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

GCE JUN 2009 : (AS 1) Cell Biology

17 pages, 28 questions, 0 questions with responses, 0 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 SUBSIDIARY (AS) General Certificate of Education 2009 Biology assessing Module 1: Cell Biology ASB11 Assessment Unit AS 1 [ASB11] MONDAY 1 JUNE, 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. Write your answer to Section B on the lined paper at the end of this booklet. Answer all eight questions. You are provided with Photograph 1.3 for use with Question 3 in this paper. Do not write your answers on this photograph. INFORMATION FOR CANDIDATES The total mark for this paper is 55. Section A carries 43 marks. Section B carries 12 marks. You should spend approximately 15 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. 3905 For Examiner s use only Question Number 1 2 3 4 5 6 7 8 Total Marks Marks Section A Examiner Only Marks 1 Remark The statements in the table below refer to different processes by which molecules may be moved across the cell-surface membrane. If the statement is correct, place a tick ( ) in the appropriate box and, if the statement is incorrect, place a cross ( ) in the appropriate box. (Do not leave any boxes empty.) Active transport Diffusion Facilitated diffusion Involves carrier molecules Involves energy expenditure Occurs against a concentration gradient [3] 3905 2 [Turn over 2 Glucose molecules can be linked together to form polysaccharides. Examiner Only Marks Remark -glucose molecules form the helical and branched polysaccharide, amylopectin. -glucose molecules form straight, unbranched cellulose chains found within bundles of straight chains held together by many hydrogen bonds along their lengths. (a) State what type of reaction occurs when one glucose molecule bonds with another glucose molecule. _______________________________________________________ [1] (b) State which carbon atoms in adjacent glucose molecules are linked to produce a branch in amylopectin. _______________________________________________________ [1] (c) Describe an advantage of amylopectin having many branches. _________________________________________________________ _______________________________________________________ [1] (d) Name another branched polysaccharide. _______________________________________________________ [1] (e) Explain why cellulose is difficult to break down. _________________________________________________________ _______________________________________________________ [1] 3905 3 [Turn over 3 Photograph 1.3 is an electron micrograph showing part of two neighbouring plant cells. Examiner Only Marks Remark (a) Identify the features labelled A to D. A B C D [4] (b) The magnification of the photograph is 32 000. Calculate the actual diameter (in m) of the organelle along the line XY in the photograph. (Show your working in the space below.) Answer [2] 3905 4 [Turn over 4 The graph below shows changes in both cell mass and DNA mass per nucleus during several mitotic cell cycles in a mammalian embryo. Examiner Only Marks Remark X ss a ll m ce DNA mass per nucleus /arbitrary units 2 1 DNA mass per nucleus 1 0 Cell mass/arbitrary units 2 0 0 12 36 24 Time/hours 48 (a) Between which times shown on the graph does the G1 (growth 1) phase occur during the first cell cycle? _______________________________________________________ [1] (b) State what is occurring during the phase indicated by X on the graph. _______________________________________________________ [1] (c) Explain the changes in the DNA mass per nucleus during one cell cycle. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] 3905 5 [Turn over 5 (a) Explain why the genetic code is a three base or triplet code. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] (b) The table below presents the genetic code. The position of each base in a mRNA codon may be read from the table to give the amino acid for which it codes. Second base C alanine alanine alanine alanine U valine valine valine valine G A C U arginine arginine serine serine lysine lysine asparagine asparagine threonine threonine threonine threonine Start isoleucine isoleucine isoleucine G A C U C arginine arginine arginine arginine glutamine glutamine histidine histidine proline proline proline proline leucine leucine leucine leucine G A C U U 3905 A glutamic acid glutamic acid aspartic acid aspartic acid A First base G glycine glycine glycine glycine tryptophan Stop cysteine cysteine Stop Stop tyrosine tyrosine serine serine serine serine leucine leucine phenylalanine phenylalanine G A C U G 6 Third base [Turn over (i) State the mRNA codon translated as tryptophan (shown in bold). Examiner Only Marks Remark ___________________________________________________ [1] (ii) Mutations may cause a base change in the code. Using the table opposite, state the effect of changing the three base sequence GAA to GUA. _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [2] (iii) Explain how the structure of the final protein may change as a result of this mutation. _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [2] 3905 7 [Turn over 6 An experiment was undertaken to investigate the effect of pH on two proteolytic enzymes, gastric protease and pancreatic protease. Cubes of protein, each of 200 mg mass, were placed in solutions of each enzyme, at different pHs, and the time taken for the protein to be digested was measured. The results are shown in the graph below. Examiner Only Marks Remark Time for protein to be digested/minutes 80 60 pancreatic protease 40 gastric protease 20 0 0 1 2 3 4 5 6 pH 7 8 9 10 11 (a) State one factor that should be controlled in the experiment, and explain the influence of that factor on enzyme activity. Factor ___________________________________________________ Influence ________________________________________________ _______________________________________________________ [2] (b) Using the information above, calculate the rate of reaction for gastric protease at pH 2 in units of mg hour 1. (Show your working in the space below.) Answer _______________[2] 3905 8 [Turn over (c) Describe the trends shown in the graph. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (d) Explain the trends described in (c). _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 3905 9 [Turn over 7 The human protein, insulin, is involved in the homeostatic control of blood sugar. Most artificially produced human insulin is currently produced by genetically-modified bacteria, but several companies are now investigating the possibility of producing human insulin using the safflower plant, a plant which is normally grown for its oil. This method would allow large scale production and, in theory, one large North American farm would be capable of meeting the global demand for insulin. Examiner Only Marks Remark The first stage in this process would be the isolation and removal of the human insulin gene. (a) State which enzyme would be used to remove the human insulin gene from a human chromosome. [1] Once isolated, the gene is then placed into a vector. One example of such a vector is the bacterium, Agrobacterium tumefaciens, a relatively common soil bacterium that regularly infects plants. (b) Describe how the human insulin gene could be inserted into the bacterium, Agrobacterium tumefaciens. [4] 3905 10 [Turn over The genetically-modified bacterium is then allowed to infect a sample of cells extracted from the safflower plant and these infected cells can be grown on into mature plants, each being capable of producing human insulin. The human insulin produced by these plants appears to be fully effective in the treatment of diabetes. However, a patient s blood insulin cannot be raised by simply eating transgenic safflower plants. Examiner Only Marks Remark (c) Suggest why eating safflower plants containing insulin would not result in an increase in the patient s blood insulin levels. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] One possible risk of growing a genetically-modified crop in this way is that it might interbreed with wild plants. Pharmaceutical companies try to minimise such risks by growing the crop counter-seasonally to reduce the chances of the insulin gene being transferred to other plants. (d) Suggest what is meant by the term counter-seasonally . _________________________________________________________ _______________________________________________________ [1] 3905 11 [Turn over Section B Examiner Only Marks Remark In this section you are expected to answer in continuous prose, supported, where appropriate, by diagrams. You are reminded that up to two marks in this question are awarded for the quality of written communication. [2] 8 Give an account of the process of osmosis and its effect in animal and plant cells. [10] ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 3905 12 [Turn over ____________________________________________________________ Examiner Only Marks Remark ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ 3905 13 [Turn over THIS IS THE END OF THE QUESTION PAPER 3905 14 [Turn over GCE Biology Advanced Subsidiary (AS) Assessment Unit AS 1 Module 1: Cell Biology Summer 2009 Photograph 1.3 (For use with Question 3) A B X Y Source: Marilyn Schaller/Science Photo Library 3905.02 D 30 m ASB11IN1 C 937-002-1 [Turn over

Formatting page ...

Additional Info : : Gce Biology June 2009 Assessment Unit AS 1 Module 1: Cell Biology
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: