Practice Paper 1 (DP IB Biology: HL)

The electron micrograph below shows a section of part of a palisade mesophyll cell.

Which structure controls the exchange of substances into and out of the cell?

Select the table row that correctly completes the following sentence:

Cholesterol is a component of animal cell membranes. Most of a cholesterol molecule is ...I… . This means that cholesterol ...II… 

Which of the following is evidence for the endosymbiotic theory?

A study was conducted to investigate the effect of saturated fat intake on the risk of developing coronary heart disease (CHD) in women.

• The study involved 20 women, aged between 35 and 50, divided into two groups (A and B) of 10.
• Group A was given a diet rich in saturated fats, while group B followed a diet low in saturated fats.
• The levels of low-density lipoprotein (LDL) in their blood was monitored over a six month period. High LDL levels has been linked to an increase in the risk of developing CHD.

At the end of the study the levels of LDL in group A was much higher than that of group B. The scientists concluded that saturated fats increases the risk of developing CHD.

Which evaluation of their conclusion would be most valid?

Which one of the following phenomena is not a consequence of end-product inhibition in biochemical pathways?

Which of the following observations is not explained by water's high latent heat of vaporisation and specific heat capacity?

Which of the following is not a feature of lipids that contain trans-fatty acids?

Rituximab is an example of a therapeutic protein that is used to treat certain types of cancers and autoimmune diseases. It is very sensitive to temperature and pH changes and is typically injected into the bloodstream of patients.

Which of the following statements would explain why therapeutic proteins, such as rituximab, cannot be taken orally?

I. The molecule would vibrate so fast once in the stomach that the intermolecular bonds would break

II. The conformation of the protein will change once in the stomach and it may become non-functional

III. The protein may become insoluble once in the stomach and form a precipitate due to the breakage of ionic bonds

IV. Conditions in the stomach will cause the hydrophobic R-groups of the protein to be exposed to the outside of the molecule

A student drew a diagrammatic representation of a transverse section of a plant stem based on what they saw using a light microscope.

Identify the correct labels required for the drawing above.

In prokaryotes, the processes of transcription and translation are said to be coupled, which means they can proceed simultaneously.

Which is the key cellular feature of prokaryotes that allows this to happen?

The muscle protein titin is an important component of cardiac muscle tissue. Several forms of titin exist, even though it is coded for by the same gene. During the development of the foetal heart, titin exists in the form of long, springy protein strands, while in the adult heart titin is much shorter.

Which of the following provides the most plausible explanation for the occurrence of the different forms of titin?

Which of the following statements is not correct with regards to chemiosmosis in photosynthesis?

1. Protons move down their concentration gradient through ATP synthase located in the chloroplast membrane
2. The photolysis of water provides protons needed for chemiosmosis to occur
3. ADP is phosphorylated to ATP due to the energy released by the movement of electrons down the electron transport chain
4. A high concentration of protons build up outside the intermembrane space, creating a concentration gradient

The diagram below represents a simplified version of the electron transport chain and chemiosmosis.

Which row correctly describes the events labelled 1-4 above?

Which process is not part of the light-independent reaction of photosynthesis?

In a newt, normal tail length is dominant to short tail length and green scales are dominant to white scales.
A heterozygous normal tailed newt with green scales was crossed with a short tailed newt with white scales. A large number of offspring were produced. They were either normal tailed with green scales or short tailed with white scales in equal number.
What is the most likely cause of this pattern?

Which discovery was first made by Bateson and Punnett in the early 20^th century?

A game farm in South Africa has a population of about 5 000 large antelope called Kudu. Kudu bulls have large, spiralled horns which draw the attention of trophy hunters that frequently visit the game farm.

The antelope are all kept in a large, fenced-off area consisting of open grassland habitat.

Could this be considered an example of a stable gene pool?

The pedigree diagram shows the inheritance of cystic fibrosis across 3 generations.

Identify the genotype of the individuals labelled 1, 2 and 3 in the pedigree diagram.

Scientists use theories to explain observed phenomena. Which of the following combinations of observed phenomenon and explanation shows how scientists developed the theory that explains antibiotic resistance in bacteria?

In 1989 a company called AquaBounty Technologies genetically engineered (GE) Atlantic salmon to contain a growth hormone-regulating gene which had been extracted from another species of salmon (the Pacific Chinook salmon). 

The modification resulted in an increased rate of growth without impacting any other health qualities. Fully grown GE salmon were the same size as the unmodified salmon, however, it took less time for them to reach full size.

Identify which of the following options would not be considered a risk for GE salmon.

A chi-squared test was carried out to test for association between species A and species B.  The results of the chi-squared test are given below. 

Results of chi-squared test:

Critical values table:

What can be concluded from the chi-squared test for association carried out to test for association between species A and species B?

Which of the following chemical equations correctly represents one method for how carbon is made available for absorption by aquatic autotrophs?

The graph below shows the differences between the radiation reaching the earth from the sun and the radiation re-emitted by the earth.

How does this radiation cause the greenhouse effect?

Which of the following applies to the process of evolution by natural selection?

1. Changes in the phenotype of organisms in a population
2. Selection pressures favouring certain alleles within a population
3. Individuals with a certain genetic makeup will not pass on their genes
4. Changes in the allele frequencies within a population over time

Which of the following cannot be concluded from the cladogram below?

RNA analysis led to the development of the three domains system of classifying organisms. More recent methods of building evolutionary trees has led to the proposal of the two domains system. The image compares the three domains tree and the two domains tree.

Which of the following pairs of statements correctly compares the three domains and two domains trees?

Which of the following statements about inorganic nutrients are true?

1. Carbon and hydrogen are key components of inorganic ions necessary for cell growth and development
2. Inorganic ions enter the ecosystem through plant roots using energy from ATP
3. Drought leading to dry soils results in a reduced availability of inorganic ions
4. Sustainability of an ecosystems relies on inorganic ions being locked up within the biomass of an organism

Which of the following describes a function of ATP in muscle contraction?

The graph below shows plant flowering at different day lengths in a species of plant.

Which of the following provides the most accurate explanation of the data?

Which of the following does not form part of the fertilisation process in humans?

Which combination of secretions are produced by the pancreas?

Avian bird flu is caused by the H5N1 virus. Scientists are concerned that this could affect humans and cause a pandemic.

Which of these measures would help prevent the spread of disease in humans?

During a gas exchange investigation, measurements were recorded from four animals that were observed as they breathed normally over a period of 5 minutes. Note that the efficiency of gas exchange was the same in all four animals and that tidal volume refers to the volume of air that moves into the lungs with each normal breath.

Which animal had the highest oxygen intake during five minutes of normal breathing?

The diagram below shows a sensory neurone connected to its associated receptor cells.

 Which best describes the function of the structure labelled A?

The oscilloscope trace shown below was taken using a digital oscilloscope. It shows an action potential in a hippocampal pyramidal neurone of a potoroo (a small marsupial species) that occurred when the neurone was stimulated with a current pulse.

How many action potentials could be stimulated in this neurone every second?

Which of the following is not a range of movement demonstrated by a synovial joint such as an elbow or knee joint?

Water leaves the descending limb of the loop of Henlé by osmosis.

Which is the correct reason for this?

The diagram below shows the events occurring inside an ovary during oogenesis.

Which row correctly identifies the structures labelled 1-4?

Which of the following statements relating to the placenta are correct?

The surface area of the placenta increases as the foetus grows.

Maternal and fetal blood mixes in the intervillous spaces.