HSC Biology Notes PDF

HEREDITY R E P R O D U C T I O N_______________ INQUIRY QUESTION: How does reproduction ensure the continuity of a species? 1. THE MECHANISMS OF REPRODUCTION THAT ENSURE THE CONTINUTITY OF A SPECIES ⇒ 1.1 Sexual and asexual methods of reproduction in a variety of organisms...

HEREDITY R E P R O D U C T I O N_______________ INQUIRY QUESTION: How does reproduction ensure the continuity of a species? 1. THE MECHANISMS OF REPRODUCTION THAT ENSURE THE CONTINUTITY OF A SPECIES ⇒ 1.1 Sexual and asexual methods of reproduction in a variety of organisms o Reproduction is fundamental to the continuation of life o ASEXUAL is the production of offspring that are genetically identical to each other and the parent o SEXUAL is the production of genetically different offspring resulting from two parents, each producing gamete which fuse in a process called fertilisation SEXUAL REPRODUCTION ASEXUAL REPRODUCTION An essential step is cell division by Processes include binary fission and/or meiosis mitosis ​cell division Requires two parents of different Results in offspring that are genetically gender identical to the parent Requires fertilisation, which results in offspring with a new, unique combination of genetic material, some from each parent Fertilisation can occur internally or externally Dominant form of reproduction in many Dominant form of reproduction in many multicellular plants and animals unicellular, colonial or simple multicellular organisms Animal examples include egg laying in Examples include spore production in insects, crustaceans, arachnids, fungi, and budding and binary fission in amphibians, fish, birds, reptiles and bacteria or protists monotremes; live birth in placentals; immature birth. And pouch-raising in Plant examples include production of marsupials bulbs, tubers, rhizomes, stolons and corms Plant examples include production of flowers or cones o ​Meiosis ​is a cellular reproductive process that occurs in eukaryotic cells; meiosis results in the formation of gametes that contain half the normal complement of genetic material o Mitosis ​is a cellular reproductive process that occurs in eukaryotic cells, mitosis refers to the replication and division of the nucleus; mitosis results in the. production of two identical daughter cells from the parent cell; cytokinesis, which follows mitosis, results in the formation of two cells with each containing and nucleus and cytoplasm ASEXUAL REPRODUCTION o Asexual reproduction: - Occurs widely in plants, generally in the production of runners, rhizomes, tubers, bulbs, corms and spores - Results in clones of the original parent - Includes the regeneration of some simple animals (starfish, flatworms); fragments of organism grow into a new organism - Includes development of an unfertilised ovum in a process called pathogenesis in some species (shrimp, bees, ants)  - Occurs as a result of a cell division called ​binary fission ​in unicellular organisms - May involve ​budding ​as another form of asexual reproduction that results from an outgrowth or asymmetric cell division o Advantages of asexual reproduction - Only one parent is needed - Rapid population growth of identical members o Disadvantages of asexual reproduction - Lack of biodiversity within a population - Overpopulation, leading to possible negative ecological impacts SEXUAL REPRODUCTION o Sexual reproduction - Occurs widely in animals and seed-bearing plants; angiosperms (flowering) and gymnosperms (cone-bearing) - Occurs in primitive plants such as ferns, mosses and liverworts - Fungi may reproduce sexually in times of bad conditions - Results from the production of two different types of ​gametes (male and female) - Male gamete is smaller and more mobile - female is larger containing food reserves for the early development of the zygote into an embryo - Female gamete develops into the seed or egg of embryo which becomes a foetus - Comes about due to male and female gametes uniting in a process called ​fertilisation - Fertilisation results in a zygote which grows through mitotic cell divisions and differentiation to produce an ​embryo - Results from organisms of different gender, population growth rates are often linked to the proportion of females , as female reproductive cycles become the limiting factor  - Occurs in eukaryotes. As the genetic material is carried on chromosomes the gametes have half of the normal number of chromosomes - Somatic cells are diploid o Advantages of sexual reproduction - Biodiversity or offspring - Variation in offspring is the basis of evolution by natural selection - Methods of sexual reproduction promote the dispersal of offspring in some species o Disadvantages of sexual reproduction - Generally requires two parents of different sex to produce viable gametes and fertilisation - Requires fertilisation ⇒ 1.2 Advantages of external and internal fertilisation in animals o In sexual reproduction fertilisation is either internal or external o INTERNAL FERTILISATION​ occurs with the release of the motile male gamete. Within the female body such as in the vagina of placental mammals, and the fertilisation of the female gamete. Internal fertilisation ensures that fewer male gametes are unproductive. Internal fertilisation is also associated with higher levels of development of the embryo internally or under parental care - The union of male and female gametes that occur within the body of the female; in mammals this results from copulation (sex) involving penetration of the female by the penis of the male and release of semen  o EXTERNAL FERTILISATION​ ova and sperm are released into the external environment where fertilisation and subsequent development may occur - The unions of male and female gametes after their release outside the body, often in an aquatic environment INTERNAL FERTILISATION EXTERNAL FERTILISATION Gametes, zygote and embryo Gametes, zygote and embryo are contained in a protected usually in an aqueous environment environment: controlled for ready disperal temperature, moisture, free from predators Relatively high success in Development of offspring development of offspring due to independent of parents; parents increased probability of fertilisation can put energy into the production occurring and many instances of of large numbers of gametes paternal case of offspring; less need for production. Of large numbers of gametes Well suited to a range of terrestrial Well suited to moist or aquatic and aquatic environments environments ⇒ 1.3 Asexual and sexual reproduction in plants o Reproduction in terrestrial plants is both sexual and asexual o Most terrestrial plants are sessile, so successful reproduction is a means of competition and means of dispersal ASEXUAL o Involves mitotic cell division in specific locations such as buds o New individuals arise from portions of the roots or stems, leaves or buds and are genetically identical to the parents o Adult plants produce vegetative organs such as bulb, tubers, rhizomes and suckers from which new plants can arise o Known as ​vegetative propagation o It is a form of cloning; humans use it to have desirable characteristics SEXUAL o Mainly occurs in angiosperms and gymnosperms o They produce the seeds that contain the embryo o Great variety of ways male gamete is transferred to the female gamete in a process called ​pollination o Angiosperms have ovules protected within the ovary o Gymnosperms have seeds that are not protected in an ovary o Seeds produced by angiosperms and gymnosperms contain food reserves for the ​germinating ​embryo STAMEN CARPEL Anther – ​where pollen grains are Stigma – ​sticky top surface to which formed pollen adheres. May be relatively small and smooth (in insect-pollinated plants) Filament –​ stalk that carries the anther. or large and feathered (wind) The length determines whether the anthers are contained inside the petals Style – ​joins stigma to ovary for insect pollination or outside for wind pollination Ovary – ​where ovules are formed Petals – ​a whorl of leaves modified to increase the likelihood of pollination. Often brightly coloured and scented to attract pollinators. May have complete shapes to facilitate entry of particular pollinators to the flower. Receptible – ​reinforced base of the flower, which supports the weight of the reproductive structures Sepals – ​a whorl of modified leaves protecting the unopened bud - Male. Gametes inside the pollen must be carried from the anthers to the stigma a.k.a POLLINATION - Pollen tube germinates and grows down the style carrying sperm to the ovary/ovule ⇒ 1.4 Fungi: budding and spores o Fungi include yeasts, mushrooms, moulds, mildew, rust and smut o Reproduction is asexual and occurs through budding, spore production and ​fragmentation ​(fragment of organism detaches and grows into independent organism) BUDDING o Adult organism gives rise to a small bud which separates to grow into a new individual o Small outgrowth occurs on the bud, parent replicates DNA, nucleus splits o Good if there is no environmental change o Bad if environment changes, no variation, extinction  SPORES o Spores are tiny unicellular reproductive cells o Light and can be carried far distances by wind or animal, colonize new environments o Able to reproduce rapidly and colonise a wide area ensuring continuity of a species ⇒ 1.5 Bacteria: binary fission o Bacteria are prokaryotes, duplication of DNA and cell division varies from mitotic divisions in eukaryotic cells o Comes in a wide range of types and roles o Reproduce asexually through binary fission or multiple fission o Transfer genetic material in the form of a plasmid or a small circular piece of DNA o Bacteria double every 20 minutes o Binary fission is a form of mitosis that is used by unicellular organisms such as bacteria. The process starts with the copying the genetic material (in the form of bacterial chromosomes) of the parent cell. Each chromosome moves to each side of the cell. This is followed by the elongation of the cell and cytokinesis which is the splitting of the cell membrane and cytoplasm of the cell into two daughter cells. As there is no cell nucleus in bacteria, there will not be the splitting of cell nucleus. It is important to note that the parent cell won’t exist at the end because it is now part of the two daughter cells. The two daughter cells are genetically identical to each other as well as identical to the parent which they obtained their genetic information came from. ⇒ 1.6 Protists: binary fission and budding o Reproduce through binary fission and budding o When budding occurs offspring may stay attached to parent resulting in a colony o Budding in protists starts off by the parent protozoan producing a bud which is a daughter nucleus that is created based on the separation of the parent protozoan’s cytoplasm (one fission). o The mechanism of binary fission in protist is similar to that of bacteria’s binary fission process. However, as DNA is stored in the nucleus (whereas no nucleus in bacteria), the chromosome will move to each side of the nucleus before the splitting of the nucleus and eventually splitting of the cell membrane and cytoplasm into two daughter cells. 2. FERTILISATION, IMPLANTATION AND HORMONAL CONTROL OF PREGNANCY AND BIRTH IN MAMMALS ⇒ 2.1 Fertilisation in mammals o Copulation (sex) may result in internal fertilisation o Males release ​semen c​ ontaining ​spermatozoa ​from the penis in a process called ​ejaculation ​into the urogenital sinus of monotremes and marsupials and into the vagina of mammals o Spermatozoa travels to the oviducts which may contain and oocyte that is released from a follicle in the female ovary o 200-500 million spermatozoa reach the oocyte o Testes produce haploid spermatozoon through meiosis of the spermatocyte. It consists of: - A head which contains DNA - A neck which contains centrioles that support zygote division - Mitochondria to supply energy  - Flagellated tail that helps sperm swim Semen: ​fluid containing spermatozoa and other secretions for transport Spermatozoa: ​male gametes; small motile cells carrying a haploid set of chromosomes, produced in the testes Ejaculation: ​process of releasing semen from an erect penis Oocyte: ​immature female germ cells that gives rise to the ovum of female gamete containing a haploid set of chromosomes o Ovary contains follicles in which meiosis occurs to produce the oocyte - Process occurs in two stages - 1. In female foetus - 2. Occurs at intervals after puberty when the ovarian follicle ruptures to release the oocyte - Follicle becomes the corpus luteum which plays a role in pregnancy - Meiosis is complete after the entry of a spermatozoa - The oocyte is then called the ovum o Ovum in placental animals is 0/07-0.15 mm o Oocyte has two external layers; - Inner jelly coat - Outer layer of cells that are remnants of the follicle o Spermatozoa binds with receptors on the jelly coat; acrosome releases enzymes that help it penetrate the layer and change its nature - Ensures only sperm of the same species can enter o Two plasma membranes fuse, allowing the spermatozoa to enter the cytoplasm of the oocyte - Causes the cortisol granules to release their contents to further ensure only spermatozoa enters the cell o Oocyte has suspended meiosis - Entry of sperm triggers the oocyte to complete its meiotic cell division - Now called an ovum as it contains a pronucleus - Membranes of two nuclei dissipate and the two sets of haploid chromosomes join together - Pronuclei fuse, the diploid nucleus of the zygote has formed, and fertilisation is complete ⇒ 2.2 Implantation in mammals o After fertilisation, zygote starts a process of mitotic cell divisions to become a solid ball of cells called a ​morula o Morula travels down the oviduct o It divides in the ​uterus ​and differentiates into the hollow fluid-filled ball of cells called the blastocyst. This embeds (implants) into the endometrial lining of the uterus o Jelly coat is shed prior to implantation o Implantation is a complex process o Inner cell mass contains stem cells that will differentiate into the embryo, a cavity and an outer call layer called the trophoblast o Occurs in several ways - HUMANS trophoblast cells produce and release protein-dissolving enzymes that assist the erosion of the endometrium - Process assists the embedding of finger-like projections into the uterus wall - Enzymes assist by digesting some cells in the endometrium that become the source of nutrition for the developing embryo  o After blastocyst has implanted, stem cells start differentiating and the body plan of the new embryo starts to develop o After implantation in placental mammals the trophoblast develops into the placenta ⇒ 2.3 Hormonal control of pregnancy in mammals o In mammals’ ​hormones ​are released into the blood by ​endocrine glands. - Hormones promote changes in cells and tissues such as increased growth, development of secondary sexual characteristics and control of the menstrual cycle in female primates and the oestrous cycles in other groups of female mammals o Placental mammals require a complex hormonal coordination of ensure the development of embryo and foetus - Blastocyst​ produces ​CG ​(chorionic gonadotrophin) which prevents corpus luteum from degenerating - Corpus luteum is the remnant of the ovarian follicle that released the oocyte and it produces hormones that maintain pregnancy HORMONE WHERE PRODUCES ROLE Progesterone Placenta and corpus Called the hormone of pregnancy luteum because without it the endometrium would not be In human, horses, maintained or support the sheep and cates the implantation of an embryo progesterone released from the. Stops contraction of the smooth placenta is sufficient muscle of the uterus which is to maintain involved in giving birth; if occurring pregnancy sufficiently before full gestation this may result in a miscarriage Cattle, pigs, dogs and goats rely Prevents the pituitary secreting heavily on the gonadotrophin luteinising hormone progesterone and follicle stimulating hormone to released from the suppress ovulation during corpus luteum pregnancy Helps induce immune tolerance, possibly mediated by a protein called Progesterone Induced Blocking Factor (PIBF) Oestrogens Placenta, E4 from Stimulates the development of foetal liver mammary glands Stimulate the development of the uterine smooth muscle layers ready for birth; this counters the effect of the ‘progesterone block’ that suppresses uterine contractions late in pregnancy Helps induce immune tolerance, possible by expanding regulatory B and regulatory T or Tregs cells o Oestriol is made from a precursor produced in the adrenal glands of the foetus; its levels late in pregnancy are considered an accurate indicator of the health of the foetus  E3 promotes uterine growth and sensitivity to other pregnancy hormones and is believed to trigger labour when it becomes the dominate hormone E4 is believed to protect the foetus from maternal oestrogen Human Chorionic Blastocyst Prolongs the activity of the corpus Gonadotrophin (hCG) luteum Helps induce immune tolerance, possibly expanding regulatory B and regulatory T Induces production of relaxin and stimulates production of oestrogen and progesterone Its presence in urine or blood indicates pregnancy has occurred Relaxin Corpus luteum of Relaxes maternal muscle joints and ovary and placenta ligaments to allow for the expanding foetus Relaxes uterine muscles and prepares lining for implantation Corticotrophin-releasi Hypothalamus of Increases the production of the ng Hormone (CRH) brain and foetus stress hormone cortisol and placenta during pregnancy Regulates duration of pregnancy and foetal maturation Suppresses maternal immune response in early pregnancy Improves blood flow between placenta and foetus inn later pregnancy Associated with ‘late term cortisol surge’ that is believed to support maternal bonding and care in humans and some animals Placental Lactogen or Placenta Possible controls metabolism of Chorionic foetus and mother, mobilising Somatomammotropin energy reserves for the foetus  Stimulates corpus luteum function Promotes development of mammary glands before birth ⇒ 2.4 Hormonal control of birth in mammals o In placental mammals, birth is the process in which the foetus is delivered from the uterus to the outside world o Involves contractions of the uterine smooth muscles, widening and dilation of the cervix and the delivery of the foetus through the cervix and vagina o Birth is orchestrated by a number of interacting hormones which may coordinate for the same role or balance each other in contradictory roles until one becomes dominant o Birth is generally followed by the expulsion of the placenta HORMONE WHERE PRODUCED ROLE Corticotrophin-rel Foetus and uterus Believed to