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

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 ecosys...

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.  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 metabolism to dependent on their control their internal external environment environment. A B C D E F G H T H B O ers 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) YOU MAY Disadvantag DISPLAY es THE NEXT FEW of being a NOTES AS conformer? A DIAGRAM 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 Canlow you temperatures and is less adaptable to environmental change. think of any BEHAVIOURA L strategies that a conformer may employ to maintain their optimum metabolic 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.  Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (c) Regulators Regulators Can you think of any (i) advantages (ii) Disadvantage s of being a regulator? Regulators Regulators maintain their HOMEOSTASIS internal environment : regardless of external environment. To maintain the body’s They use metabolism to internal environment control their internal within environment. tolerable limits Advantage: Regulators can (regardless of occupy a greater range of changes in the external ecological niches. environment) Disadvantage: This regulation to achieve 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 Habitat: Sea water only 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 Large Mouth Bass conformer and which is a regulator. Give reasons for your answer. (c)What is the Question Time Revised Higher 2012 HOMEWORK INVESTIGATE: Atlantic Salmon can be both conformer and regulator. What is an Research the Atlantic osmoregulator? Salmon. (i)Find out why it can be termed as both a conformer and a regulator What is an thermoregulator? (ii) Give an advantage and a disadvantage to the salmon of being an osmoregulator 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)  Unit 2 Metabolism and Survival Key Area 4 Metabolism in conformers and regulators (d) Negative Feedback Control Negative Feedback Control HOMEOSTASIS RECAP: What is : HOMEOSTASIS? To maintain the body’s Homeostasis is internal maintained by negative environment feedback control. within tolerable limits Negative feedback (regardless of provides the body with changes in the stable conditions (i.e. external temperature to 37oC) environment) to function efficiently. Regulators require energy for homeostasis/negative Negative Feedback Control RECEPTORS EFFECTORS FACTOR INCREASES CORRECTIVE RESPONSE FACTOR FACTOR NO CHANGE AFFECTING AFFECTING BODY IS BODY IS NORMAL 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. 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 RESPONSE TO OVERHEATING Blood vessel DILATES OVERCOOLING Blood vessel (VASODILATION) CONSTRICTS (VASOCONSTRICTION) Increased HEAT LOSS by Heat is conserved. radiation. Thermoregulation VASODILATI THERMORECEPT ON ORS IN ELECTRICAL INCREASED HYPOTHALAMU IMPULSES SWEATING S DETECT SENT ALONG TEMPERATUR NERVES TO HAIRS CHANGE E CHANGE EFFECTORS LOWERED (INCREASES) DECREASE IN METABOLIC NO CHANGE NORMAL BODY NORMAL BODYRATE TEMP. 37OC TEMP. 37 C O VASOCONST RIC-TION TEMPERATUR THERMORECEPT E CHANGE ORS (DECREASES) ELECTRICAL HAIRS IN IMPULSES RAISED HYPOTHALAMU SENT ALONG S DETECT NERVES TO SHIVERING CHANGE EFFECTORS INCREASE IN METABOLIC RATE temperature It is important to regulate temperature (thermoregulation) for: 1. optimal enzyme activity Why is it important to 2. high diffusion rates maintain body temperature to maintain at 37oC? metabolism. 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 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)  Unit 2 Metabolism and Survival Key Area 5 Metabolism and adverse conditions (a) Surviving adverse conditions 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? 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. 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 withhigh their definitions 1. below: A. To survive temperatures/ drought conditions. PREDICTIVE 2. B. (‘Daily sleep’) a period of reduced activity in some animals with high CONSEQUENTI metabolic rates. 3. AL C. Organism becomes dormant BEFORE the onset of adverse HIBERNATIO conditions. D. To survive cold conditions 4. through winter/ low temperatures N when food may be scarce. AESTIVATIO E. Organism becomes dormant 5. N DAILY AFTER the onset of 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: 1. C. Organism becomes dormant BEFORE the onset of adverse PREDICTIVE conditions. E. Organism becomes dormant 2. AFTER the onset of adverse CONSEQUENTI conditions. D. To survive cold conditions through 3. AL winter/ low temperatures when food may be scarce. HIBERNATIO A. To survive high temperatures/ 4. drought conditions N AESTIVATIO B. (‘Daily sleep’) a period of 5. N DAILY reduced activity in some animals with high metabolic rates. 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: PREDICTIVE 1. HIBERNATION CONSEQUEN 2. AESTIVATION TIAL 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 areMetabolic low andrate food is scarce. 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 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  Unit 2 Metabolism and Survival Key Area 5 Metabolism and adverse conditions (b) Avoiding adverse conditions 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 Can you more suitable think of any species environment. which migrate? Migration MANY BIRD HUMPBACK SPECIES 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 BE 1. Bird – Leg ringing AND RECOVERED recovery (RECAPTURED) 2. Turtle- Satellite tracking Satellite tracking-DON’T NEED TO BE RECOVERED BUT IS MORE EXPENSIVE 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? 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?  