OCR Use of Biological Resources Booklet PDF

Use of Biological Resources Booklet UNIT 7 USE OF BIOLOGICAL RESOURCES LEARNING OUTCOMES 5a Food production 5.1 describe how glasshouses and polythene tunnels can be used to increase ☺ 😐☹ the yield of certain...

Use of Biological Resources Booklet UNIT 7 USE OF BIOLOGICAL RESOURCES LEARNING OUTCOMES 5a Food production 5.1 describe how glasshouses and polythene tunnels can be used to increase ☺ 😐☹ the yield of certain crops 5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses 5.3 understand how the use of fertiliser can increase crop yield 5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants 5.5 understand the role of yeast in the production of food including bread 5.6 practical: investigate the role of anaerobic respiration by yeast in different conditions 5.7 understand the role of bacteria (Lactobacillus) in the production of yoghurt 5.8 understand the use of an industrial fermenter and explain the need to provide 5.9 understand the methods used to farm large numbers of fish to provide a source of protein, including maintaining water quality, controlling intraspecific and interspecific predation, controlling disease, removing waste products, controlling the quality and frequency of feeding, and selective breeding 4b Inheritance (part) 3.14 understand that the genome is the entire DNA of an organism and that a gene is a section of a molecule of DNA that codes for a specific protein 3.15 understand that the nucleus of a cell contains chromosomes on which genes are located 3.16 describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine (C) with guanine (G) (b) Selective breeding 5.10 understand how selective breeding can develop plants with desired characteristics 5.11 understand how selective breeding can develop animals with desired characteristics (c) Genetic modification (genetic engineering) 5.12 understand how restriction enzymes are used to cut DNA at specific sites and ligase enzymes are used to join pieces of DNA together 5.13 understand how plasmids and viruses can act as vectors, which take up pieces of DNA, and then insert this recombinant DNA into other cells 5.14 understand how large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter 5.15 understand how genetically modified plants can be used to improve food production 5.16 understand that the term transgenic means the transfer of genetic material from one species to a different species (d) Cloning 5.17 describe the process of micropropagation (tissue culture) in which explants are grown in vitro 5.18 understand how micropropagation can be used to produce commercial quantities of genetically identical plants with desirable characteristics 5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep 5.20 understand how cloned transgenic animals can be used to produce human proteins FOOD PRODUCTION GLASSHOUSES AND POLYTHENE TUNNELS 5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops 5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses Glasshouse Polythene Tunnel Both protect crops from harsh weather conditions. The conditions inside can be monitored to ensure high crop yields (a large mass of crop). Suited to crops that do not grow as well outside eg. tomatoes/lettuce/strawberries. 5.3 understand how the use of fertiliser can increase crop yield Fertilisers contain mineral ions/salts for optimum growth. Mineral ions are absorbed by active transport at the roots. They are transported alongside water up the xylem. Magnesium ions Used to make chlorophyll Nitrates Used to make amino acids, which make proteins, for growth and repair Phosphates Used to make energy and genetic material Potassium ions Used to activate enzymes Note: Do not write just magnesium, it is magnesium ions! 5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants Biological Chemical Selective to a particular species Not selective/can kill harmless Specificity eg. ladybirds kill aphids only, not organisms any other type of insect. No (bio) accumulation (not a Chemicals can be persistent and (Bio)accumulat chemical) remain in the environment for a ion long time More permanent but …. Less permanent, effects do not last Permanence of · Can fail due to insufficient long. Regular treatment necessary Control research for permanent control · The biological control agent can become a pest too! No resistance (not a chemical) Pests may develop resistance to Development the pesticide chemical. More of resistance doses needed for the same effect. Bioaccumulation Organisms lower down the food chain contain a small amount of chemical (this could be a pesticide). When they are eaten, the chemical builds up in the next trophic level, until large organisms at the end of a food chain contain large quantities of the chemical. This could have a detrimental effect on their health, and the health of humans if we were to eat this organism. MICRO-ORGANISMS 5.5 understand the role of yeast in the production of food including bread Yeast undergoes a type of anaerobic respiration, called fermentation. When yeast solution is mixed with flour, water and some sugar it makes a dough. The dough rises because of the carbon dioxide forming gas bubbles that are trapped within it. When baked in the oven at a hot temperature, the ethanol evaporates and the yeast cells die. 5.6 practical: investigate the role of anaerobic respiration by yeast in different conditions We can count gas bubbles of carbon dioxide over a period of time, eg. 5 minutes, to measure the rate of fermentation. We could modify this experiment by changing the temperature of the water bath to see how temperature affects the rate of reaction. Yeast cells contain enzymes which control the reaction, they work at an optimum temperature. If too hot, the enzymes will denature. 5.7 understand the role of bacteria (Lactobacillus) in the production of yoghurt Sterilise the equipment to remove unwanted bacteria Pasteurise the milk at 90OC to kill unwanted bacteria in the milk (to avoid them competing with the wanted bacteria - lactobacillus, added in the next step) Cool milk to 40OC Add the lactobacillus bacteria Incubate at 40OC for several hours. Lactobacillus will ferment the lactose sugar and make lactic acid. This sours the milk and thickens it to form yoghurt. Cool to 5OC to stop fermentation. Flavoring and colouring may be added. 5.8 understand the use of an industrial fermenter and explain the need to provide Oxygen supply For aerobic respiration Air Filter To remove microorganisms/prevent competition Nutrients To provide glucose for respiration/nutrients for growth Stirring paddles To mix contents, prevent settling, distribute heat Cooling water jacket To control the temperature and prevent over-heating pH buffer To maintain the pH to provide optimum conditions Clean with steam To sterilise, remove microorganisms/prevent competition FISH FARMING 5.9 understand the methods used to farm large numbers of fish to provide a source of protein, including maintaining water quality, controlling intraspecific and interspecific predation, controlling disease, removing waste products, controlling the quality and frequency of feeding, and selective breeding SELECTIVE BREEDING 5.10 understand how selective breeding can develop plants with desired characteristics. We can selectively breeding plants by: Choose two flowering parents plants with the desired features (wee below) Remove the pollen from the anther of one parent flower using a cotton bud Place the pollen on the stigma of the other parent flower Cover with transparent plastic (to prevent other pollen entry) Wait for the seeds to form in the fruit. Collect the seeds and plant them. Wait for the offspring plants to grow and select the ones that contain the desired feature. Repeat for many generations Plants are selectively bred by humans for development of many characteristics, including: disease resistance in food crops increased crop yield hardiness to weather conditions (e.g. drought tolerance) better tasting fruits large or unusual flowers 5.11 understand how selective breeding can develop animals with desired characteristics We can selectively breed animals by artificial insemination: Choose two parents with the desired features (see below) Collect the sperm from the male parent and insert into the female. Wait for offspring to develop. Select the offspring with the desired features. Repeat for many generations. Animals are commonly selectively bred for various characteristics, including: cows, goats and sheep that produce lots of milk or meat chickens that lay large eggs sheep with good quality wool horses with fine features and a very fast pace INHERITANCE (PART) 3.14 understand that the genome is the entire DNA of an organism and that a gene is a section of a molecule of DNA that codes for a specific protein 3.15 understand that the nucleus of a cell contains chromosomes on which genes are located DNA Deoxyribonucleic acid. A molecule that contains genetic information about how to make proteins. Made from basic units called nucleotides, associated with one of 4 different bases. gene A section of DNA that carries information about how to make one specific protein. chromosomes Many genes together make up a single chromosome. protein A molecule that is made as a result of a gene being ‘read’. Each triplet base sequence in a gene codes for an amino acid in a protein. DNA is a molecule called deoxyribonucleic acid. It looks like a ladder. The sides of the ladder are made from phosphate