trigger a rise in oestriol easing hormone and when this hormone becomes (CRH) and cortisol dominant, birth ensues; these stress (stress hormone) hormones are the result of the increased pressure due to the growing foetus and their levels rise just before birth Oestrial (E3) – an Placenta Counters the role of progesterone oestrogen on suppressing uterine contractions associated with increases sensitivity of uterus to birth other hormones Oxytocin Hypothalamus and stored and Has a major role in birth as well as released from posterior other functions such as ejection of pituitary; also released from milk while breastfeeding and foetus maternal bonding Initiates and strengthens rhythmic uterine contractions Prostaglandins Uterus Helps initiate labour and uterine contractions by reducing progesterone (which. Inhibits uterine contractions) Relaxin Ovaries Helps dilate (open) the cervix to allow passage of foetus; widens pubic bone and relaxes pelvic ligaments 3. THE IMPACT OF SCIENTIFIC KNOWLEDGE ON THE MANIPULATION OF PLANT AND ANIMAL REPRODUCTION IN AGRICULTURE o Human population increases has increased the demands on agricultural production ⇒ 3.1 Impact of scientific knowledge on the manipulation of plant reproduction in agriculture ASEXUAL TECHNIQUES o Use of cloning plants through vegetative ​propagation ​which allows rapid development of plants with known qualities o Plants often are able to regenerate after damage - Cutting a section of stem, leaf, root and treating it with plant growth hormones to stimulate the development of roots or mitosis and then planting these ‘cuttings’, results in plants identical to the parent o Tissue culture uses knowledge of where cell division occurs in plants to produce new plants in a sterile growth medium o Development of more sophisticated plant propagation practices - Grafting (segment of tissue is inserted in a cut of another plant - Grows disease resistant plants o All vegetative propagation techniques contribute to a lack of genetic diversity but produce large numbers of plants with predictable characteristics SEXUAL TECHNIQUES o Propagation of plants by selectin and germination of seeds results in plant biodiversity and produces large numbers of desirable agricultural plants o Ripened ovaries and associates structures of flowering plants provide many foods called ​fruits o The ​artifificial selection ​of plants with more desirable seeds and fruit has led to a greater diversity of plant foods - Seed banks store seeds from a variety of original plant varities - Factors such as palatability, disease resistance, storage time, size and quantity of produce have been selected to increase agricultural production o Understanding the structure and function of flowers has led to the ability to control pollination or to cross-pollinate or hybridise varieties of plants to benefit agriculture in a manner that has taken artificial selection one step further  - Incidence of ​polyploidy ​(cells containing more sets than the diploid set of chromosomes) o Conventional breeding along with other changes to agricultural practices result in what has been termed the ‘Green Revolution’. o Rice and maize are crops of hybridisation o Maize has both male and female flowers, so it naturally cross-pollinates - Removing tassels or stamens from male flowers is a simple way of producing hybrids o Conventional selective breeding used in natural variation is the deliberate attempt to produce variation by exposing plants to mutagens o Insertion of genes from one species into another is known as ​gene technology or genetic engineering - Genetically modified organism is the production of Bt cotton which contains a soil bacterium that is toxic to insect larvae ⇒ 3.2 Impact of scientific knowledge on the manipulation of animal reproduction in agriculture o Domestication of livestock relies on mainly sexual reproductive techniques o Selective breeding resulted in the development of animals for agricultural purposes o Disadvantages: - Negative effects on reproductive performance (fertility) - Inbreeding due to lack of genetic diversity o Artificial insemination ​is the collection, storage and transport of semen from male animals with desirable characteristics so that more female  can be impregnated and larger numbers of offspring with the desirable characteristics are produced C E L L R E P L I C A T I O N ____________ INQUIRY QUESTION: How important is it for genetic material to be replicated exactly 1. THE PROCESSES INVOLVED IN CELL REPLICATION ⇒ 1.1 Mitosis o The cell replication in which one cell becomes two identical cells - They are somatic (body) and allow growth, repair, asexual reproduction and regeneration in multicellular organisms o Mitosis and ​cytokinesis ​are processes involved in cell replication in eukaryote ⇒ 1.2 Meiosis o Cell division of one diploid cell to become 4 unique haploid cells that have the potential to become gametes  CELL REPLICATION IN PROKARYOTES o DNA is in a tangled or intertwined loop in the nucleoid ⇒ 1.3 DNA replication using the Watson and Crick DNA model o Here are key events in the lead up to the discovery of the structure and function of DNA Researcher and date Discovery Edwin Chargaff (1940s) Found that there is always the same amount of adenine as thy mine and cytosine as guanine this is called Chargaff’s rule Rosalind Franklin and Maurice X-ray crystallised forms of DNA to Wilkins (1953) show a helical arrangement James Watson and Francis Crick Built a model of DNA that showed (1953) the arrangement of nucleotides which explained ability of DNA to replicate THE WATSON AND CRICK DNA MODEL o X-rays of DNA crystals provided data for model building in the structure of a ​double helix ​spiral of two sugar phosphate backbones  running in opposite directions with internal bases held together in their matching pairs of hydrogen bonds ⇒ 1.4 Nucleotide composition o NUCLEOTIDES - Nucleotide monomer in DNA consist of one deoxyribose sugar, one phosphate group and one nitrogenous base o PHOSPHATE GROUP - The phosphate group is derived from phosphoric acid - Acids contain hydrogen ions or protons which they release o SUGAR-PHOSPHATE BACKBONE - Alternating sugar and phosphate groups make up sugar-phosphate o NITROGENOUS BASES - The nitrogenous bases that make up DNA exist in two forms: purines and pyrimidines Pyrimidine bases contain four carbon and two nitrogen atoms in a hexagonal ring with other functional groups Purine bases contain two carbon-nitrogen ring bases totalling five carbon atoms and four nitrogen with functional groups attached ⇒ 1.5 Pairing and bonding o Stability of the DNA macromolecule is due to the large number of hydrogen bonds that results from the pairing of A with T and C with G o The shape of each bases is such that only adenine and thymine align so that hydrogen bonds between hydrogen and nitrogen can form and cytosine and guanine align so that three hydrogen bonds between oxygen and hydrogen and nitrogen and hydrogen can form ⇒ 1.6 The processes involved in cell replication: DNA replication o DNA replication occurs during the synthesis phase of interphase o STEPS: - 1. DNA double helix uncoils and the strands separate when an enzyme breaks the hydrogen bonds between the matching base pairs - 2. The strand terminating in a phosphate group is called the leasing strand; the strand that started the uncoiling from its hydroxyl end - 3. Units called ​primers ​bind with the DNA to start the copying. Primers bind with DNA of the lagging strand at short intervals - 4. Nucleotides slot into place in a continuous process along the leading strand. Hydrogen bonding between base pairs helps to ensure faithful replication of the base sequence - 5. Enzyme removes all RNA primers and the vacant slots are filled with the appropriate nucleotides. Fragments associated are fused together. They are checked for any errors corrected by enzymes - 6. Two identical molecules of DNA have been formed. Each contains one strand from the DNA that acted as a template and one new strand. 2. THE EFFECT OF THE CELL REPLICATION RPOCESSES ON THE CONTINUITY OF SPECIES o Continuity of a species depends on effective reproduction. - For most unicellular organisms, reproduction depends on individuals reaching maturity and either sexually or asexually producing offspring - These processes depend on cell replication o Continuity in a changing environment relies on diversity within a species - Diversity depends on the cellular processes of meiosis and fertilisation o During an organism’s life, cells replicated to provide growth align with repairing and regenerating cells to maintain function  - Processes rely on the integrity of mitosis to ensure faithful copies of cells and their DNA - Key processes include: DNA replication, including proofing and repairing of mistakes Chromosome duplication to form two chromatids joined by a centromere Chromatids faithfully separating. Into different daughter cells Cytokinesis ensuring both daughter cells are viable by containing sufficient cytoplasm to function o Sexual reproduction relies on the transmission of genes - Meiosis is the key cell divisions essential for the production of gametes - Processes include Crossing over of paired chromatids, resulting in exchange of genes and DNA and new combinations of genes aligning a chromosome Random and independent segregation of chromosomes Halving of the number of chromosomes DNA AND POLYPEPTIDE S Y N T H E S I S _______________________ INQUIRY QUESTION: Why is polypeptide synthesis important? 