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 any other Can you reasons think of any why microorgani microorgani sms we use sms are in industrial ideal for processes mass or for production research? of products? Adaptability FOR INFO ON 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) ENVIRONMEN TAL FACTORS Conditions required for growth Optimum pH Energy of microorgan Source isms (chemical: i.e. glucose GROWTH OR light) Raw MEDIUM Optimum materials oxygen (i.e. concentrati vitamins, on 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 Maintain Mixes nutrient controls levels s solution of factors that temperat affect Oxyge Temperatu pH growth Glucos ure n re e Controls oxygen levels Maintain Sets and detects s sterility temperature Sterile conditions in fermenters reduce competition with desired micro-organisms for nutrients and reduce the risk of spoilage of the product. Fermenters THINK: How can pH can be controlled by using pH pH be BUFFERS. controll ed? Question Time Revised Higher 2014 Question Time Revised Higher 2014  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/ STATIONA DEATH PHA A EXPONENTIAL B C RY PHASE D PHASE PHASE SE Phases of growth TASK: Read the descriptions below try to work out which phase is which 4. DEATH PHASE 1. LAG PHASE Toxic accumulation of Enzymes are induced to metabolise new metabolites Lack of nutrients in substrates. the culture. 2. LOG/ EXPONENTIAL 3. STATIONARY PHASE PHASE Most rapid growth of Nutrients in the micro-organisms due to culture media become plentiful nutrients. depleted. 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 metabolise new Most rapid growth of substrates. micro-organisms due to plentiful nutrients. Stationary Phase: Death Phase: Nutrients in the Toxic accumulation of culture media become metabolites depleted. Lack of nutrients in Toxic secondary the culture. metabolites produced Phases of growth LAG LOG/ STATIONA DEATH PHA EXPONENTIAL RY PHASE PHASE PHASE SE ENZYMES INDUCED Phases of growth LAG LOG/ STATIONA DEATH PHA EXPONENTIAL RY PHASE PHASE PHASE SE 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/ STATIONA DEATH PHA EXPONENTIAL RY PHASE PHASE PHASE SE 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/ STATIONA DEATH PHA EXPONENTIAL RY PHASE PHASE PHASE SE 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 Q1: This growth curve shows viable cell numbers are decreasing. 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 Lagday 2. phase so enzymes are still being induced/ 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  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 (b) genetic Name 2material. 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 formsInversion, Translocation, of chromosome mutation Duplication, Deletion (e) Horizontal How is genetic gene material transferred transfer- i.e. between exchanging bacteria? 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 Mutagenesis Mutagenesis is the creation of mutations. (i) What do you The rate of mutagenesis think mutagenesis can be increased by is? exposing the microorganisms to a (ii)How do you mutagenic agent (e.g. UV think the rate light, other forms of of mutagenesis radiation, chemicals). can be increased? Mutagenesis is useful during industrial processes as it allows more opportunity to develop new properties 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. Eukaryotes RECAP: (a) Name cells that are (i) Prokaryotes (ii) Eukaryotes (i) Prokaryotes: Bacteria (ii) Eukaryotes: Animal, (b) plant, How isyeast 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  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 Using extracted from an the E chromosome? enzyme C D 3. How is the plasmid opened up toUsing an the receive enzyme desired gene? 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 PLASMID CHROMOSOME 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 1. Restriction site: restriction site, selectable Contain target markers, origin of sequences of DNA replication and regulatory 1. restriction site where specific sequences. restriction 2. (marker gene) endonucleases cut. 3. Origin of replication A recombinant plasmid Vectors 1. restriction site 2. Selectable marker genes: such as 2. (marker gene) antibiotic resistance genes protect the micro- organism from a selective agent (antibiotic) that would normally kill 3. Origin of replication or prevent it A recombinant growing. plasmid Selectable marker genes present in the vector ensure that only micro-organisms that have taken up Vectors 1. restriction site 2. (marker gene) A recombinant 3. Origin of plasmid 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 3. Origin of plasmid 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 technology Each technology E,A,C,B,D TASK: Read the statements below and place them in the correct order (record letters only- don’t A. copy theextracted Plasmids statements) 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 technology TASK: Using the labels below, complete and annotate 1. DNA your extracted fromdiagram 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. 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 (e) State mRNA 3transcripts methods of (1)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 How do you think INTRONS and they cannot scientists FOLD proteins 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 (i) Restriction which cuts plasmids endonuclease at specific restriction sites; (ii) Ligase (iii) Seals DNA into (ii) naming the second plasmid enzyme required to modify plasmids; 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 c. Breakdown of glucose d. The role of ATP e. Metabolic pathways of respiration: Glycolysis, Citric Acid Cycle, Electron Transport Chain f. ATP synthesis g. 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 e. Abiotic Factors f. Conformers g. Regulators h. Negative feedback control and thermoregulation i. 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 d. Growth media and environmental factors e. Phases of growth of microorganisms f. Control of metabolism through the addition of metabolic precursors, inducers or inhibitors to give a required product. Key area 7: Genetic Control of Metabolism g. Improvement of wild strains of bacteria h. Recombinant DNA technology Unit 2 Revision Choose from: Past paper questions Working on mind maps or tick sheet for unit 2 Problem solving booklet OR…