CfE Higher Biology- Unit 2 Metabolism and Survival (PDF)

CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (a) Abiotic Factors Abiotic factors List as many abiotic factors which can effect the variety of life in an ecosystem… A...

CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (a) Abiotic Factors Abiotic factors List as many abiotic factors which can effect the variety of life in an ecosystem… Abiotic factors pH Temperature Salinty Moisture Abiotic factors The ability of an organism to maintain its metabolic rate is affected by external abiotic factors such as temperature, pH and salinity. CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (b) Conformers Conformers Vs Regulators- which is which? Conformers internal Regulators use environment is dependent metabolism to control on their external their internal environment. environment A B C D E F G H T H BO Conformers The internal environment of a conformer (e.g. Snakes, lizards, frogs) is directly dependent on the abiotic factors that affect the external environment (i.e. temperature, salinity if marine). Can you think of any (i) advantages (ii) Disadvantages YOU MAY DISPLAY THE of being a NEXT FEW conformer? NOTES AS A DIAGRAM IF YOU LIKE Conformers Advantage of being a conformer: Metabolic costs are low as they do not use metabolism to control their internal environment. Disadvantage of being a conformer: Restricted to a narrow ecological niche i.e. most snakes cannot tolerate low temperatures and is less adaptable to environmental change. Can you think of any BEHAVIOURAL strategies that a conformer may employ to maintain their optimum metabolic rate? Conformers Many conformers use behavioural responses which allow them to tolerate variation in their external environment to maintain their optimum metabolic rate. E.g. Lizards bask in the sunshine to raise their internal body temperature. CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (c) Regulators Regulators Can you think of any (i) advantages (ii) Disadvantages of being a regulator? Regulators Regulators maintain their internal environment regardless of external environment. HOMEOSTASIS: They use metabolism to control To maintain the their internal environment. body’s internal environment within tolerable limits Advantage: Regulators can occupy (regardless of a greater range of ecological changes in the niches. external environment) Disadvantage: This regulation to achieve homeostasis requires energy, increasing metabolic costs. Conformers Vs Regulators THINK: Complete the graph by adding a line for A- Conformers and B- Regulators to show the effect of increasing air temperature on body temperature. Conformers Vs Regulators THINK: Look at the graph below. From what you know about conformers and regulators, which is which? Conformers Vs Regulators Spider Crab Shore Crab Habitat: Sea water only Habitat: Sea water and river estuaries Conformer Regulator THINK: (i) What do you think would happen to each of these species if placed in pure water? (ii) Which is a conformer and which is a regulator? Conformers Vs Regulators Able to osmoregulate and survives Shore Crab Spider Crab Dies in less salty water  Conformers Vs Regulators TASK: a) Compare how body River Otter temperature in river otters and large mouth bass varies with ambient temperature. b) Which is a conformer and which is a regulator. Give Large Mouth Bass reasons for your answer. (c) What is the advantage of this metabolic state to the i. The otter ii. The bass Question Time Revised Higher 2012 HOMEWORK INVESTIGATE: Atlantic Salmon can be both conformer and regulator. What is an Research the Atlantic Salmon. osmoregulator? (i)Find out why it can be termed as both a conformer and a regulator (ii) Give an advantage and a What is an disadvantage to the salmon of being thermoregulator? an osmoregulator (iv) Create an A3 poster summarising your notes and comparing conformers and regulators  Question Time CfE Higher 2016 (i) Describe and compare anabolic and catabolic reactions (4 marks) (ii) Describe and compare metabolism in conformers and regulators (4 marks) CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (d) Negative Feedback Control Negative Feedback Control RECAP: What is HOMEOSTASIS? HOMEOSTASIS: Homeostasis is maintained by To maintain the negative feedback control. body’s internal environment within Negative feedback provides the tolerable limits body with stable conditions (i.e. (regardless of temperature to 37oC) to changes in the external function efficiently. environment) Regulators require energy for homeostasis/negative feedback. Negative Feedback Control RECEPTORS EFFECTORS FACTOR INCREASES CORRECTIVE RESPONSE NO CHANGE FACTOR AFFECTING FACTOR AFFECTING BODY IS NORMAL BODY IS NORMAL FACTOR CORRECTIVE DECREASES RESPONSE RECEPTORS EFFECTORS Thermoregulation Thermoregulation is an example of negative feedback. It is the process by which mammals maintain their body temperature at a constant 370C. The hypothalamus The hypothalamus is the body’s temperature monitoring centre. THINK: 1. How is information about body temperature communicated to the hypothalamus? 