Practice Paper 1 (DP IB Biology: HL)

Halophytes are plants that are able to survive in regions where they are regularly covered by salty seawater. 

Which adaptation would you expect halophytes to have to enable them to live in this environment?

What properties does a human cell have just before it enters prophase?

The table shows the percentages of bases in DNA samples from various organisms.

Which row of the table below correctly reflects the missing data values?

In the graph, Z represents the relationship between the initial rate of an enzyme-catalysed reaction and the concentration of its substrate under optimal conditions and without an inhibitor.

Which curve would represent the same experiment carried out in the presence of a low concentration of a non-competitive inhibitor?

The nomogram below shows the range and classification of body mass index (BMI) values.

A person of height 170 cm has a mass of 105 kg.

What is the amount of mass this person would have to lose to reach a body mass within the normal BMI range?

Which property of carbon makes it a good basis for organic molecules?

Which activity was not a direct contributor to Crick and Watsons' discovery of the double-helix structure of DNA?

Which is the most correct statement about chlorophyll?

John Cairns carried out a study in which he kept E. coli bacteria in a solution containing radioactive thymine. 

What was he able to conclude from the results of his study?

The following statement describes some of Louis Pasteur’s findings:

What did these findings suggest?

Which of the following statements help to explain why DNA replication happens before meiosis?

1. A gamete-producing cell ends up producing 4 gametes.
2. The cell undergoes reduction division during meiosis.
3. Gametes contain double the amount of genetic material than somatic cells.
4. Each parent's genome is replicated to allow two copies of their alleles to be inherited with equal probability.

Events in meiosis play an important role in determining the inheritance of alleles. Which row of the table states the correct words to name the processes being described?

Which of the following species are most closely related?

1.  Marsh tit (Poecile palustris)
2. Coal tit (Periparus ater)
3. Marsh warbler (Acrocephalus palustris)
4. Willow tit (Poecile montanus)

Why are ecosystems considered to be sustainable?

From each molecule of substance X (in the diagram), how many molecules of ATP can be produced?

From the three examples listed below, which describe the occurrence of speciation?

I. Two plant populations of the same species are pollinated by different species of insect that are active at different times of the day. There is no overlap between when the two insect species are active. Mutations occur within the two populations leading to them to become genetically distinct from each other. 

II. A small number of lizards float on a wooden log and start a new population on another island. Mutations occur within the two populations leading to them to become genetically distinct from the original population.  

III. A mutation occurs that causes a small population of a species of plant to become tetraploid instead of the usual diploid cells.

Theories can change when new evidence emerges. Evidence relating to the evolutionary relationships between organisms can lead to their reclassification. What led to the reclassification of the figwort plant family?

In eukaryotic cells, ribosomes can be either free or bound.

Which of the following proteins would most likely be synthesised by bound ribosomes?

Which of the following statements about metabolism are correct?

1. Metabolism involves chemicals called metabolites.
2. Metabolism involves reactions in a linear chain.
3. Metabolism involves reactions in a cycle.
4. Metabolism involves only the breakdown of molecules.

A student studied the structure of a blood vessel and found:

1. An innermost layer of endothelial cells
2. A thick middle layer of smooth muscle and elastic tissue
3. An outer layer of collagen fibres

Which vessel was the student studying? 

Bacteria and viruses are the main pathogens in humans. Antibiotics can be used to treat bacterial infections but not viral infections.

Which of the following statements explains why?

What is specific immunity?

Which event directly results in the production of an action potential?

The bambooleaf wrasse, Pseudolabrus japonicus, is a species of fish found off the coast of Japan. During the breeding season male wrasse release gametes (a process known as spawning) on a daily cycle in the presence of a single female.

The graph below shows some of the events occurring inside the testes of bambooleaf wrasse during a 24 hour period.

Note that lobules are regions within fish testes.

Which of the following statements relating to spermatogenesis and fertilisation in wrasse are correct?

Wrasse spawning occurs between 06:00 and 10:00.

Both mitosis and meiosis are occurring between 00:00 and 15:00.

The percentage increase in the number of sperm per lobule between 00:00 and 06:00 is 66. %.

A specific androgen receptor (AR) found in the cytoplasm of cells interacts with the sex hormone, testosterone. 

A repeating nucleotide base sequence, CAG, found in the gene for AR has been associated with the risk of developing prostate cancer.

The table below shows the results of two statistical tests which found an association between the number of CAG repeats and the risk of developing prostate cancer.

The null hypothesis was;

'There is no significant association between the number of CAG repeats and the risk of developing prostate cancer'

Identify the conclusion which can be drawn from the data in the table.

The simplified diagram below shows a section of DNA where a methyl (-CH₃) group has been added to a cytosine base.   

Which of the following best describes the outcome of direct methylation of DNA?

The following steps describes the events taking place during the elongation of a polypeptide in no particular order.

1. Free tRNA molecules bind to their corresponding amino acids due to their specific anticodon and transport it to the ribosome 
2. A tRNA with a complementary anticodon binds to the "A" site bringing its specific amino acid along
3. The initiator tRNA moves from the "P" to the "E" site on the ribosome where it initiates translation
4. The amino acid carried by the tRNA at the "P" site is linked to the polypeptide chain by a peptide bond
5. tRNA carrying the peptide chain moves from the "A" site to the "P" site as the ribosome moves in the 5' → 3' direction along the mRNA molecule

Which of these steps contain incorrect information?

Which of the following is not a correct description of the “transition state” in enzyme-controlled reactions?

Which statements correctly describe phosphorylation and dephosphorylation reactions?

1. The phosphorylation of ADP is an endergonic reaction.
2. The dephosphorylation of ATP is an endergonic reaction.
3. The phosphorylation of ADP is a hydrolysis reaction.
4. The dephosphorylation of ATP is a hydrolysis reaction.

Which of the following would be a suitable definition for the term 'photolysis'?

Identify which of the adaptations below is not found amongst the group of plants known as xerophytes.

Which of the following best describes the factor that determines the direction of mass flow of phloem sap between leaves and fruit?

What would not be considered a function of auxins?

Which event causes genetic variety in the gametes formed during meiosis?

The diagram shows a pair of homologous chromosomes at the beginning of prophase I of meiosis and four possible examples of crossing over, A - D

Which of the four representations of crossing over cannot occur in meiosis I?

If a patient is given a transfusion of the wrong blood type, an immune response results. This response involves agglutination followed by haemolysis, where red blood cells are destroyed and blood may then coagulate. Blood typing involves mixing blood samples with antibodies. The diagram below shows the results of a blood typing test, showing the reactions between blood types (rows) and antibody serums (columns). The first column shows the appearance of each blood sample before testing occurred.

Identify the row in the table below that correctly identifies the blood type of blood samples I - IV.

The diagram below shows the sarcomere of a muscle fibre.

Which of the following statements correctly describes the events observed during a muscle contraction?

Which of the following statements describe features that aid the process of ultrafiltration?

1. The glomerulus has an afferent arteriole and an efferent arteriole.
2. The blood in the afferent arteriole has a different composition to the blood in the efferent arteriole.
3. The basement membrane prevents the passage of large proteins out of the glomerulus.
4. The afferent arteriole is wider than the efferent arteriole.

The zona pellucida in mice contains three different types of glycoprotein, known as ZP1, ZP2, and ZP3. The roles of each glycoprotein type are thought to be as follows:

ZP1 - provides structural support to the zona pellucida.

ZP2 - a secondary binding protein to which sperm cells bind after the initial stages of fertilisation are complete. The enzymes contained in cortical granules are thought to break down ZP2.

ZP3 - a primary binding protein to which sperm bind at the beginning of the fertilisation process.

Which row correctly explains the mutation that is most likely to result in polyspermy?