
	Trending ▼ ICSE CBSE 10th ISC CBSE 12th CTET GATE UGC NET Vestibulares ResFinder

GCE May 2007 : (A2 3A) Synoptic Paper

16 pages, 30 questions, 1 questions with responses, 1 total responses,

	gce	+Fave Message
	Profile Timeline Uploads Q & A

Home > gce >

Instantly get Model Answers to questions on this ResPaper. Try now!
NEW ResPaper Exclusive!

Formatting page ...

Centre Number 71 Candidate Number ADVANCED General Certificate of Education 2007 Biology assessing Module 6A: Synoptic Paper A2B31 Assessment Unit A2 3A [A2B31] TUESDAY 29 MAY, AFTERNOON TIME 1 hour. INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces provided at the top of this page. Write your answers in the spaces provided in this question paper. Answer all four questions. 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS INFORMATION FOR CANDIDATES The total mark for this paper is 50. Section A carries 35 marks. Section B carries 15 marks. You should spend approximately 20 minutes on Section B. You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section B. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. A data sheet is provided for use with this paper. For Examiner s use only Question Number 1 2 3 4 Total Marks A2B3AS7 2827 Marks 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS BLANK PAGE A2B3AS7 2827 2 [Turn over Section A Examiner Only Marks 1 Remark (a) Transport of glucose to all cells is a key function of the blood circulation. In humans, the normal level of blood glucose is about 90 mg/100 cm3 of blood, but this can vary. For example, during an extended period without food, or after prolonged and heavy physical activity, the blood glucose level may drop to as low as 70 mg/100 cm3. After a meal rich in carbohydrate has been digested, the blood glucose level may rise to 150 mg/100 cm3. (i) Explain why it is important that the blood glucose should not drop to too low a level. ______________________________________________________ ___________________________________________________ [1] (ii) What would be the consequences of glucose rising to too high a level in the blood? ______________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ___________________________________________________ [1] A2B3AS7 2827 3 [Turn over (b) Two hormones are involved in the regulation of blood glucose levels, insulin and glucagon. The concentrations of blood glucose and of each of these hormones was measured in a group of people over a period of 5 hours, during which time a carbohydrate-rich meal was ingested. The results are shown in the graphs below. Examiner Only Marks Remark Blood glucose concentration/mg 100 cm 3 meal taken 150 140 130 120 110 100 90 80 70 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS Blood hormone concentration/arbitrary units 100 glucagon 80 60 40 20 insulin 0 0 A2B3AS7 2827 1 2 3 Time/hours 4 4 5 [Turn over (i) Describe the trends evident in the graphs. Examiner Only Marks Remark ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [3] (ii) Changes in blood glucose determine the levels of insulin and glucagon in the blood. What is the effect on each hormone of an increase in blood glucose? Explain how the information shown in the graph provides an example of negative feedback. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [3] (c) Some people develop a form of diabetes in which the body fails to regulate blood glucose because of a failure of insulin production. Treatment involves regular injections of insulin which is produced by genetically engineered micro-organisms (GEMs). Outline two distinct steps in the production of insulin-producing GEMs. 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS 1. _______________________________________________________ __________________________________________________________ 2. _______________________________________________________ _______________________________________________________ [2] (d) Diabetes is often diagnosed because glucose is excreted in the urine. State the specific test for the presence of glucose in urine. _______________________________________________________ [1] A2B3AS7 2827 5 [Turn over 2 In pea plants the gene coding for seed coat colour has two alleles, one allele producing a yellow seed coat, the other allele producing green. Mendel crossed pea plants grown from yellow seeds with pea plants grown from green seeds. All the seeds produced from this cross (the F1 generation) were yellow. Mendel then allowed the F1 generation to breed together and collected a total of 8023 seeds (the F2 generation): 6022 of these seeds were yellow, 2001 were green. Examiner Only Marks Remark Use this information to help you answer the following questions. (a) (i) Which of the two alleles, yellow or green, is dominant? ___________________________________________________ [1] (ii) What is the genotype of the seeds in the F1 generation? ___________________________________________________ [1] (b) A 2 test was carried out on the results of the F2 generation to see if the observed data from Mendel s breeding experiment followed the expected ratio of 3 yellow seeds to 1 green seed. The result of the test was a 2 value of 0.015. (i) State the null hypothesis for this test. ______________________________________________________ ___________________________________________________ [1] (ii) State the degrees of freedom. ___________________________________________________ [1] (iii) State the probability value for the calculated 2. ___________________________________________________ [1] 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS (iv) State your decision about the null hypothesis. ___________________________________________________ [1] (v) What can be concluded about the F2 generation? ______________________________________________________ ___________________________________________________ [1] A2B3AS7 2827 6 [Turn over (c) A student repeated Mendel s breeding experiment using peas identical to Mendel s F1 generation. These were allowed to breed together and the colours of the seeds produced in the F2 generation were recorded. The student carried out a 2 test on their results to see if they followed the expected ratio of three yellow seeds to one green seed. The student s observed results are shown in the table below. Seed colour Observed number Yellow Remark 37 Green Examiner Only Marks Expected number 23 (i) Complete the table above by filling in the expected numbers for yellow and green seeds in the F2 generation. (Show your working in the space below.) [1] (ii) The student s calculated 2 value was 5.69. What does this suggest about whether or not the F2 results follow the expected 3:1 ratio? Justify your decision with reference to the probability value for the calculated 2. ______________________________________________________ ______________________________________________________ ______________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ___________________________________________________ [2] (d) Suggest why the outcomes of the 2 tests of Mendel s and the student s results are different. __________________________________________________________ __________________________________________________________ _______________________________________________________ [1] A2B3AS7 2827 7 [Turn over 3 Read the passage below and then use the information in the passage, and your ownExaminer Only Marks Remark understanding, to answer the questions which follow. Dinoflagellates are microscopic, unicellular, flagellated algae belonging to the kingdom Protoctista (division Dinoflagellata). There are nearly 2000 known living species of dinoflagellates, classified into about 125 genera. Ninety percent of all dinoflagellates are marine plankton, though there are many freshwater species. They may be photosynthetic, or non-photosynthetic heterotrophs; about half of the species fall into each category. Dinoflagellates swim by means of two flagella. They are surrounded by a complex covering consisting of outer and inner continuous membranes, between which lie a series of flattened vesicles which, in armoured forms, contain cellulose plates. This armour may be lacking in some species. The cytoplasm contains rough and smooth endoplasmic reticulum, Golgi apparatus, mitochondria, lipid droplets, starch grains and vacuoles. The nucleus contains chromosomes which do not possess histones and which remain permanently condensed, though they do unwind for replication of the DNA during interphase. In photosynthetic forms, there is a triple membrane around the chloroplasts, while the lamellae contain chlorophyll c as well as chlorophyll a. Some species of dinoflagellates produce chemicals which act as neurotoxins in organisms which feed on them, such as shellfish, or other organisms further along the food chain, including humans. The neurotoxin saxitoxin, produced by Protogonyaulax catanella and Gessnerium monilatum, inhibits the conduction of action potentials along excitable membranes by blocking sodium ion channels, thus affecting muscle activity. Eating contaminated shellfish causes paralytic shellfish poisoning (PSP). The worst cases of PSP result in respiratory failure and death within 12 hours. 10 15 20 25 30 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS Some species are capable of producing light through bioluminescence. In dinoflagellates bioluminescence is triggered by deformation of the cell surface by minute forces (even when surrounding water is agitated, such as in the wake of a ship or a breaking wave). The reaction which causes the emission of light occurs when the compound luciferin (a substrate chemically similar to a chlorophyll precursor) is oxidised by the enzyme luciferase, a process which requires both ATP and oxygen. 5 A2B3AS7 2827 8 [Turn over (a) Dinoflagellates are classified within the kingdom Protoctista [line 2]. Identify one feature which explains why the dinoflagellates are not classified within the following kingdoms. Examiner Only Marks Remark (i) Animalia ______________________________________________ ______________________________________________________ (ii) Plantae _______________________________________________ ______________________________________________________ (iii) Prokaryotae ____________________________________________ ___________________________________________________ [3] (b) The cellular structure of dinoflagellates while obviously eukaryotic has a number of features which are unique. Identify two of these unique features. 1. _______________________________________________________ __________________________________________________________ 2. _______________________________________________________ _______________________________________________________ [2] (c) The neurotoxin saxitoxin blocks sodium ion channels, affects muscle activity and may result in respiratory failure. (i) State the type of molecule of which the sodium ion channel [line 21] would be composed. ___________________________________________________ [1] (ii) Suggest why saxitoxin would affect muscle activity [line 22]. 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ______________________________________________________ ___________________________________________________ [1] (iii) Explain why death would result from respiratory failure [line 23]. ______________________________________________________ ___________________________________________________ [1] A2B3AS7 2827 9 [Turn over (d) Bioluminescence is sometimes described as photosynthesis in reverse. Identify three ways in which bioluminescence contrasts with photosynthesis. Examiner Only Marks Remark 1. _______________________________________________________ __________________________________________________________ 2. _______________________________________________________ __________________________________________________________ 3. _______________________________________________________ _______________________________________________________ [3] (e) Suggest a role for bioluminescence in dinoflagellates. __________________________________________________________ __________________________________________________________ __________________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS _______________________________________________________ [2] A2B3AS7 2827 10 [Turn over Section B Examiner Only Marks Remark You are expected to answer the following question in continuous prose. Diagrams may be used, but you should make sure that they are relevant and add extra information to your account. It will be marked for its biological content, coverage of the topic, and the quality of written communication. In this question up to two marks are awarded for the quality of written communication. 4 [2] Write an account of the importance of surface area to volume ratio in cells, organs and organisms . Your account should show understanding of general principles and of at least two topics which you have studied. [13] ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ A2B3AS7 2827 11 [Turn over Examiner Only ____________________________________________________________ Marks Remark ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ A2B3AS7 2827 12 [Turn over Examiner Only ____________________________________________________________ Marks Remark ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ A2B3AS7 2827 13 [Turn over Examiner Only ____________________________________________________________ Marks Remark ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ A2B3AS7 2827 14 [Turn over 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS THIS IS THE END OF THE QUESTION PAPER A2B3AS7 2827 15 [Turn over S 6/06 0000 7-089-1 [Turn over 1 22.6.06EA 2 27.7.06EA 3 7.12.06RTS

Formatting page ...

Top Contributors
to this ResPaper
(answers/comments)

Ng Tsz Wing
(1)

Formatting page ...

Additional Info : Gce Biology May 2007 Assessment Unit A2 3A Module 6A: Synoptic Paper
Tags : General Certificate of Education, A Level and AS Level, uk, council for the curriculum examinations and assessment, gce exam papers, gce a level and as level exam papers , gce past questions and answer, gce past question papers, ccea gce past papers, gce ccea past papers

gce chat

Horizontal lines at:
Guest Horizontal lines at:
AutoRM Data:
Box geometries: