IB Biology Standard Level

1. What is the name of the cell component labelled Y? A. Golgi apparatus B. Nucleus C. Cytoplasm D. Vacuole

2. Which feature of the cell in the micrograph is consistent with the endosymbiotic theory? A. X has a single membrane. B. Y has a double membrane. C. X contains 70S ribosomes. D. Y contains 80S ribosomes.

3. Which sequence has the cells arranged according to their ability to differentiate, starting from the least able? A. bone marrow, neuron, embryonic, umbilical B. neuron, bone marrow, umbilical, embryonic C. umbilical, embryonic, bone marrow, neuron D. embryonic, umbilical, bone marrow, neuron

4. The diagram shows a section through a membrane. What are the modes of transport in the diagram? I II I II A. simple diffusion osmosis B. active transport facilitated diffusion C. simple diffusion facilitated diffusion D. facilitated diffusion active transport

Turn over 5. How many chromosomes are there in a cell during anaphase of mitosis, if the diploid number of the cell is 20? A. 10 B. 20 C. 40 D. 80

6. What are the type of reaction and the product(s) shown in this reaction? OH OH OH HO O O P O CH2 OH HO O O P O CH2 OH OH OH OH HO O O P O CH2 OH OH O HO O O P O CH2 H2O + Reaction Product(s) A. condensation two nucleotides B. condensation one dinucleotide C. hydrolysis two nucleotides D. hydrolysis one dinucleotide

Turn over 7. The chart shows ranges of body mass index (BMI) for children and teenagers. 12 10 2 3 4 5 6 7 8 9 10 11 13 12 14 15 16 17 18 19 20 14 16 18 20 22 26 28 30 32 34 BMI / kg m–2 24 Age / years Obese Overweight Healthy weight Underweight A 9-year-old boy has a height of 120 cm and weighs 28.8 kg. What weight category is he in according to his BMI? A. Underweight B. Healthy C. Overweight D. Obese

8. The genetic code is shown. 2nd base U C A G 1st base U Phe Ser Tyr Cys U 3rd base Phe Ser Tyr Cys C Leu Ser STOP STOP A Leu Ser STOP Trp G C Leu Pro His Arg U Leu Pro His Arg C Leu Pro Gln Arg A Leu Pro Gln Arg G A Ile Thr Asn Ser U Ile Thr Asn Ser C Ile Thr Lys Arg A Met Thr Lys Arg G G Val Ala Asp Gly U Val Ala Asp Gly C Val Ala Glu Gly A Val Ala Glu Gly G In a coding gene, the DNA triplet in the transcribed strand is changed from AGG to TCG. What would be the result of this change in the genome? A. A non-functional protein B. A different but functional protein C. No change in the protein D. Termination of the polypeptide

9. The diagram represents transcription and translation. A A A A G G C A A A T T T T T T C T A A A A A A A U U U U U U U X Y C C G G What structures do the letters X and Y represent? X Y A. DNA anticodon B. mRNA anticodon C. DNA codon D. mRNA codon

Turn over 10. What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)? A. It does not denature at high temperatures. B. It produces Okazaki fragments more rapidly. C. It allows translation to proceed rapidly. D. It works efficiently with helicase in PCR.

11. The diagram shows a respirometer. Experimental tube Screw clip Small organisms Gauze Manometer tube containing coloured fluid 1 cm3 syringe Glass beads What solution should be in the bottom of each tube and in which direction will the manometer fluid move? Solution placed in the bottom of each tube Direction of movement of fluid in the manometer A. acid up on the left side B. alkali down on the right side C. acid up on the right side D. alkali down on the left side

12. Plants produce carbon dioxide in respiration and use carbon dioxide in photosynthesis. The graph shows the volume of carbon dioxide exchanged in a plant at different light intensities. 0 Light intensity Carbon dioxide exchange W X Y Z What is shown by the graph? A. There is no photosynthesis between W and X. B. There is no photosynthesis between Y and Z. C. There is more respiration than photosynthesis between Y and Z. D. There is more respiration than photosynthesis between W and X.

Turn over 13. In the pedigree chart, individuals affected by a genetic disease are shown as shaded symbols. Squares represent males and circles females. What is the mode of inheritance of the genetic disease? A. Inherited as a dominant autosomal allele B. Inherited as a recessive autosomal allele C. Inherited as a recessive sex-linked allele D. Inherited as a dominant sex-linked allele

14. Tall heterozygous pea plants were crossed and the resulting seeds grown. Out of 360 plants, 270 were tall and 90 dwarf. What describes the expected genotypes resulting from the cross? A. All 270 tall plants were heterozygous. B. All 270 tall plants were homozygous. C. Only 90 plants were homozygous. D. All dwarf plants were homozygous.

15. What are all the possible phenotypes of children born to a mother with blood group AB and a father with blood group A? A. AB only B. A and B C. AB, A and B D. AB, A and O

16. Which level(s) of ecological complexity involve(s) biotic factors but not abiotic factors? I. Community II. Ecosystem III. Population A. I only B. II only C. I and II only D. I and III only

17. How can a chi-squared test be used in ecological research? A. To test the effect of an abiotic factor on one plant species B. To test whether two species tend to live together C. To test whether one population of plants is taller than another D. To test whether one species is more tolerant to heavy metals than another

18. Under certain conditions, living organisms on Earth produce and release methane. What favours the production of methane? A. Forest fires B. High light intensity C. Anaerobic conditions D. Dry conditions

19. The oceans absorb much of the carbon dioxide in the atmosphere. The combustion of fossil fuels has increased carbon dioxide ocean concentrations. What adverse effect does this have on marine life? A. Heterotrophs consume more phytoplankton. B. Phytoplankton have increased rates of photosynthesis. C. Corals deposit less calcium carbonate to form skeletons. D. Increased pH reduces enzyme activity in marine organisms.

20. What process best explains the formation of different pentadactyl limbs? A. Adaptive radiation B. Interbreeding C. Selective breeding D. Convergence