Photosynthesis and Cellular Respiration in Biology, Exams of Advanced Education

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Biology paper 2 2022

In the following passage the numbered spaces can be filled with biological terms. During photosynthesis plants produce 1 compounds which contain carbon, such as carbohydrates, lipids and proteins. Most of the sugars synthesised by plants are used by the plants in 2. The rest are used to make other groups of biological molecules. These biological molecules form the biomass of the plant. Biomass can be measured in terms of mass of 3 per given area per given time. The chemical energy store in dry biomass can be estimated using 4.(2 marks) - 1) organic

2. Respiration 3)Carbon 4)calorimeter Describe the light-independent reaction of photosynthesis. (6 marks) - 1)RUBP (Ribulose bisphosphate) binds with carbon dioxide but because its unstable it breaks up.
3. Producing two glycerate phosphate (GP) through reducing ATP into ADP using Rubisco
4. GP is reduced to trisoe phosphate through the oxidation of NADPH from the light dependent reaction as the electrons that are released are gained by GP.
5. using reduced NADP 5)Using energy from ATP
6. some of the Triose phosphate leaves the cycle and is converted to glucose and the rest is used to regenerate RUBP. Put a tick in the box next to the equation that shows how the net production of consumers, N, can be calculated where: I represents the chemical energy store in ingested food F represents the chemical energy lost to the environment in faeces and urine R represents the respiratory losses to the environment. (1 mark) - N=I-(F+R) (box 2)

In December 2017, the female breeding herd was 48% of all female cattle in the UK. Use table 1 to calculate the percentage of all the female cattle that were beef cows in the UK in December 2017.( mark) - 21. or 22 Use table 1 to calculate the increase in the number of dairy cows in the UK female breeding herd between December 2013 and December 2017. (2 marks) - 88500/ Farming cattle for humans to eat is less efficient that farming crops because of energy transfer. Explain why. (2 marks) - Energy lost between trophic levels. Energy lost via respiration/excretion/faeces. Apart from temperature and pH, give two variables the scientist would have controlled when preparing the liquid medium culture. (2 marks) - 1)volume of bacteria 2)concentration of bacteria 3)concentration of glucose 4)volume of ammonium chloride 5)time 6)volume of oxygen 7)concentration of nitrogen. A student concluded that this investigation showed that ammonia inhibits nitrogenase activity in nitrogen-fixing bacteria. Use all the information to evaluate the students conclusion. (3 marks) - (for) Nitrogenase activity decreases with increase in ammonium chloride. Nitrogenase activity zero with high concentrations of ammonium chloride (Against) Only used one species results may be due to chloride ions

Nitrogenase catalyses the reduction of nitrogen during nitrogen fixation. The reaction requires 16 molecules of ATP for each molecule of nitrogen that is reduced. When ammonia inhibits nitrogenase activity, nitrogen-fixing bacteria may benefit. Explain how. (2 marks) - Less/no ATP/energy required ATP/energy can be used for growth/synthesis/replication OR Lower rate of respiration required Put a tick in the box next to the process that occurs in anaerobic respiration but does not occur in aerobic respiration (1 Mark) - Reduction of pyruvate (box 3) During the 48 hours, the coloured liquid moved to the left. explain why. (3 marks) - 1)Oxygen is used by seeds 2)carbon dioxide given out by the seeds is absorbed by the KOH 3)Decrease in pressure/volume (of air inside) Apart from time, give two measurements the student would have to make to determine the rate of aerobic respiration of these seeds in cm^3hour^-1 (2 marks) - 1)distance liquid moves 2)diameter of tubing/luming The student used the same apparatus to determine the volume of carbon dioxide the seeds produced during 48 hours. Give the change the student would need to make to the contents of the apparatus and describe how he could calculate the volume of carbon dioxide produced (3 marks) - 1) Removing potassium hydroxide and replace it with water

2. Record distance liquid moves
3. Use difference in distance liquid moves (with potassium hydroxide and without potassium hydroxide) calculate the oxygen uptake in cm^3g^-1hour^-1 (1 mark) - range between: 3x10^-7 and 3.33x10^-

Using figure 2, give three conclusions you can make about the distribution of these lemur species.( marks) - 1) E. Rufus in the west

2. E. rufifrons in south 3)Actual distribution similar to expected distribution using all the information, suggest how speciation happened to produce two species of lemur. (5 marks) - 1)Allopatric speciation
3. Reproductive separation (no gene flow) 3)Different selection pressures (different environmental/abiotic conditions/ factors) 4)Variation due to mutations in different populations 5)Different/ advantageous alleles passed on 6)Eventually different species cannot interbreed to produce fertile offspring Suggest one precaution needed when marking the lemurs to make sure the estimate of the number of lemurs is valid (1 marks) - Marking doesn't affect survival/predation/recapture using the information provided calculate, how many lemurs in the second sample were marked. ( mark) - 3 Give the genotype of the ABO blood groups for individuals 1 and 2. do not include the genotypes for the Rhesus groups in your answer. (1 mark) - |A|O and |A|B Explain one piece of evidence from figure 3 that allele for Rhesus positive is dominant. (2 marks) - 1) Rhesus positive parents produce 7/Rhesus negative child 2)Both Rhesus positive/ 3 and 4 are heterozygous/carriers calculate the probability of individual 1 and 2 producing a Rhesus positive son with blood group A. you can assume that the individual 1 is heterozygous for the Rhesus blood group. show workings (2 marks) - 0.125/ 1/8 /12.5% 6.5 how many degrees of freedom should apply (2 marks) - chi squared