groups and sugar groups. The rungs of the ladder are made from two of 4 different bases called adenin, guanine, thymine and cytosine.. A single unit of DNA is called a nucleotide, and it consists of one base, one sugar and one phosphate. Each ‘rung’ of the ladder is made of two bases that are complementary to one another. The DNA molecule coils to form a double helix. It is the order of the bases running along the length of a DNA molecule that gives the cell information on how to build a protein. This length of DNA is known as a gene. A long length of DNA, with many genes, is called a chromosome.. Normal human cells contain 46 (or 23 pairs – since one is maternal and the other paternal) 3.16 describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine (C) with guanine (G) One side of the DNA molecule can be ‘read’ by enzymes in the cell. Each triplet base (3 base sequence) represents one amino acid. eg. An ACG base order codes for an amino acid represented by a yellow triangle. GENETIC MODIFICATION IN BACTERIA CELLS 5.12 understand how restriction enzymes are used to cut DNA at specific sites and ligase enzymes are used to join pieces of DNA together Restriction enzymes cut DNA at very specific base sequence sites. Many create what is termed as a ‘sticky end’ because they cut DNA in a zig-zag fashion. 5.13 understand how plasmids and viruses can act as vectors, which take up pieces of DNA, and then insert this recombinant DNA into other cells Vectors transport DNA and insert it into cells we have chosen to take up the DNA. Plasmids are often used to transform bacteria and fungal cells. Virus’ can also be used as vectors for other cell types. 5.14 understand how large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter See learning objective 5.8 in this booklet to remind you how we can grow bacteria in fermenters. We can grow other proteins in the same way, such as human growth hormones. IN PLANTS 5.15 understand how genetically modified plants can be used to improve food production The DNA from another species could include a gene that assists with: Increased resistance to a range of pests and pathogens Increased heat and drought tolerance Increased salt tolerance A better balance of proteins, carbohydrates, lipids, vitamins and minerals TRANSGENIC DEFINITION 5.16 understand that the term transgenic means the transfer of genetic material from one species to a different species Genetic engineering is a term usually used to refer to the manipulation of the DNA sequences of an organism Scientists have been able to artificially change an organism's DNA by combining lengths of DNA from different sources The altered DNA is called recombinant DNA (rDNA) Transgenic means the transfer of genetic material from one species of organism to a different species of organism ○ If an organism contains DNA from a different species it is called a transgenic organism Any organism that has introduced genetic material is a genetically modified organism (GMO) CLONING MICROPROPAGATION IN PLANTS 5.17 describe the process of micropropagation (tissue culture) in which explants are grown in vitro 5.18 understand how micropropagation can be used to produce commercial quantities of genetically identical plants with desirable characteristics Main Points to be made using a typical markscheme (although must be in sentences): Explant / Callus Small pieces of plant Agar jelly is the solid medium Nutrient / named nutrient eg. glucose Sterile conditions Use of hormones Plants growing in a fogging greenhouse (a damp place to help reduce water loss) Temperature / light / carbon dioxide levels also controlled Why? All plants are genetically identical (therefore have desired characteristics) Quick process Can be grown all year round CLONING MAMMALS: DOLLY THE SHEEP 5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep Dolly is genetically identical to the Finn-Dorset sheep because it is this cell that provided the genetic material MAKING HUMAN PROTEINS 5.20 understand how cloned transgenic animals can be used to produce human proteins It took scientists 276 attempts to successfully clone a sheep Scientists created Dolly the sheep because they were exploring the possibility of producing medicines in the milk of mammals A transgenic animal that contains a gene within their genome that causes them to produce a useful compound within their milk is produced Once this has been done the animal can be cloned to produce a whole herd or flock, all of which produce the same special milk This process is known as pharming Pharming has been used to produce: ○ Antibodies for targeting cancer cells in humans ○ Blood clotting factor IX for haemophilia (blood clotting disorder) ○ Alpha-1-antitrypsin for cystic fibrosis sufferers