Practice Paper. AS Level Biology B (Advancing Biology) H022/02 Biology in depth Prac, Exams of Biology

Download Practice Paper. AS Level Biology B (Advancing Biology) H022/02 Biology in depth Prac and more Exams Biology in PDF only on Docsity! Practice Paper. AS Level Biology B (Advancing Biology) H022/02 Biology in depth MARK SCHEME Duration: 1 hour 30 minutes MAXIMUM MARK 70 H022/02 This document consists of 18 pages Mark Scheme June 20XX MARKING INSTRUCTIONS PREPARATION FOR MARKING SCORIS 1. Make sure that you have accessed and completed the relevant training packages for on-screen marking: scoris assessor Online Training; OCR Essential Guide to Marking. 2. Make sure that you have read and understood the mark scheme and the question paper for this unit. These are posted on the RM Cambridge Assessment Support Portal http://www.rm.com/support/ca 3. Log-in to scoris and mark the required number of practice responses (“scripts”) and the required number of standardization responses. 2 H022/02 The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary: • The science content determines the level. • The communication statement determines the mark within a level. Level of response questions on this paper are 2(a) and 3(a(iv)). 11. Annotations Annotation Meaning DO NOT ALLOW Answers that are not worthy of credit IGNORE Statements that are irrelevant ALLOW Answers that can be accepted ( ) Words that are not essential to gain credit __ Underlined words must be present in answer to score a mark ECF Error carried forward AW Alternative wording ORA Or reverse argument 5 12. Subject-specific Marking Instructions INTRODUCTION Your first task as an Examiner is to become thoroughly familiar with the material on which the examination depends. This material includes: • the specification, especially the assessment objectives • the question paper • the mark scheme. You should ensure that you have copies of these materials. You should ensure also that you are familiar with the administrative procedures related to the marking process. These are set out in the OCR booklet Instructions for Examiners. If you are examining for the first time, please read carefully Appendix 5 Introduction to Script Marking: Notes for New Examiners. Please ask for help or guidance whenever you need it. Your first point of contact is your Team Leader. Question Answer Marks Guidance 1 (a) (i) Forced expiratory volume in first second (of exhaling) Peak expiratory flow rate 2 (ii) 3.5 - 1.8 1.7  2 (iii) idea that PEFR will be the slope of (the steepest part of) the line 1 (b) (i) idea of a compare to the allergen reaction / AW  1 ALLOW any reference to subtracting this score from the 7 mounting and microscopy is given with some features of monocot root structural features. There is a description of methodology which has some structure. The information presented is largely relevant. Level 1 (1–2 marks) A description of either sectioning, staining, mounting or microscopy is given. Features of monocot root structure may be missing or incorrect. There is a description of some methodology which may be unstructured. Some irrelevant or incorrect information may be presented. 0 marks No response or no response worthy of credit. • reference to different colours for different tissues / differential staining • detail of colours (for toluidine blue, xylem is blue, phloem purple) • reference to mounting on slide and use of cover slip • reference to focus or magnification used • reference to presence of endodermis • reference to circle of xylem and phloem in monocot roots (within endodermis) • reference to presence of 'X' shaped xylem in dicot roots (within endodermis) • reference to phloem between the arms of the 'X' shape • reference to using a fresh specimen ALLOW information presented as annotated diagrams. Question Answer Marks Guidance 2 (b) Peanut Cumin Kingdom 3 Both genera correct = 1 mark Arachis and Cuminum must be spelled correctly and have initial capital letter 5 taxon terms correct = 2 marks 3 taxon terms correct = 1 mark 10 Class Order