (wrapped around histones to form chromosome) DNA location no nucleus or nuclear membrane Membrane bound nucleus but have nucleoid region where chromosomal DNA is located Relative amount of Small Large DNA DNA replication Fast Relatively slow speed Additional DNA Plasmids (small rings of non Mitochondria and chloroplast have chromosomal DNA) their own DNA Coding DNA Less non coding (introns) dna More non coding (introns) dna model the process of polypeptide synthesis, including: Polypeptide synthesis A polypeptide is a molecule made up of a chain of many amino acids, and one or more polypeptides folded and joined together form a protein - The path from a DNA molecule to the production of a protein: DNA → RNA → amino acids → polypeptide → protein - All cells function through their proteins. - DNA stores genetic information to control the production of proteins - Polypeptide synthesis allows for the creation of new proteins for the organism to use - Includes two processes which are: - Transcription - Translation – transcription and translation Transcription: An mRNA copy of a gene is made, using DNA template – happens in the nucleus. PROCESS 1. RNA polymerase (enzyme) attaches to DNA at the start (promoter) of the desired gene and separates the strands to expose the nucleotide in that region. NOTE: unlike in dna replication, the two strands aren't unwinded completely, instead only a section (a gene) is unzipped but both ends are still together 2. One strand is used as a template to make an complementary mRNA strand, through complementary base pairings (U → A, no T in RNA), copied in the 5’ → 3’ direction 3. RNA polymerase adds free floating RNA nucleotides to pair with their complementary bases on the template strand to make a chain of mRNA, the og dna strand rejoins behind this so it doesn't remain exposed 4. The RNA polymerase reaches a stop codon, marking the end of the gene, and lets go of the template DNA strand – pre-mRNA has been produced: pre-mRNA is made up of exons(coding) and introns(non coding) ↳ for prokaryotes mRNA production is complete 5. In eukaryotes, introns are spliced out of the strand and exons are stuck together to form the final mRNA strand (mature mRNA) 6. mRNA molecules leave the nucleus through a nuclear pore and enter the cytoplasm and attach to a ribosome. Translation: The process where nucleic acid (mRNA) is translated into a protein. – happens in ribosomes. PROCESS 1. mRNA attaches to a ribosome at a specific start codon NOTE: (codon AUG) is the start codon for the synthesis of a polypeptide 2. The ribosome moves along the mRNA molecule. The mRNA sequence is read by the ribosome in triplets of bases called codons. 3. Free floating tRNA molecules have specific anticodon sequences (triplet of bases that corresponds to a specific mRNA codon, complementary) 4. One end of the tRNA has three unpaired bases which attach to mRNA while the unpaired side attaches to amino acids 5. A second tRNA molecule attaches to the next codon on the same mRNA strand in the same way 6. The ribosome catalyses the formation of a peptide bond between adjacent amino acids (when catalysed the tRNA molecule moves away from the ribosome, leaving only its amino acid) until it reaches a stop codon 7. When stop codon is reached, the new polypeptide chain and mRNA strand and tRNA molecule are release from the ribosome 8. The polypeptide chain then folds into a certain shape to form a functional protein. The mRNA can be used again to produce more of the same protein – assessing the importance of mRNA and tRNA in transcription and translation tRNA and mRNA are vital in the transcription translation process In transcription, mRNA is essential to carry genetic code stored in DNA from nucleus to ribosome. Without mRNA, the DNA code specifying the sequence of amino acids would not form. In translation, tRNA is attracted into the ribosome to deposit their corresponding amino acids onto the polypeptide chain. Without tRNA, the mRNA sequence could not be converted into a distinct sequence of amino acids. If mRNA and tRNA did not exist or function correctly, proteins could not be made in a cell and life would not exist – analysing the function and importance of polypeptide synthesis Polypeptide synthesis is extremely important as it is responsible for the transformation of the information in our DNA (genotype) to a physical expression (phenotype). It is important because it requires the accurate translation of the DNA code into a functional protein. These proteins have important structural, enzymatic and hormonal roles within cells. Also crucial for evolution, as mutations in polypeptide synthesis allow for new variations of proteins and structures (advantages or not) to be introduced into species. – assessing how genes and environment affect phenotypic expression Genotype: the genetic make-up of an individual organism. Phenotype: the observable characteristics, determined by both genotype and environment Genotype + Environmental factors = Phenotype The main two factors that affect phenotypic expression are genes and environment: 1. Genes Due to hereditary genes, you may be more inclined to receive a certain disease more than others, especially if there is history of that disease within your family - Genes affect phenotypes such as eye colour and blood type 2. Environment Differences in phenotype caused by environmental factors are not passed from one generation to the next. - A person with dark skin tone due to excessive sunbed use will not pass this on to her children. They have no effect on the person’s genotype so therefore cannot be passed on - Other eg: - pH of soil - Hydrangeas - those grown in acidic soil have blue flowers, in alkaline have pink flowers - The organism’s diet or availability of food/water: nutrition may affect factors such as height and weight  investigate the structure and function of proteins in living things STRUCTURE→ There are 4 levels of protein structure 1. Primary Structure - the sequence of amino acids. - There are 20 different amino acids that can link together in a number of different combinations. 