2. What is the overall aim of thermoregulation? The hypothalamus The hypothalamus is the body’s temperature monitoring centre. Information is communicated by electrical impulses through the nerves to the effectors, which bring about corrective responses to return temperature to normal. The Skin The skin is also an effector responding to nerve impulses from the hypothalamus. Correction of overheating THINK: What happens to your skin when you get too hot? 1. Vasodilation of blood vessels. Increased blood flow to the skin increases heat loss by radiation. 2. Increased sweating. Body heat used to evaporate water in the sweat, cooling the skin. 3. Decreased metabolic rate. Less heat produced. Correction of overcooling THINK: What happens to your skin when you get too cold? 1. Vasoconstriction of blood vessels. Decreased blood flow to the skin decreases heat loss by radiation. 2. Hair erector muscles contract. Traps a layer of insulating air 3. Shivering Muscle contraction generates heat. 4. Increased metabolic rate More heat produced The Skin RESPONSE TO OVERHEATING RESPONSE TO OVERCOOLING Blood vessel DILATES Blood vessel CONSTRICTS (VASODILATION) (VASOCONSTRICTION) Increased HEAT LOSS by radiation. Heat is conserved. Body cools down. Thermoregulation VASODILATION INCREASED THERMORECEPTORS ELECTRICAL SWEATING IN HYPOTHALAMUS IMPULSES DETECT CHANGE SENT ALONG HAIRS TEMPERATURE NERVES TO LOWERED CHANGE EFFECTORS (INCREASES) DECREASE IN METABOLIC RATE NO CHANGE NORMAL BODY NORMAL BODY TEMP. 37OC TEMP. 37OC VASOCONSTRIC- TION TEMPERATURE CHANGE (DECREASES) THERMORECEPTORS ELECTRICAL HAIRS RAISED IN HYPOTHALAMUS IMPULSES DETECT CHANGE SENT ALONG SHIVERING NERVES TO EFFECTORS INCREASE IN METABOLIC RATE temperature It is important to regulate temperature (thermoregulation) for: 1. optimal enzyme activity 2. high diffusion rates Why is it important to maintain body temperature at to maintain metabolism. 37oC? Question Time Revised Higher 2015 Question Time CfE Higher Specimen For enzymes to work at optimum temperature Hypothalamus Nerve impulse Vasoconstriction (vessels get narrower) Reduce blood flow so less heat is lost via radiation Question Time Revised Higher 2014 Question Time Revised Higher 2015 Question Time Revised Higher 2013 Question Time Revised Higher 2012 Hair erector muscles Contracts to raise hairs (1) to trap air for insulation (1) Question Time Revised Higher 2012 Blood vessel Vasoconstriction (narrows ) (1) to decrease blood flow to skin so less heat is lost by radiation Question Time Revised Higher 2012 Keeps temperature within tolerable limits AND For optimal enzyme activity OR For high diffusion rates Basking in the sun Salinity/ Salt concentration Question Time Give an account of metabolism under the following headings: i.) Conformers (4) ii.) Regulators (4) iii.) Thermoregulation (2) CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 5 Metabolism and adverse conditions (a) Surviving adverse conditions Metabolism and adverse conditions Adverse conditions are those that vary beyond the tolerable limits for normal metabolic activity for any particular organism. Some animals have adapted to SURVIVE these adverse conditions while others AVOID them. THINK: How might animals: (i) Survive adverse conditions (ii) Avoid adverse conditions? Surviving adverse conditions Many organisms have adapted to survive adverse conditions by REDUCING METABOLIC RATE. Organisms do this by having a period of DORMANCY during periods when the costs of continued normal metabolic activity would be too high. The advantage of this is that it saves energy. Surviving Adverse Conditions During DORMANCY, metabolic rate, heart rate, breathing rate and body temperature decrease. Dormancy can be PREDICTIVE or CONSEQUENTIAL and can come in several forms: TASK: Try to match the words with their definitions below: 1. PREDICTIVE A. To survive high temperatures/ drought conditions. 2. CONSEQUENTIAL B. (‘Daily sleep’) a period of reduced activity in some animals with high metabolic rates. 