1. REPRESENTATIONS TO MODEL AND COMPARE THE FORMS IN WHICH DNA EXISTS IN EUKARYOTES AND PROKARYOTES ⇒ 1.1 Modelling forms of DNA o Modelling often involves simplification so that the key processed are understood and not overwhelming PROKARYOTE EUKARYOTE  Most genetical material is in a DNA found in the nucleus as supercoiled DNA found in the chromatin nucleoid Protein package is a histone Protein help to form some loops or bends DNA replication starts from a Replication occurs in interphase single origin progresses in both before mitosis directions 12% is non-coding DNA 98% is non-coding DNA Has one copy of each gene Homologous pairs contain two copies of each gene DNA replication is fast Relatively slow No nucleus DNA found in membrane-bound nucleus No organelles Organelles are membrane-bound o Similarity is that they both have ribosomes 2. MODELLING THE PROCESS OF POLYPEPTIDE SYNTHESIS ⇒ 2.1 Polypeptide synthesis o GENES - Genes carry the inherited information give organisms their characteristics and enable them to function - Major part of gene expression is polypeptide synthesis o POLYPEPTIDES - Polypeptide is a long chain of ​amino acids ​that make up proteins - Peptide bonds join amino acids into the chain o RIBONUCLEIC ACID (RNA) - RNA is nucleic acid made up of nucleotides - Sugar in RNA is ribose FORM OF RNA DESCRIPTION AND ROLE Messenger RNA (mRNA) Single strand of RNA that complements the base sequence of the DNA which is the template triplets of bases are codons that link to a specific for amino acid It is bound to proteins It transfers the genetic code from DNA in the nucleus to the ribosome in the cytoplasm Transfer RNA (tRNA) Convoluted and relatively short segment of RNA contains a bond to an amino acid and, at the other end, an anticodon triplet of bases slots into mRNA at a ribosome ‘reads’ the genetic code to insert amino acids into the polypeptide chain Ribosomal RNA (rRNA) Forms a complex with protein to make. Up the large and small ribosomal subunits that come together during translation and then disband Holds mRNA in place for insertion of tRNA ⇒ 2.2 Transcription o DNA is transcribed and then translated into a polypeptide chain o Both steps involve RNA that carry a sequence of triplets of nitrogenous bases o Enzymes facilitate the process and ensure the accuracy of the conversion of genetic code, as stored on the DNA, to functional polypeptides and hence proteins o First process is transcription of DNA into messenger RNA (mRNA) o The transcription process is how the genetic code stored in DNA is copied into another form, mRNA  o Transcription is a rapid process that occurs in quick succession when polypeptides are needed o DNA in the nucleus carries the genetic code. o DNA is unzipped and then a starter is identified and one strand acts as the template for the manufacture of one strand of mRNA. This is processed and carried out through the nuclear pore into the cytoplasm o Enzymes such as RNA polymerase assist the manufacture of mRNA by unwinding the DNA, moving the RNA nucleotides into position and promoting attachment and elongation o Each triplet of bases is called a ​codon o Start and stop codons control the part of the DNA template that is ‘read’ in the process of transcription o mRNA leaves the nucleus through the pores and enters the cytoplasm. There it attached to a small subunit of ribosome ⇒ 2.3 Translation o The process occurs on the ribosomes o Uses mRNA codons as the template for coding for a sequence of amino acids in a polypeptide chain o tRNA anticodons carry the appropriate amino acid into place o translation is often divided into three stages: initiation, elongation and termination  o INITIATION - Once in the cytoplasm, a ‘start’ codon on the mRNA binds. Between the small and the large ribosome subunits - Start codon on the first part of the mRNA contains the AUG bases. This matches with the tRNA anticodon UAC and carries the amino acid methionine o ELONGATION - Ribosome acts like a conveyer belt, moving the mRNA along, and the large. Subunit has grooves into which fit two tRNA units that each carry an amino acid o TERMINATION - Terminal sequence of the mRNA stops the elongation process and releases polypeptide chain ⇒ 2.4 Importance of mRNA and tRNA in transcription and translation o In polypeptide synthesis DNA remains within the nucleus. The ribosomes are in the cytoplasm. mRNA is essential to carry the genetic code stored in DNA from the nucleus to the ribosomes o Three nucleotides in mRNA form a codon that match with an anticodon o AUG is the start codon o Stop codons include UAG, UAA and UGA which terminate the polypeptide chain o tRNA caries a specific amino acid to be joined into the polypeptide chain o Correct matching of the codon on the mRNA to the anticodon on the tRNA is critical for the correct sequence of. amino acids in the polypeptide chain ⇒ 2.5 Analysing the function and importance of polypeptide synthesis o Inheritance and specie continuity depend on polypeptide synthesis o Polypeptide syntheses provides the means for the inherited qualities that are carried in the DNA to be mobilised into cellular structure and function ⇒ 2.6 Assessing how genes and environmental affect phenotypic expression  o Total base composition and arrangement of the DNA in an organism is called its ​genome o Genetic composition is called the ​genotype o The traits of an organism are qualitied such as height and eye colour which is known as the ​phenotypes Researcher(s) Discovery Associate Professor Jeff Craig Environment in the womb has a large impact on later health Professor Brian Byrne Investigated reading ability and literacy development and found impact of teacher not as high as expected as twins in separate classrooms developed similar literacy skills as those in the same classroom Professors Sam Berkovic Dispelled belief that most forms of epilepsy were due to injury and demonstrated that one serious form was not a result of immunisation but was caused by a gene mutation a diet avoiding glucose was demonstrated to be an effective treatment in some cases Perminder Sachdev and Julian Trollor OATS is investigating environmental versus genetic factors that contribute to amyloid plaque development 3. THE STRUCTURE AND FUNCTION OF PROTEINS IN LIVING THINGS o The sequence of amino acids on the polypeptide chain(s) determines the three-dimensional shape of a protein o Proteins are essential to the structure, function and regulation of the body’s cells, tissues and organs o Protein structure is described using four levels: primary, secondary, tertiary and quaternary o Proteins spontaneously fold into three dimensional shapes that is determined by amino acid sequences o Proteins contain functional groups in the amino acids with varying chemical properties Function Catalysts (enzymes) - Promote and control metabolism  - Control the chemical reactions Transport - Allows the selective entry and exit of materials - Proteins may be involved in active or passive transport - Some proteins facilitate in the transport of body fluids Storage proteins - Some contain molecules that hold metals that help store oxygen - Other proteins store amino acids for the growth and development of embryos, foetuses and infants Mechanical support - Proteins provide the strength and varying levels of elasticity needed in many tissues and organs - Many of these proteins are extracellular Immune protection - Detection and destruction of foreign microbes is facilitating by the structure and function of antibody proteins Generate movement - Cells can change shape because of proteins that interact to use energy to produce force and movement Messengers (hormones) - Control of growth and differentiation G E N E T I C V A R I A T I O N___________ INQUIRY QUESTION: How can the genetic similarities and difference within and between species be compared? 1. VARIATIONS IN GENOTYPES OF OFFSPRING ⇒ 1.1 Predicting variations in the genotypes of offspring by modelling meiosis o Sexual reproduction depends on fertilisation which will also be a source of variation which can be mathematically predicted o Diploid organisms possess homologous pairs of chromosomes. The autosomes ​are the chromosomes that carry genes for normal development and appear as identical pairs in a ​karyotype o Humans have 23 homologous pairs, that is 22 autosomal pairs and one pair of sex chromosomes ⇒ 1.2 Random segregation ⇒ 1.3 Crossing over of homologous chromosomes o Crossing over involves chromatids breaking at the same point and re-joining in two reciprocal non-parental combinations o Combined with random segregation of homologous chromosomes, many possible combinations of alleles located along the same chromosome can be predicted.  ⇒ 1.4 Fertilisation o Predicting variations of genotypes from fertilisation is demonstrate by analysing a Punnett square diagram o The intersection of rows and columns contains the possible genotype in male and female offspring X Y X XX XY X XX XY ⇒ 1.5 Mutations o Caused by genotype variation o They result in new alleles o There is a change in the DNA o Mutations can be both harmful and beneficial to an organism o Genotypes for a trait on an organism are expressed as letters that represent the alleles o The letters are the same then it is said to be ​homozygous o If the letters are different then it is ​heterozygous 2. FORMATION OF NEW COMBINATIONS OF GENOTYPES PRODUCED DURING MEIOSIS ⇒ 2.1 Autosomal inheritance o Inheritance pattern occurring similarly in males and females because alleles responsible are carried on autosomes o Breakthrough was by Gregor Mendel’s pea plants o It was apparent that for each phenotype, one form of allele was dominated o One trait will be ​dominant w​ hilst the other is ​recessive o These are called Mendelian ratios o Pedigree diagrams ​are another method of showing inheritance of characteristics over at least one generation o Circles represent females, squares represent makes, shading indicates those expressing the trait, horizontal lines show parets/siblings ⇒ 2.2 Sex-linked inheritance o Some genes are carried on the sex chromosomes o This inheritance pattern is called ​sex-linked ​and is associated with gender o Male ​Y ​do not carry alleles that are carried on ​X ⇒ 2.3 Co-dominance o When both alleles are expressed, they are described as co-dominant ⇒ 2.4 Incomplete dominance o The heterozygous form results in a. blend of both allele characteristics ⇒ 2.5 Multiple Alleles o Some traits have more than two forms within the gene pool 3. REPRESENNTING FREQUENCIES OF CHARACTERISTICS IN A POPULATION ⇒ 3.1 Examining frequency data  o Genetic diversity between species is based on comparison of overall genomes o Gene pool ​is all the copies of all the alleles of all the genes in a population - It is a stock of different genes in an interbreeding population - A large gene pool is an indicator of genetic diversity within a species o Allele frequencies ​is the proportion or percentage of all possible alleles at a locus of one particular allele - It indicates the genetic diversity or richness of a gene pool - The allele frequency is expressed as a proportion or percentage of the allele/gene frequency in a population or species o Genotypes are used to provide data for calculation of allele frequency o Phenotypes are used to collect data on allele frequency o It is possible for some alleles in a population to have no variation - Occurs when a particular characteristic is essential for survival o Factors such as genetic isolation, migration, mutation, natural and artificial selection and chance can affect allele frequencies o Population genetics is involved with the study of allele frequencies in a population ⇒ 3.2 Analysing single nucleotide polymorphism (SNP) o SNPs are variations in one nucleotide base, such as thymine being substituted by cytosine on a particular point in the DNA o SNPs may occur in coding and non-coding sections of the genomes but are most common in the sections between genes o SNPs account for 90% of naturally occurring human DNA variation and occur on average once every 300 nucleotides o When SNPs occur, they may impact a gene’s function and directly cause a disease o Alternatively, they can be used as biological markers to help scientists locate genes associated with disease o SNPs can also be used in sustainable agriculture ⇒ 3.3 Identifying trends, patterns and relationships o Trends​ are identified by comparing data over time or across different locations or population groups o Patterns​ are detected when there are similar trends such as an increase in allele frequency over time for several alleles o Relationships​ occur when a trend can be linked to external factors. Changes in human skin pigmentation have been linked to adaptations for protection from skin cancer and the ability to make vitamin D from exposure to UV radiation ⇒ 3.4 Limitations in data  o Collecting data on characteristic frequency is dependent on observational data, obtaining accurate family records, and decisions about aspects of particular phenotypes o Collecting data on SNPs provides an accurate snapshot for specific alleles of genes but the data collection relies on sampling INHERITANCE PATTERNS IN A P O P U L A T I O N__________________ INQUIRY QUESTION: Can population genetic patterns be predicted with any accuracy? 1. USE OF TECHNOLOGIES TO DETERMINE INHERITANCE PATTERNS IN A POPULATION ⇒ 1.1 DNA sequencing o DNA sequencing ​is a complex set of technology dependent processes used to determine the sequence of nucleotide bases in a genome o It is the process used to determine the order of nucleotides in DNA o Involves the following processes - DNA is denatured into separate strands - Primers and specific enzymes are used to make copies of the labelled strands - This amplifies DNA through ​polymerase chain reaction (PCR) PCR is a form of artificial DNA replication that uses specific enzymes and heating and cooling to make unlimited copies of a specific DNA sequence - DNA strands are broken into labelled pieces by using particular enzymes called nucleases in a process known as hydrolysis - Pieces of DNA are separated so the labelled bases can be identified in order: one traditional method of separation of the fragments is electrophoresis o From this process, it is possible to discover genetic patterns and changes in populations, such as mutations, SNPs and other changes in DNA nucleotide sequences ⇒ 1.2 DNA profiling o Also known as DNA fingerprinting o It is the process used to determine an individual’s DNA characteristics, often for the purposed of paternity testing, genealogy, identification of remains or criminal investigation o Used in forensics and in the identification of family relationships o Criminal investigation relies on the purity of the DNA samples o The process involves the following steps: - Collection of biological samples, DNA extraction and purification - Restriction fragment length polymorphism (RFLP) ​where lengths of DNA have been cut by restriction enzymes in specific locations into fragments that are separated and compared. The fragments vary in length between individuals as they contain variable number tandem repeats - Fragments are separated through electrolysis - Fluorescent dyes may replace radioactive probes - They are transferred to a membrane in a process called blotting - X-ray film is used to detect a radioactive pattern followed by a comparison of other DNA samples  2. USE OF DATA ANALYSIS FROM A LARGE-SCLAE COLLABORATIVE PROJECT ⇒ 2.1 Population genetics in conservation management o The study of the frequencies of variants of alleles, the process bringing about changes in alleles, population structures and divisions o It is the study of genetic characteristics of populations and how and why the allele frequencies change over time and space o Many genes in a population are polymorphic meaning there exists more than one o Data analysis of information contributes to decisions about conservation of endangered species, provides evidence for the genetic component cause of some diseases and provides evidence of human evolution and migration o Diversity in a gene pool may result from population size, mutation, genetic drift, natural selection, diverse environments and population movements resulting in gene flow o TASMANIAN DEVIL - Population of Tasmanian Devil is under threat from the Devil Facial Tumour Disease which is contagious - An unstable climate 5000 years ago caused a dramatic reduction in population, distribution and diversity - Lack of genetic diversity (only 1 million SNPs) is a factor in susceptibility to the disease - Devils have low diversity in the genes - Genetic studies have allowed researchers to observe mutations found in cancer cells - Genetic investigations are focusing on behavioural adaptations to reduce the spread of cancer - It allows cancer-free preserves of the population to be established ⇒ 2.2 Inheritance of a disease or disorder o Almost all non-infectious disease has a genetic component o Genetically isolated populations such as Iceland and Finland have proved useful in the identification of rare recessive disease genes Description of the project Trends, patterns and Strategies, goals, relationships outcomes, data analysis WTCCC Compared DNA of Compared 500000 SNPs Large series of people with tuberculosis, of people with single case-control studies coronary heart disease, disease findings included combines with research type 1 diabetes, type 2 a clear genetic link to Map variation in human diabetes, rheumatoid obesity and three new genotypes across the UK arthritis, Crohn’s disease, genes linked to type 2 bipolar disorder and diabetes  hypertension with 3000 Major gene region on healthy controls chromosome 9 was verified Four chromosome regions containing genes that can predispose people to type 1 diabetes were discovered ⇒ 2.3 Human evolution o Moderns humans share a recent link with the Neanderthals and the Denisovans o Analysing data shows us the similarities and differences in organism alleles from different populations GENETIC CHANGE M U T A T I O N________________________ INQUIRY QUESTION: How does mutation introduce new alleles into a population? 