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

Temperature affects the rate of biological processes in all organisms.

Describe how enzyme activity is influenced by changes in temperature.

Explain how mammals regulate body temperature through feedback mechanisms.

Explain how one named mammal and one named plant regulate their internal conditions in response to changes in temperature.

Describe adaptations that enable plants and animals to maintain homeostasis in hot desert environments, including named examples.

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.

pH affects the rate of biological processes in all organisms.

Describe how changes in pH influence enzyme activity.

Explain how humans regulate blood glucose concentration through feedback mechanisms.

Describe adaptations that enable plants and animals to maintain homeostasis in tropical rainforest environments, including named examples.

Describe how the rate of photosynthesis changes with light intensity and carbon dioxide (CO₂) concentration.

Starch and cellulose are both polysaccharides made up of many glucose molecules made during photosynthesis.

Describe and explain how the structures of starch and cellulose molecules relate to their functions.

Explain how plants can act as both carbon sinks and carbon sources in the carbon cycle.

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.

Explain how gene expression is regulated in eukaryotic cells.

Describe how signal transduction pathways regulate gene expression in response to environmental stimuli.

Discuss how environmental regulation of gene expression contributes to adaptation and evolution in populations.

Explain how energy from light is converted into chemical energy during photosynthesis.

Compare and contrast the roles of chemiosmosis in photosynthesis and aerobic respiration.

Discuss how the efficiency of energy transfer affects primary productivity and trophic structure in ecosystems.

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.