3. HIBERNATION C. Organism becomes dormant BEFORE the onset of adverse conditions. D. To survive cold conditions through winter/ 4. AESTIVATION low temperatures when food may be scarce. E. Organism becomes dormant AFTER the 5. DAILY TORPOR onset of adverse conditions. Surviving Adverse Conditions During DORMANCY, metabolic rate, heart rate, breathing rate and body temperature decrease. Dormancy can be PREDICTIVE or CONSEQUENTIAL and can come in several forms: C. Organism becomes dormant BEFORE 1. PREDICTIVE the onset of adverse conditions. E. Organism becomes dormant AFTER the 2. CONSEQUENTIAL onset of adverse conditions. D. To survive cold conditions through winter/ 3. HIBERNATION low temperatures when food may be scarce. A. To survive high temperatures/ drought 4. AESTIVATION conditions B. (‘Daily sleep’) a period of reduced activity 5. DAILY TORPOR in some animals with high metabolic rates. Surviving Adverse Conditions TASK: Watch the video clips and with the help of the text book (page 173 onwards). Give an appropriate example for AND for 1-3, state whether you think it is PREDICTIVE or CONSEQUENTIAL: 1. HIBERNATION PREDICTIVE 2. AESTIVATION CONSEQUENTIAL 3. DAILY TORPOR Predictive Dormancy When an organism becomes dormant before the adverse condition arrives. Example: Trees respond to decreasing day length and a drop in temperature by shedding their leaves in Autumn. This slows the growth of the trees until optimum growth conditions return in spring! Consequential Dormancy When an organism becomes dormant after the adverse condition arrives. Hibernation Hibernation is a form of dormancy that allows mammals to survive adverse conditions in winter (low temperatures). An organisms metabolic rate is reduced when temperatures are low and food is scarce. Metabolic rate reduced. Decrease in body temperature. Slower heart rate. Slower breathing rate. Less energy required Aestivation Aestivation is a form of dormancy that allows animals to survive adverse conditions of high temperatures and drought. The animal remains in a state with its’ metabolic rate at a minimum level until favourable conditions return. Daily Torpor Some organisms (eg. Humans) have a very high metabolic rate. Daily torpor is the name given to a period of time (every 24 hours) when the metabolic rate of an organism is greatly reduced. Question Time CfE Higher Specimen Describe how animals survive in adverse conditions (4) Question Time Revised Higher 2013 Question Time Revised Higher 2012 Question Time Revised Higher 2015 Saves energy Aestivation, Dormancy, Hibernation Question Time Revised Higher 2014 0.2* 2500*24 =12000 cm3 oxygen CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 5 Metabolism and adverse conditions (b) Avoiding adverse conditions Avoiding Adverse Conditions Some organisms attempt to avoid adverse conditions all together. Can you think of any ways this may be done? MIGRATION Migration Migration avoids metabolic adversity by expending energy to relocate to a more suitable environment. Can you think of any species which migrate? Migration MANY BIRD SPECIES HUMPBACK WHALES TURTLES CARIBOU Migration Migration needs energy and therefore has a high metabolic cost. Studying Migration (i) Why might scientists want to study migrating organisms? (ii) What techniques might they employ to do this? Studying Migration Specialist techniques are used to study long distance migration: Leg rings- NEED TO 1. Bird – Leg ringing AND BE RECOVERED recovery (RECAPTURED) 2. Turtle- Satellite tracking Satellite tracking-DON’T NEED TO BE RECOVERED BUT IS MORE EXPENSIVE Influences on migratory behaviour Migratory behaviour can be: INNATE: Inherited and inflexible. LEARNED: Begins after birth and is influenced by an organisms experiences. Which of these behaviours plays the primary role in migration? Influences on migratory behaviour Behaviour is either: INNATE: Inherited and inflexible. Plays a primary role in migratory behaviour. Occurs in all members of a species. Usually in response to an external stimuli e.g. photoperiod (day length) LEARNED: Begins after birth and is influenced by an organisms experiences. Is flexible Plays a secondary role in migratory behaviour. Influences on migratory behaviour TASK: Use Pages 182-183 to produce your own notes on the following experiments and how they are used in the study of behavioural influences on migration. 1.)Displacement Experiments 2.)Investigating directional tendencies. 