1. HOW A RANGE OF MUTAGENS OPERATE ⇒ 1.1 Mutations o Mutations are permanent changes in the DNA or RNA of a cell o It includes changes to the nucleotide sequence of DNA or RNA o DNA replication and synthesis have built-in checks and repair pathways o A mutation is permanent when the repaid process fails to correct the error o Mutations may harm cells and cause diseases like cancer o Mutations may arise spontaneously o Mutagens ​are chemicals or energy forms such as radiation that promote changes in the genetic material (DNA) and hence mutations o Mutagens are often classed as physical (electromagnetic radiation) chemical (cigarette smoke) or natural (viruses) o Mutations can be harmful, neutral or positive o Endogenous mutagens come from the inside the organism’s body  o Exogenous mutagens come from outside the organisms body ⇒ 1.2 Electromagnetic radiation sources o The oscillating electric and magnetic fields, which travel at right angles to each other in a bundle of energy called a photon o It refers to a range of photons carrying energy in the form of electromagnetic fields through time and space o Many high radiation energy types (small wave length) cause mutations such as UV, X-rays and Gamma rays o UV LIGHT - Damages living tissues - Makes skin cells cancerous o X-RAYS - High frequency causes damage to cell DNA causing cell death or uncontrollable division which causes cancer o GAMMA RAYS - An ionising radiation - Break down DNA molecules, damages base and causes large chromosomal deletions - Increases potential of cancer to develop ⇒ 1.3 Chemicals o Substances that increase the likelihood of mutations o Cause changes to the DNA nucleotide bases ⇒ 1.4 Naturally occurring mutagens o Physically or chemically promote mutations o Can come from biological and non-living origins o Microbes, plants, animals, chemicals o HPV and HIV can change the functioning of cells and trigger cancers o HPV infectious disrupt the normal functioning of cells o HIV and HCV affect the body’s immune system 2. THE CAUSES, PROCESSES AND EFFECTS OF DIFFERENT TYPES OF MUTATION ⇒ 2.1 Point mutation o A change in one nucleotide in a DNA sequence is called a ​point mutation o It is when one base is substituted for another o If a substitution of a nitrogenous base occurs in a coding part of DNA it could result in the substitution of an amino acid for another polypeptide synthesis o Substitution in a non-coding region could alter the expression of a gene o Other changes from point mutations include, insertions or deletions which may result in frameshift mutations o Point mutations usually occur spontaneously during DNA replication when a cell is undergoing mitosis or meiosis ⇒ 2.2 Chromosomal mutations o Occurs when a cell is undergoing cell division o Occur due to exposure to radiation or chemicals o Occur by chromosome rearrangement and changes in chromosome numbers o Main types include - Deletion - Duplication - Inversion - Translocation o Chromosomal mutations in germ-line cells in humans result. In a substantial proportion of congenital abnormalities which can impact the offspring that are produced o Chromosomal mutations in somatic cells may. Result. In cell death, or loss/reduction of cell function which may contribute to cancer 3. SOMATIC MUTATIONS AND GERM-LINE MUTATIONS AND THEIR EFFECT ⇒ 3.1 Somatic mutations  o Mutations in the somatic or normal. Body cells that occur in individuals after conception o They cannot be passed on to offspring o The mutations are carried in the daughter cells of the original mutant cell and. therefore, the initial impact is only o specific cells and tissues o Somatic mutations can cause cancer and disease in organisms o They do not directly change the allele frequency in the gene pool ⇒ 3.2 Germ-line mutations o Germ line cells are the gametes that carry DNNA and genes through fertilisation to the next generation zygote o Mutations in germ-line cells result in them being carried to all cells in the offspring o Inherited diseases and disorders are a result of mutations in germ-line cells o They have the potential to change allele frequency 4. THE SIGNIFICANT OF ‘CODING AND ‘NON-CODING’ DNA SEGMENTS IN THE PROCESS OF MUTATION ⇒ 4.1 Mutation in ‘coding’ DNA segments o Coding sections of DNA segments are comprised of the genes that are templates for the formation of polypeptides o If a mutation occurs in the coding, then the consequences can include - A different mRNA codon but the same amino acid ​(silent mutation) - A point mutation may result in a different amino acid ​(missense mutation) - Mutation may result in the substitution of a ‘stop codon (missense mutation) ​which terminates the synthesis of the rest of the polypeptide chain and hence the protein Then becomes non-functional o SILENT MUTATION - A base substitution mutation that results in the same amino acid in the resulting polypeptide and thus no observable impact o MISSENSE MUTATIONN - A base substitution mutation that results in one changed amino acid in the polypeptide sequence and may or may not change the functioning of the resulting protein o NONSENSE MUTATION - A mutation that results in a stop codon being prematurely inserted into a polypeptide, so its synthesis is terminated, and it becomes non-functional ⇒ 4.2 Mutation in ‘non-coding’ DNA segments  o ‘Non-coding’ DNA segments have a range of functions including gene expression o If a ‘non-coding DNA experiences a mutation is a promoter sequence, DNA polymerase may not be able to bind, thereby preventing the transcription of a polypeptide 5. THE CAUSES OF GENETIC VARIATION RELATING TO THE PROCESSES OF FERTILISATION, MEIOSIS AND MUTATION o Mutations are the ultimate source of new alleles and genetic change Fertilisation Meiosis Mutation How this causes Allows new Random Produces new genetic variation combinations of segregation alleles and alleles causes new changes in gene combinations of regulation and chromosomes and expression or hence alleles chromosome Crossing over number and gives new arrangement combinations of alleles among chromosomes Impact on gene Natural selection The process in Potential to pool may play a role by meiosis result in change allele increasing the variation in frequency in gene chances of more combinations of pool ’fit’ parents alleles but not producing the alleles frequency gametes o Fertilisation and meiosis are the key events that facilitate genetic variation in sexual reproduction o In-vitro fertilisation is used, along with genetic screening to reduce the chance of genetic disease 6. THE EFFECT OF MUTATION, GENE FLOW AND GENETIC DRIFT ON THE GENE POOL OF POPULATIONS o Diversity within a gene pool may result from population size, mutation, genetic drift, ​natural selection, diverse environments and population movements resulting in ​gene flow  o The effect of mutations, genetic drift and gene flow on the gene pool are better in small populations Cause Effect Evaluation MUTATION Initially mutation Most significant cause of increases the variety of change to gene pool alleles in the gene pool mutation impact may be positive, negative or neutral GENETIC DRIFT Random changes in allele Least important and less frequency due to a range likely to alter gene pool of factors in small composition unless the populations random population is very small events might lead to increases or decreases of allele frequency GENE FLOW Migration into a Generally positive impact population can increase by increasing the diversity the genetic diversity due of the gene pool to gene flow Conservation management practices include the maintenance of wildlife corridors to ensure gene flow B I O T E C H N O L O G Y_______________ INQUIRY QUESTION: How do genetic techniques affect Earth’s biodiversity? 1. INVESTIGATE THE USES AND APPLICATION OF BIOTECHNOLOGY (PAST, PRESENT AND FUTURE) ⇒ 1.1​ ​Past uses of biotechnology ⇒ 1.2 Present uses of biotechnology o AGRICULTURAL USES AND APPLICATIONS - Transgenic crops counter abiotic and biotic factors - Crops with increased nutritional benefits increase vitamin content. This is achieved through selective breeding and genetic modification - RNAi has been used to reduce the function of three genes to retain higher levels of oleic acid - GM canola produces an oil resembling that from coconuts or palms o INDUSTRIAL AND ENVIRONMENTAL USES AND APPLICATIONS  -Products and processes that degrade toxic or harmful chemicals and wastes by the use of bacteria or other microorganisms have been developed - Diagnostic tests detect and eliminate the illegal use of endangered species - Biofuels are made from plant materials and animal waste - Biodegradable plastics are made from petrochemicals and can be broken down more quickly - Bioplastics have been made from corn starch o MEDICAL USES AND APPLICATIONS - Biopharming produces proteins, vaccines, hormones and blood clotting and blood thinning agents - RNAi gene silencing is used to improve the production of antibodies for treating human diseases ⇒ 1.3 Possible future uses of biotechnology o AGRICULTURAL USES AND APPLICATIONS - Isolation and insertion of genes has reduced the need for nitrogenous fertilisers - There has been an expansion in the ability to control the gender of animals - Marker-assisted breeding to breed hornless cattle in order to end the painful practice of dehorning o INDUSTRIAL AND ENVIRONMENTAL USES - Climate change, food and energy security and waste disposal - Biomarkers act as environmental indicators assess the level of exposure and the impact of pollution or damage from pollutants - Possibility of eliminating some exotic pests o MEDICAL APPLICATIONS - Cultures of human stem cells for drug trials - Development of virus free cells, tissues or organs - Elimination of certain infectious diseases - Recombinants antibodies ⇒ 1.4 The social implications of biotechnology o Possible impacts