2. Secondary Structure - Polypeptide chain then folds up in various ways. - Most proteins will have sections that fold into a coiled α-helix and other sections that fold into a β-pleated sheet. 3. Tertiary Structure - a precise 3D structure formed by the folding of secondary structures into a complex shape - held together by links made between secondary structures. 4. Quaternary Structure - Some complex proteins consist of more than one polypeptide chain. Each polypeptide chain is referred to as a subunit FUNCTION Type of protein Function Example Structural - Support and movement Collagen and keratin (hair - Maintain shape of cells, tissues, organs and systems and nails - Form a cytoskeleton - Important for growth and repair of tissue Enzyme - Speed up biochemical reactions (catalyse) Amylase: breaks down ↳ especially in respiration and digestion starch and starch in saliva Communication - Work in conjunction with endocrine and nervous system Insulin - regulates blood (hormone) - Travel to target tissue to cause a change in activity sugar level Transport and - Ligand (molecule) binding Haemoglobin: delivers storage - Release ligand when needed oxygen red blood cell Immunity - Antibodies are proteins involved in the immune response Immunoglobulin (antibodies) - React with antigens to fight infection  Genetic Variation $ IQ: How can the genetic similarities and differences within and between species be compared? conduct practical investigations to predict variations in the genotype of offspring by modelling meiosis, including the crossing over of homologous chromosomes, fertilisation and mutations Genetic variation: describes the differences between the genomes of individuals in the same species Process How genotype variation is produced Meiosis - 1 parent cell → 4 daughter cells - Changes genetic composition of chromosomes - This results in new combinations of alleles on a Crossing over chromosome - This produces new variation of genotype upon When 2 homologous fertilisation as some chromosomes will have both chromosomes swap sections maternal and paternal genes Independent assortment - In M1, chromosomes line up with their homologous pair, however the pairs arrange themselves independently to each other (different combinations) - As a result from independent assortment: when the ↓ chromatids segregate, the set of chromosomes in the daughter cells is random Random segregation - This produces new variation of genotypes as different combos of chromatids end up in the gametes Fertilisation - The union of male and female gamete - A gamete has a genetically unique haploid genome - Contributes to genetic variation because it allows for different gametes (containing different alleles) to combine Mutation - A change in the DNA sequence - A mutation can occur during meiosis to produce a new allele in a gamete - The mutant allele will combine with an allele in another gamete at fertilisation to produce a new genotype - a change in the DNA = different genes = different traits = different phenotype - Introduces brand new alleles into population PRAC: pipe cleaners ?  model the formation of new combinations of genotypes produced during meiosis, including but not limited to: – interpreting examples of autosomal, sex-linkage, codominance, incomplete dominance and multiple alleles Types of chromosomes 1. Sex chromosomes: any chromosome which codes for sexual characteristics (1 pair) NOTE: these chromosomes still contain genes that aren't sex specific 2. Autosome: any chromosome that is not a sex chromosome. Only contain genes that code for non sex specific traits (22 pairs in humans) Sex-linked inheritance Patterns in the expression of characteristics found on sex chromosomes (X and Y) Sex-linked inheritance is different to autosomal due to 2 factors, 1. Y chromosome has fewer genes than the X chromosome (Y chromosomes is shorter) 2. Males only have 1 copy of the X chromosome (means men only have 1 copy of certain genes) / if a man inherits a faulty allele on X chromosome he doesn't have a backup and it will have to be expressed ↳ X-linked: Transmission of genes which are found on X chromosome - Recessive: affect men more than women - higher chance of a man inheriting one faulty X chromosome than a woman inheriting 2 fault X chromosomes (if she has a dominant normal allele, it masks the effects) - E.g. red-green colour blindness / haemophilia - Dominant: affect genders equally - Only takes 1 X chromosome - E.g. vitamin D rickets disorder ↳ Y-Linked: transmission of genes found on the Y-chromosome Only ever passed from father to son: never seen in females Autosomal inheritance Patterns in the expression of characteristics found on autosomes ↳ dominant/recessive inheritance - Dominant allele is always expressed (in homozygous dominant and heterozygous) - e.g. brown eyes - Recessive allele is only expressed when no dominant allele is present (homozygous recessive) - e.g. blue eyes ↳ codominant When both alleles are expressed in the phenotype, creating a new phenotype Eg.1 roan cattle In punnett squares, different capital letters are used to represent codominant alleles Genotype: 100% RW Phenotype: 100% roan (both alleles are dominant and both are expressed) NOTE: never use the words “blending” or “mixing”. The DNA hasn't mixed to create a new allele, instead some cells are expressing one allele, and other cells are expressing others We