3.)Cross-fostering experiments. Question Time CfE Higher specimen Question Time Revised Higher 2014 Metabolic rate can be reduced when less food available Daily torpor Migration ringing AND recovery, satellite tracking Question Time Revised Higher 2013 Revised Higher 2013 Q9 printed copy Recap: 1. Name the 3 domains of life 2. Give reasons why microorganisms are useful to humans? CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 6 Environmental control of metabolism (a) Growth and metabolism of microorganisms Microorganisms Microorganisms use a wide variety of substrates for metabolism and produce a range of products from their metabolic pathways. Microorganisms are used because of their adaptability, ease of cultivation and speed of growth. The term microorganism encompasses species from archaea, bacteria and some species of eukaryotes. Uses of Microorganisms Microorganisms are used in many industrial processes as well as research as they make a wide range of metabolic products. Can you think of Can you think of any other any reasons why microorganisms microorganisms we use in are ideal for industrial mass production processes or for of products? research? Adaptability FOR INFO ONLY Microorganisms are ideal for mass production in industrial processes because they: 1. are easy to grow (culture) 2. can reproduce and grow quickly 3. can produce many different useful products 4. their metabolism can be manipulated (changed) easily 5. they can metabolise cheap food substances (e.g. waste products from biotechnological industries).  Optimum temperature (i.e. 37oC) ENVIRONMENTAL FACTORS Conditions required for Optimum pH Energy Source growth of microorganisms (chemical: i.e. glucose OR light) GROWTH MEDIUM Raw Optimum materials (i.e. oxygen vitamins, fatty concentration acids) Growing microorganisms Their growth is controlled by the ingredients of the growth medium AND environmental factors such as temperature etc. Growth Medium A growth medium such as nutrient broth requires an energy source from either a chemical substrate (i.e. glucose) or light in photosynthetic microorganisms. Many microorganisms can produce all the complex molecules (such as amino acids, vitamins and fatty acids) required for biosynthesis without the addition of other raw materials… BUT other microorganisms require more complex compounds to be added to the growth media, including vitamins and fatty acids or beef extract for biosynthesis of proteins and nucleic acids etc. Growing microorganisms Most microorganisms are grown in the lab using aseptic (sterile) techniques to avoid contamination. Other microorganisms that contaminate the sample will compete with the desired microorganism for resources such as food. Fermenters Growth medium (nutrient solution) Computer controls Maintains Mixes nutrient levels of factors temperature solution that affect growth Oxygen Temperature pH Glucose Controls oxygen levels Maintains Sets and detects temperature sterility Sterile conditions in fermenters reduce competition with desired micro-organisms for nutrients and reduce the risk of spoilage of the product. Fermenters THINK: pH can be controlled by using pH BUFFERS. How can pH be controlled? Question Time Revised Higher 2014 Question Time Revised Higher 2014 CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 6 Environmental control of metabolism (b) Phases of growth Phases of growth The mean generation or doubling time is the time taken for a cell to divide in two. A microbe’s pattern of growth varies over time. There are 4 distinct phases. Phases of growth LAG LOG/ EXPONENTIAL STATIONARY DEATH A B PHASE C PHASE D PHASE PHASE Phases of growth TASK: Read the descriptions below try to work out which phase is which 4. DEATH PHASE 1. LAG PHASE Enzymes are induced to Toxic accumulation of metabolise new substrates. metabolites Lack of nutrients in the culture. 2. LOG/ EXPONENTIAL PHASE 3. STATIONARY PHASE Most rapid growth of Nutrients in the culture micro-organisms due to media become depleted. plentiful nutrients. Toxic secondary metabolites produced Phases of growth TASK: Annotate your graph with the statement that describes each phase. Lag Phase- Slow growth Log phase- Maximum rate of growth Enzymes are induced to Most rapid growth of metabolise new substrates. micro-organisms due to plentiful nutrients. Stationary Phase: Death Phase: Nutrients in the culture Toxic accumulation of media become depleted. metabolites Toxic secondary Lack of nutrients in the metabolites produced culture. Phases of growth LAG LOG/ EXPONENTIAL STATIONARY DEATH PHASE PHASE PHASE PHASE ENZYMES INDUCED Phases of growth LAG LOG/ EXPONENTIAL STATIONARY DEATH PHASE PHASE PHASE PHASE MAXIMUM RATE OF GROWTH Log/ Exponential Growth FOR INFO ONLY An organism with a doubling time of 0.5 hours would increase as shown in the table. TASK: Draw a line graph of this data Log/ Exponential Growth In the log/ exponential phase, cell number increases so rapidly that it becomes very difficult to plot on normal graph paper. Semi logarithmic scales are used in producing and/or interpreting growth curves of microorganisms. Log/ Exponential Growth 2018 Paper Q8 Salmon can be reared in fish farms where they are sometimes fed small fish such as anchovies. Anchovies feed on animal plankton which feed on plant plankton. The energy contents at each trophic level in this food chain are shown on a log scale in the bar graph. (a) (i) State the energy content fixed in the biomass of salmon. 