on developing countries through losing traditional markets and products o Food safety and security o Potential for environmental damage o Loss of autonomy o Potential for bioterrorism or the use of biological weapons in warfare o Lab safety and security of genetically modified plants and animals o Ethical concerns about future directions o Less starvation and undernutrition o Less environmental damage because of more efficient food production o Increased life expectancy and quality of life  o Personalised medicine and management of health risks o More resources and environmentally friendly and reliable energy supplies ⇒ 1.5 The ethical uses of biotechnology o Use of animal parts o Deliberately breeding animals for research of disease o Change the genomes of other organisms and potentially changing ecosystems and biodiversity ⇒ 1.5 Researching future directions of the use of biotechnology o Bio-computers which control gene expression being inserted into a living cell o Gene therapy involves attempting to correct faulty genes in human cells ⇒ 1.6 Evaluating the changes to the Earth’s biodiversity due to genetic techniques o Tools of genetic research are included o Covered in genetic technologies o Initial increase in genetic diversity o Uptake of the use of genetically identical or similar organisms o Increase in rate of species extinction o Increase in life expectancy and size of human population o Elimination of species considered as pests to humans ⇒ 1.7 Evaluating the potential benefits for society of research using genetic technologies o Less starvation and undernutrition o Less environmental damage because of more efficient food production o Increased life expectancy and quality of life, personalised medicine and management of health risks o More resources and environmentally friendly and reliable energy supplies, including better waste management or elimination and less pollution G E N E T I C T E C H N O L O G I E S___ INQUIRY QUESTION: Does artificial manipulation of DNA have the potential to change the population forever? 1. INVESTIGATE THE USES AND ADVANTAGES OF CURRENT GENETIC TECHNOLOGIES THAT INCLUDE GENETIC CHANGE 2. COMPARE THE PROCESSES AND OUTCOMES OF REPRODUCTIVE TECHNOLOGIES ⇒ 2.1 Artificial insemination o Collection, storage and transport of semen from male animals with desirable qualities used to fertilise a large number of females o Large numbers of more desirable animals o Less genetic diversity o Global benefits from storage and transport of semen ⇒ 2.2 Artificial pollination o Involves the transfer of pollen to stigmas to enable pollination and fertilisation o Can be used to deliberately produce hybrids or for selective breeding o Natural pollinations need to be prevented by physically removing stamens or using other techniques to induce male sterility o Improved plant cultivars such as rice and many types of plant hybrids with hybrid vigour 3. INVESTIGATE AND ASSESS THE EFFECTIVENESS OF CLONING ⇒ 3.1 Whole organism cloning o Produces multiple identical copies of organisms with selected characteristics o Plant cloning is used to produce large numbers of the desired plant - Tissue culture is the predominant method used here o Animal cloning occurs in two procedures - Embryo splitting results in identical cells that develop into genetically identical individuals. The qualities of the embryo are often unknown - Somatic cell nuclear transfer (SCNT) uses genetic material from mature animals to result in animals with identical genomes o Effectiveness is: - High pregnancy losses and high morbidity and mortality during neonatal period - May preserve endangered species - Cloning is expensive and prone to failure - Surrogate mothers suffer increased health risks - Used cloned animals for food remains ⇒ 3.2 Gene cloning o Uses vector plasmid results in multiple copied of genes usually in bacterium such as E. coli o Genes that have been expressed can be cloned o The polymerase chain reaction PCR is one method of copying DNA or genes o It is fast and efficient and allows high throughput o It is useful when there are only small amounts of the required gene/DNA 4. DESCRIBE TECHNOLOGIES AND APPLICATIONS USED IN RECOMBINANT DNA TECHNOLOGY ⇒ 4.1 Recombinant DNA technology o Involved gene-shuffling o A specific segment of FNA is isolated and removed from one organism and attached to another piece of DNA, often from a different organism o Produces new characteristics in the host organism or enables the host organism to produce specific substances o Essential steps - Gene of interest is identified and the DNA containing the gene is extracted and purified - Cutting and joining the DNA is done by using a restriction enzyme which results in a single piece of DNA containing DNA from two different species joined together - Monitoring the cutting and joining – electrophoresis can be used to separate DNA fragments - The recombinant DNA is amplified or modified  - Transforming hosts, such as bacteria with the recombinant DNA allows the genes to be carried into nuclear DNA in multicellular organisms 5. EVALUATE THE BENEFITS OF USING GENETIC TECHNOLOGIES IN AGRICULTURAL, MEDICAL AND INDUCTRIAL APPLICATIONS ⇒ 5.1 Agriculture o The ability to more rapidly, precisely and cheaply breed organisms that are more suitable for growth in changing environments; increased salinity, increased drought frequency or exposure to new diseases o The ability to produce more nutritious foods o Need for less or more effective use of pesticides o Less use of labour because of a reduced need for cultivation o Ability to raise livestock more humanely o Ability to control the gender of animals in order to increase productivity and eliminate exotic pests ⇒ 5.2 Medicine o GM vaccines are safer and no longer made from denatured pathogens which occasionally cause disease o Genetic engineering has been used to mass-produce insulin, human growth hormones, follistim, human albumin, monoclonal antibodies, blood clotting and thinning factors, vaccines and many other drugs o Better analytical techniques can be used to detect substances such as specific proteins in cell and tissues samples o Discovering the functions of certain genes has led to a better understanding of some diseases o Cancer-treatment peptides can stimulate the ability of the immune system to recognise the difference between self and non-self-resulting in more effective treatments ⇒ 5.3 Industry o Mass quantities of proteins o Gene technologies allow the development of highly sensitive analytical procedures o Processes and products that would be difficult to develop using traditional biotechnological techniques o Ability to produce renewable and better fuels and products to clean up existing pollution o Biodegradable plastics 6. EVALUATE THE EFFECT ON BIODIVERSITY OF USING BIOTECHNOLOGY IN AGRICULTURE  7. INTERPRET A RANGE OF SECONDARY SOURCES TO ASSES THE INFLUENCE OF SOCIAL, ECONOMIC AND CULTURAL CONTEXTS ON A RANGE OF BIOTECHNOLOGIES INFECTIOUS DISEASES CAUSES OF INFECTIOUS D I S E A S E S__________________________ INQUIRY QUESTION: How are diseases transmitted? - Disease Any condition that impairs the normal living processes and is recognised by the presence of specific symptoms. Has adverse effects on the normal functioning of a living thing or parts of a living thing Can vary significantly in cause, severity and symptoms they cause - Infectious diseases Have a causative agent or infective agent  Known as ​A PATHOGEN They are usually contagious Caused by the invasion of the body by a disease-causing agent - Non-infectious diseases Caused by genetics, environment influences or cellular malfunctions Multiple factors contribute to the development of non-infectious diseases They do not involve a pathogen and are not contagious - Communicable disease Word used to describe a disease than can be transmitted from plant to plant or from animal to animal. 1. INFECTIOUS DISEASES CAUSED BY PATHOGENS ⇒ 1.1 Pathogens: microorganisms, macro-organisms and noncellular o Infection is the presence of a disease-causing organism in or on the body of a host o Infectious diseases are caused by invasion by a ​pathogen ​and can be transmitted from one host to another ⇒ 1.2 Classifying different pathogens that cause disease in plants and animals o Pathogens can be prions, bacteria, viruses, protozoa or protists, fungi or macroscopic parasitic animals o MICROSCOPIC: bacteria, viruses, fungi and protozoans o MACROSCOPIC: parasites like arthropods, flatworms and roundworms Type of Pathogen Some Distinguishing Features Prion Defective form of a protein molecule; does not contain DNA or RNA; mostly attacks brain or nerve cells Virus Non-cellular; contains DNA, RNA and protein coat; requires a living host cell to replicate Bacteria Prokaryotic cell; divides quickly and/or produces toxins Protozoan Eukaryotic cell (single-celled organism); may have a complex life cycle Fungi Eukaryotic cell with cell wall; spreads via spores or rapid division; some infect  external skin and nails while others enter the host’s body Macroparasites Eukaryotic cell with cell wall; spreads via spores or rapid division; some infect external skin and nails, while others enter the body PRIONS - Infectious agents that consist only of protein; no nucleic acid therefore non-cellular - Able to induce abnormal folding of specific normal cellular proteins knows as prion proteins - Prion