know this as if we cross 2 roan cattle we get one of 3 genotypes Genotype: 25% RR red 50% RW roan 25% WW white Phenotypes ration: 1:2:1 Therefore og white and red alleles are still present and not mixed with each other E.g. 2 human blood type ↳ incomplete dominance The dominant allele is only partially expressed A blending of the features of the two alleles expressed, giving a hybrid that is intermediate Eg. snapdragon flower Red snapdragon flowers crossed with white snapdragon flowers give pink flowers. The red allele only partially masks the white allele, resulting in a pink flower NOTE: Special notation is used to represent alleles that do not show complete dominance. - A letter is chosen to represent the gene – for example, C for colour. - The alleles are written as superscripts next to the gene, so the allele for red would be CR and the allele for white would be Cr Multiple alleles Multiple allele inheritance occurs when there are three or more possible alleles for a gene. While the genotype of an individual will only ever have two alleles at a locus, there is a higher number of possible genotypes (and hence phenotypes) at the locus. Genotype Phenotype E.g. blood groups A A I I A or I i A - Three alleles IA, IB, and i, - Can make one of six genotypes IB IB or IB i B - These genotypes are expressed as one of 4 phenotypes: A, B, AB, O IA IB AB ii O – constructing and interpreting information and data from pedigrees and Punnett squares Pedigrees Used to identify inheritance patterns of a particular trait in family lineage and can be used to determine genotypes of certain individuals and predict if they will express the trait in their phenotype. Also make predictions about the expected genotypes and phenotypes of future offspring. Features Most common inheritance pattern: - Autosomal dominant / recessive - Sex-linked dominant/ recessive How to read: Step 1: check the key Step 2: look at the genders - Autosomal: no. of affected females is around the same as no. of affected males - Sex-linked: almost all affected individuals are male Step 3: look at generations - Dominant: usually appears in every generation - Recessive: two normal parents have an affected offspring Step 4: check estimates with punnett square Punnett square Used to predict all possible genotypes and phenotypes of a genetic cross between 2 individuals with their given genotypes. - Can calculate percentages and ratios - E.g. mendel pea plant - only have 2 alleles for height, tall and short (T and t)  collect, record and present data to represent frequencies of characteristics in a population, in order to identify trends, patterns, relationships and limitations in data, for example: – examining frequency data Allele frequency refers to the relative proportion of a particular allele in a population. ​ You can work out allele frequencies by taking a sample of the population, as long as that sample is big enough for us to say that it is likely to be representative. Allele frequencies can be calculated from information about alleles, or by looking at phenotypes so long as we know the relationship between genotype and phenotype. Also the Hardy-Weinberg model - describes and predicts allele frequencies in a non-evolving population. - Hardy-Weinberg equilibrium states that allele frequencies will stay the same across generations, as long as no evolutionary processes occur. – analysing single nucleotide polymorphism (SNP) The most common type of variation in DNA is a single base substitution, known as a Single Nucleotide Polymorphism (SNP). They are formed when a mutation occurs where a single nucleotide is replaced by another nucleotide and this specific mutation must be present in at least 1% of the population. Are categorised into Coding (in exon): change the protein product of the gene Non-Coding (in intron): affect how much protein is produced from the affected gene - Mostly occur in introns - Account for 80% of human genetic variation - There are approximately 300 million different SNP’s Usefulness: - SNP’s serve as genetic markers. Certain SNPs are present in high frequency in individuals with specific diseases, so by identifying whether or not a specific individual has these SNPs, their predisposition of a disease can be determined. - Mutations allow variation: enzyme functioning changes, appearance changes, disease susceptibility Limitations of SNPs: - Most SNPs occur in introns which are removed, so cannot be recorded by scientists  ! IQ: Can population genetic patterns be predicted with any accuracy? investigate the use of technologies to determine inheritance patterns in a population using, for example: − DNA sequencing and profiling PCR and gel electrophoresis are essential to both techniques Polymerase chain reaction (PCR) A technique used to amplify DNA (make lots of copies of a segment) in vitro Steps 1. Denaturation - 95º Template strand is heated to break h-bonds, separating the two single strands 2. Annealing - 55º Cooled to allow primers (short single stranded pieces of chemically synthesised DNA which bind to the beginning of the target section) to anneal (bind) to the template DNA 3. Elongation - 72º Heat stable DNA polymerase binds at the primers and moves down the template, synthesise new DNA 4. Denaturation pt 2 -95º Once the region of DNA has been copied, it is heated back in order to separate the strands and stop DNA synthesis so the whole process can be repeated Gel electrophoresis A technique used to separate and visualise DNA fragments according to size Steps 1. Prepare set up - Liquid agarose, which contains a dye that binds to DNA, is poured into a casting chamber and sets as a gel. Well comb is used to create wells - This gel is then submerged in a buffer solution which can conduct