Family Arachis Cuminum  Species  (c) (i) V – (B / T-helper) lymphocyte  W - plasma cell  X - mast cell  3 (ii) (Step 3) cytokine(s)  (Step 8) histamine  2 Total 14 Question Answer Mark Guidance 3 (a) (i) aerobic respiration OR synthesis of ATP 1 ALLOW Krebs cycle, link reaction, oxidative phosphorylation, protein synthesis, (mitochondrial) DNA replication 11 (ii) X 5150 2 Correct answer = 2 marks ALLOW X 5100 to X 5200 If answer is incorrect look for: 51 to 52 mm OR 5.1 to 5.2 cm (from scale bar) converted to µm Answer divided by 10 (iii) (membranes have) phospholipids and proteins and cholesterol (phospholipids) arranged as a bilayer (proteins) free to move / AW, within bilayer  ref to intrinsic and extrinsic proteins  ref to cholesterol (molecules), spanning bilayer  3 IGNORE ref to glycoprotein or glycolipids 12 Level 3 (5–6 marks) A comparison of proteins and RNA which is chemically 6 Indicative scientific points may include: 15 detailed and includes reference to the bonds in the molecules. There is a well developed description of monomers polymers and bonds for both molecules which is clear and structured to give a comparison. The information presented is relevant. Level 2 (3–4 marks) A comparison of proteins and RNA with some chemical detail. There is a description of monomers polymers and bonds for both molecules which is clear and logically structured. The information presented is relevant. . Level 1 (1–2 marks) An outline of the structure of RNA or protein with limited comparative statements. There is a general description of both monomers and polymers which may be unstructured. Some irrelevant or incorrect information may be presented. 0 marks No response or no response worthy of credit. FOR RNA • nucleotide as the monomer • nucleotide structure as a pentose sugar, a phosphate and a (nitrogenous) base • RNA nucleotide sugar is ribose • 4 RNA bases • RNA bases are adenine, uracil, cytosine and guanine. • adenine and guanine are purines • cytosine and uracil are pyrimidines • condensation reactions (between nucleotides) • formation of phosphodiester bonds FOR PROTEIN • amino acid as monomer • 20 different amino acids • joined by condensation reactions • formation of peptide bonds • carboxyl groups and amine groups • secondary structure / alpha helix / beta pleated sheet • hydrogen bonding • tertiary structure with bonds between R groups • ionic bonding • disulphide bonding • hydrophobic and hydrophilic interactions. 16 Question Answer Mark Guidance (b) polysaccharide  1 ALLOW phonetic spelling (c) (i) (both are) glycosidic  P - (alpha) 1,4 and Q- (alpha) 1,6  2 Examples of how to award the marks, P glycosidic, Q glycosidic = 1 mark P glycosidic, Q peptide = 0 marks P 1-4, Q 1-6 = 1 mark P 1-4 glycosidic, Q 1-6 glycosidic = 2 marks P 1-6 glycosidic, Q 1-4 glycosidic = 1 mark (ii) condensation  1 (iii) Appearance – idea that: granules appear smaller OR (some) granules permanently present OR more granules Explanation – idea that: some / AW of glycogen molecule remains OR short branches still left on the molecule OR molecules still synthesised but not broken down 2 Explanation must correspond to the appearance Total 18 17 5 (a) measure / AW, crown - rump length and biparietal diameter  extrapolate / AW, from growth charts  2 (b) Advantage compared with CVS and AMNIOCENTESIS 1. non-invasive test  2. no risk of test causing miscarriage  3. earlier than amniocentesis  4. idea that it could be carried out as part of a routine scan / test Disdvantage compared with CVS and AMNIOCENTESIS 5. idea that only risk given / does not confirm diagnosis / not definitive  6. consequence of false positive / negative  4 2 ALLOW reverse argument 'There is a risk of miscarriage with CVS/ AMNIOCENTESIS. 5 ALLOW reverse argument e.g. only karyotyping is definitive (c) (i) 0.1 (per 100 000) 1 (ii) vaccination programme / most people vaccinated as children  herd immunity  2 20 Question Answer Mark Guidance idea that not all cases are reported (as symptoms are mild)  Total 9 21 Question Answer Mark Guidance BLANK PAGE 22