200 kJ (ii) Plant plankton fix 2% of the solar energy they receive in their biomass. Calculate the total solar energy to which the plant plankton were exposed. Space for calculation 5000000/ 5 million Phases of growth LAG LOG/ EXPONENTIAL STATIONARY DEATH PHASE PHASE PHASE PHASE NUTRIENTS BEGIN TO RUN OUT. TOXIC SECONDARY METABOLITES BUILD UP Secondary Metabolism Secondary metabolism occurs during the stationary phase. It results in the production of secondary metabolites (e.g. Antibiotics). These are not used for growth or the production of new cells, but may give the microorganism an ecological advantage by allowing the micro-organisms which produce them to outcompete other micro-organisms. They may be toxic to the microorganism. We can use many of these secondary metabolites (e.g. Ethanol) Phases of growth LAG LOG/ EXPONENTIAL STATIONARY DEATH PHASE PHASE PHASE PHASE LACK OF FOOD/ NUTRIENTS. BUILD UP OF TOXIC (WASTES) METABOLITES Cell counts When cell counts are performed, they fall into one of two categories: 1. A viable cell count is where only living cells are counted. 2. A total. cell count involves counting living (viable) and dead cells. Only viable cell counts show a death phase where cell numbers are decreasing. Q1: This growth curve shows viable cell numbers of B.subtilis. Give evidence from the graph to justify this statement. Cell number decreases during death phase Question Time CfE Higher specimen Question Time Revised Higher 2013 By using a buffer Question Time Revised Higher 2013 Lag Log OR exponential Stationary Death 2 Question Time Revised Higher 2013 W (lag) Lack of nutrients/ food OR build up of toxic (waste) metabolites Question Time Revised Higher 2012 Question Time Revised Higher 2014 Citrate is used in the food industry as a flavouring agent. Large quantities of citrate are produced in fermenters by the fungus Aspergillus niger. The fungus was added to a growth medium and grown in a fermenter for 14 days. The graph below shows the changes in biomass of the fungus and in the concentration of citrate over the growth period. (a) Suggest one reason why citrate was not produced until day 2. Lag phase so enzymes are still being induced/ produced Question Time Revised Higher 2014 2 Less citrate will be changed to intermediate compounds Question Time Revised Higher 2014 Acetyl group/ pyruvate/ oxaloacetate OR inducers OR vitamins/ fatty acids/ beef extract CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 7 Genetic Control of Metabolism (a) Improving Wild Strains of Microorganisms  Mutations RECAP: a) What is mutation ? A random occurrence low frequency change to genetic material. b) Name 2 mutagenic agents UV light, gamma radiation, mustard gas etc (c) Name 3 forms of single gene mutations and describe them Substitution- replacing one base pair for another, Insertion- adding a base pair, Deletion- removing a base pair (S- point, I and D- frameshift) (d) Name 4 forms of chromosome mutation Translocation, Inversion, Duplication, Deletion (e) How is genetic material transferred between bacteria? Horizontal gene transfer- i.e. exchanging genetic material/ plasmids Strain Improvement Wild strains of microorganisms are selected to be used in industrial processes. The following techniques can be used to improve these strains to give a more desired product, faster production rate etc.: Mutagenesis Recombinant DNA technology Strain Improvement- Mutagenesis Mutagenesis is the creation of mutations. The rate of mutagenesis can be (i) What do you increased by exposing the think microorganisms to a mutagenic mutagenesis is? agent (e.g. UV light, other forms (ii) How do you think of radiation, chemicals). the rate of mutagenesis can Mutagenesis is useful during be increased? industrial processes as it allows more opportunity to develop new properties in microorganisms that are useful to humans. Strain Improvement- Mutagenesis Occasionally a mutant strain is improved by mutagenesis and has some desired feature e.g. rapid growth. Genetic Instability Mutant strains of microorganisms tend to be genetically unstable. Sometimes they undergo reverse mutations and go back to being the less useful wild type. Prokaryotes vs Eukaryotes RECAP: a) Name cells that are (i) Prokaryotes (ii) Eukaryotes (i) Prokaryotes: Bacteria (ii) Eukaryotes: Animal, plant, yeast b) How is DNA organised in