electricity 2. Load DNA samples and DNA ladder - DNA samples (usually amplified by PCR) loaded into own wells at the negative end - DNA ladder is a control (mixture of known DNA fragments to compare to) 3. Run the gel - An electric charge runs through the gel sp that one end is negative and one is positive - Since DNA is negatively charged (phosphates in backbone are negative), opposites attract and DNA migrates towards the positive end of the box 4. Visualising DNA - Shorter fragments migrate faster and further than larger ones - Dye binds to the DNA as it migrates, allows us to see the lines in the gel called bands (contain large number of same size DNA fragments - which travel to same position in gel) DNA sequencing - process of determining the sequence of nucleotide bases in a piece of DNA. A laboratory technique used to determine the exact nucleotide sequence of a DNA segment, or of a whole genome. The sequence tells scientists the kind of genetic information that is carried in a particular DNA segment. Scientists can use sequence information to determine which stretches of DNA contain genes and which stretches carry regulatory instructions, turning genes on or off. **DNA profiling - process of analysing dna variations, for the purpose of identification DNA profiling generates a specific DNA pattern, or profile, of an individual at a specific loci that can then be matched to a known control Genetic markers: regions of DNA which usually vary between individuals → can be used to construct dna profiles Most common genetic markers: - Short tandem repeats (STRs) ↳ a string of repeating nucleotide units (usually 2-5 bases long), where the number of repeats varies between people - NOTE: non coding DNA Result: people have STRs that are different lengths (i.e. different number of nucleotides) - Single nucleotide polymorphism (SNP) - Restriction fragment length polymorphism (RFLP) Sanger sequencing investigate the use of data analysis from a large-scale collaborative project to identify trends, patterns and relationships, for example: − the use of population genetics data in conservation management Another example is the Tasmanian Devil. Study of SNPS showed that Tasmanian devils have very little genetic diversity. This meant many of them had a predisposition to not fight the fatal DFTD. In 2017 scientists found a way to force the expression of genes which fight the cancer. − population genetics studies used to determine the inheritance of a disease or disorder CF - potential carriers must be screened − population genetics relating to human evolution The Human Genome Project (HGP) was the international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings. Every part of the genome sequenced by the Human Genome Project was made public immediately. The Human Genome Project could not have been completed as quickly and as effectively without the strong participation of institutions from the United States, the United Kingdom, France, Germany, Japan and China. DNA Sequencing Technologies: Various methods include Sanger sequencing, Sanger Sequencing: - Uses dideoxynucleotides to terminate DNA replication at specific points. - Produces DNA fragments of varying lengths, which are then separated and analysed. Applications: - Identifying genetic mutations linked to diseases. - Mapping entire genomes of organisms. - Tracing evolutionary relationships between species. Inheritance Patterns: - Identifies specific gene variants within a population. - Helps determine how traits and genetic disorders are passed from one generation to the next. DNA Profiling Technologies: Common methods include Short Tandem Repeat (STR) analysis and Single Nucleotide Polymorphism (SNP) analysis. STR Analysis: - Examines specific regions in the DNA where short sequences of base pairs repeat. - Highly variable between individuals, making it useful for identification. SNP Analysis: - Looks at single base pair variations in the genome. - Useful for studying genetic diversity and disease susceptibility. Applications: - Forensic science for identifying criminals and victims. - Paternity and maternity testing. - Studying population genetics and migration patterns. Inheritance Patterns: - Reveals how genetic markers are passed from parents to offspring.  - Helps in understanding the distribution of genetic traits within a population. - Combined Use in Population Studies Mapping Genetic Traits: Both sequencing and profiling provide detailed information on genetic variation. Helps in identifying and tracking inheritance patterns of both normal and disease-associated genes. Population Genetics: Analyzes the genetic structure of populations. Assesses genetic diversity, gene flow, and evolutionary processes. Disease Association Studies: Links specific genetic variations to diseases. Aids in developing targeted treatments and personalized medicine. Case Studies and Examples Human Genome Project: Utilized sequencing technologies to map the entire human genome. The HGP successfully sequenced 99% of the human genome and identified key genetic variants, including Single Nucleotide Polymorphisms (SNPs). It provided a reference genome for understanding genetic structure and function, crucial for identifying genes associated with diseases. Impact on Inheritance Pattern Studies: The HGP enabled the identification of genetic variations that underlie inheritance patterns, particularly in relation to genetic disorders. It facilitated genome-wide association studies (GWAS) that link specific genetic variants to inherited traits and diseases across populations. The project laid the groundwork for personalized medicine, where genetic information guides the prevention and treatment of diseases based on individual inheritance patterns.