diseases are also called transmissible spongiform - encephalopathies - Creutzfeldt-Jakob disease (CJD) VIRUSES - Microscopic pathogens from 20-40 nanometres - Is small piece of genetic material encased in a shell called a capsid - Referred to as non-cellular pathogens - Can infect all types of living things - Zika Virus BACTERIA - Prokaryotic, unicellular microorganisms, DNA in a single loop - 1% are disease causing - 1000 nanometres in size - Bordatella pertussis is a bacterium that causes whopping cough PROTOZOANS - Eukaryotic microorganisms, larger than bacteria, DNA in nucleus - Most are less than 50 micrometres  - Parasitic protozoans have complex life cycles involving several hosts - ​ lasmodium falciparum Malaria from mosquito p FUNGI - Fungi are eukaryotic organisms - Yeasts, moulds and crop-destroying rusts and smuts - Many fungi are beneficial and play a key role as decomposers in ecosystems and in the fermentation process however some cause disease MACROPARASITES - Microorganisms that can cause diseases - Ticks, leeches, flees, tapeworms - Have complex lifecycles ⇒ 1.3 Modes of transmission of infectious diseases o Spread involves a wide range of interrelated factors o Transmission must occur for an infection to spread DIRECT CONTACT - Direct contact between people (touch, saliva, mucus, contaminated blood or other bodily fluids) - Individuals physically transferring the pathogens, e.g. through touching, kissing or having sexual intercourse - Direct droplet transmission ​occurs when someone sneezes or coughs and small droplets of mucus which may contain pathogens are ejected as fine spray  INDIRECT CONTACT - Airborne transmission of droplets; respiratory pathogens are usually transmitted through the air - Transmission from ​formites ​(inanimate objects that be​ ​come contaminated) - Transmission from contaminated food and drinking water - Transmission from an infected animal - Involves objects being contaminated with pathogens, e.g. a used tissue, a fork with saliva traces, used bedsheets, or contaminated medical equipment VECTOR TRANSMISSION - Can be mechanical or biological - Mechanical involves an animal carrying a pathogen from one host to another without being infected itself - Biological transmission includes insects and other arthropods - Spread of pathogens by contaminated air, food and water - Involves animals assisting in the transfer of pathogens between individuals - Biological vectors​, mosquitos, transfer the pathogen from one individual to another - Mechanical vectors s​ uch as flies, physically transfer the pathogen from one person to another without being infected themselves Sarah gets the cold sore virus from Direct contact kissing her aunt Dylan goes bush walking and gets a tick Vector transmission bite. This tick transmits bacteria into him that cause Lyme disease Judy catches influenza from a man sitting Direct contact beside her on the train A body piercing salon accidentally Indirect contact reuses a needle, spreading hepatitis C virus from one client to the next Jodi eats chicken that is slightly raw and Vehicle transmission gets salmonella poisoning Alyssa gets bacterial conjunctivitis (eye Indirect contact infection) after playing with a contaminated doll at preschool Nate has unprotected oral sex and as a Direct contact result gets syphilis, a bacterial sexually transmitted infection Pip and John share a drink bottle, which Direct contact also results in them sharing the glandular fever virus James drinks tap water in South America Vehicle transmission and gets giardia Ivan gets bitten by a mosquito in the Vector transmission tropics and develops malaria Jan eats contaminated beef and gets Vehicle transmission Creutzfeldt-Jacob disease Andrew had diarrhoea after touching a Indirect contact contaminated door knob ⇒ 1.4 Investigating the transmission of a disease during an epidemic o An ​epidemic ​is an outbreak or unusually high occurrence of a disease in a population or region o It is the rapid spread of a infectious disease to a large number of people in a particular population in a relatively short period of time o ​Affect those in the population who do not have an acquired or inherent immunity o When it spreads to the entire nation or other countries it is called a pandemic o A ​pandemic ​is an outbreak of a disease over a whole country or on a global scale o Epidemics and pandemics are becoming more prevalent o TRANSMISSION  It is usually rapid There are many factors that increase exposure to pathogens and cause the spread of disease Continual source of a disease is known as a reservoir (infected person during AIDS epidemic, rats and fleas during the Black Death, contaminated water in choler and typhus epidemics) In dense area (cities) pathogens can spread more easily and rapidly, humans are in close proximity with each other and livestock Social and economic factors like contaminated water supply and poor sanitation facilities Environmental factors (change in climate), e.g. ticks inn Africa, Asia and southwest Europe spread due to global warming Loss of healthcare systems and shortages of medical supplies (civil war) Natural disasters (heavy rain, mudslides, cyclones, earthquakes and flooding) damage sewerage infrastructure, causes contamination or water Viruses can evolve and spread faster Globalisation (global trade, migration and global travel) help spread disease Change is susceptibility YEAR DISEASE REGION NUMBER OF DEATHS 541-2 Bubonic plague Europe and Asia 25-50 million 1346-53 Black death Europe, Asia, 72-200 million Africa 1545 and 1576 Smallpox Mexico 17 million 1665-66 Bubonic plague Europe 100 000 1817-24 Cholera pandemic Asia, Europe >100 000 1918-20 Spanish flu Worldwide 20-50 million 1980s HIV Worldwide 35 million 2003 SARS Asia and Canada 800 deaths 2013-16 Ebola West Africa >11 300 deaths 2017 Plague Madagascar 207 2. INVESTIGATING THE WORK OF ROBERT KOCH AND LOUIS PASTEUR ⇒ 2.1 Pasteur’s experiment on microbial contamination o It used to be believed that living matter (moulds, maggots) could generate spontaneously ​also known as ​spontaneous generation ​from non-living matter o Louis Pasteur discovered the microbes (bacteria and moulds) can cause ​contamination​ and disease o He demonstrated this with his swan-neck flask experiment disproving spontaneous generation - Pasteur discovered that microbes were responsible for the souring of alcohol and developed the process called pasteurisation - It led to the development of vaccinations - ⇒ 2.2 Koch’s postulates o Koch showed that bacteria were the cause of a disease called anthrax o He designed four rules of procedure for showing that a particular microorganism is the cause of a particular disease - 1. It must be shown that the microorganism believed to be the cause of the disease is always present in the diseased organisms - 2. Microorganism must be isolated and grown in a pure culture; that is, a. culture only containing that microorganism - 3. Microorganisms from the pure culture, when injected into a healthy organism without the disease, must produce the disease - 4. Microorganisms isolated from the experimental organisms, grown inn pure culture, and compared with the microorganisms in the original culture, are shown to be identical 3. THE CAUSES AND EFFECTS OF DISEASES ON AGRICULTURAL PRODUCTION ⇒ 3.1 Animal diseases DISEASE CAUSE EFFECT Sheep lice Insect: ​Bovicola ovis Sheep lice costs producer’s inn NSW >$100 million per year in lost production and treatment costs Anthrax I humans, ​ acillus Bacterium: B Passed on through cattle, sheep, horses, anthracis the inhalation of goats and deer spores which have been known to survive for 70 years. Has a mortality rate of 50% to 80% Newcastle disease. In Virus: ​Avian. The disease is highly fowls, turkeys, Pneumoencephalitis contagious pigeons, parrots and other domestic and wild birds Foot-and-mouth Virus with seven Caused losses of $19 disease in cattle, serotypes: A, O, C billion. It is highly water buffalo, sheep, SAT1, SAT2, SAT3 contagious goats, pigs, antelope, and Asia 1, and over bison and deer 60 strains ⇒ 3.2 Plant diseases - Plant crops are often staple foods - Losses from diseases are particularly damaging DISEASE CAUSE EFFECT Potato blight Fungi Caused 1 million deaths from starvation Golden potato cyst Globodera Crop damage was a nematode rostochiennsis serious threat to Australia’s potato industry Blast and bacterial Blast fungus blight in rice Stem rust and leaf Stem rust in wheat Caused losses of $19 blotch in. wheat stem and barley billion. It is highly rust in barley contagious Leaf blight and Leaf blotch Altogether these 3 bacterial. Stalk rot. In diseases caused half maize of the population cereal food grain loss *below* Grain smut in sorghum other domestic and wild birds Foot-and-mouth Virus with seven disease in cattle, serotypes: A, O, C water buffalo, sheep, SAT1, SAT2, SAT3 goats, pigs, antelope, and Asia 1, and over bison and deer 60 strains 4. THE ADAPTATIONS OF DIFFERENT PATHOGENS THAT FACILITATE THEIE ENTRY INTO AND TRANSMISSION BETWEEN HOSTS ⇒ 4.1 Adaptations of different pathogens that facilitate their entry into hosts o Pathogens have adaptations that facilitate their entry into cells and tissues and their transmission between hosts o Pathogens have elaborate ways of adaptation o In plants, protective barriers include physical barriers - Thick cells walls - Thick cuticles