IB Biology Higher Level

1. Chlorella and Paramecium are both unicellular eukaryotic organisms living in freshwater. Chlorella is photosynthetic and has a cell wall. Which organelle will be found in Paramecium but not in Chlorella? A. Chloroplast B. Contractile vacuole C. Rough endoplasmic reticulum D. Mitochondrion

2. The electron micrograph shows a section through a cell. Y X 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. 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 4. What would show that a person has developed metastatic cancer? A. Alveolus cells forming a tumour in the lungs B. Cancer cells producing the skin pigment melanin in the liver C. A tumour in the prostate gland increasing levels of prostate-specific antigen D. Cancerous lymphocytes in blood plasma

5. 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 6. 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

7. 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.

8. The table shows the mass of different types of fat in some foods. Mass per 100 g food Food Saturated fat Polyunsaturated fat Monounsaturated fat Trans fat Palm oil 50 9 23 0 Canola oil 7 28 63 0 Sunflower oil 10 40 45 0 Partially hydrogenated soybean oil 30 10 15 45 Which oil would be least recommended for inclusion in the human diet? A. Palm oil B. Canola oil C. Sunflower oil D. Partially hydrogenated soybean oil

9. The first iron ore deposits in rocks appeared about 1.8 billion years ago. What took place to make this occur? A. Some prokaryotic organisms began to absorb carbon dioxide from seawater. B. Some eukaryotic organisms began to absorb carbon dioxide from seawater. C. Some prokaryotic organisms began to release oxygen into seawater. D. Some eukaryotic organisms began to release oxygen into seawater.

10. 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

Turn over 11. 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

12. In DNA profiling, short tandem repeats (STRs) of DNA are used, as these vary a great deal between individuals. Some skin cells were retrieved from a crime scene. Three STR sections of the DNA from these cells, from the victim and from a suspect, were analysed and the results are shown in the table. STR base sequence Number of repeats of STR base sequence Victim Skin cells at crime scene Suspect GTCA 10 5 30 ATGG 40 50 66 ATTA 24 13 13 What can be concluded from the gel electrophoresis data? A. The suspect was at the crime scene. B. The victim has the band moving the least distance. C. The suspect and the victim have bands moving the same distance. D. The skin cells have the band moving the greatest distance.

13. Testing the chromosomes of a girl with Turner syndrome produced the following karyogram. The condition can result from non-disjunction occurring in anaphase I of meiosis in an egg cell. Two cells result from the first division, one of which would lead to Turner syndrome. Which chromosomes will be in the other cell (polar body) at the end of meiosis I? A. 44 autosomes and X B. 44 autosomes and XX C. 22 autosomes and X D. 22 autosomes and XX

Turn over 14. 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

15. 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.

16. Plankton are major producers in marine ecosystems. Only a small proportion of the energy harvested by plankton is passed to the primary consumers. Which process in phytoplankton results in the largest loss of energy that could otherwise be utilized by consumers? A. Reproduction B. Homeostasis C. Excretion D. Respiration

17. What would restrict evolution by natural selection, if a species only reproduced by cloning? A. Too few offspring would be produced. B. Mutations could not occur. C. The offspring would show a lack of variation. D. The offspring would be the same sex as the parent.

18. An animal has the following characteristics: bilateral symmetry, mouth but no anus, ribbon shape. Which phylum does the animal belong to? A. Mollusca B. Cnidaria C. Annelida D. Platyhelmintha

Turn over 19. The cladogram shows some of the groups in the three domains. What domains do X, Y and Z represent? Domains X Y Z A. prokaryote archaea eukaryote B. archaea eubacteria prokaryote C. eubacteria archaea eukaryote D. eubacteria prokaryote eukaryote

20. The photomicrograph shows a section through a human small intestine. X Y Z Which statement corresponds to the labelled structures? A. X moves food along the intestine. B. Y is the mucosa. C. Y contains lacteals. D. Z causes peristalsis.