prokaryotes? Circular chromosomes and plasmids (c) How is DNA stored in most eukaryotes? Linear in a nucleus and also as circular chromosomes in mitochondria and chloroplasts (d) How is DNA stored in yeast cells? Same as c but they can also have plasmids CfE Higher Biology- Unit 2 Metabolism and Survival Key Area 7 Genetic Control of Metabolism (b) Recombinant DNA technology Genetic Engineering NAT 5 RECAP: 4. What does ligase do? Ligase JOINS fragments of DNA together 2. How is the gene extracted from the chromosome? Using an enzyme E C 3. How is the plasmid opened up to D receive the desired gene? Using an enzyme Recombinant DNA technology Scientists can transfer genes from one organism to another and even one species to another. This allows microorganisms to produce plant or animal proteins. The microorganism is said to be artificially transformed. Vectors A vector is a DNA molecule used to carry foreign genetic information into another cell. Both plasmids and artificial chromosomes are vectors during recombinant DNA technology. ARTIFICIAL CHROMOSOME PLASMID 1. restriction site 2. (marker gene) 3. Origin of replication Artificial Chromosomes Artificial (man-made) chromosomes are preferable to plasmids as vectors when much larger fragments of foreign DNA are required to be inserted. Restriction Endonuclease A restriction endonuclease is an enzyme which cuts target sequences of DNA and can leave sticky ends (unpaired bases). Restriction endonucleases are used to: 1. Cut specific genes out of chromosomes 2. Cut open bacterial plasmids 2. Plasmid cut open using restriction endonuclease. 1. Gene cut out of chromosome using restriction endonuclease. Restriction Endonuclease Complementary sticky ends are produced when the same restriction endonuclease is used to cut open the plasmid and the gene from the chromosome. Vectors To be an effective vector, a plasmid must have a restriction site, 1. Restriction site: selectable markers, origin of Contain target replication and regulatory sequences. sequences of DNA 1. restriction site where specific restriction 2. (marker gene) endonucleases cut. 3. Origin of replication A recombinant plasmid Vectors 1. restriction site 2. Selectable marker genes: such as antibiotic 2. (marker gene) resistance genes protect the micro-organism from a selective agent (antibiotic) that would normally kill or prevent it growing. Selectable marker genes 3. Origin of replication present in the vector A recombinant plasmid ensure that only micro-organisms that have taken up the vector grow in the presence of the selective agent (antibiotic) Vectors 1. restriction site 2. (marker gene) A recombinant plasmid 3. Origin of replication 3. Origin of replication: allows self replication of the plasmid/ artificial chromosome. Essential for making many copies of the plasmid (and the required gene) which can be passed on to daughter cells. Vectors 1. restriction site 2. (marker gene) A recombinant plasmid 3. Origin of replication 4. Regulatory sequences: control gene expression. Ligase Ligase is an enzyme that is able to seal the gene into the plasmid. Applying your knowledge TASK: Use pages 221-223 of Torrance and answer Q8a-e Question Time Revised Higher 2013  EcoR1 Complementary sticky ends Ligase 50 Origin of replication Question Time Recombinant DNA technology Each Recombinant DNA technology E,A,C,B,D TASK: Read the statements below and place them in the correct order (record letters only- don’t copy the statements) A. Plasmids extracted from microorganism and cut open using the same restriction endonucleases to ensure complementary sticky ends. B. Genes are often added as a safety mechanism to prevent the organism surviving in the external environment. C. Desired genes transferred into plasmids and DNA fragments of desired genes are sealed in using ligase (as well as a marker gene). D. Plasmids are inserted into bacterial host cells and cells are grown on an agar medium containing antibiotics. E. DNA extracted from organism and restriction endonucleases used to cut out target sequences of desired DNA and leave sticky ends. Recombinant DNA technology TASK: Using the labels below, complete and annotate your diagram 1. DNA extracted from organism and restriction endonucleases used to cut out target sequences of desired DNA and leave sticky ends. 2. Plasmids extracted from microorganism and cut open using the same restriction endonucleases to ensure complementary sticky ends. 3. Desired genes transferred into plasmids and DNA fragments of desired genes are sealed in using ligase (as well as a marker gene). 4. Genes are often added as a safety mechanism to prevent the organism surviving in the external environment. 5. Plasmids are inserted into bacterial host cells and cells are grown on an agar medium containing antibiotics to ensure desired gene is present. Adding Genes Genes can be introduced that remove inhibitory controls or amplify metabolic steps in a pathway to increase yield. As a safety mechanism, genes are often introduced that prevent the survival of the microorganism in an external environment. Question Time Revised Higher 2015  Structure of the Genome RECAP: a) What are regions of non- coding DNA known as? INTRONS b) Give two uses of this non- coding DNA (i) Regulation of transcription (ii) Some is transcribed but never translated i.e. rRNA and tRNA (c) What do exons do? Code for protein (d) Explain how one gene can code for many proteins Alternative RNA splicing. Depending on which sections of DNA are treated as introns and exons (1) different sections can be joined together to produce different mRNA transcripts (1) (e) State 3 methods of post translational modification of polypeptides (i) Cutting AND combining polypeptide chains (ii) Adding a phosphate (iii) Adding carbohydrate groups Limitations of prokaryotes Plant or animal DNA expressed in bacteria may result in inactive polypeptides that are folded incorrectly. Recombinant yeast cells are used to produce active forms of the protein which are inactive in bacteria as yeast can fold proteins. This is because prokaryotic DNA contains EXONS but no INTRONS How do you think and they cannot FOLD proteins scientists overcome this problem? Question Time CfE Higher 2015 Question Time Revised Higher 2012 Question Time Revised Higher 2013 Question Time Revised Higher 2014 citrate Acetyl group OR oxaloacetate OR inducers OR vitamins/fatty acids/ beef extract Mutagenesis OR recombinant DNA technology Question Time Revised Higher 2012 Two different enzymes are required to produce the modified plasmid. Complete the table below by: (i) naming the enzyme which cuts plasmids at specific (i) Restriction restriction sites; endonuclease (ii) naming the second enzyme required to modify plasmids; (ii) Ligase (iii) Seals DNA into plasmid (iii) describing the function of the second enzyme. Question Time Revised Higher 2012 The gene for resistance to antibiotic Y has been broken Question Time CfE Higher 2015 To ensure sticky ends are complementary Question Time CfE Higher 2015 Ligase Only those bacteria with the modified plasmid will be able to survive the antibiotic Origin of replication Question Time CfE Higher 2015 protein is folded incorrectly Use yeast cells instead of bacteria Question Time CfE Higher 2016 Restriction endonuclease OR ligase RE: cuts (target sequences) DNA/ genes out L: Seals gene into plasmid Question Time CfE Higher 2016 Grow the cells on ampicillin (1) Only modified cells survive (1) Plasmid/ DNA/ genes passed between bacteria horizontally Kills other microorganisms which may contaminate the culture and compete for resources Unit 2 Key areas Key Area 1: Metabolic Pathways and their control a. Introduction to Metabolic Pathways i. Anabolic (energy requiring) and catabolic (energy releasing) pathways ii. Cell membrane structure b. Control of metabolic pathways- enzymes i. Enzymes- Induced fit ii. Enzyme inhibition- competitive, non competitive and feedback inhibition Key area 2: Cell Respiration a. Breakdown of glucose b. The role of ATP c. Metabolic pathways of respiration: Glycolysis, Citric Acid Cycle, Electron Transport Chain d. ATP synthesis e. Substrates for respiration Unit 2 Key areas Key Area 3: Metabolic Rate a. Measuring metabolic rate b. High metabolic rates: Heart and lung structure c. Physiological adaptations of animals for low oxygen niches. d. Maximum oxygen (VO2 max) uptake as a measure of fitness in humans. Key area 4: Metabolism in Conformers and Regulators a. Abiotic Factors b. Conformers c. Regulators d. Negative feedback control and thermoregulation e. Importance of regulating temperature for enzymes and diffusion Unit 2 Key areas Key Area 5: Metabolism in Adverse Conditions a. Surviving adverse conditions b. Avoiding adverse conditions c. Extremophiles Key area 6: Environmental Control of Metabolism in Microorganisms a. Growth media and environmental factors b. Phases of growth of microorganisms c. Control of metabolism through the addition of metabolic precursors, inducers or inhibitors to give a required product. Key area 7: Genetic Control of Metabolism a. Improvement of wild strains of bacteria b. Recombinant DNA technology Key area 8: Ethical considerations in the use of microorganisms — hazards and control of risks. Unit 2 Revision Choose from: Past paper questions Working on mind maps or tick sheet for unit 2 Problem solving booklet OR…