The scientists conclude that the observed frequencies of the four phenotype differed significantly from the expected frequencies. use your knowledge of the Hardy-Weinberg principle to suggest two reasons why. (2 marks) - 1) Selection 2)High rate of mutation 3)Immigration/emigration 4)No random mating Give two reasons why transmissions across a cholinergic synapse are unidirectional. (2 marks) - 1) only the presynaptic neuron/knob/membrane releases/has neurotransmitter 2)only the postsynaptic neurone/membrane has receptors Name and explain the type of summation shown in figure 4. (2 marks) - 1)Temporal 2)Several/repeated impulses in short time provide enough neurotransmitter/acetylchloride to reach threshold Mestinon is a drug that inhibits the enzyme acetylcholinesterase. Mestinon can help in the treatment of MG. Suggest and explain how MG can weaken contraction muscles. (2 marks) - 1)Less/no acetylcholine/ neurotransmitter binds to receptors

2. less/ no depolarisation Mestinon can help in the treatment of MG. Explain how. (3 marks) - 1) Less/no acetylecholine/ neurotransmitter broken down
3. more acetylcholine attaches to receptors
4. Depolarisation occurs Or action potential produced calculate how many grams of STZ should be injected into a rat with a mass of 230.45g. show your working (2 marks) - 8.1/ 8.07/ 8.066/ 8.0658/ 8.06575x10^-

Suggest and explain why STZ was injected per unit body mass. (1 mark) - for comparison as rats vary in mass The scientist concluded that group B rats could be used for studying type II diabetes in humans. Use all the information and your knowledge of type II diabetes to evaluate this conclusion. (5 marks) - 1) SD's do not overlap (for blood glucose concentration) 2)So significant difference/increase (in blood glucose concentration) 3)(Type II diabetes) cause high blood glucose concentration 4)Obesity/high body mass is a risk factor in type II diabetes 5)Investigation done on rats no humans 6)Only shows results after short period The scientist repeated the investigation using much higher dosses of STZ. This led to destruction of pancreatic cells. The scientist concluded that these rats would not be suitable for studying type II diabetes. Give two reasons why the scientist made this conclusion.(2 marks) - 1) Type II still produces/release insulin

2. type II cells/receptors less/not responsive/ sensitive to insulin
3. Pancreatic cells not destroyed in type II diabetes 4)Damage to pancreatic cells may affect processes/ reactions in the body Name the part of the body which releases antidiuretic hormone (ADH)into the blood. (1 mark) - Posterior pituitary Alcohol decreases the release of adh into the blood. suggest two signs or symptoms which may result from a decrease in ADH. (2 marks) - 1) Dehydration/ thirst
4. Frequent urination
5. Less concentrated urine Describe the effect of ADH of the collecting ducts in kidneys. (3 marks) - 1) stimulates addition of channel proteins into membrane

2. increase permeability to water
3. by osmosis BRCA1 and BRCA2 are human genes that code for tumour suppressor proteins. Mutations in BRCA1 and BRCA2 can cause cancer. explain how (3marks) - 1) Change in DNA base sequence/triplet
4. change in sequence of amino acids
5. Results in rapid/uncontrollable cell division Genetic testing, using DNA from saliva can screen for all known harmful mutations in both genes. Describe how this DNA could be screened for all known harmful mutations in both genes. (4 marks) - 1) Use of PCR to amplify DNA/sample 2)Cut DNA using restriction endonuclease/ enzyme
6. Separate DNA fragments using electrophoresis 4)Addition of labelled DNA probes and binding (by DNA hybridisation) 5)mutation identified by fluorescence/ radioactivity Effective treatment of ER-positive breast cancer often involve the use of drugs which have similar structure to oestrogen. suggest and explain how these drugs are an effective treatment of ER-positive breast cancer. (3 marks) - 1)Drug binds to receptor 2)Prevents binding of oestrogen
7. No/fewer transcription factors bind to promoter Blood tests can be used to test for cancers. However, the result of blood test may not be conclusive when testing for prostate cancer. Explain why. (2 marks) - 1) High/increased concentration of PSA not always linked to prostate cancer
8. could be due to urinary infection Treatment with drugs might be able to reverse the epigentic changes that cause cancer. suggest and explain how. (3 marks) - 1)Drugs could increase methylation of oncogene
9. Drugs could decrease methylation of tumour suppressor genes
10. increased methylation of DNA/ genes inhibits transcription/ expression of gene

4)Decreased acetylation of histones inhibits transcription