Extended Response Questions (DP IB Biology: HL): Exam Questions

Plants require a constant supply of water and minerals to maintain turgor pressure, carry out photosynthesis, and transport nutrients.

Explain how osmosis and active transport allow water and minerals to enter root cells.

Describe how cohesion and adhesion of water allow transport through the xylem.

Some xerophytic plants have specialist adaptations, such as sunken stomata, to minimise the loss of water by transpiration.

Outline how natural selection results in the evolution of sunken stomata as an adaptation to dry environments in xerophytic plants.

Explain how the processes of the Krebs cycle lead to the production of ATP during aerobic respiration.

Explain how the structure of the mitochondrion is adapted for the production of ATP by aerobic cell respiration.

Explain how root pressure and water potential contribute to the uptake of water by plants growing in a hypertonic environment.

Cells lining the ileum absorb glucose into the blood.

Describe the mechanism by which glucose is absorbed.

Compare and contrast the transport of oxygen by foetal and adult haemoglobin.

Explain how oxygen reaches the respiring tissues through the formation of tissue fluid.

The storage, replication, and amplification of genetic material are essential for the continuity of life and for modern applications in biotechnology.

Describe the semi-conservative nature of DNA replication, including its role in maintaining the DNA code.

Outline the process and primary purpose of PCR.

Contrast DNA and RNA in eukaryotic cells.

The human body relies on a range of defences to prevent and respond to infection.

Explain how vaccination leads to long-term immunity.

Outline the action of phagocytes in controlling infection.

Describe the process of blood clotting in response to a cut in the skin.

Genetic variation within populations arises through mutation and sexual reproduction, providing the raw material for natural selection to act upon.

Explain the importance of mutation and sexual reproduction in the process of natural selection.

Distinguish between allopatric and sympatric speciation.

Explain how stabilising and directional selection affect the distribution of phenotypes.

Outline the structural changes that occur within a muscle during contraction, and the mechanism by which muscle contraction occurs.

Explain how the antagonistic action of the internal and external intercostal muscles facilitates ventilation of the lungs.

Outline the roles of skeletons in locomotion.

The kidneys play an essential role in maintaining water balance and blood solute concentration in mammals.

Explain how the glomerulus and Bowman's capsule in the kidney are adapted for ultrafiltration.

Explain how water and solute concentrations are adjusted in the nephron to maintain osmotic balance in the body.

Outline the adaptations in the structure of cells lining the proximal convoluted tubule that increase their efficiency in reabsorbing substances from the filtrate.