Prueba Del Ib

IB DIPLOMA PROGRAMME PROGRAMME DU DIPLÔME DU BI PROGRAMA DEL DIPLOMA DEL BI

M07/4/BIOLO/SP3/ENG/TZ1/XX/M+

MARKSCHEME

May 2007

BIOLOGY

Standard Level

Paper 3

19 pages

http://www.xtremepapers.net

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M07/4/BIOLO/SP3/ENG/TZ1/XX/M+

This markscheme is confidential and for the exclusive use of examiners in this examination session. It is the property of theInternational Baccalaureate and must not be reproduced or distributed to any other person without the authorization of IBCA.

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M07/4/BIOLO/SP3/ENG/TZ1/XX/M+

Subject Details:
Mark Allocation

Biology SL Paper 3 Markscheme

Candidates are required to answer ALL questions in each of TWO Options (total [18 marks]). Maximum total = [36 marks]. General A markscheme often has more specific pointsworthy of a mark than the total allows. This is intentional. Do not award more than the maximum marks allowed for part of a question. When deciding upon alternative answers by candidates to those given in the markscheme, consider the following points: Each marking point has a separate line and the end is signified by means of a semicolon (;). An alternative answer or wording is indicated in themarkscheme by a “/”; either wording can be accepted. Words in ( … ) in the markscheme are not necessary to gain the mark. Words that are underlined are essential for the mark. The order of points does not have to be as written (unless stated otherwise). If the candidate’s answer has the same “meaning” or can be clearly interpreted as being the same as that in the markscheme then award the mark. Markpositively. Give candidates credit for what they have achieved, and for what they have got correct, rather than penalizing them for what they have not achieved or what they have got wrong. Remember that many candidates are writing in a second language. Effective communication is more important than grammatical accuracy. Occasionally, a part of a question may require a calculation whose answer isrequired for subsequent parts. If an error is made in the first part then it should be penalized. However, if the incorrect answer is used correctly in subsequent parts then follow through marks should be awarded. Indicate this with “ECF”, error carried forward. Units should always be given where appropriate. Omission of units should only be penalized once. Indicate this by “U-1” at the first pointit occurs. Ignore this, if marks for units are already specified in the markscheme. Do not penalize candidates for errors in significant figures, unless it is specifically referred to in the markscheme.

–6– Option A — Diet and Human Nutrition A1. (a) (b) fats/lipids and carbohydrates/sugars Need both to receive the mark.

M07/4/BIOLO/SP3/ENG/TZ1/XX/M+

[1]

both rise (from one to fourmonths); those with added protein rise more slowly / those without the extra protein rise more quickly / difference increases; those with no added protein always higher; there is not a lot of difference / no significant difference between them; 80.5(±0.1) − 79.2(±0.1) × 100; 80.5(±0.1) = 1.6 ( ±0.3) % ; (unit not required)

[2 max]

(c)

[2]

(d)

graph shows (some evidence of) less gainin body mass with additional protein; the difference with additional protein is small; the hypothesis is not strongly supported; both groups may eventually regain all the body mass; experiment not left long enough: differences still increasing after three months;

[3 max]

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A2. (a)

M07/4/BIOLO/SP3/ENG/TZ1/XX/M+

Award [2] for four correct answers, [1] for three or two correct answersand [0] for one correct answer. retinol/vitamin A; cyanocobalamin/vitamin B12; ascorbic acid/vitamin C; calciferol/vitamin D; tocopherol/vitamin E; etc.; Do not accept vitamin B unqualified.

[2 max]

(b)

link to health / prevention of certain diseases / deficiency diseases; only needed in small amounts; cannot be made by body (except vitamin D); Award [1 max] for vitamin and correct use...