Structure and functions in living organisms: Practice Questions

Which organelle is known as the site of aerobic respiration within a cell?

An enzyme-controlled reaction is heated from \(20^\circ\text{C}\) to \(70^\circ\text{C}\). The rate of reaction increases initially but then falls to zero. Which statement best explains why the reaction stops at \(70^\circ\text{C}\)?

An enzyme-controlled reaction was monitored at different pH levels. At pH 2, the rate of reaction was high, but at pH 9, the reaction stopped completely. Which statement provides the most accurate explanation for why the reaction stopped at pH 9?

Which of the following identifies the correct levels of organisation in a multicellular organism, arranged from simplest to most complex?

Which of the following describes the correct hierarchical level of organization for the human heart and the sequence it follows in a multicellular organism?

Explain how the shape and internal composition of a red blood cell are specifically adapted for the transport of oxygen in the human body.

Describe the specific mechanism of ventilation in the human thorax during inhalation, including the actions of the external intercostal muscles, the diaphragm, and the resulting change in thoracic pressure.

A student investigates the movement of water in plant tissue. Explain the process of osmosis in terms of water potential and describe how a high concentration of solutes in the vacuole affects this movement.

A student investigates the rate of movement of a dye through agar jelly to model the transport of substances in cells.

(a) State three factors that affect the rate at which substances move into and out of cells by diffusion. (3)

(b) Explain why simple, unicellular organisms like Chlorella can rely on diffusion for gas exchange, whereas larger multicellular organisms require specialized transport systems. (2)